Management of Construction Processes and Techniques

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Sarens_Fundamentals_MobileTowerCranes_R07_Final_01-03-2022.pdf

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1/03/2022

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

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

Source: Sarens, 2017

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WE ARE AN INTERNATIONAL COMPANY INTRODUCTION

9 Geographical Regions, 67 Countries, 100 Offices

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

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

THE USE OF CRANES INTRODUCTION

Question:

Why do we use cranes?

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THE USE OF CRANES INTRODUCTION

 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

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.

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

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

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

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

PLANNING FACTORS The Fundamentals of Mobile Crane Planning

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HEAVY LIFT PLANNING FUNCTIONAL MODEL PLANNING FACTORS

(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

(Adapted from Hornaday et al., 1993)

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INPUTS

 Crane Data:

– Physical dimensions.

– Crane capacities.

– Cost.

– Availability.

– Reliability.

– Service record.

PLANNING FACTORS

(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

(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

(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

(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

(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

(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

(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

(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

(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.

(Adapted from Hornaday et al., 1993)

PLANNING FACTORS

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TYPES OF MOBILE CRANES TYPES OF MOBILE CRANES

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

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

(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.

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?

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

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

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

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

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.

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.

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.

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.

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.

CONSEQUENCES OF POOR PLANNING

UNDERSTANDING LIFT PLANS The Fundamentals of Mobile Crane Planning

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WHAT IS A LIFT PLAN?

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.)

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.

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

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

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

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

TOWER CRANE COMPONENTS The Fundamentals of Tower Crane Planning

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COMMON TOWER CRANE COMPONENTS TOWER CRANE COMPONENTS

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

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).

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

TOWER CRANE COMPONENTS

PLANNING FACTORS The Fundamentals of Tower Crane Planning

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TOWER CRANE HEIGHT PLANNING FACTORS

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

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.

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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

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

INTERFACE WITH THE PERMENANT STRUCTURE PLANNING FACTORS

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

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.

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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.

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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.

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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.

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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.

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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.)

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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).

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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.

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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.

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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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