Computationally Informed Methodologies for Capturing the Effect of Intervening Structures During Truck Impact Events: Phase II

Details

• Creators:
  Salahat, Fahed H. ; Jones, Christopher A. ; Rasheed, Hayder A.
• Corporate Creators:
  Kansas State University Transportation Center
• Corporate Contributors:
  Kansas. Department of Transportation. Bureau of Materials and Research
• Subject/TRT Terms:
  Bridge Piers Bridges Design Finite Element Method Impact Loads Load And Resistance Factor Design Reinforced Concrete Specifications Trucks
• Publication/ Report Number:
  K-TRAN: KSU-21-7
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States ; Kansas
• Edition:
  Final Report: August 2020 – August 2023
• Corporate Publisher:
  Kansas. Department of Transportation. Bureau of Materials and Research
• Abstract:
  Reinforced concrete (RC) barriers are often used as railings to protect bridge piers against vehicular collision force (VCF). RC barriers absorb collision energy and/or redirect vehicles. According to bridge design specifications of the American Association of State Highway and Transportation Officials (AASHTO), barriers used to protect bridge piers should have a minimum height of 42 in. and survive MASH Test Level 5 (TL-5). Although many barriers in current use do not meet this requirement, these sub-standard barriers can reduce the severity of vehicle-pier collisions and decrease the AASHTO-specified VCF for pier resistance in upgraded bridges. The primary objective of this research was to assess the performance of sub-standard RC barriers as protection for bridge piers against VCF and quantify their reduction of the equivalent static force (ESF) that piers must resist according to AASHTO specifications. This report describes current procedures to determine the transverse static capacity of RC barriers and proposes alternative, accurate methodologies. A matrix of crash scenarios is simulated in dynamic explicit analysis using the finite element software LS-DYNA to comprehensively encapsulate the behavior of sub-standard RC barriers. The investigated parameters include energy dissipation, velocity reduction, contact force absorption, and lateral displacement. This research also utilized a simulation matrix on a bridge pier that failed to withstand the ESF under the required AASHTO’s extreme load event behind a sub-standard barrier. A series of dynamic impact force time histories was used to extract the ESF and compare the resulting ESF to the AASHTO-required force, leading to a proposed reduction in the ESF due to the presence of sub-standard RC barriers. Research results showed that AASHTO’s existing procedure to determine the transverse static capacity of RC barriers may underestimate capacity by approximately 50%. In addition, the inadequacy of sub-standard barriers to absorb and/or redirect an impacting vehicle was shown to relate to geometrical deficiency (insufficient height), meaning that sub-standard barriers can resist high-impact load demands and protect piers if the barrier is a sufficient height (i.e., 42 in. for TL-4). Sub-standard barriers may reduce the AASHTO-required ESF for bridge piers by at least 25%.
• Format:
  PDF
• Funding:
  C2167
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:2aeaf1874b1c5410ee4700916b1122352bab9a8d70b351d111146fe60819d3b4af6288a61b03d21e94b2b90cea720153e2f5f7b3ca8caeba24cff992a2a3e628
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/91807/dot_91807_DS1.pdf
• File Type:
  [PDF - 10.56 MB ]