Repairable Precast Bridge Bents

Sponsors:  

The Precast/Prestressed Concrete Institute (PCI), and the National Center for Transportation Infrastructure Durability and Life-Extension (TriDurLE)  – University Transportation Center (UTC) 

Project Funds:  $134,444 ($40,000 from PCI, $67,045 from TriDurLE, and $27,399 match from SDSU) 

Year:  2021-2022

Personnel:  

PI:  Mostafa Tazarv, PhD, PE

Graduate Research Assistants:  Kallan Hart, Received the PCI Dennis R. Mertz Bridge Research Fellowship, Oct. 14, 2020.

Project Technical Panel:  Yahya Kurama (uni. of Notre Dame), Jared Brewe (PCI), Glenn Myers (Atkins Global), Richard Potts (Standard Concrete), Kevin Eisenbeis (Burns and McDonnell), Wael Zatar (Marshall Uni.)

Project Summary:

Bridges designed with current seismic codes exhibit large displacement capacities, and the bridge total collapse is prevented.  However, this performance objective is usually attained at the cost of damage to target ductile members.  For conventional reinforced concrete bridges, the columns are usually the main source of ductility during an earthquake in which concrete cover, core, and reinforcement may damage, and the column may experience a permanent lateral deformation.  Minor damages can be repaired but excessive damages such as core crushing, bar buckling, and/or bar fracture are hard to repair and will usually result in the bridge replacement.  According to FHWA, approximately 25% of the US bridges require rehabilitation, repair, or total replacement.  Furthermore, within the next 50 years, many bridges located in the 16 seismic prone states of the nation will experience large earthquakes that may cause significant damage.  Induced seismic activities in formerly non-seismic states such as Oklahoma may also damage bridges with poor seismic detailing.  

Even though current practice is successful in attaining the no-collapse objective, a new design paradigm is needed to minimize bridge damage incorporating low- to no-damage techniques.  The benefit can be enhanced if those low-damage technologies are combined with precast techniques to accelerate bridge construction.  The main goal of the proposed work is to develop new details for precast bridge columns, which significantly accelerate bent construction and minimize the post-earthquake column damage to a few hairline cracks.  The only component that is allowed to damage is detachable exposed reinforcement in the column plastic hinges.  The exposed bars can be quickly replaced with new ones after extreme events, if needed.   

Project Work Plan:

Task 1:  Detailing Alternative Development,

Task 2:  Evaluation of Detailing Alternatives,

Task 3:  Experimental Investigations,

Task 4:  Analytical Investigations,

Task 5:  Recommendations,

Task 6:  Prepare a final report documenting all aspects of the project.

Publications:

1. Tazarv, M., and Hart, K. (2023). “Repairable Precast Bridge Columns for Seismic Events”, PCI Journal, In Press.  

2. Tazarv, M., Hart, K., Khan, A. (2023). “Rocking Bridge Columns with External Replaceable Tendons,” Journal of Bridge Engineering, ASCE, In Press.  

3. Hart, K., and Tazarv, M. (2022). “Repairable Precast Bridge Bents for Seismic Events,” National Center for Transportation Infrastructure Durability and Life Extension (TriDurLE) Report No: 2021-SDSU-02, Washington State University, Pullman, WA, 354 pp. (Link)

Proposed Repairable Precast Column Testing