The Structures Laboratory's focus on the behavior of bridge systems—in both typical and extreme loading conditions—is vital to the Nation's transportation system. There are more than 600,000 bridges in the United States, and the studies conducted here improve the safety, durability, reliability, and cost-effectiveness of each one. Data from these studies informs upgrades to the design specifications for future bridges. The Structures Laboratory consists of five individual facilities: the main Structures Laboratory, the Structures Laboratory Annex, the outdoor testing facilities, the computer modeling and simulation facility, and the material testing facility.

The Structures Laboratory has a variety of static-loading rams, including the high-force hydraulic ram that is used to slowly apply a load to test specimens. In contrast, static loads, as their name suggests, do not move. They are commonly used to calculate the maximum load a structure and other objects can withstand. Static-loading rams can place loads ranging from 50,000 to 2,000,000 pounds.

The Structures Laboratory and facilities use a network of closed-loop servo-hydraulic test stations with servo-hydraulic actuators—devices that produce physical movements by converting hydraulic energy into mechanical force. These actuators can apply loads in a rapid, cyclic manner similar to live traffic, including two actuators that can apply loads in excess of 200,000 pounds.

This type of test setup was developed to study the prestressing strands embedded in concrete materials as well as the development length of large-diameter prestressing strands embedded in ultra-high performance concrete. The use of prestressing strands can reduce the volume of concrete required in construction and boost durability and service life.

This frame is used to evaluate the ability of different components of structures (e.g., bolted steel connections) to withstand long-term stresses. This testing equipment was recently used to study innovative connection technologies for steel bridge construction.

The two high bay roll-up doors in the main Structures Laboratory make it possible to move large test specimens and other large equipment in and out of the lab. These doors measure 14 ft x 16 ft and 20 ft x 20 ft.

The Structures Laboratory facilities contain several types of load frames. High-force vertical load frames are used to place vertical loads of up to 1,000,000 pounds on test specimens. These frames have recently been used to study innovative construction details for accelerated bridge construction and to investigate cement-based materials' resistance to a specific type of stress.

This testing frame is mainly used for fatigue testing of bridge girders—cases where loads are applied quickly and repeatedly. The beam's behavior in flexure and shear can also be studied using this testing frame. It was recently used to study innovative welding technologies for steel bridge construction.

This test will reveal the strength and resiliency of a concrete bridge beam made of ultra-high performance concrete (UHPC), an advanced material far stronger and more durable than the concretes commonly used today. In this test, researchers are investigating how the UHPC performs when being subjected to millions of cycles of heavy truck traffic. Every second this beam is being loaded with more than 200,000 pounds of force, then unloaded again to allow it to relax and return to its original position.

This testing frame is used to conduct large- and full-scale experiments on bridge girders—also referred to as beams. The large-scale beam static testing frame is commonly used for static testing—cases where loads are immovable and applied slowly. It is also used to study the behavior of beams in flexure and shear (e.g., bending and deforming under large loads).

Shear walls were constructed in the Structures Laboratory to test and endure structural loads in horizontal or slanted directions to simulate the impact caused by wind or earthquake forces.

The strong floor is one of the most important pieces of equipment in the Structures Laboratory. It allows the research team to conduct indoor testing of full-scale bridge structures and large components. Heavy-loading events, such as traffic, can be simulated here.

The Structures Laboratory has two concrete mixing stations to create test specimens. One station can mix up to 5 cubic feet of concrete and the other up to 14 cubic feet of concrete. In this area, standard material tests are conducted on fresh concrete properties.

This large machine offers both high capacity and a large displacement range to allow for the tensile testing of high-strength materials. Reinforcing bars, post-tensioning products, rolled steel plates, and bolted or welded connections can all be tested in this machine.

This high-capacity machine has a servo-hydraulic actuator to allow for controlled compression testing of structural materials. The stress-strain response of concrete with compression strength greater than 20 kilopounds per square inch (ksi) is commonly captured using this machine.

The Structures Laboratory has a set of fixed testing frames that are used for the static and fatigue testing of structural materials. These machines have sensor-based feedback control, allowing high-quality test data to be captured as the materials are reaching their failure limit. The load capacity of these machines ranges from 22,000 to 222,000-pounds.  

The Structures Laboratory has a set of fixed testing frames that are used for the static and fatigue testing of structural materials. These machines have sensor-based feedback control, allowing high-quality test data to be captured as the materials are reaching their failure limit. The load capacity of these machines ranges from 22,000 to 222,000-pounds.