Spring is upon us and the short break from road work is officially over. Along with the warmer weather comes the need for repair to roads and, more specifically, bridges that have taken a beating over the potentially harsh winter weather.
Now here is where we could go into a cookie-cutter post about what equipment is typically used on these projects, but a lot of that equipment and, for that matter, the topic itself, has been thoroughly regurgitated by every major rental company out there. Instead, today, we’re going to focus on some of the unsung pieces of equipment that we have seen go out on some of these jobs and the unique ways they’ve been applied to accomplish the jobs at hand.
Jack and Slide: Modern bridge construction has begun trending toward the rapid bridge construction model, which has now made sliding a bridge into place a more common sight. Once the new bridge construction has been completed, there needs to be a system to safely, quickly and efficiently move the new bridge onto the supports left from the demolition of the previous bridge and a jack and slide system has been an option to accomplish that task, replacing the standard spreader beam installation as the only practical setup. The system allows for controlled movement of an object with use of a synchronous hydraulic pump but can also be powered by most 10,000 psi double-acting pumps. With either 10’ or 15’ track length sections, the only limit to distance covered by this system is the amount of track ordered. For longer distances or wider bridges, leap-frogging track lengths allows for a nearly infinite distance to be handled with the same system without requiring lever hoists, winch lines or hold backs that makes for a safer and more efficient move of the bridge than previously seen with the overhead spreader beam or rollers.
Synchronous Lifting System: For those of you that are unfamiliar with a synchronous lifting system, LGH has two varieties of sync lift systems available that make lifting an object that needs to stay completely level with multiple lifting points, such as a bridge, a snap. For this type of project, however, there is a larger system that allows anywhere from 8-24 lifting points to be raised or lowered synchronously to within 0.040” through the use of an onboard computer that monitors and stores data for all connected cylinders and adjusts as needed. This tool is a great option for tilting, leveling and final positioning of a bridge once in place. When using this system, it is highly recommended to have an engineer and someone that is willing to read through and understand the use and care manual or, ideally, someone that has used the system on a prior job. The manufacturer is also willing to send a tech out to run the system for a fee, ensuring no issues along the way.
Hydraulic Cylinders: You may question why hydraulic rams are included on this list. In addition to raising the defunct bridge off the supports and lowering the new bridge onto the support columns during rapid bridge construction, rams have been used in many different situations. Cylinders have a long-standing history of use during bridge installation, but their use during repair is not as commonly seen, but equally valuable as a safe method of performing various tasks. We’ve seen some of our customers use rams to relieve the pressure on counterweights prior to swapping them or other mechanicals of a bridge out and to aid in the final placement of a bridge following successful service.
Tuggers (possibly accompanied by snatch blocks): Not commonly seen on bridge jobs, air tuggers can play a pivotal role in lowering a draw bridge at a controlled rate of speed. While the job may require a low speed winch that is not commonly found, other methods can be used to both increase the lifting capacity of a winch while simultaneously lowering the rate of pulling speed. Such a situation was handled by LGH on a previous job, working on the Congress Parkway Bascule Bridge in Chicago, IL. The customer was directed to bring in a specific tugger with a low rate of speed and high capacity but, through the extensive knowledge of their rental representative and collaboration between our customer, their engineer and LGH, a more efficient and lower cost option was explored and enabled the job to be completed on time, safely and under budget. More about this project can be found at the following link: Rehabilitating the Congress Parkway.
While there are certainly numerous other functions each of the above-mentioned equipment can perform during traditional bridge work, we invite you to keep some of these ideas in mind and would be happy to see some alternative uses you may have for using any of our equipment. If you have any projects with photos you would like to share of a unique project using any LGH supplied equipment you can submit your project at http://lgh-usa.com/hit-us-best-shot/.
Please visit our website to view more case studies of projects with our equipment.