Design and evaluation of steel bridges with double composite action

Details

• Alternative Title:
  Design and evaluation of continuous span steel bridges utilizing double composite action
• Creators:
  Sen, Rajan ; Stroh, Steven
• Corporate Creators:
  Florida. Dept. of Transportation. Structural Research Center ; University of South Florida. Department of Civil and Environmental Engineering
• Subject/TRT Terms:
  • Steel bridges
  • Composite structures
  • Iron and steel bridges--Design and construction. Composite construction.
• Resource Type:
  Research Paper
• Geographical Coverage:
  Florida
• Corporate Publisher:
  Florida Department of Transportation
• Abstract:
  This report presents findings from a cooperative USF/URS/FDOT research study undertaken to develop design rules for ; double composite steel bridges. In the study, a 48 ft long, 16 ft wide, 4 ft. 10⅛ in. deep trapezoidal HPS 70W box section ; designed to AASHTO’s LRFD 2004 specifications was fabricated and tested. The section has an 8 in. thick top slab and a 7 ; in. thick bottom slab and represented the entire negative moment region of a full-size, continuous bridge. ; The specimen was tested to evaluate fatigue, service and ultimate provisions of the AASHTO code. Instrumentation was ; provided to monitor load, strain, slip deflection and crack widths at critical locations. Results showed that after 5.6 million ; cycles of fatigue loading there was a 17% loss in stiffness but no slip. The service tests showed that 1% reinforcement for ; the top slab is adequate. The specimen failed due to crushing of the bottom slab caused by buckling of the thin (3/8 in.) ; bottom flange in the final service test. Finite element analysis was used to simulate the failure and showed that the bottom ; flange buckles at relatively low loads, but due to composite action with concrete at shear stud locations, it can still ; effectively carry additional compressive load until the bottom flange yields due to plastic buckling. Subsequently the ; concrete bottom slab carries all additional load until it crushes. ; Supplementary provisions are proposed for designing double composite members. These limit the maximum compressive ; stress in the bottom slab to 0.6f'c and set a requirement for the location of the neutral axis to ensure ductility. Due to the ; strain limit on the concrete bottom slab, it may not be possible to achieve net section plastic capacity. An illustrative ; numerical application of these rules is included as a MATHCAD file.
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• Format:
  PDF
• Funding:
  BD544-18
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/17626/dot_17626_DS1.pdf
• File Type:
  [PDF - 16.12 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:ed732b1942e75b3ad46871dd5254cfb23ac9be415c17472dbd13e86bc4a1764c