Rutgers Unveils the BEAST to Study Lifespan of Bridge Construction Materials

It took about a decade of planning to come up with the concept of full-scale, accelerated bridge testing.

📅   Tue November 17, 2015 - National Edition
Brenda Ruggiero - CEG CORRESPONDENT



Rutgers University’s Center for Advanced Infrastructure and Transportation (CAIT) recently unveiled the BEAST (Bridge Evaluation and Accelerated Structural Testing) a facility created to study future performance and lifespan of materials and elements, as well as maintenance, rehabilitation and preservation techniques for aging highway bridges.

The system is designed to quantitatively measure stresses and deterioration caused by extreme traffic and environmental loading on full-scale bridge systems and to do so in an extremely compressed time frame. Data from the BEAST will allow the projection of future performance and longevity of bridge materials and components.

“The BEAST uniquely subjects full-scale bridge deck and superstructure systems of up to 50 ft. (15.24 m) long by 28 ft. (8.53 m) wide to extreme traffic loading and rapid-cycle environmental changes in a controlled environment. This extreme loading ’fast forwards’ aging by as much as 30 times, making it possible to simulate 15 to 20 years of wear-and-tear in just a few months,” explained Andrés Roda, research engineer for the project.

Roda noted that the system’s 24-7 traffic loading delivers up to 60,000 lbs. (27,215 kg) total applied vertical force through two closely spaced axles, replicating the stresses of 17,500 trucks rolling over the deck in a day. Inside the BEAST, rapid-cycling temperatures can fluctuate from 0 to 104 degrees F (minus 17 to 40 C) to reproduce a range of weather conditions; combined with salt brine applications, these conditions simulate the environmental impact of 15 years’ worth of seasonal changes in just a six-month testing period.

“It is critical to understand the durability of our bridges,” Roda said. “In particular, knowing how long a bridge deck, patching material, overlay and other elements of the bridge are going to last can make a big difference in bridge management. Being able to forecast the longevity of these materials has been an uncertainty. What if we could speed up time? What if we could put a bridge into ’fast forward’ to examine the long-term effects and identify the life of each element? FHWA’s Long-Term Bridge Program has examined these questions for some time, and it identified a need for more rapid assessments. Our team responded to this challenge by building the BEAST.”

According to Roda, it took about a decade of planning to come up with the concept of full-scale, accelerated bridge testing. The process sped up over the past two years, when the team identified a suitable site, established footprint constraints, developed specifications for the equipment, and secured a contract with Applied Research Associates (ARA). ARA collaborated with CAIT and its partners to design and construct the BEAST.

“There were many key decisions made with regard to experiment capabilities, such as brine application, number of potential girders on bridge specimens and others,” Roda said. “The team made concessions and worked within budget to establish realistic parameters for researchers to adopt during experimentation so that results would be applicable to inventory bridges.”

The facility was dedicated on Oct. 14, during a public event that included a dedication and ribbon cutting, demonstration, and tours.

Currently, the team is developing the details for the first experiment. Once the first bridge is constructed and installed, testing will begin.

The BEAST Specifications & Testing Capabilities

Basic Specifications:

• Accommodates spans up to 50 ft. long by 28 ft. wide

• Traffic loading: Two-axle loading cart applies 10 to 60 kips (60,000 lbs.) continuous at 20 mph (32.3 kph); more than 17,500 passes per 24 hour period

• Environmental loading: Rapid cycling temperature fluctuations, 0 to 104 degrees F

• Application of salt brine 1 percent to full saturation (standard testing will use 15 percent soluble solution)

Construction materials:

• 31 tons (28.12 t) of rebar

• 540 cu. yds. (412.85 cu m) of concrete

• 90 tons (81.64 t) of steel

• 6,600 ft. (2011.6 m) of high voltage cable and 1,300 ft. (396.2 m) of ground wire

• More than 50 gal. (189 L) of yellow paint

Testing Capabilities: Bridge Systems, Components and Materials

• Concrete: Any concrete bridge deck mix design, corrosion inhibitors, supplemental cementing materials and additives

• Decking Systems: Open, filled, partially-filled or unfilled grid decks such as exodermic bridge deck systems; orthotropic or other metal deck systems; prefabricated deck systems; precast slabs; and others

• Rebar: Steel, epoxy coated, galvanized, stainless steel, steel clad, glass and carbon fiber polymer, etc.

• Prestressing and Post-tensioning Strands: Bar, wire, strands, couplers, anchorages, ducts and other components

• Coatings and Sealants: Latex-modified concrete, joint sealants, epoxy waterproofing seal coating, etc.

• Superstructure Frames: Structural steel, reinforced concrete, precast concrete, prestressed concrete and timber

• Joints: Preformed joint filler, elastomeric joint assemblies, strip seal expansion dams, modular bridge joint systems, longitudinal joints, shear locks and others

• Bearings: Bearing pads, reinforced elastomeric bearing assemblies, high-load multi-rotational bearing assemblies and others

• Deck Drainage: Scuppers, inlets, downspouts, grates and other drainage elements

• Safety Devices: Striping paint, pavement reflectors, auditory safety devices (e.g. Bott’s dots, rumble strips, etc.), ITS devices and sensors, traffic cams, signage materials, and more

Testing for materials and components not listed above may also be available. An expert panel will review requests and advise regarding customized experiments.

For more information, visit http://cait.rutgers.edu/beast.