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SARENS NOTHING TOO HEAVY, NOTHING TOO HIGH
STRUCTURE OF THE PRESENTATION
Introduction
1. Who are Sarens?
2. Who am I?
3. Aim of the Presentation.
4. Why do we need cranes?
Lecture 1: Mobile Cranes
1. Types of Mobile Cranes
2. Planning Factors
3. Planning The Operation
4. Consequences of Poor Planning
5. Understanding Lift Plans
INTRODUCTION
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Lecture 2: Tower Cranes
1. Types of Tower Cranes
2. Tower Crane Components
3. Planning Factors
4. Tower Crane vs. Mobile Crane
Conclusion
1. Aim of the Presentation
2. Additional Resources
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WHO ARE SARENS?
Sarens is an international heavy lift and transport company.
At Sarens, we have the noble mission to be the reference in crane rental services, heavy lifting, and engineered transport for our clients.
To do this, we deploy our 5 unwavering values:
Dedication to Safety
Zeal for Excellence
Love for Tradition
Brilliant Solutions
Global Spirit
INTRODUCTION
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Source: Sarens, 2017
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WE ARE AN INTERNATIONAL COMPANY INTRODUCTION
9 Geographical Regions, 67 Countries, 100 Offices
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OUR MAIN SECTORS INTRODUCTION
Oil and Gas Mining Infrastructure Offshore & Module Yards
Solar On-Shore and Offshore Wind Forwarding General Industry
Maintenance and Installation Thermal and Nuclear Power Plants
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OUR FLEET AND EQUIPMENT
CRANES TRANSPORT SPECIAL EQUIPMENT
Hydraulic Cranes
Lattice Boom Cranes
Heavy Luffing Tower Cranes
Conventional Trailers
Modular Trailers
Self-propelled Modular Trailers
Barges
Gantries
Jacking
Strand Jacks
Twin Barges
Modular Barges
Skidding
INTRODUCTION
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WHO AM I?
Andrew Cockshoot EngTech TMIET
– Loughborough University Graduate
– Sarens Project Engineer
– Engineering Technician of the Institution of Engineering and Technology
Education:
– Civil Engineering Higher National Degree 2013 - 2016
– Construction Engineering Management BSc 2017 – 2021
Work Experience
– Sir Robert McAlpine, Lift Planning CAD Technician 2012 - 2017
– Sarens UKTS, Project Engineer 2019 - Present
INTRODUCTION
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AIM OF THIS PRESENTATION
By the end of this presentation you should be able to:
…understand the different types of cranes.
…identify the components of mobile and tower cranes.
…recognise common constraints inherent in crane operations.
…read and understand crane schemes.
…understand where mobile cranes and tower cranes are the suitable option.
If you have any questions during this presentation, please feel free to ask at any time!
INTRODUCTION
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THE USE OF CRANES INTRODUCTION
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Question:
Why do we use cranes?
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THE USE OF CRANES INTRODUCTION
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Crane provide vertical and horizontal movement to materials / loads.
Cranes enable us to be build bigger and higher structures.
They are an essential part of modern construction.
Their need is further expanding with the increased use of pre-fabrication.
THE FUNDAMENTALS OF MOBILE CRANE PLANNING Lecture 1 of 2
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TYPES OF MOBILE CRANES The Fundamentals of Mobile Crane Planning
TYPES OF MOBILE CRANES TYPES OF MOBILE CRANES
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Question:
What types of mobile cranes are there?
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TYPES OF MOBILE CRANES
1. All-Terrain Crane
2. Lattice Boom Crawler Crane
3. Telescopic Boom Crawler Crane
4. Self-Erecting Mobile Tower Crane
5. Lattice Boom Truck Crane
6. Telescopic Truck-Mounted Crane
7. Rough Terrain Crane
8. Pick and Carry Crane
TYPES OF MOBILE CRANES
Crane types you are most likely to encounter in the UK.
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ALL-TERRAIN CRANES
Telescopic main boom.
High level of mobility; able to drive on public roads.
Short mobilisation and set-up time (dependent on configuration).
Versatile due to the wide variety of lifting accessories.
Capacities from 5 to 1,200Te.
Higher capacity all-terrain cranes may need to travel without the boom attached.
TYPES OF MOBILE CRANES
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LATTICE BOOM CRAWLER CRANES
Transported by truck and assembled on site.
Suitable for the heaviest of loads.
Boom length can be adjusted by the addition and removal of boom sections – requires an additional support crane to do so.
Can have a relatively compact footprint for the capacities offered.
Can track (travel) with a load.
Capacities range from 50 to 3,200Te.
TYPES OF MOBILE CRANES
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TELESCOPIC CRAWLER CRANES
Crane on crawlers with telescopic boom.
Combines the advantages of a hydraulic boom with the stability and manoeuvrability of a crawler crane.
Can track while carrying a load.
Capacities range from 16 to 220Te.
Can self-rig or use support cranes for initial set up.
TYPES OF MOBILE CRANES
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LATTICE BOOM TRUCK CRANE
Road-going substructure consists of the slewing ring and a partial superstructure and derrick mast.
The rest of the crane is delivered by additional truck transport
Requires support cranes for rigging.
Combines the mobility of all-terrain cranes with the capacity range of crawler cranes.
Capacities range from 130 to 1,200Te.
TYPES OF MOBILE CRANES
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SELF-ERECTING MOBILE TOWER CRANES
A tower crane that can drive on public roads.
Self-erecting, can erect itself in approximately 15mins.
Taxi crane, no additional support vehicles are required.
Best-suited for when reach is more important than capacity.
Can be operated remotely or by a height-adjustable operating cab.
Capacities range from 5 to 18Te.
TYPES OF MOBILE CRANES
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TELESCOPIC TRUCK-MOUNTED CRANES
Telescopic boom superstructure fitted to a conventional truck chassis.
Efficient road transport and fast mobilisation makes these perfect taxi cranes.
Designed for frequent and long distance travel.
Capacities range from 30 to 80Te
TYPES OF MOBILE CRANES
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ROUGH TERRAIN CRANES
Designed to operate in the roughest conditions.
Compact and versatile.
Excellent gradeability.
Can drive with small suspended loads.
Capacities range from 12 to 150Te.
TYPES OF MOBILE CRANES
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PICK AND CARRY CRANES
Designed to be able to pick up and travel with a suspended load.
Work ready, no outriggers are required.
Typically used in industrial contexts rather than construction projects.
Capacities range from 5 to 40Te.
TYPES OF MOBILE CRANES
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PLANNING FACTORS The Fundamentals of Mobile Crane Planning
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HEAVY LIFT PLANNING FUNCTIONAL MODEL PLANNING FACTORS
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(Adapted from Hornaday et al., 1993)
INPUTS
Inputs relate to the physical aspects of the operation including the crane, load and site.
Inputs can be categorised into:
– Crane data sourced from CAD models, manufacturer manuals and websites.
– Load data is defined by manufacturer shop drawings.
– Site details are described by architectural and engineering drawings.
PLANNING FACTORS
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(Adapted from Hornaday et al., 1993)
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INPUTS
Crane Data:
– Physical dimensions.
– Crane capacities.
– Cost.
– Availability.
– Reliability.
– Service record.
PLANNING FACTORS
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(Adapted from Hornaday et al., 1993)
INPUTS
Load Data:
– Dimensions and shape.
– Weight.
– Centre of gravity location.
– Fabrication and delivery schedule.
└ these establish a work window.
PLANNING FACTORS
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(Adapted from Hornaday et al., 1993)
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INPUTS
Site Data:
– Spatial layout and dimensions.
– Ground conditions.
– Changes in onsite structures over time:
└ Permanent structures.
└ Mobile structures (scaffold etc.).
PLANNING FACTORS
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(Adapted from Hornaday et al., 1993)
CONTROLS
Controls relate to aspects of the operation that constrain the planning scope and dictates how the operation can be undertaken.
Controls can be categorised into:
– Spatial constraints defining the space for the operation.
– Structural constraints strength of the crane, site and load.
– Schedule constraints describes when the project needs to be done and the variance of the spatial and structural constraints.
PLANNING FACTORS
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(Adapted from Hornaday et al., 1993)
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CONTROLS
Spatial Constraints
– Volume of work.
– Access / egress from site.
– Space for the crane.
– Space for the load to move (lift path).
– Pinch points.
└ Minimum clearance defined to accommodate for boom deflection, settlement and on-site inaccuracies in positioning.
PLANNING FACTORS
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(Adapted from Hornaday et al., 1993)
CONTROLS
Structural Constraints
– Determine the required strength of:
└ The crane
└ The site
└ The load
– The load’s ability to accommodate the forces imparted into it during the lift operation is the client’s responsibility.
– Client should calculate and define the ground’s allowable bearing pressures.
PLANNING FACTORS
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(Adapted from Hornaday et al., 1993)
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CONTROLS
Schedule Constraints
– Become more powerful as the operation date gets closer.
– Other construction operations may be taking place at the same time.
– Interfering structures may be constructed before or after the operation.
– Critical activities may need completing before the lift can be undertaken (foundations etc.).
PLANNING FACTORS
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(Adapted from Hornaday et al., 1993)
MECHANISMS
Mechanisms are the factors that bring a lift plan into existence; i.e., the exchange of information.
Mechanisms can be categorised into:
– Constructor provides information about the site and / or load to the lift planner.
– Engineering Consultants provides information as per their role to the lift planner (i.e. ground investigation studies etc.).
– The Owner has final ownership of the project information, and therefore must ensure sufficient information is provided to the lift planner to enable them to safely plan the operation.
The final execution of the lift plan is the responsibility of the Lift Planner.
PLANNING FACTORS
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(Adapted from Hornaday et al., 1993)
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OUTPUTS
The interaction of the inputs, controls and mechanisms will define the outputs of the planning activity.
Outputs can change as a reaction to a change in the inputs, controls and mechanisms.
Outputs can exist in three forms:
– Preliminary: to confirm the feasibility of the operation.
– Detailed: to represent the optimisation of the preliminary output.
– Final: the final scheme for execution.
The output will be in the form of a single or a series of technical drawings detailing the operation with associated risk and method statements (RAMS).
PLANNING FACTORS
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(Adapted from Hornaday et al., 1993)
HEAVY LIFT FUNCTIONAL MODEL
A simple model to understand the interaction of factors in lift planning.
Was originally developed to describe lifts in industrial settings (oil and gas) so not all outputs need to be considered for every lift operation.
Overlap between controls, inputs and mechanisms since they are not undertaken in isolation.
The interaction of controls, inputs and mechanisms defines the operation, its feasibility and its optimum form.
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(Adapted from Hornaday et al., 1993)
PLANNING FACTORS
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TYPES OF MOBILE CRANES TYPES OF MOBILE CRANES
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Question:
Can you identify what controls were in the previous video?
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PLANNING THE OPERATION The Fundamentals of Mobile Crane Planning
HEAVY LIFT PLANNING STEPS
STEP-1: Determine load radius
STEP-2: Determine minimum hook height (minimum boom length) └ Min. Hook Height = Elevation + Clearance + Load Height + Tackle Height + Chandelier Height
STEP-3: Define an approximate boom length requirement
STEP-4 Determine total load └ Total Load = Net Load + Tackle + Hook block
STEP-5: Propose an initial crane.
STEP-6: Check proposed crane’s capacity.
STEP-7: Calculate outrigger loads
STEP-8: Optimise the preliminary proposal.
PLANNING THE OPERATION
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STEP-1: DETERMINE LOAD RADIUS
What is the maximum radius you need to reach?
Where can the crane be cited in relation to the load?
– Available space on site.
– Current plant onsite.
– Storage areas on site.
– Sufficient bearing capacities.
– Voids / trenches.
– Proximity to structures.
PLANNING THE OPERATION
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STEP-2: DETERMINE MIN. HOOK HEIGHT
Elevation + Clearance + Load Height + Tackle Height + Chandelier Height └ Elevation = difference between the level of the
crane and the load (-’ve if load is lower than the crane).
└ Clearance = allowance for clearance to obstructions.
└ Chandelier height = minimum distance between the head sheave and the hook block.
PLANNING THE OPERATION
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STEP-3: DETERMINE HOOK HEIGHT
Using Step 1 and 2 an approximate boom length can be calculated.
C = (𝐴 +𝐵 )
Where:
(A) = Min. Hook Height
(B) = Load Radius
This will give an approximate boom length.
PLANNING THE OPERATION
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(C)
(B)
(A)
Example: C = ( 3900 + 10450 + 11120) + 12000 C = 28,155mm (~28m Boom)
STEP-4: DETERMINE TOTAL LOAD WEIGHT
Net Load + Tackle + Hook Block
Everything underneath the sheave needs to be considered in the load weight.
PLANNING THE OPERATION
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STEP-5: PROPOSE AN INITIAL CRANE
With the results of stages 1-4 in mind a preliminary crane can be defined.
A lift weight, lift radius and approximate boom length is the minimum information you need to define a crane.
Online crane calculators, specialist lift planning software (Liebherr Crane Planner 2.0) or engineering experience can be used to speed up the process.
Trial and error is also an option.
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PLANNING THE OPERATION
STEP-5: PROPOSE AN INITIAL CRANE
Crane choice can be dictated by a number of external factors: – Availability: is the crane you need
available, do you need to substitute for a larger crane?
– Cost: is the crane within the clients budget?
– Reliability: is the proposed crane reliable, subject to regular breakdowns?
– Reputation: is the company supplying the crane you want reliable? Is it available from other crane rental companies with a better reputation?
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PLANNING THE OPERATION
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STEP-6: CHECK PROPOSED CRANE’S CAPACITY
First, consult crane capacity charts.
Use manufacturer provided capacity charts.
Maximum utilisation should ideally not exceed 90% └ Maximum utilisation = ( lift weight ÷ ( capacity –
deductions ) ) x 100
└ Generally work to a 10% safety factor.
The glossy brochures provided by crane manufacturers do not provide a complete representation of a crane’s capacities.
PLANNING THE OPERATION
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STEP-6: CHECK PROPOSED CRANE’S CAPACITY
The glossy brochure only considers best case capacity at a defined radius for a boom length. However, each boom length has multiple hydraulic configurations with different capacities.
41.3m [00, 92, 92, 92, 92] └ 17.4Te at 7.0m
41.3m [46, 46, 92, 92, 92] └ 17.9Te at 7.0m
41.3m [46, 92, 92, 92, 46] └ 20.9Te at 7.0m
41.3m [92, 92, 92, 46, 46] └ 22.4Te at 7.0m
PLANNING THE OPERATION
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STEP-6: CHECK PROPOSED CRANE’S CAPACITY
It is very common for crane capacities to be subject to deductions.
– External factors (site constraints).
– Internal factors (crane specific).
Neither the glossy brochure or the manufacturers literature will include deductions in their capacities; the latter will define what the deductions should be.
PLANNING THE OPERATION
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STEP-6: CHECK PROPOSED CRANE’S CAPACITY
Internal sources affecting crane capacities: – Lifting with the fixed fly stowed on the main
boom.
– Lifting with the TY-frame stowed on the main boom.
Exact capacity deductions will depend on length of main boom and the crane model.
Components can be removed to negate the deductions but tends to be avoided if possible.
PLANNING THE OPERATION
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STEP-6: CHECK PROPOSED CRANE’S CAPACITY
External factors affecting crane capacities:
– Operating in sensitive areas (i.e. nuclear) where higher safety factors are required.
– Operating in proximity to Network Rail assets (in accordance with CPA-1801).
– Client request.
Common deduct is 25% of rated capacity.
PLANNING THE OPERATION
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STEP-7: CALCULATE OUTRIGGER LOADS
The crane will impart load into the ground via the outriggers.
This load from the outriggers is dictated by the lift weight, lift radius and the configuration of the crane.
The ground must be checked to ensure it can accommodate the anticipated loads.
Outrigger loads can be distributed through the use of outrigger mats to reduce the bearing pressures.
PLANNING THE OPERATION
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STEP-8: OPTIMISE THE PRELIMINARY PROPOSAL
Go back through the operation, can the crane be made smaller from the current proposal?
What can be done to make the crane smaller?
What risks can be avoided?
Reduced counterweight requirements or the use of a main boom only configuration can reduce the required transport.
Check the crane plan against all new information
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PLANNING THE OPERATION
CONSQUENCES OF POOR PLANNING The Fundamentals of Mobile Crane Planning
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MODES OF FAILURE
Crane accidents can be categorised as either:
– Structural failure
– Stability failure
A multitude of factors can cause a structural or stability failure.
Commonly, a crane accident can be linked to insufficient or incorrect planning.
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CONSEQUENCES OF POOR PLANNING
STABILITY AND STRUCTURAL FAILURE
Stability or structural failure.
– Exceeding the crane’s rated capacity.
– Pulling or dragging a load.
– Excessive swinging the load due to improper control of the crane
– Operating in excessive wind conditions.
– Lifting submerged loads.
Failure by structural failure can also be a result of poor maintenance.
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CONSEQUENCES OF POOR PLANNING
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FAILURE DUE TO GROUND CONDITIONS
Insufficient distance from trenches or underlying voids (basements etc.).
The ground does not have sufficient bearing capacity to carry the weight / loading of the crane.
Ground is not level or within the acceptable incline that the crane is rated for.
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CONSEQUENCES OF POOR PLANNING
FAILURE DUE TO CLASHES
Collision with street furniture.
Collision with permeant or mobile structures.
Contact with overhead services.
Contact with a leading edge.
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CONSEQUENCES OF POOR PLANNING
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OTHER FAILURES
Not all failures of planning lead to an accident / incident.
Other outcomes can include:
– Failure of the crane to fit on-site (access / egress).
– Clashes between the crane and ground-based obstructions (street furniture etc.)
– Becoming jib bound.
– Crane becomes unavailable.
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CONSEQUENCES OF POOR PLANNING
UNDERSTANDING LIFT PLANS The Fundamentals of Mobile Crane Planning
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WHAT IS A LIFT PLAN?
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UNDERSTANDING LIFT PLANS
A document that collates all information about a proposed lift into a single (or series) of drawings.
It is a living document, even during the operation in some cases.
A ‘simulation’ of the proposed lift to identify areas of concern / risk.
A means of communicating a visual representation of the operation to the client and operational team.
INFORMATION REQUIRED FOR A LIFT PLAN
A lift plan requires the following: – Information / layout of the site.
– Sections / elevations of any obstruction / surrounding structures.
– Local ground levels.
– Local underlying services.
– Local street furniture
– Access / egress route restrictions.
– Load weight and load dimensions.
– Lifting points on the load.
– Location of site obstructions (storage areas, trenches, scaffolding etc.)
– Pickup and laydown positions of the load.
– Available resources on site (existing matting etc.)
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Preferably in a useable CAD format if available.
UNDERSTANDING LIFT PLANS
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CONSTITUENT PARTS OF A LIFT PLAN
A lift plan details the following: – Crane manufacturer and model
– Crane configuration
– Lift weight
– Deductions considered.
– Lift radius
– Crane capacities (capacity utilisation)
– Hook block type
– Crane mat requirements
– Outrigger loads (bearing pressures)
– Plan and Section
– Relevant warnings / risks identified.
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UNDERSTANDING LIFT PLANS
EXAMPLE LIFT PLAN UNDERSTANDING LIFT PLANS
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THE FUNDAMENTALS OF TOWER CRANE PLANNING Lecture 2 of 2
TYPES OF TOWER CRANES The Fundamentals of Tower Crane Planning
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TYPES OF TOWER CRANES TYPES OF TOWER CRANES
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Question:
What types of tower cranes are there?
TYPES OF TOWER CRANES
Tower cranes are usually categorised by what type of jib they utilise:
1. Saddle Jib (Hammerhead)
2. Luffing Jib
3. Topless (Flat Top)
4. Articulated
5. Self-Erecting
TYPES OF TOWER CRANES
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SADDLE JIB (HAMMERHEAD) TOWER CRANES
Horizontal jib that can be erected in several lengths, commonly 30 – 70m
The trolley travels along the jib to change the lifting radius (aka. racking).
Suitable where oversailing issues are not a critical factor.
Interaction between other cranes need to be carefully planned as they affect a large airspace.
Oversailing a major concern with this type of tower crane.
TYPES OF TOWER CRANES
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LUFFING JIB TOWER CRANES
The jib can be luffed up and down to reduce or increase the lifting radius.
Larger minimum radius than flat-jib alternatives.
Can utilise several jib lengths, commonly 30 – 60m
When left out-of-service the crane can reduce its radius to minimise oversailing issues.
Reduced out of service also enables closer spacing of tower cranes.
Ideal for congested sites.
TYPES OF TOWER CRANES
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TOPLESS (FLAT TOP) TOWER CRANES
Similar in operation to a Saddle Jib tower crane.
No A-frame and associated tie-bars for neighbouring cranes to clear, resulting in overall lower tower heights for all site cranes.
Ideal for congested sites.
Jib can be installed piecemeal instead of needing to be installed as fully constructed jib.
Typically offer lower capacities than Saddle Jib alternatives.
TYPES OF TOWER CRANES
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ARTICULATED TOWER CRANES
Specially designed for inner-city sites where air space restrictions are the driving factor.
The out-of-service radius is the smallest out of all available tower crane types.
Minimised tail-swing.
Capacities are more limited, maximum of ~8.0Te.
Minimised base loadings and component weights.
– Possible to fix these cranes to slipform rigs.
TYPES OF TOWER CRANES
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SELF ERECTING TOWER CRANES
Smaller, lower capacity alternatives to traditional tower cranes best suited for smaller projects.
Transported to site as a single unit plus counterweight and able to erect itself.
Minimal foundation requirements.
Can be easily relocated around site as needed.
Horizontal jib will require detailed planning for oversailing and interface with other cranes on site.
TYPES OF TOWER CRANES
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TOWER CRANE COMPONENTS The Fundamentals of Tower Crane Planning
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COMMON TOWER CRANE COMPONENTS TOWER CRANE COMPONENTS
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Mast
Base and Foundation
Counter jib
Trolley Slewing Ring
Jib
A-Frame
Operators Cab
Base and Foundation
Mast
Slewing Ring Operators Cab
Jib
Counter jib
A-Frame
Saddle Jib Tower Crane Luffing Jib Tower Crane
TOWER CRANE FOUNDATIONS
Tower cranes can have a variety of base types, each type will affect:
– Free-standing height
– Spatial implications of the base.
Common foundation types are:
– Cast-in Concrete foundations
– Ballasted Bases
– Grillages
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TOWER CRANE COMPONENTS
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TOWER CRANE FOUNDATIONS
Tower crane bases are the main factor affecting stability.
Bases need to be able to effectively resist:
– Vertical Reactions (V).
– Horizontal Forces (Hx, Hy).
– Moments (My, Mx).
– Torque (Mt).
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TOWER CRANE COMPONENTS
TOWER CRANE FOUNDATIONS
Cast-In Concrete Bases
– Specific designs vary but are based around casting in a set of threaded bars or a frame into a concrete base to which the tower crane fixing angles are connected to.
– Depending on ground conditions and the specific crane the base will be supporting, the concrete base can either:
• be a simple concrete pad where the self weight of the concrete provides stability, i.e., a gravity base
• or may require piles
These types of bases can enable higher crane free-standing heights.
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TOWER CRANE COMPONENTS
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TOWER CRANE FOUNDATIONS
Cast-In Concrete Bases
– Concrete bases can be relatively compact enabling them to be constructed within the building.
– If effectively planned, the crane can take advantage of the permanent structure’s foundations.
– When decommissioning the tower crane the base can either be broken out or simply left in place and covered.
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TOWER CRANE COMPONENTS
TOWER CRANE FOUNDATIONS
Ballasted Bases
– Sometimes also referred to as ‘Gravity Bases’.
– Ballasted bases rely on the weight of ballast to provide stability to the crane.
– These bases can either be founded on the engineered ground, on a concrete foundation or on rails.
– The amount of counterweight required depends on the crane and will be specified by the manufacturer.
– Loads exerted by the base are purely compressive – no tension.
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TOWER CRANE COMPONENTS
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TOWER CRANE FOUNDATIONS
Grillages
– A steel frame to which a tower crane is connected to.
– Commonly used when positioning a crane on top of a building’s core.
– Can be either ballasted or tied into the building structure.
– May affect the design of the core (the permanent structure) due to the increased tension loads imparted by the crane.
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TOWER CRANE COMPONENTS
MAST
The mast gives the crane its height and strength.
All mast will be of a lattice structure.
Common mast dimensions:
– 1.6m Square
– 2.0m Square
– 2.5m Square
– 4.5m Square
– 5.0m Square
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TOWER CRANE COMPONENTS
5.0m or 10.0m height
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MAST
Masts can be of three main types:
– Standard
– Climbing
– Reinforced
A crane can be designed to take advantage of a variety of mast types to maximise its free-standing height.
– I.e., the use of dimensionally larger or reinforced sections at the base of the tower.
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TOWER CRANE COMPONENTS
2.45m2
Adapter
Base
2.00m2
SLEWING RING
This component enables the top assembly of the crane to slew (rotate).
The slewing ring contains the gear and motors to enable rotation.
Commonly one of the heaviest individual components.
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TOWER CRANE COMPONENTS
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OPERATORS CABIN
Where all the crane controls are located.
Room for a single operator.
Cranes can be remote controlled in some situations, albeit this is uncommon on construction sites.
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TOWER CRANE COMPONENTS
COUNTER JIB
The counter jib is a structural element that contains both winches and counterweight.
The winches operate the trolley, jib and hoist line.
The counterweight balances the crane by offsetting the weight of the jib and thus enables the tower crane to pick up and move loads.
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TOWER CRANE COMPONENTS
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A-FRAME
The A-Frame supports both the jib and counter jib by way of the fore and rear pendants.
A-Frames are not present on topless tower cranes.
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TOWER CRANE COMPONENTS
JIB
The working arm of the crane that provides the necessary reach needed for the project.
Commonly a modular, lattice-based structure.
Increasing the length of a boom will typically reduce the capacity of the crane.
Allowable jib lengths are defined by the crane manufacturer.
Can be either luffing or static.
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TOWER CRANE COMPONENTS
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TROLLEY
Since the jib on saddle and topless tower cranes is stationary, the lifting radius is modified by the horizontal movement of a trolley.
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TOWER CRANE COMPONENTS
PLANNING FACTORS The Fundamentals of Tower Crane Planning
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TOWER CRANE HEIGHT PLANNING FACTORS
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Question:
What factors on site will affect the choice, position and height of a tower crane?
PLANNING FACTORS PLANNING FACTORS
Tower Crane Scheme
Interface w/ other Cranes
Surrounding Structures
Tower Crane Erection / Dismantle
Wind Restrictions
Interface with Permanent Structure
Capacity Requirements
Oversailing RestrictionsOut-of-Service Conditions
Type of Tower Crane
Number of Cranes Req’d
Cost of Hire
Availability
Reliability
Coverage Requirements
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INTERFACE WITH OTHER CRANES
The interface between cranes needs to be carefully planned to ensure that they cannot clash when out-of- service.
Luffing jib tower cranes can be cited closer together as they have lower out-of-service radii. – Luffing Jib Tower Crane Out-of-Service
= Out-of-Service Radius
– Hammerhead / Flat Top Tower Cranes Out-of-Service = Full Jib Length
PLANNING FACTORS
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SURROUNDING STRUCTURES
Surrounding structures will affect the height to tower cranes on a project.
High surrounding buildings will force higher tower crane heights.
Allowable clearances will be dependent on the owners of the surrounding buildings.
PLANNING FACTORS
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WIND RESTRICTIONS
The wind will have a significant affect on tower crane heights.
The UK has two main wind categories:
– C25: 28m/s Storm Wind with a 25-year reoccurrence
– D25: 32m/s storm wind with a 25-year reoccurrence.
PLANNING FACTORS
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WIND RESTRICTIONS
What this means is that cranes in a D25 area will, when compared to the same crane in a C25 area, have:
– Lower maximum free-standing heights.
– Requirement for stronger tower sections.
– Higher base loads and moments.
– Higher requirements for ballasting
– Increased base strength / sizes.
PLANNING FACTORS
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INTERFACE WITH THE PERMENANT STRUCTURE
Tower cranes can be positioned both internally and externally to a building.
Tower crane position is primarily defined by required coverage.
A crane located centrally within a building can provide more effective coverage than externally located tower cranes.
PLANNING FACTORS
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INTERFACE WITH THE PERMENANT STRUCTURE PLANNING FACTORS
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Question:
Why might you position a crane within a building’s footprint rather than outside it?
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INTERFACE WITH THE PERMENANT STRUCTURE PLANNING FACTORS
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INTERFACE WITH THE PERMENANT STRUCTURE
When citing a crane within a building the following needs to be considered:
– Size of the void needed (deflection)
– Affect on completion of units
– Waterproofing
PLANNING FACTORS
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INTERFACE WITH THE PERMENANT STRUCTURE
Size of the of void needed:
– Minimum size of the void should be the mast size plus 1.0m X, Y (0.5m clearance off each face) as a rule of thumb.
– Needs to be checked against anticipated mast deflection.
– Cranes will naturally deflect when in operation and out of service.
– Deflection will be can be calculated by the manufacturer on an as-requested basis.
– Deflections for standard mast configurations may also be given.
PLANNING FACTORS
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INTERFACE WITH THE PERMENANT STRUCTURE
Affect on completion of units:
– Cannot complete areas where the crane mast penetrates.
– May require the temporary omission of structural members.
– Common to try and site tower cranes in areas that will have the least impact, i.e., atriums or courtyards.
– Possible to locate cranes within lift shafts also if space permits.
PLANNING FACTORS
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INTERFACE WITH THE PERMENANT STRUCTURE
Waterproofing:
– Voids created by cranes means water can enter the unfinished building.
– Materials subject to water damage should not be installed in areas where the crane penetrates the building.
– Area around the crane cannot be completed until the crane is removed.
PLANNING FACTORS
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CAPACITY REQUIREMENTS PLANNING FACTORS
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Question:
For what anticipated load would you design your crane scheme around?
– Heaviest?
– Average?
– Other?
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CAPACITY REQUIREMENTS
An important planning decision.
Do you plan for:
– the most common load weight and hire in additional craneage to lift heavier loads
– …or do you plan for the tower crane to be able to lift all anticipated loads?
Project dependent since weights will vary project to project.
PLANNING FACTORS
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COVERAGE REQUIREMENTS
Tower cranes should be able to cover as much of the building as needed.
Multiple cranes may be required to cover the building.
Cranes must be able to reach both the building and any loading areas to minimise double handling.
PLANNING FACTORS
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OUT OF SERVICE CONDITIONS
All tower cranes have an out-of- service radius, albeit some smaller than others.
When out-of-service the crane must be allowed to freely slew with the wind.
Failure to do so can cause the crane to fail and potentially collapse.
Out-of-service conditions are defined in the manufacturer literature.
PLANNING FACTORS
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OVERSAILING RESTRICTIONS
If a crane over-sails a neighbouring property, permission from the owner of said property needs to be sought.
This can be costly or hard to get – wholly dependant on the property owner in question.
Some owners may refuse entirely.
PLANNING FACTORS
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Source: Wonkabar007, 2020
OTHER FACTORS
Cost of Hire – Transport costs
– Erection / dismantle costs
– Weekly hire rates
– Maintenance
Availability – What cranes are actually available?
Reliability – How reliable is the proposed crane
– Maintenance schedule
– Plan in the event of breakdown
PLANNING FACTORS
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ERECTION AND DISMANTLE 4. PLANNING FACTORS
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Source: FilmSpektakel, 2014
ERECTION AND DISMANTLE PLANNING FACTORS
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Question:
What was missing in the previous video?
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ERECTION AND DISMANTLE
Erecting the tower crane is typically easier than dismantling it.
Dismantling is more complex since the building will now be constructed and may obstruct access.
Dismantling therefore needs to be considered prior to erection to ensure the crane can be actually be dismantled.
Typically a mobile crane will be used to dismantle the tower crane but in more complex projects other methods may be utilised.
PLANNING FACTORS
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TOWER CRANE OR MOBILE CRANE? The Fundamentals of Tower Crane Planning
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TOWER CRANE VS. MOBILE CRANES
Tower Cranes are suited for… … high-density sites due to their small footprint.
… where lifting to extreme heights is necessary.
… ’small’ repetitive lifts.
… where reach is important.
However, tower cranes… … require erection and dismantle operations,
foundations and regular on-site maintenance resulting in increased costs.
… cannot be easily relocated if the need arises.
… long preparations before the first lift (i.e. testing etc.)
TOWER CRANE OR MOBILE CRANE?
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TOWER CRANE VS. MOBILE CRANES
Mobile cranes are suited for… … where multiple lifts from different positions are
necessary.
… singular heavy lifts
… where capacity is important.
… fast mobilisation is required.
However, mobile cranes… … require more space for rigging and operation
than tower cranes.
… operate ‘below’ obstructions so may not be able to reach all areas of a site.
… may not be cost-effective for long projects (site / project dependent).
TOWER CRANE OR MOBILE CRANE?
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WHAT TYPE OF CRANE SHOULD YOU USE?
Completely dependent on the project at hand.
– Construction of a tower block in a city would favour a tower crane.
• Relatively small, repetitive lifts to height.
– Constructing an oil and gas refinery would favour mobile cranes, specifically a crawler crane.
• Large, singular lifts.
– Construction of domestic houses would favour mobile cranes.
• Small singular lifts
– Construction of a large shopping complex would favour tower cranes
• Need for increased reach.
TOWER CRANE OR MOBILE CRANE?
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WHAT TYPE OF CRANE SHOULD YOU USE?
In reality, the question isn’t to decide one- or-another, it will define your primary means of lifting.
Mobile cranes will still be needed on sites with tower cranes.
TOWER CRANE OR MOBILE CRANE?
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CONCLUSION The Fundamentals of Mobile Crane Planning
AIM OF THIS PRESENTATION
You should now be able to:
…understand the different types of cranes.
…identify the components of mobile and tower cranes.
…recognise common constraints inherent in crane operations.
…read and understand crane schemes.
10. CONCLUSION
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MOBILE CRANES: ADDITIONAL RESOURCES
Video recommendations:
– Practical Engineering: Why Cranes Collapse
• https://youtu.be/swk3IjxzZB4
– Practical Engineering: Why Things Fall Off Cranes
• https://youtu.be/swk3IjxzZB4
– Lifting accident Alphen aan den Rijn
• https://youtu.be/LJevke4_i5Y
– Waikato Crane Accident
• https://youtu.be/PhaBAMyUbdk
– Big Blue Crane Accident
• https://youtu.be/6PRk_iKdiTA
10. CONCLUSION
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Book recommendation:
– Cranes and Derricks, 4th Edition: Lawrence and Jay Shapiro.
TOWER CRANES: ADDITIONAL RESOURCES
Video recommendations:
– Practical Engineering: Why Cranes Collapse
• https://youtu.be/swk3IjxzZB4
– Practical Engineering: Why Things Fall Off Cranes
• https://youtu.be/swk3IjxzZB4
– How to Build a Tower Crane
• https://youtu.be/UC9m3sGRlnE
– Tower Crane Erection
• https://youtu.be/yHQfEvzNeKE
– ICE District Crane Removal
• https://youtu.be/9c_K5YX2LnI
– East Tower Crane Removal
• https://youtu.be/FlMjfT2cHWY
5. CONCLUSION
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Book recommendation:
– Cranes and Derricks, 4th Edition: Lawrence and Jay Shapiro.
Website Recommendation:
– The Do’s and Don’ts of Crane Hire
• https://www.constructionnews.co.uk/buildings/cost- effective-crane-hire-reducing-costs-and-improving- profit-margins-08-06-2020/
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Name: Andrew Cockshoot TMIET
Function: Project Engineer
E-mail: [email protected]
www.sarens.com
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American Foreign Policy
Chapter 18 talks about American foreign policy, which is without a doubt, a very complex subject. The nature and dynamics of international relations are not an easy subject. The world changed drastically after the terrorists attacks of 9/11 and today we face many threats. International relations have many players, many interests, many fragile situations and many challenges and therefore, today more than ever, it's very important to be informed about what happens outside our shores. In a world where the concept of globalization is king, every event that happens in any part of the world affects us some way or another.
◦ This forum has 2 parts. Create a new thread for your initial post. ◦In the subject area write down your first and last name only. ◦Each of your answers in each of the parts must be written in small paragraphs of 5-7 complete and well-written sentences. Use good spelling, good grammar, and good word choice. ◦Use good spacing between paragraphs. Do not write everything in one long paragraph, you will lose points if you do.
Part I
1. If you had to choose between having a strong economy and a weak military or having a weak economy and a strong military, which would you choose? (Note: answers like 'it depends'; 'a little bit of both' will not be accepted. I know it's hard but you must pick one and explain why in detail.)
2. Do you think the United States has a moral responsibility to spread our political/economic/cultural values throughout the world? If so, how should it be done? If not, why not? List 3 advantages and 3 disadvantages of trying to spread our values.
3. What constitutes 'a threat' to American interests? Describe 3 specific scenarios that would make war permissible.
4. In your opinion, should the United States start a war if there is an imminent threat of being attacked ourselves? List 3 advantages and 3 disadvantages of doing acting preemptively.
5. In recent years, the American armed forces have been called on to perform duties that are more humanitarian than militaristic, such as aiding countries after an earthquake or hurricane. Should we continue to come to the aid of countries living circumstances like these or should that be left to private relief agencies such as the Red Cross? Yes? No? Why? Explain your answer.
6. Who do you believe should have jurisdiction if an American soldier is arrested in another country by the local police and charged with raping a foreign woman? Why? Explain your answer.
a) Incarcerate the soldier and let the local police in the country where the crime was committed hear his case.
b) Bring the soldier back to the U.S. and let his case be heard by the U.S Supreme Court.
c). Incarcerate the soldier in the country where he committed the crime and let the International Court of Justice hear his case (the International Court of Justice is part of the United Nations.)
d ) Bring the soldier back to the U.S. and let his case be heard by the U.S. Military Court that has jurisdiction over that branch of the military.
7. Should the United States continue funding international organizations such as the United Nations even if other countries do not contribute as much but benefit from its work? Yes? No? Why? Explain your answer.
8. If a cure for COVID19 is discovered in another country, should the United States government allow its citizens to acquire it even if it does not have the approval from the Food and Drug Administration (FDA) nor the Center for Disease Control and Prevention (CDC)? Yes? No? Why? Explain your answer.
C O M P U T E R - A I D E D P L A N N I N G F O R H E A V Y L I F T S
By W. C. Hornaday I and C. T. H a a s , 2 Associate Members, A S C E , J. T. O'Connor, 3 Member, A S C E , and J. W e n 4
ABSTRACT: This article presents research into automating some lift planning prac- tices common to industrial construction contractors and owners. A detailed inves- tigation of heavy-lift planning methods was conducted through a series of interviews and lift studies with expert lift planners. This investigation documented a wide variety of manual and computer-aided lift planning methods to perform similar types of planning tasks. Based on the information collected from these interviews and lift studies, a structured systems model was developed of the typical heavy-lift planning process. This structured model is used as an architecture for the devel- opment of computer software to aid key planning tasks. An examination of major planning tasks indicates that significant reductions in direct planning costs and indirect construction heavy-lift costs are possible through the implementation of computer-aided planning procedures. Computer-aided procedures would also im- prove the overall quality of lift planning practices through the automation of tasks which are difficult to perform and are critical to heavy-lift planning accuracy.
INTRODUCTION
I n industrial c o n s t r u c t i o n , it is b e c o m i n g m o r e c o m m o n t o r e d u c e plant e q u i p m e n t fabrication costs b y fabricating larger p o r t i o n s o f e q u i p m e n t at specialized off-site locations ( F i t z s i m m o n s 1991). This e q u i p m e n t includes pressure vessels, r e a c t o r c o l u m n s , a n d e q u i p m e n t skids l o a d e d with h e a v y steel walls o r f r a m i n g systems, internal piping, a n d trays, which collectively can weigh up to 900 t (1,000 tons). T h e lifting costs to erect these large, heavy objects in place g r o w excessively as t h e lifting c a p a c i t y o f t h e c r a n e increases. H e a v y lifts using s t a n d a r d c r a n e c o n f i g u r a t i o n s can have total planning and e x e c u t i o n costs r a n g i n g f r o m $50,000 to $300,000. Five p e r c e n t to 10% o f the lift cost is c o n s u m e d b y p l a n n i n g activities while the m a j o r i t y o f the total cost is a t t r i b u t e d t o the lifting e q u i p m e n t itself ( H o r n a d a y 1991).
A n estimated $25 m i l l i o n - S 5 0 million is spent a n n u a l l y b y U . S . industrial owners, designers, and c o n t r a c t o r s o n the p l a n n i n g o f $500 million w o r t h of heavy crane lifts ( H o r n a d a y 1991). T h e cost o f the lift is d e p e n d e n t o n the lift p l a n n e r ' s e x p e r i e n c e a n d skill in selecting e q u i p m e n t a n d p r e p a r i n g lift plans t h a t are o p t i m u m f o r given sets o f conditions. T h e n u m b e r o f lift specialists with the e x p e r i e n c e r e q u i r e d t o effectively plan critical lifts is dwindling, while the n u m b e r o f h e a v y lifts being p e r f o r m e d each y e a r is increasing (C. W. M c C o y , vice p r e s i d e n t , D o w C h e m i c a l ; heavy-lift s u r v e y interview; July 11, 1991). T h e activities o f t h e lift p l a n n e r are highly spe- cialized and well r e w a r d e d b y c o n t r a c t o r s .
T h e h e a v y reliance o f industrial c o n s t r u c t o r s o n a small p o o l o f highly specialized p l a n n e r s to plan a g r o w i n g n u m b e r o f lifts o f increasing mag-
1Appl. Const. Res., 902 Meriden, Bldg. B, Austin, TX 78703; formerly, Res. Asst., Univ. of Texas, Dept. of Civ. Engrg., 5.2 ECJ Hall, Austin, TX 78712-1076.
2Asst. Prof., Dept. of Civ. Engrg., 5.2 ECJ Hall, Univ. of Texas, Austin, TX. 3Assoc. Prof., Dept. of Civ. Engrg., 5.2 ECJ Hall, Univ. of Texas, Austin, TX. 4Res. Asst., Dept. of Civ. Engrg., 5.2 ECJ Hall, Univ. of Texas, Austin, TX. Note. Discussion open until February 1, 1994. To extend the closing date one
month, a written request must be filed with the ASCE Manager of Journals. The manuscript for this paper was submitted for review and possible publication on August 3, 1992. This paper is part of the Journal of Construction Engineering and Management, Vol. 119, No. 3, September, 1993. �9 ISSN 0733-9364/93/0003- 0498/$1.00 + $.15 per page. Paper No. 4520.
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J. Constr. Eng. Manage., 1993, 119(3): 498-515
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Construc~ion Lift Planning
I Comme*cial I
Sm~cmnfl I ~ction
Gin Polc
Comulting Engine, ors
Rotary Subcontractors Crmes
FIG. 1. Scope of Construction Lift Planning Studied
nitude is a costly a n d risky practice. O p t i m u m use o f available c r a n e equip- m e n t might n o t always t a k e place with limited p l a n n i n g resources. C o n - struction c o n t r a c t o r s are also increasing their risk b y relying o n a few k e y planners for t h e success o f lifts in which accidents can cost millions o f dollars. T h e research discussed h e r e was m o t i v a t e d b y t h e n e e d t o b o t h i m p r o v e the effectiveness a n d l o w e r t h e total cost o f heavy-lift planning. It is e x p e c t e d that i m p r o v e d lift p l a n n i n g will also l o w e r t h e risks and costs associated with the lift itself.
T h e scope o f this p a p e r is limited t o the p l a n n i n g o f h e a v y o r critical lifts p e r f o r m e d o n industrial c o n s t r u c t i o n p r o j e c t s using s t a n d a r d c r a n e config- urations. I n d u s t r y lift p l a n n e r s define a h e a v y lift as a lift o f o v e r 2 2 - 4 0 t ( 2 5 - 5 0 tons), d e p e n d i n g o n the c o m p a n y . B u t as lifting e q u i p m e n t has improved, the heavy-lift c u t o f f has increased. A s a result m a n y lift p l a n n e r s identify lifts as critical, y e t m a k e n o distinction o f t h e lift's n o m i n a l weight o r heaviness. A critical lift is d e f i n e d b y lift p l a n n e r s as e i t h e r a lift o v e r an area o f c o n c e r n such as an o p e r a t i n g process area, o r a lift t h a t exceeds a certain p e r c e n t a g e o f a c r a n e ' s capacity. This critical definition allows plan- ners to d e v o t e their effort t o t h e least reliable types o f lifts. This p a p e r encompasses b o t h types o f definitions o f lifts a n d defines t h e lifts studied merely as lifts requiring detailed planning. T h e detailed p l a n n e d lift, as a m a t t e r o f c o n v e n t i o n , will be r e f e r r e d to as a heavy lift t h r o u g h o u t this
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document. This type of lift makes up less than 30% o f industrial crane lifts, but requires the majority of planning effort from lift specialists.
Some of the very heavy lifts over 400 t (500 tons) use specially designed lifting or jacking systems. The majority of heavy lifts, though, are p erfo rm ed using standard crane configurations. Primarily this study is focused on the use of single cranes that have the capacity to lift the object alone but often use tailing cranes or "J-rails" for uprighting objects (Shapiro et al. 1991). Lifts requiring the lifting capacities of multiple cranes were not examined in detail in this study, but many of the basic planning functions identified for single main crane lifts are applicable to multiple crane or multiple lift object planning. Fig. 1 illustrates the segment of the lift planning industry discussed.
This paper presents an overview of current industry practices, followed by a formalized model of the heavy-lift planning process. Th e potential impact of computer-aided lift planning methods is illustrated through an examination of a common planning task. Using the planning model as an architecture, a complete computer-aided planning system is proposed. Prog- ress to date on the implementation of this system is described as well as current research and development activities.
BACKGROUND
Methods of heavy-lift planning and execution in industry have many com- mon elements that are independent of the project or organization involved. But as the heavy-lift industry is introduced to new technology, these planning methods are undergoing changes. The first m a j o r change has been the result of the steady introduction of cranes with ever-larger lifting capacities. A heavy lift around 1960 was defined as up to 22 t (25 tons), while today rotary cranes are performing lifts 10 times that magnitude or m o re (Donnie Gosch Sr., heavy-lift planner, Brown & Root, Inc., Houston, Tex.; heavy- lift survey interviews; April 10, 1991, June 11, 1991). A second m aj o r change is also evolving. New computing technologies, including computer-aided design (CAD), geographic information systems (GIS), and artificial intel- ligence (AI) tools are beginning to initiate significant changes in the way planning is done (Varghese 1992).
Industrial heavy-lift planning is p e r f o r m e d in three basic stages:
1. Preliminary planning begins 12-24 months before the actual lift date. Its purpose is to examine feasibility and establish the scope of the lift plan. The planner uses preliminary vessel dimensions to make approximate es- timates and consults preliminary site plans to establish lift requirements. The results include an estimate of lift cost, an analysis of preliminary fea- sibility, an outline for the detailed lift plan, and sometimes a short list of potentially feasible cranes.
2. Detailed planning begins when the vessel information and the con- struction schedule are accurate enough to commit to a schedule for a lift date and equipment rentals. Based on a fixed set of site conditions and vessel data, the planner determines, for example, what specific crane con- figurations can perform the lift and where the equipment should be located. The planner must also design the vessel rigging and the crane mat.
3. Final planning involves evaluation of the detailed plans and final se- lection. Detailed lift plans are usually developed for at least two models of cranes to allow for the competitive procurement of lift equipment (Donnie
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Gosch Jr., heavy-lift planner, Brown & Root, Inc., Houston, Tex.; heavy- lift survey interviews; April 10, 1991, June 11, 1991). A ft er a level of ac- ceptable risk has been determined, the selection of the lift plan is based primarily on cost. The selection and evaluation phase is often a cooperative effort between the construction contractor and the facility owner because of the risk and high public profile of the heavy-lift execution.
Delays in the execution of detailed lift plans can have a n u m b er of causes. The vessel delivery date, for instance, cannot be accurately determined to within less than one week at almost any time during its fabrication. Many planners will not commit to a detailed lift plan until the vessel has actually entered the site due to the numerous fabrication and transportation prob- lems that can delay a scheduled lift (Frankie Spates, lift planner, D o w Chemical, Freeport, Tex.; heavy-lift survey interview; July 11, 1991). Th e detailed planning period is therefore often very constrained. A structured analysis of heavy-lift planning proves useful for understanding how complex and conflicting planning factors are dealt with in this constrained time frame.
STRUCTURED ANALYSIS OF HEAVY-LIFT PLANNING
Industrial heavy-lift planning can be modeled as a function with inputs, outputs, controls, mechanisms, and an internal process ( " I D E F I " 1981). Heavy-lift planning takes as basic inputs the site, characteristics of the lift object (vessel), and crane data. From this information a n u m b er of plan outputs are produced (Fig. 2). T h e process is controlled by the lift planner based on structural, spatial, and schedule constraints. Lift plan outputs increase in detail as the lift plan evolves from preliminary planning, to detailed planning, to final evaluation and selection. Cost and reliability are of constant concern throughout this process. Those employed to execute
Inputs Cranes Lift Object Site ~'~
Controls Spatial Constraints
Stnlctural COnsSctrt ~ e C onstraints
1 + Heavy Lift Planning
~prFeasible Cranes & Partial Lift Plan eliminary Feasibility Planning) I
Feasible Cranes & Optimum Lift Plans I (Detailed Optimization Planning) I
l
I Optimum Crane & Lift Plan (Final Evaluation & Selection)
Planning Criteria Cost Reliability
Outputs
-I~Crane Location ~ e s s e l Pick Location ~ V e s s e l Lift Path "l~'Failing Crane Location ~ e s s e l Upright Location ~ V e s s e l Upright Path
Constructor Owner Engineering Consultant Mechanisms
FIG. 2. Heavy-Lift Planning Functional Model
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the planning functions include the construction lift planner, owner repre- sentative, and engineering consultants.
Lift Plan Inputs The inputs to the lift plan correspond to the physical breakdown of the
lift: the object, site, and crane. The characteristics of the cranes are orga- nized in substantial manuals of information on each piece of lifting equip- ment. Architectural and engineering drawings typically represent the site data. The lift object or vessel is described by manufacturer shop drawings.
The lift object (vessel) can be described by three basic categories of characteristics. The dimensions and shape of the vessel represent the in- formation used to evaluate spatial constraints (Dharwadkar 1991). Th e lo- cation and magnitude of the weight of the vessel determine the lifting ca- pacity required to perform the heavy lift. The fabrication and delivery schedule of the vessel establishes the work window in which the lift will be performed.
The second input to heavy-lift planning is the site. Th e site can also be described by several basic characteristics. The spatial layout and dimensions of the site are typically represented by drawings for lift planners. T h e struc- tural stability of the site is represented quantitatively by engineering sheets for specific areas of interest. The state of the site's spatial and structural conditions is also represented as it changes with time by the project con- struction and plant operations schedule.
The crane can be represented by five primary categories of characteristics. The crane's physical dimensions define its spatial operating requirements. The structural design and weight characteristics define the forces and stresses that the crane can endure for a lift. The crane is also characterized by its cost and availability. Subjectively, the crane is also characterized by its reliability and service record.
Lift Plan Outputs The lift planner structures the planning process around six basic spatial
outputs for each of a number of crane configurations. A single crane con- figuration may include b o o m length, counter weight, b o o m size, jib type, and boom tip type. Through each stage of the planning process, the n u m b er of crane configurations are reduced while the lift plan outputs are refined. In preliminary planning, approximate regions of feasible locations for the lift plan spatial outputs are determined. In detailed planning, these regions are more accurately determined and the location of each lift plan output is optimized for each crane configuration. The objective is to choose outputs that minimize the structural and spatial requirements of the crane to directly improve the reliability and performance of the lift. Th e six outputs for the uprighting and lifting of a single critical lift are:
�9 Main crane location: The main crane location is the plan location of the center pin and the elevation of the top of the crane mat.
�9 Tailing crane location/path: T h e tailing crane location and/or path is defined similarly as its center pin location as it uprights the vessel or lift object.
�9 Vessel upright location: The vessel upright location is the main crane hook location at which the vessel is uprighted for a lift.
�9 Vessel upright path and vessel lift path: Th e upright path and lift path are the paths traveled by the main crane h o o k during uprighting and lifting.
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�9 V e s s e l pick l o c a t i o n : T h e vessel p i c k l o c a t i o n is t h e u p r i g h t e d p o i n t at which t h e m a i n lifting c r a n e first c a r r i e s t h e full w e i g h t o f t h e vessel.
�9 Vessel p l a c e l o c a t i o n : T h e p l a c e l o c a t i o n is usually n o t v a r i a b l e a n d is d e f i n e d as t h e c r a n e hoist h o o k l o c a t i o n w h e r e t h e vessel rests a t t h e e n d o f t h e lift.
Lift Planning Mechanisms T h e m e c h a n i s m s o f t h e lift p l a n n i n g f u n c t i o n a r e p r i m a r i l y t h e r e s p o n -
sibility o f t h e lift p l a n n e r a n d t h e facility o w n e r . F o r e x a m p l e , o n e l a r g e - plant o w n e r supplies c o n s t r u c t i o n c o n t r a c t o r s with p r e l i m i n a r y lift plans. M o r e typically, t h e o w n e r r e q u i r e s d e t a i l e d lift p l a n s f r o m t h e c o n s t r u c t i o n c o n t r a c t o r . T h e lift p l a n n e r a n d t h e o w n e r in t u r n r e c e i v e i n f o r m a t i o n f r o m technical c o n s u l t a n t s such as c r a n e m a n u f a c t u r e r s , s t r u c t u r a l e n g i n e e r s , a n d o t h e r lift p l a n n i n g e x p e r t s . W h i l e n u m e r o u s p a r t i e s s u p p l y i n f o r m a t i o n t o the lift p l a n n e r a n d t h e o w n e r , t h e e n d r e s p o n s i b i l i t y f o r t h e e x e c u t i o n o f the lift p l a n falls with t h e lift p l a n n e r , a n i n d i v i d u a l o r s u b c o n t r a c t o r w h o is usually e m p l o y e d b y t h e c o n t r a c t o r .
Lift Plan Controls H e a v y - l i f t p l a n n i n g is c o n t r o l l e d b y s p a t i a l s t r u c t u r a l , a n d s c h e d u l e c o n -
straints. Spatial c o n s t r a i n t s t a k e i n t o c o n s i d e r a t i o n t h e w o r k v o l u m e o r s p a c e on the site r e q u i r e d f o r t h e c r a n e t o m o v e t h e v e s s e l t h r o u g h t h e lift p a t h . T h e lift p l a n n e r c a n n o t c h e c k t h e i n t e r f e r e n c e o f e v e r y p o i n t o n t h e vessel, crane, o r site with e a c h o t h e r . T h e lift p l a n n e r t h e r e f o r e uses e x p e r i e n c e to identify t h e p o i n t s o n t h e lift c o m p o n e n t s t h a t a r e m o s t likely to i n t e r f e r e with e a c h o t h e r . Fig. 3 is a small m a t r i x o f t h e c o m m o n i n t e r f e r e n c e c o n - ditions t h a t a lift p l a n n e r c h e c k s f o r c l e a r a n c e r e q u i r e m e n t s . F o r e x a m p l e , o n e o f the m o s t c o m m o n c o n d i t i o n s limiting a lift is t h e i n t e r f e r e n c e o f t h e c r a n e b o o m b o d y with t h e v e s s e l h e a d .
D u e to t h e u n c e r t a i n t y o f t h e d i m e n s i o n s o f t h e c r a n e , vessel, a n d site
Common I Spatial Inteferences L ~ E I I I I
-~ front swin
boom tiol I I I I I
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Typical Heavy-Lift Interference Points
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during dynamic lift conditions, the lift planner defines the tolerances re- quired at these interference points. This tolerance given by the lift planner varies depending on the subjective analysis of the likelihood of an inter- ference condition. T h e crane has unquantified variances such as b o o m flex- ure, foundation settlement, and general mechanical slip. T h e vessel has variances due to sway and hoist line elasticity during the lifting operations. The shear size of the crane components justifies the planner's assumption that there is uncertainty in the control of the lift. A critical lift clearance allowance is that between the crane b o o m body and the top o f the lift object. A typical minimum clearance for this critical point is 6 0 - 9 0 cm ( 2 4 - 3 6 in.).
The structural constraints on the lift plan require determination of the required strength of the vessel, site, and crane, as well as allowable loads plus a safety factor. The weights of the lift components make up the static forces acting on the lift. The safety factor to account for dynamic conditions and uncertainties is typically set by the owner in consultation with the lift planner, and is generally based on perception of risk. Th e lift planner and consulting engineers often have difficulty evaluating the true capacity of the lift when different structural guidelines apply to different components o f the lift. The issue of the effectiveness of multiple structural safety factors on the reliability of the heavy lift has been addressed in a previous lift study (Duer 1989).
As the lift date approaches, the schedule begins to impose more fixed constraints. The pick location for the vessel may be constrained by the date that a certain construction activity must take place. Interfering structures may be erected before or after a lift. In addition, physical precedences exist such as the requirement for construction of a vessel foundation and pad before placement. The schedule describes the time variance o f spatial and structural constraints as well as the objectives of the project managers.
Evaluating Lift Plans The complete lift plan is optimized with the simultaneous objectives o f
cost, reliability, safety, and performance. Interdependencies abound. F o r example, the cost of a crane greatly increases as its structural capacity increases.
The weight of each of these objectives or evaluation criteria varies, but the method by which each criteria is applied to the lift plan is fairly uniform throughout the industry.
In terms of reliability or safety, the lift planner's objective is to minimize the chances of catastrophic accidents and general lift failures. Catastrophic- type accidents are failures involving the loss of life or extreme damage to hazardous processes such as chlorine gas removal. Lift failures are defined as structural failures or spatial interferences causing damage. Th e clearest indicator of reliability of a lift is the percentage of the crane capacity used. This is established by the fact that most lift failures are caused by the overturning of cranes, or by exceeding the structural stable capacity of the crane.
Primary lift cost components are the crane lease rate, crane transportation/ setup, engine mat/foundation construction cost, and the cost impact on area construction activities. Ideally, the lift planner evaluates these components together and selects the best lift plan, but typically the lift planner minimizes the cost of the lift through the selection of the most economical crane based on fixed object and site information. In the early planning stages, though, lift planners are able to b e t t e r reduce the total lift cost by evaluating the
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site constraints on the lift along with the lift conditions (Donnie Gosch Sr., heavy-lift planner, Brown & R o o t , Inc., Houston, Tex.; heavy-lift survey interviews; April 10, 1991, June 11, 1991). For example, a single crane foundation can be used for the execution of several heavy lifts in an area. This requires the coordination of construction plans to ensure that area structures are constructed in a sequence that allows access to multiple place points from a single crane location.
Performance criteria are also used by lift planners to optimize lift plans. One performance factor is the use history of the crane. Th e history o f the crane impacts both the structural and spatial reliability of the equipment and potential maintenance and servicing costs. A u t o m a t e d measurement devices have recently been introduced to allow the lift history o f the crane be economically recorded.
DEVELOPMENTS IN COMPUTER-AIDED PROCEDURES AND THEIR IMPACT ON LIFT PLANNING METHODS
A presentation of research findings for a common lift planning task serves to illustrate the impact of computers on the overall lift planning process. The sample planning task is the identification of the minimum radius at which a single crane can lift an object. Since the structural reliability of the lift increases significantly as the lift radius decreases, a primary objective of all heavy lifts is to perform the lift as close to this minimum radius as possible. The interference of the lift object with the crane base o r b o o m determines the minimum radius on the majority of heavy lifts p e r f o r m e d with rotary cranes. Occasionally, stability with respect to the crane's coun- terweights will also affect the minimum radius.
The method of performing this task for six engineering/procurement/ construction (EPC) contractors is presented in this section ( H o r n a d a y 1992). The purpose of this section is to provide insight into planning methods of industrial constructors, not to rank or compare. Some of the contractors studied specifically requested that company references in lift planning ma- terials not be disclosed. Thus, the planning methods and the drawings shown in this section are not specifically referenced.
Three of the six E P C contractors and owners studied currently use manual lift planning procedures. In determining the minimum crane radius, an elevation view of the vessel is hand-drafted by the lift planner. Th en , for each crane configuration under study, the lift planner drafts an elevation view of the crane body and boom. T h e process of determining whether the boom clears the vessel height is performed iteratively. F o r a single crane configuration and vessel pair, lift planners take about 8 man-hours to ac- curately calculate and document the minimum crane radius.
Lift planners may use shortcuts to improve the efficiency o f this planning task. One planner keeps a n o t e b o o k of sketches of co m m o n crane models drawn to scale. Common rigging attachments are also filed in a second notebook. Using a photocopier, portions of the drawings are constructed using cut-and-paste methods. Other planners who draw out the individual components of the crane take shortcuts by only drawing the critical dimen- sions needed. In Fig. 4, a lift planner sketched only the critical crane di- mensions like the b o o m length and rotation center line.
The remaining three of the six planners use computers to aid in the planning of heavy lifts ( H o r n a d a y 1992). Different levels o f technology were observed.
The first documented use of computers for heavy-lift planning was a
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FIG. 4. Drafted Elevation Working Drawing of Crane Lift
planner's use of A u t o C A D in 1982. Various common crane components, such as boom sections, types of rigging, and crane bases, were saved to scale in files. Once the vessel was drafted on the computer from shop drawings, the lift planner would insert common crane components to con- struct the lift plan. This planner still uses A u t o C A D to store common crane components and to document the heavy-lift plan. Once all of the vessel information is entered into a drawing file, the calculation and documentation of a crane configuration's minimum crane radius for that vessel takes about one man-hour.
Another integration of the computer encountered was the use of site range scanning technology to quickly construct standard D X F (drawing exchange format) drawings of existing vessels to be lifted. The owner com- pany performs mostly maintenance construction of existing plant equipment.
In this case, the lift planner uses A u t o C A D to store graphic represen- tations of crane components. The transfer of vessel dimensions is performed via the D X F files produced by the scanner. The calculation of the minimum crane radius takes about an hour once the vessel information is transferred into A u t o C A D . The primary automation advantage is the reduction of the time-consuming process of field measurement of existing vessels.
Another E P C contractor has invested a significant sum of money in the development of a computer-aided heavy-lift planning system running on
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graphics workstation computers. This system is used to automate the cal- culation and documentation of common lift planning procedures. This plan- ning system uses applications developed with MicroStation | for a graphic display of lift configurations and for graphic interactive user interfaces (Alex- ander 1992). Many of the common planning tasks are performed in the
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background by in-house programs developed in the language C + + , an object-oriented language. T o calculate the minimum radius o f a crane con- figuration, the user constructs or imports a drawing of the vessel. Lifting constraints such as required clearances and type of rigging are selected. T h e user then specifies a trial radius and the crane configuration is graphically constructed in seconds. T h e experienced lift planner, after a few trial radii, constructs the crane's minimum radius configuration in about 1 min. A sample illustration of a crane configuration and vessel pair produced by this system is presented in Fig. 5.
Excluding the cost and time to develop and implement computer planning aids, the task of calculating a crane and vessel pair's minimum radius was reduced from an eight-hour work day to 1 min. This task is only a co m p o n en t of the total heavy-lift planning process. H o w e v e r , significant improvements to the process can be realized through the improvement of individual tasks.
INTEGRATED COMPUTER-AIDED HEAVY-LIFT PLANNING SYSTEM
The opportunities to use computer tools to improve heavy-lift planning are far broader than the previous examples may suggest. Some o f the tools and their potential applications are summarized in Table 1. Th e challenge is integrating these tools into a useful computer-aided heavy-lift planning system. The system should enhance and amplify the planner's capabilities, but not replace the planner, who is ultimately responsible for the final lift plan.
A computer-aided heavy-lift planning system could conceivably reduce by one-half the total number of hours spent on lift planning activities. It should also result in better lift plans and reduced lift costs.
In the next section the requirements of such a system are discussed. Th en , the writers' progress toward implementation is described. This progress is representative of the related efforts of several private groups within the heavy-lift industry. T h e writers' research seeks to integrate and advance these efforts.
System Requirements A computer-aided lift planning system must recognize the practical re-
quirements of the heavy-lift industry. Industry lift planners must be able to transition from current practices to automated methods or automated meth- ods will not be accepted.
TABLE 1. Technologies for Computer-Aided Planning
Technology Use for computer-aided heavy-lift-planning (1) (2)
Computer-aided design (CAD)
Geographic information system Graphical user interface Relational data base management
system Robotics path planning
Computer graphics simulation/ animation
Model crane, vessel, and site geometry; interference checking
Model site layout and subsurface conditions Enhance user productivity Store, maintain, and organize graphical and
nongraphical data Provide algorithms for spatial reasoning and path
planning Visualize lift for review and execution instruction
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The owner requires management control information from the lift planner relating to the cost, reliability, and schedule of the lift. Since lift cost is typically excessive relative to other construction operations, owners require a detailed breakdown of where resources are being consumed in the lift (Larry Londot, lift planner, The M. W. Kellogg Co., Houston, Tex.; heavy- lift survey interview; June 13, 1991). A second requirement by the owner is a verification of the lift's reliability. Owners currently review lift plans for the most critical lifting conditions based on knowledge of past accidents (Frankie Spates, lift planner, Dow Chemical, Freeport, Tex.; heavy-lift survey interview, July 11, 1991). As a result, the lift plan requires docu- mentation of critical parameters such as close clearances and structural capacity utilization. Another control function is the assurance of schedule progress. Lift planners are usually required to provide the owner with work plans and evidence of schedule progress (Marshall Wheeler, erection field engineer, Becon Construction, Co. Inc., Kingsport, Tenn.; heavy-lift survey interview; May 28, 1991). These three management control functions are a required component of a complete lift planning system that serves the owner and the lift planner. The system should produce appropriate reports and output for these functions.
A primary requirement made by lift planners is the need to integrate planning methods with the information received from outside sources. Even with CAD modeling of the crane, vessel, and site, planners often have to reconstruct aspects of the lift plan. This would not be required if information from different sources could be integrated more easily (Donnie Gosch Jr., heavy-lift planner, Brown & Root, Inc., Houston, Tex.; heavy-lift survey interviews; April 10, 1991, June 11, 1991). A second requirement of lift planners is the ability to better model structural planning tasks. Currently these tasks are performed by external consulting engineers at substantial cost and time (Donnie Gosch Sr., heavy-lift planner, Brown & Root, Inc., Houston, Tex.; heavy-lift survey interviews; April 10, 1991, June 11, 1991). A third requirement is better lift scheduling and crane availability tracking. Planners sometimes must delay commitment to crane rentals until the vessel or lift object actually arrives on-site. With crane costs from $10,000 per month, planners are challenged by the task of tracking available equipment to meet changing schedules. A fourth requirement is that a computerized system must facilitate the natural iterative nature of lift Planning and not artificially constrain the planner to rigid sequences of procedures.
Implementation Initial efforts at implementing an integrated computer-aided heavy-lift
planning system have resulted in the successful demonstration of a heavy- lift planning simulator called HELPS1, which runs on a Silicon Graphics IRIS workstation using W A L K T H R U . HELPS1 enables the lift planner to visualize the execution of the heavy lift. The simulation process also enables the real-time monitoring of spatial interferences and the crane's structural capacity (Wolfhope 1991). A sample view of the computer monitor during a lift simulation is pictured in Fig. 6.
Efforts are under way by the writers to develop a more completely in- tegrated computer-aided heavy-lift planning system (called HELPS2) on a microcomputer platform that will incorporate many of the system require- ments discussed previously. Fig. 7 is a functional model of this planning system. The two darker outlined components in the figure represent pro- totype implementationsz (1) The graphic simulation of the lift plan using
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FIG. 6. HELPS Lift Simulation
HELPS1; and (2) algorithms for determining minimum lift radius ( H o r n a d a y 1992).
The microcomputer-based system will serve as a powerful interactive tool for the heavy-lift planner. It incorporates a personal computer-based C A D software package (MicroStation) and data-base software (Oracle) in order to perform both preliminary planning and detailed planning efficiently. The system is being developed in the MicroStation Development Language (MDL).
It has the ability to query the data base through graphic entities such as crane booms or lifting blocks. T he software has been partially implemented, and development is in progress. Its architecture is summarized in Fig. 8. The functional hierarchy of the software modules illustrates the division of the software into a model builder, a data-base manager, and a planning manager (Fig. 9). A more detailed description of the software design is beyond the scope of this paper, but it is presented in a forthcoming paper on the design of the system and its algorithms.
The system implements some limited constraints on planning procedures in its preliminary implementation. T he planner sets the spatial clearances that he determines to be reliable. T he planner also sets the acceptable percentage of crane capacity ranges.
Each possible configuration of a crane is treated as a separate crane model, therefore each combination of boom length, counter weight, boom size, jib
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System D a t a b a s e Application Modules
'-Preliminary Feasibility Planning'~
�9 Automated Calculation of 1 ~_ Preliminary Lift Data
Detailed Optimization Planning /
J ( Interactive Generation "~ | and Optimization | L of Lift Plans J V
] Optimized Lift Plans [
V Plan Evaluation and Selection ] (HELPS i simulation module)
I Selected ~ft Plan I
V Automated Lift
Execution and Control
FIG. 7. Computer-Aided Heavy-Lift Planning Process Model (Hornaday 1992)
type, and b o o m tip t y p e is e v a l u a t e d s e p a r a t e l y f o r feasibility. T h e v e s s e l is t r e a t e d as a c o n s t a n t a n d t h e site a p e r f e c t p l a n e .
A c o n c e p t u a l d e s c r i p t i o n ( H E L P S 2 is n o t y e t fully i m p l e m e n t e d ) o f a typical u s e r session c a n b e d e s c r i b e d as follows.
A site m o d u l e is a c t i v a t e d t o d i s p l a y a t h r e e - d i m e n s i o n a l site l a y o u t a n d a t w o - d i m e n s i o n a l p l a n view. Site i n f o r m a t i o n such as g r o u n d c o n d i t i o n s , access r o a d s , u n d e r g r o u n d c o n s t r u c t i o n is m a r k e d in r e d to aid in t h e s u i t a b l e location o f t h e c r a n e . I n f o r m a t i o n c o m p i l e d f o r t h e s e site entities is a c c e s s e d b y simply clicking a m o u s e c u r s o r o n t h e g r a p h i c i m a g e s o n t h e s c r e e n . F o r e x a m p l e , d o u b l e clicking o n a n u n d e r g r o u n d p i p e w o u l d r e v e a l a w i n d o w with p l a n n i n g i n f o r m a t i o n like t h e d e s i g n e d a l l o w a b l e b e a r i n g p r e s s u r e . T h e p l a n n e r m a y n e x t r e v i e w v e s s e l o r lift o b j e c t d a t a t h r o u g h a v e s s e l m o d u l e . Clicking t h e m o u s e c u r s o r o n t h e v e s s e l o p e n s a w i n d o w c o n t a i n i n g d i m e n - sions, views, w e i g h t , a n d d e l i v e r y s c h e d u l e i n f o r m a t i o n .
B a s e d o n t h e v e s s e l i n f o r m a t i o n a n d site c o n d i t i o n s , t h e lift p l a n n e r c a n select t h e c r a n e f o r a specific lift. A c r a n e m o d u l e allows t h e lift p l a n n e r to e v a l u a t e t h e m i n i m u m lift r e q u i r e m e n t s a g a i n s t c r a n e capabilities. T h e p l a n n e r m a y e d i t this list o f f e a s i b l e c r a n e m o d e l s . F o r e a c h c r a n e , s e v e r a l c o m b i n a t i o n s o f b o o m l e n g t h , c o u n t e r w e i g h t s , b o o m tip t y p e , a n d jib t y p e can b e selected. F o r e a c h c o n f i g u r a t i o n , t h e c o m p u t e r c a l c u l a t e s a n d au- tomatically displays t h e p o s s i b l e c r a n e l o c a t i o n a r e a o n t h e site l a y o u t p l a n . This a r e a is c a l c u l a t e d o n t h e basis o f t h e site c o n d i t i o n s , t h e v e s s e l p l a c e
511
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other applications (scheduling, -gH
estimating, etc.)
~ h computer aided eavy lift planning software
f usg:aphiCf~ce ~'~
/ i site, orane "~ \ J retrieve k & lift objects )
,.~ database ~ C A D e n g i n e ~ planning ~algorithms
graphical menu driven lift plan design file data importing of export and import
crane data and planning A preferences
& plan reporting 3D graphical simulation
and walk through
FIG. 8. HELPS2 System Architecture
Computer Aided I C~cal L~
Planning System A0
i Model Builder 1 I DMaat na ~b~ e~rr 1
. ~ Crane Graphic jCrane Database~ Module .~ ~ Module
~__fG Site Objects ~'~Vessel Database~ raphic Module ..~ �9 Module
~Vessel Graphic j Site Database .o~ 1
._~ Schedule Manager 1
FIG. 9. HELPS2 Functional Hierarchy
I Planning Manager 1
.~Crane Selection Module 1
~_~ Crane Monitor Module 1
._~Crane Location Planning 1
__._~pCrane Lift Path lanning Module 1
...~Crane Simulator Module .~
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FIG. 10. Detailed Planning Lift Plan View
location, the k e y dimensions of the selected crane, and the crane m i n i m u m and m a x i m u m radii.
The planner then selects the crane location based on experience. The optimal crane location minimizes the furthest radius that must be
reached in the execution of the lift plan. H e clicks a point at the center of the rotation within the feasible crane position region. T h e selected crane is then placed on this point, with the m i n i m u m and m a x i m u m working circles placed about the center as illustrated in Fig. 10. Within the working area of the crane and the feasible vessel pick area, the planner selects the vessel pick location. A f t e r the crane location and the vessel pick locations have been selected, the lift p a t h can be generated automatically (Morad et al. 1992) based on the following criteria:
�9 Perform the lift as close to the m i n i m u m radius as possible. �9 Prioritize hoisting and swinging motions o v e r crane b o o m i n g m o -
tions. �9 Reduce the n u m b e r o f crane operations (the ideal lift p a t h is the
simplest one).
The system will also generate cost estimate, clearance, and crane capacity utilization reports. T h e close integration o f a C A D system, data base, and development language m a k e this possible.
FINAL SELECTION, EVALUATION, AND REVIEW USING COMPUTER-AIDED HEAVY-LIFT PLANNING SYSTEM
An o p t i m u m lift can b e selected based on reliability and cost criteria. T h e reliability of the lift is related to the spatial clearances, the structural util-
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ization, and the schedule availability. Graphical simulation software such as that implemented in HELPS1 can be used in the evaluation process for a final three-dimensional check of spatial and structural constraints as well as for visualizing the lift plan. HELPS2 is intended to also have this ability in the future. Clients are beginning to demand a high-resolution graphical simulation for review prior to final lift plan confirmation. Th ey will also typically demand documentation of the planning clearances that were used to determine the feasible crane and the optimum lift plan. A computer- aided planning system will be able to report this information automatically.
The structural reliability of the lift can be evaluated based on the per- centage of the capacity used for each of the structural components of the lift. This information can be reported automatically using the HELPS1 soft- ware. A listing of the lift structural components and their structural utili- zation allows lift planners to identify the weakest link in the lift plan. A similar listing was used in the evaluation of a lift of a nuclear reactor vessel (Duer 1989).
The primary cost of increased structural reliability is in the crane, so owners often prefer to evaluate the cost of the lift along with the percentage of the crane capacity utilized. This crane capacity utilization is often ex- pressed to lift owners by planners as the lift safety factor (Donnie Gosch St., heavy-lift planner, Brown & R o o t , Inc., Houston , Tex.; heavy-lift sur- vey interviews; April 10, 1991, June 11, 1991).
Computer-aided heavy-lift planning allows the planner to generate several alternative detailed lift plans. Comparing the lift safety factor and the lift cost for each lift plan enables the planner to select an optimal combination of cost and risk, to generate alternatives for procurement within certain cost and safety constraints, and to present the owner with the costs of reducing risk.
CONCLUSIONS
Industrial owners and contractors are expanding the n u m b er and size of large prefabricated equipment pieces requiring heavy-lift erection. O t h er sectors of the construction industry are also moving toward prefabrication and modularized erection methods. This shift in construction methods will expand the number and size of lifts and indirectly increase the need for more reliable and economical heavy-lift planning methods.
Many of the lift planning procedures of industrial contractors can be aided and improved with the use of computers. A model of heavy-lift planning methods common to industrial constructors presented in this paper serves as an architecture to build a computer-aided lift planning aid. A few in- dustrial leaders have already implemented powerful computer-aided lift planning tools. An integrated, microcomputer-based, heavy-lift planning system is being implemented by the authors that will lead to further ad- vances.
The tools described in this paper have the potential to improve upon current planning methods in several ways. Lift planners will be able to evaluate hundreds rather than a few possible crane configurations, thus improving the likelihood that a good plan will be generated. In conclusion, computer-aided lift planning should:
�9 Improve the reliability and accuracy of lift planning. �9 Reduce the cost of planning.
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�9 R e d u c e the total lift cost t h r o u g h m o r e effective selection o f cranes. �9 I n c r e a s e the level o f p l a n n i n g f r o m "will it w o r k " to t h a t o f " o p -
t i m i z a t i o n . " �9 I n t e g r a t e disparate sources o f lift plan i n f o r m a t i o n . �9 A l l o w f o r the s i m u l t a n e o u s e v a l u a t i o n o f multiple p l a n n i n g c o m -
p o n e n t s .
APPENDIX. REFERENCES
Alexander, S. (1992). "Avoiding trouble with rigorous planning: Load lifts modeled on MicroStation." MicroStation Manager, 2(8).
Dharwadkar, P. (1991). "3-D modeling and graphical simulation of mobile crane to assist planning of heavy lifts." MS thesis, The Univ. of Texas, Austin, Tex.
Duer, D. (1989). "Lift of Shippingport Reactor pressure vessel." J. ofConstr. Engrg. Mgmt., 116(1), 188-197.
Fitzsimmons, J. A. (1991). Operations management course lecture notes. Univ. of Texas, Austin, Tex.
Hornaday, W. C. (1991). "Survey of industrial construction heavy lift planning meth- ods." Research Report to Dr. Carl Haas, Univ. of Texas, Austin, Tex.
Hornaday, W. C. (1992). "Computer aided planning for construction heavy lifts." MS thesis, The Univ. of Texas, Austin, Tex.
"IDEF1, Architecture part II, Volume V - - I n f o r m a t i o n modeling manual." (1981). UM 110231200, Air Force Systems Command, Wright-Patterson Air Force Base, Ohio.
Morad, A., Belivean, Y., Cleveland, A., Francisco, V., and Dixit, S. (1992). "Path- Finder: An AI-based path planning system." J. Comput. Civ. Engrg., ASCE, 6(2).
Shapiro, H. I., Shapiro, J. P., and Shapiro, L. K. (1991). Cranes and derricks. 2nd Ed., McGraw-Hill, Inc., New York, N.Y.
Varghese, K. (1992). "Automated route planning for large vehicles on industrial construction sites." Dissertation, The Univ. of Texas, Austin, Tex.
Wolfhope, J. (1991). "Design of a computerized heavy lift planning system for construction." MS thesis, The Univ. of Texas, Austin, Tex.
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School of Architecture, Building and Civil Engineering Coursework Brief
1
Module Code: 21CVP326 Module Name: Management of Construction Processes and Techniques Assessment Title: Canada Tower Group Coursework Assessment Type: Report Other: Date Due: 9 May 2022 Date
Returned: Week commencing 30 May 2022
Method of Submission
Virtual only Feedback delivery:
Feedback Proforma
Weighting: 40% Other: 2 reports, each makes 20% Individual or Group:
Group
Word Length Other Other: 2 reports, each 2500 words max Total number of hours expected to be spent on assignment:
45
Assessment aims: You are an ‘up and coming’ construction and project management organisation having been asked to help a high-profile client, Innovation Inc., to plan a complex construction project, Canada Tower, in Central Business District in the City of Birmingham, UK. You need to produce an ‘early-stage’ summary construction strategy (Report 1) and a risk assessment (Report 2).
Task description: The proposal is for a mixed-use development including a 49- storey, 150m tall residential tower with a 9-storey podium which includes market rental housing, commercial uses, and a childcare facility. There is also a six-storey building providing retail and office space.
The project area is 60670 m2, including:
• 39465 m2 strata residential • 6340 m2 rental residential • 6300 m2 retail • 5935 m2 office space • 650 m2 childcare
The client is very keen on innovation; they do not need to choose the cheapest first cost option, they are after a high-quality end product.
The client’s project manager who is assessing the report has a good knowledge of construction techniques and therefore you should not concentrate on basic construction technology aspects. Rather you should focus on the innovative technologies to be employed and on your strategy to deliver the project on time, on budget and to the required quality. This will require some additional research on site strategy, means and methods.
School of Architecture, Building and Civil Engineering Coursework Brief
2
Summary details of the project are available on LEARN – you will have to make assumptions regarding certain aspects of the project, buildings and surrounding area.
There will be various bookable coursework tutorials through the semester.
Do not contact anyone connected with the development of the project. This is important for us to retain our credibility within the industry.
Report requirements and assessment criteria: Report 1 - Construction strategy (50% of coursework weight, max 2500 words)
…including rationale for what was considered and chosen, including but not limited to:
a. Main materials, methods & techniques b. Site layout c. Major plant and equipment, including a detailed lift plan for one important mobile crane d. Summary programme of main activities
Assessment based on:
• Explanation of technical aspects and practicality of construction strategy • Detailed lift plan (including a discussion) for one important mobile crane • Response to site constraints • Response to client’s needs • Annotated construction site layout plan and schedule • Presentation and clarity in communication
Report 2 - Innovation & risk management (50% of coursework weight, max 2500 words)
… focussing on three main innovations.
Assessment based on:
• Clarity in the description of innovation and the related dimension • Identification of risks associated with innovative technologies used along with the timeframe
for each risk • Identification of risk owners and reporting mitigation plans • Report specifically written for the client and sensitive to clients’ requirements for RM plan • Presentation and clarity in communication
Extra marks for the two reports will be given for evidence of additional research work, however, do not include large amounts of unnecessary literature.
Specific requirements and submission details: 1. This coursework must be done in groups of four (with the same group for both Reports 1 & 2).
You have a freedom to select and form a group with your colleagues. However, there must be at least 2 different nationalities in a group. This should provide an effective cross-cultural learning opportunity.
School of Architecture, Building and Civil Engineering Coursework Brief
3
2. Precise format of the report is up to you, but make sure you pay sufficient attention to readership, and produce a ‘professional’ report.
3. Please submit Reports1 & 2 separately via the portal on the module LEARN. 4. Please state the word count on the cover. The length of discussion should be no more 2500
words for each report. Additionally, you may include other information as appendices. The reference list and appendices are not part of the word count. Please note that the appendices should: (i) include only necessary information, (ii) be kept to a minimum, and (iii) be referred to, in the main report. These appendices will not be marked, but they are only included to provide support to your discussion in the main report. Thus, the report should be focussed, succinct, and contain no unnecessary detail.
5. Each report and its appendices should be submitted via LEARN in one PDF file. Name the file with: “Group [number]_Report 1” and “Group [number]_Report 2”.
Peer assessment Peer assessment is an essential requirement for each submission. You will need to agree with your group, a percentage of group mark which each individual member should be awarded. This percentage will be used as a multiplication factor to produce mark for individual member. For example, if a group report is awarded 68%, and a percentage awarded to a member is agreed to be 95%, then the individual mark for this member is 65%. If the group agrees to award each member 100% of group mark, then all members will be awarded 68%. The proforma for the peer assessment is provided below. For each report, completed and signed proforma must be included in a page after the cover page. Should there be anomaly in the percentages, the module leader reserves the right to adjust the individual marks, as he deems appropriate and reflecting the quality of the submitted reports. As it is an essential requirement, a submitted report without signed proforma will not be marked, and no mark will be awarded to each group member.
Our group has agreed the following percentage of group mark should be awarded to our group member.
Student name Percentage of group mark awarded to
Signature Date
Student A
Student B
Student C
Student D
School of Architecture, Building and Civil Engineering Coursework Brief
4
Robby Soetanto Francis Edum-Fotwe
February 2022

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