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Structure Testing

The Structure Testing Laboratory at NTRC is operated by the T Bridge Research Laboratory (TBRL) Group from the University of Tennessee (UT), Department of Civil and Environmental Engineering (CEE). The group has access to two lab spaces: 1) the Structure Testing Laboratory at NTRC and 2) a lab in the CEE building on the UT main campus. The group studies the behavior and design of pre-stressed concrete bridges, mechanics and applications of high-performance concrete and fiber-reinforced polymer composites, and accelerated construction in highway bridges.

Current Research Projects

TBRL is involved with three active research projects: cast-in-place reinforced connections for precast deck systems; design and construction guidelines for long-span decked precast, prestressed concrete girder bridges; and behavior and design of FRP-decked concrete bridges.

Cast-in-Place Reinforced Connections for Precast Deck Systems

This project was funded by the National Research Council (NRC) through the Transportation Research Board’s National Cooperative Highway Research Program. The objectives are to

  • develop detailed design, fabrication, construction, and performance criteria that must be satisfied to provide durability, strength, fatigue resistance, seismic resistance, and rapid construction;
  • develop conceptual designs for cast-in-place reinforced concrete connections: at least three for longitudinal or transverse connections between full-depth deck panels or deck flanges. Connections should not require overlays or post-tensioning. Emphasis is placed on increasing construction speed while achieving durability and ride quality; and
  • develop specification language and commentary for recommended changes to the American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) bridge design and construction specifications as necessary to implement the recommended connection details.

The typical sequence of erecting bridge superstructures in the United States is to erect the precast prestressed concrete or steel beams, place formwork, place deck reinforcement, cast deck concrete, and remove formwork if necessary. This project focuses on systems that eliminate the need to place and remove formwork thus accelerating construction and improving safety.

Long-Span Decked Precast, Prestressed Concrete Girder Bridges

This project, funded by NRC, addresses I-beam, bulb-tee, or multi-stemmed girders with integral decks cast and prestressed with the girder. The TBRL Group is currently developing design and construction guidelines for long-span decked precast, prestressed concrete girder bridges. This method of bridge construction is expected to reduce total construction time, reduce accident risk, and yield environmental and economic benefits.Concerns about design and construction issues have limited the use of decked precast, prestressed concrete girders. TBRL research is addressing issues such as connection methods, live load distribution, lateral load resistance, maintenance, and other factors. The resulting guidelines will be in a format suitable for consideration by the AASHTO as part of their LRFD Bridge Design Specifications.

Behavior and Design of FRP-Decked Concrete Bridges at Very Cold Temperatures

This research, funded by the National Science Foundation, deals with an integrated research and education plan to evaluate and develop a durable bridge system with accelerating renewal features for use in various applications and environments including very cold temperatures. The bridge system consists of glass fiber reinforced polymer (FRP) composite deck and precast/prestressed concrete I-girders. The primary objectives are understanding the synergistic effects of low temperature and low-temperature thermal cycling combined with fatigue loading on the performance of FRP composite bridge decks, quantifying the horizontal shear stiffness of typical deck-to-girder connection systems, and developing the connection design criteria based on the shear stiffness rating of the connection.

Expertise

Student researchers at the Structure Testing Lab are led by UT Structural Engineering Program professorial staff comprising three Ph.D.s in civil engineering, and one Ph.D. in structural engineering. The teaching staff combine expertise in probabilistic-based design and analysis of structures and field testing of structures. They are assisted by graduate and undergraduate students, and by visiting scholars.

R&D Facilities

Both of the TBRL Group’s lab spaces are designed to undertake a range of structural tests. Each lab contains a “strong floor” essential to the research performed. The strong floor at the Structure Testing Lab is 20 x 60 ft; the strong floor at the CEE lab is 20 x 46 ft. Both labs are equipped with overhead cranes. The facilities at the Structure Testing Lab are easily accessible through an entry 20 ft wide by 18 ft high, allowing very large structures to be brought in and assembled over the strong floor.

Major equipment accessible to the TBRL group includes:

  • Two 55-kip MTS actuators with 10-in. stroke
  • Two 22-kip MTS actuators with 10-in. stroke
  • MTS FlexTest GT controller
  • MTS Model 505.30 Hydraulic Power Unit and 293.11 Hydraulic Service Manifold, two station, 50 gpm
  • MTS Axial-Torsional Load Frame (55 kip axial, 25 kip/in. torsional)
  • MTS 810 Materials Test System
  • MTS 651 Environmental Chamber
  • Two 200-kip, 8-in. stroke Milwaukee Cylinder actuators with 200-kip compression load cells
  • 128-channel LabView data acquisition system
  • MegaDac data acquisition system; approximately 100 channels


Structure Testing photo

Distinguishing Capabilities

Equipment Highlights:

• Strong floors, 20 x 60 ft and 20 x 46 ft

• Tension/compression load cells from 50 to 200 kip

• Variety of reaction frames including triangular frame for applying horizontal load and vertical frames

• Axial-torsional load frame

• Actuators ranging from 22 kip with 10-in. stroke to 200 kip with 24-in. stroke

• Linear variable displacement transducers from ±1 in. to ±3 in.

 

Expertise Highlights:

Dr. Z. John Ma, Group Leader

• 2004 National Science Foundation Faculty Early Career Development Award

• 2002 T. Y. Lin Award,
American Society of Civil Engineers

Dr. Edwin G. Burdette

• Fred N. Peebles Professorship

• Recipient of numerous University of Tennessee awards including Chancellor’s Research Scholar Award, College of Engineering Teaching Fellow Award, National Alumni Association Outstanding Teacher Award, and University Macebearer

Research Accomplishments

• Over 50 journal and refereed conference papers published

• An extensive research effort devoted to the testing of anchors in concrete provided data that were instrumental in the development of methodology used for prediction of anchor capacity

• Field experiments validated the effectiveness of Tennessee Department of Transportation’s bridge design criteria, which specify the use of piles and abutments as a structurally sound option to minimize the use of expansion joints

Contact

Dr. Z. John Ma
Associate Professor, Department of Civil and Environmental Engineering
University of Tennessee
(865) 974-7276

http://web.utk.edu/~zma2