This material was produced under grant SH-17794-08-60-F-51 from the Occupational Safety and Health Administration, U.S. Department of Labor. It does not necessarily reflect the views and policies of the U.S. Department of Labor, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.
This course is intended to provide general information to engineers and managers for use in identifying and addressing their responsibilities with respect to construction worksite safety. The program cannot possibly cover all safety issues that may be encountered at the construction worksite, and it is not a substitute for prudent judgment or professional expertise. It does not constitute legal advice. The information provided in this course should not be used without first securing competent advice with respect to its suitability for any general or specific application. ASCE and the Construction Institute disclaim all warranties regarding this course, whether implied, express or statutory, including without limitation, any implied warranty of merchantability, fitness for use, or fitness for a particular purpose. ASCE and the Construction Institute make no representation concerning the accuracy, completeness, suitability, or utility of any information, apparatus, method, product, or process discussed in this course and assume no liability therefore. Anyone utilizing the information provided in this course assumes all responsibility or liability arising from such use.
The two cranes used on this concrete beam allowed the beam to be landed first on one end
The two cranes were probably on the jobsite, resulting in cost savings
Two Cranes – Horizontal Loads
Two Cranes – Horizontal Loads
Here two matched cranes lift an asymmetrical load
Careful CG calculation and load distribution is very important
Two Cranes – Horizontal Loads
Two Cranes – Horizontal Loads
Two unequal cranes lifting a process module
This lift was carefully planned, allowing the larger crane to lift at a greater radius and allowing for a proportional lift
Two Cranes – Horizontal Loads
Two Cranes – Horizontal Loads
Connecting two similar cranes with a long lift beam enables the cranes to reduce their respective operating radii, thereby increasing their lifting capacities
Utilizing two cranes to make a vertical lift should require a high level of planning . It is essential to consider:
The orientation and the initial layout
Boom side clearance and two-blocking
The changing of loads on all cranes
Minimum and maximum radii
Method of safely unhooking the rigging
Insure one crane doesn’t get ahead of the other
A lift of this nature should always be an engineered lift
Two Cranes: Tailing
Two Cranes: Tailing
Most larger vertical loads require trailing with a crane or an equivalent tailing device
Sometimes two tail cranes are used
The crane or device must be able suspend (or support) the proportionate load- whether moving into the hook of the main erection crane or remaining at radius while the erection crane booms out to the tail crane
Two Cranes: Tailing
Not all vertical loads require tailing with a second crane