Mechanically Spliced Precast Bridge Columns 

Sponsors:  

Mountain-Plains Consortium (MPC) – University Transportation Center (UTC) 

Project Funds:  $465,535 ($228,262 from MPC and $237,273 match from Industry and SDSU)

Year:  2019-2021

Personnel:  

PI:  Mostafa Tazarv, PhD, PE

Co-PI:  Nadim Wehbe, PhD, PE

Graduate Research Assistant:  Mathew LaVoy, Theodore Sjurseth, Kallan Hart, Evan Greeneway

Undergraduate Research Assistant:  Selene Renes

Industry Collaborators/Donors:  Dayton Superior Corp.,  Dextra America, Inc.,  nVent LENTON Corp.,  Headed Reinforcement Corp.,  Splice Sleeve North America, Inc., and Contractors Materials Company 

Project Summary:

Mechanical bar splices, which are commonly referred to as bar couplers, have been utilized mainly in laboratories to connect precast columns to footings or cap beams.  Nevertheless, bar couplers are currently banned in seismic bridge design codes for the incorporating in the plastic hinge regions of either cast-in-place or precast columns.  This is mainly because the coupler behavior and the seismic performance of mechanically spliced columns are largely unknown.  

A recent study at South Dakota State University (SDSU) attacked the first problem by testing more than 160 bar couplers including nine products from six manufacturers, and established a comprehensive database of the coupler behavior.  Furthermore, they proposed standard test methods to systematically quantify the coupler performance, and also proposed acceptance criteria for couplers to be incorporated in bridge columns.  The acceptable mechanical bar splices were categorized as “seismic couplers”.  Nevertheless, test data regarding the performance of mechanically spliced bridge columns is scarce, and the available data is for columns with different geometries, confinement levels, and testing procedures.  

To better understand the seismic performance of mechanically spliced bridge columns, testing of large-scale precast columns spliced with different bar couplers is proposed.  Establishing a comprehensive precast column experimental database will allow to verify or further modify emerging design methods and might provide a justification to relax current coupler ban for bridge columns.  Furthermore, the experimental study will identify new and feasible detailing for mechanically spliced precast columns to promote accelerated bridge construction (ABC) for bents.  

Project Work Plan:

Task 1:  Perform a literature review on the performance of mechanically spliced bridge columns,

Task 2:  Identify couplers and the number of test specimens by contacting all the US mechanical bar coupler manufacturers,

Task 3:  Prepare test matrix, design column test specimens and setup, prepare test setup,

Task 4:  Construct and instrument all the specimens then perform cyclic testing,

Task 5:  Post-process the test data and develop a comprehensive database of seismic performance of mechanically spliced bridge columns,

Task 6:  Verify/update current design methods for mechanically spliced bridge columns,

Task 7:  Prepare a final report including an executive summary, measured test data in the form of figures and tables, and recommendations.

Publications:

1. Tazarv, M., LaVoy, M., Sjurseth, T., Greeneway, E., and Wehbe, N. (2023). “Analysis and Design of Mechanically Spliced Precast Bridge Columns,” Engineering Structures, Vol. 280, 115726, 16 pp. (Link).

2.  Tazarv, M., Sjurseth, T., Greeneway, E., Hart, K., LaVoy, M., and Wehbe, N. (2022). “Experimental Studies on Seismic Performance of Mechanically Spliced Precast Bridge Columns,” Journal of Bridge Engineering, ASCE, Vol. 27, No. 11, 11 pp. (Link).

3. Sjurseth, T., Greeneway, E., Hart, K., LaVoy, M., Tazarv, M., and Wehbe, N. (2022). “Mechanically Spliced Precast Bridge Columns,” North Dakota State University - Upper Great Plains Transportation Institute, Fargo: Mountain-Plains Consortium (MPC), MPC Report No. 22-451, 359 pp. (Link).

4. Greeneway, E., "Seismic Performance of Mechanically Spliced Precast Bridge Columns with New Couplers" (2021). MS Thesis, South Dakota State University, 271 (Link). 

5. Sjurseth, T.D. (2021), "Mechanically Spliced Precast Bridge Columns," MS Thesis, South Dakota State University, 197 pp. (Link)

6. LaVoy, M.R. (2020). "Seismic Performance of Mechanically Spliced Bridge Columns through Analytical Studies," MS Thesis, South Dakota State University, 105 pp. (Link). 

7. TRB Research in Progress (Link)