Development, field testing, and implementation of improved bridge parapet designs.

Details

• Creators:
  Kalabon, Amy ; Hedges, Lauren ; Delatte, Norbert
• Corporate Creators:
  Cleveland State University. Dept. of Civil and Environmental Engineering
• Corporate Contributors:
  United States. Federal Highway Administration
• Subject/TRT Terms:
  • Parapets
  • Bridge design
  • Cracking
  • Fiber reinforced concrete
  • Field tests
  • Cutting
  • Joints (Engineering)
  • Bridge construction
• Publication/ Report Number:
  FHWA/OH-2015/5
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Corporate Publisher:
  Ohio. Dept. of Transportation. Office of Statewide Planning and Research
• Abstract:
  A total of 22 test parapets was constructed as part of this project to evaluate different approaches to address ; premature cracking. The experiments included the use of deeper saw cuts through glass fiber reinforced polymer ; (GFRP) reinforcement or field cut steel reinforcement, with the saw cut depth increased from 1 ½ inches (38 mm) ; to 3 ½ inches (89 mm). Another experimental modification was the use of polypropylene fibers in the mixture at ; two different dosage rates, 1 lb/yd3 (0.59 kg/m3) and 2 lb/yd3 (1.19 kg/m3). The research team monitored bridge ; parapets during and immediately after construction. This included instrumentation with embedded maturity ; sensors to capture temperature history of the parapets, using Command Center technology. Researchers also ; observed and documented parapet construction. It was important to note any constructability issues that may ; arise that may be related to the proposed solutions, since they would potentially impact the cost of ; implementation. Crack surveys were performed once formwork was removed and sawcutting had been ; completed. The stiffness gain of parapets and joint cracking were monitored using ultrasonic pulse velocity (UPV) ; technology. While all of the eight control bridges showed mid-panel cracking, only four of the twelve experimental ; bridges had mid-panel cracking. Both parapets with Vandal Protection Fence (VPF) posts showed cracks near the ; posts. The main purpose of using GFRP or field cut steel reinforcement with the 3.5 inch (89 mm) deep saw cut is ; to create a weakened plane at the control joint through the gap provided in the reinforcement, in order initiate ; cracking at the joints and reduce the risk of cracking elsewhere on the parapet. From the data gathered, this ; modification allowed more joints to crack at early stages, and prevented uncontrolled cracking. The parapets with ; fibers showed no measurable improvement over the parapets without fibers in regards to preventing shrinkage ; and temperature cracking. Reducing the joint spacing over negative tension areas was found to reduce ; uncontrolled bridge parapet cracking. However, since the experimental parapets with the reduced joint spacing ; were coupled with another modification of either the polypropylene fibers or the deeper saw cut, it was hard to ; determine if this alone would solve uncontrolled bridge parapet cracking.
  More +
• Format:
  PDF
• Funding:
  SJN 134818
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/28692/dot_28692_DS1.pdf
• File Type:
  [PDF - 3.29 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:03b811098f1a218eb1bcb43901a388622783ea1f3bb563fbd616aa6c5a886591