CHOOSING THE RIGHT TOWER CRANE FOR THE JOB
- FACT - 90% of all accidents are caused by improper set up of mobile cranes.
- FACT - Tower crane efficiency is greatly affected by proper planning in the preliminary construction project stage.
- Question:
- What Tower Crane is right for my job?
- Typical Answer:
- 200 ft of boom with a capacity of 6,000 lbs at the maximum radius and the height of my building is 150 ft.
- Comment:
- Most planning supervisors rely on their crane suppliers to come up with suggestions to supply equipment and sometimes the renters offer equipment they have rather than what equipment is best for the job. This is like putting the cart before the horse. Do your planning early.
1 - Choose a location to position the tower crane.
- Things to Consider
- Will this position allow sufficient crane capacity at project perimeters?
- Will this position create air rights / over flying problems with neighboring structures?
- Will this position interfere with the project structure or related systems?
- Will this position interfere with access into the construction project?
- Will this position make the erection & dismantle process easier and save costs?
- Is this the best position for construction material unloading?
- Is this the best position for ease of storage?
- How will this position effect high wind situations. Are we able to work downwind?
2 -What hook height is required?
- Things to Consider
- Can we freestand this crane to the required height?
- How much will the crane tower move when freestanding?
- Will freestanding the cranes impact our production efficiency?
- Will this height allow for rigging of all of the loads?
- Will this height allow the loads to safely clear all obstruction and personnel?
- Will we have to climb the tower crane above the initial erection height?
- When climbing, what cranes to building support systems are available?
- What is the jib tip height with maximum load?
- Does the boom deflect below 0 degrees?
- How does the height of this crane impact other cranes working on site?
3 - What working radius is required to access all areas of the project?
- Things to Consider
- Where is the center of gravity of all loads in relation to the maximum reach of the tower crane?
- What is the dimension of all loads in relation to the maximum reach of the tower crane?
- What is the weight of the loads as it relates to the crane capacity chart?
4 -What lifting capacity is required at the maximum radius?
- Things to Consider
- What lifting capacity is required for the heaviest load and at what distance?
- What effects will wind have on our capacities?
- What effects will operator control have on our capacities?
5 - What type of tower crane foundation suites the project?
- Things to Consider
- Should we use a concrete base type foundation with it recessed?
- Should we use a concrete base type foundation with is raised?
- Should we use a static base type foundation which uses central ballast?
- Should we use a static base type foundation which uses concrete anchorage?
- Should we use a rail travel base type foundation with central ballast?
- What types of anchorage systems are available for the selected tower crane type?
- How do these tower crane support system costs compare for this project?
- How these tower crane support system do compare for this and future projects?
- How does the area wind zone affect the tower crane foundation?
6 - Tower Crane Climbing / Dismantle
- Things to Consider
- Do we have sufficient clearances to climb the tower crane?
- Is the tower orientated in the correct position for top climbing?
- What mobile cranes are available for the dismantle process?
- Do we require a special derrick crane for the dismantle process?
- How will the area wind conditions effect climbing of the tower crane?
7. What does the rental / sale include?
- Things to Consider
- Parts? Does the supplier have a stock of parts available?
- Service? What service personnel are available in our area?
- Parts and Service Contract will cover what? What is additional?
- What value of the equipment is stated for insurance purposes?
- What is the cost of the foundation anchors?
- Is the foundation anchorage system per the manufacturer?
- Engineering? What engineering services are available for this type of equipment?
- Climbing support systems?
- Top climber included?
- Building tie-in arms or braces?
- Building connection plates?
- What are the payment terms of the equipment rental?
- Does the rental include re-torqueing of the tower?
- Who supplies the lubrication materials for the crane?
- What length of power cable is supplied?
- What length of hoist rope is supplied?
- What tower crane operators are available?
- What if the tower crane operator gets sick? Who is available to replace the operator?
- Is the operator experienced with this type of tower crane?
- Who supplies the crane log book?
- When can we get a copy of the crane manual?
- How often do we need to inspect the tower crane?
- What is the maintenance schedule?
- What is required of our site personnel to ensure the crane is maintained?
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