This innovative method of rigging modules and other loads substantially reduces the HSE exposure hours and increases the cost-effectiveness of the overall heavy-lift program. 

Modularization of heavy industrial plant construction in the oil and gas and petrochemical industries is a standard mode of operation, utilized to reduce costs, site congestion and schedule. Standard modules are 20 feet wide, from 80 to 120 feet long, up to 24 feet high, and range in weight from 50 to 160 metric tons. Using a heavy crane, modules are lifted into place using tall columns that extend from the top of the module. These “pick points” can vary in number and configuration, depending on the size and composition of the module. Modules also have different centers of gravity, depending on their contents.

Configuring the rigging to accommodate the different pick point configurations and centers of gravity has traditionally been a time-consuming and often dangerous process. With PCL’s engineered module lift frame, however, rigging crews can simply slide the connections into place using a patented slider assembly. What used to take up to a day now takes a matter of minutes, setting a new bar for productivity and safe work practices.

“The construction industry has for many years used a traditional rigging approach to lifting and placing these modules onto their foundations or supporting structures. Though the combination of spreader bars, slings, and rigging hardware is well accepted and proven, the approach retains inherent risks and can induce stresses within the lifted module,” said manager of construction engineering Rick Hermann.

“Rigging is brought to the ground for reconfiguration between lifts to accommodate changes in the dimensions and center of gravity of the load to be lifted as well as the number of points to which the rigging will be attached. This process—affecting a crew of at least eight over five to ten hours—involves handling heavy shackles, rigging components and wooden timbers, while increasing exposure to potential stored energy in the slings, and moving rigging objects around the workers as they reconfigure the rigging assembly.”

When the module does not rise evenly on the lift, the rigging is disconnected and additional shackles and rigging components are handled to make the adjustments that will balance the load. During the assembly and hookup of the rigging to the module, the rigging often hangs unevenly until it is hooked up to the module due to the unsymmetrical configuration and the shackles added to balance the load during lifting. During the assembly and hookup of the rigging to the module, the slings and spreader bars can rotate and must be controlled by taglines, especially when wind is present.

Some projects have a larger-than-average variety of module bay dimensions and number of pick points. On a recent heavy industrial project, the rigging had to be modified between lifts 58% of the time. Adjustments were made, over and above that, to modify the center of gravity in both directions. The effect can easily extend the heavy lift program by a few months, expose workers to pinch points and other risk hazards and add a huge cost to a project.

To service the variety of rigging configurations possible on a project using traditional rigging methodology, a large inventory of slings, shackles, spreader bars and rigging hardware is required. It can take one full crew, on-site transporters, and extra mobile cranes to manage the handling of these various components and transport them to the lift sites on a project.

When a module is unequally loaded and relatively flexible, significant deflection can occur, which has the potential to damage the module during lifting. If severe, this can be very difficult to compensate for using traditional rigging methods. Safety, schedule, and cost savings are the primary drivers for inventing a better rigging methodology.

“Knowing all the issues that come with traditionally rigging and lifting these modules,” said vice president Travis Chorney, “we took a hard look at where we could improve the process that's been done the same way over and over again. We got together with folks from the field who actually plan and execute the rigging and looked at a process. We looked at different ideas: what can we make things more effective?”

PCL engineered, designed and fabricated (in-house) an innovative method of rigging modules to reduce site costs and improve safety. The PCL Engineered Module Lift Frame is designed to meet AMSE BTH-1 design category B class 0, and also Alberta OH&S, ASME B30-20 and CSA S16. It can easily handle a 160-metric ton module for six to 16 point picks, 16- to 24-foot-wide modules, and lengths up to 140 feet. To mitigate risk, the lift frame was load tested three times and assembly tested once before placing it into service. The lift frame has a provisional patent in place.

PCL’s patented lift frame has reduced by as much as 90% the time required to modify rigging configurations over traditional rigging assemblies. This substantially reduces the HSE exposure hours and increases productivity of the heavy-lift program.

PCL’s module lift frame was first to put to use for a client in August 2012 at the ConocoPhillips Surmont Phase 2 project near Anzac, Alberta, where it lifted 50 modules ranging from six to 16 points and weighing up to 148 metric tons. Since then, PCL has fabricated two additional frames. To March 2017, PCL’s lift frames have been employed on five projects and lifted 643 modules.

The new lift frame uses two main running beams and a slider (a beam clamp-type mechanism) that allows for easy adjustment to the bay dimensions, while also allowing for the center of gravity adjustments without the addition of shackles. These sliders are interconnected to enable easy adjustment of the rigging along the longitudinal axis and can be locked in place at the end to prevent movement. The width of the module lift frame can be adjusted from 16 to 24 feet in six-inch increments. These adjustments are performed more safely at ground level and take less than an hour to perform as compared to five to 10 hours for traditional rigging.

“It takes an average of a half-hour to modify the rigging as compared to two to 10 hours for traditional rigging,” said operations manager Jamie Feuffel. “And due to the symmetrical design, the module lift frame always picks level, making it significantly easier to hook up to the module.”

Most of the adjustments to the lift frame for bay dimensions, the number of pick points, and the center of gravity do not require the use of assist cranes as do most traditional rigging assemblies. The rigging height from the top of the module to the crane hook block is 95 feet as compared to 130 to 165 feet for traditional rigging.  The rigging weight for 12- to 16-point pick modules is quite similar to that of traditional rigging.  The reduction in rigging height has the potential to reduce the main boom length, which enables a higher crane capacity.

For transportation on-site, the lift frame is folded down with the top spreader bar and slings removed, before being shipped on a transporter. This substantially reduces the time required to dismantle and assemble the rigging. The stiffness of the lift frame reduces the load redistribution forces within the module as compared to traditional rigging.  Dynamic finite element analysis was performed that indicates an average reduction of 50%.

This results in less deflection of the module during lifting, and a reduction of potentially damaging stresses within the module. Due to the efficiency of the rigging changes of the lift frame as compared to traditional rigging assemblies, the duration of the heavy-lift program can be reduced by approximately 30%.  This is a significant gain in schedule that frees up areas for other trades to perform their work.“Though other companies have attempted to form a rigid frame, truss, or other rigging configuration to reduce the schedule and the cost of module installation,” said vice president Chris Pullen, “PCL’s new system is much more flexible and more quickly modified for the variety of modules that are installed on projects. The inherent time savings it provides—as much as 90% over traditional rigging configurations is huge. Every moment we can pull out of the schedule and reduce safety exposure is great for us and our clients.”

The benefits are less exposure, lower risk to our workers doing the rigging, better productivity, and better cost and schedule,” said Chorney. “In a nutshell, we've achieved all that with our lift frame.”

PCL is continuing to improve the design, to make the fold-down procedure easier, and to extend the lift frame for longer and heavier modules.