Inspecting or cleaning bridges presents a logistics challenge in most cases. While there are some low-lying bridges that can be accessed by a team standing underneath, more often than not some sort of method of access needs to be employed.
There are Many Ways to Get Under a Bridge
Depending on the purpose and the type and location of the bridge, the options available for practical access varies. For example, bridge inspection teams can use ladders, rigging or scaffolds in some situations. If the bridge spans a waterway, boats or barges can sometimes be used.
While not uncommon, some teams occasionally employ climbers who either free climb, or rappel and make use of suspended chairs. When inspectors climb on the bridge members to gain access, safety awareness is highly important. When using this method, the inspector is tied off to the bridge using an independent safety harness and lanyard.
Large bridge structures often are engineered with permanent inspection structures or catwalks. A traveler is another permanent bridge inspection platform like a catwalk except that it is movable. A traveler platform is typically perpendicular to the girders and the platform runs on a rail system between substructure elements. Having the platform perpendicular to the girders allows the inspectors a wider range of movement and enables them to see more of the superstructure elements.
And, when it is deemed too difficult to reach or extremely dangerous for a human to access, inspection Robots or drones might be employed. Although a robot can never replace a qualified inspector, it can detect flaws that may not be visible to the human eye. And a robot that is equipped with sonar capabilities can detect internal flaws in bridge members.
Using Vehicles for Under Bridge Access
There are many types of vehicles available to assist an inspector or technician to gain access alongside of and under a bridge so they can perform “hands-on” inspection or maintenance of bridge members. Here are some of the most common types of access vehicles used in bridge inspection.
Scissor lifts can be used to inspect bridges that have low clearance between the bridge and the roadway underneath. Scissor lifts typically have a maximum vertical reach of 20 feet. These lifts are designed for use on relatively level ground.
Manlifts are vehicles with a platform or bucket that can hold one or more workers. The platform is attached to a hydraulic boom mounted on a carriage. A worker operates the carriage using controls in the bridge inspection platform. Although four-wheel drive models are available, manlifts are limited for use on level terrain. Manlifts are designed with vertical reaches ranging from 40 feet to over 170 feet.
Bucket trucks are similar to manlifts except that, unlike a manlift, a bucket truck can be driven on a highway and the worker controls the bucket movement. As with the manlift, a bucket truck needs to be used on fairly level terrain.
Choosing the Ideal Under Bridge Inspection Platform
An under bridge inspection vehicle is a specialized bucket truck with an articulated boom designed to reach under the superstructure of a bridge while parked on the bridge deck. Typically, the third boom can extend and retract, allowing for greater reach and access under a structure.
Some larger under bridge inspection vehicles have four booms, allowing an even greater reach. Some under bridge inspection vehicles have a two or three-person bucket on the end of the third boom. Other models, such as the HPT43, are equipped with a multiple-person platform on the third boom with a ladder on the second boom.
Because of the available capabilities of different under bridge inspection vehicles, determining the best choice for your work or project hinges on the structure and terrain. While pricing is a factor, capabilities and needs should be the dominate deciding factors. Having a professional firm you can rely on to guide your through the process of hiring the right vehicle and bridge inspection platform equipment for your project is key to making the proper choice.
We take a great deal of pride in being the only company in California that offers total under bridge access. By offering high quality customer service, we have managed to build long-lasting relationships with our esteemed customers. And we intend to keep it that way. Contact us today to discuss your requirements.