Load distribution and fatigue cost estimates of heavy truck loads on Louisiana state bridges.

Details

• Creators:
  Saber, Aziz
• Corporate Creators:
  Louisiana Tech University. Dept. of Civil Engineering
• Corporate Contributors:
  United States. Federal Highway Administration
• Subject/TRT Terms:
  • Overweight loads
  • Fatigue (Mechanics)
  • Bridge superstructures
  • Finite element method
  • Costs
  • Traffic distribution
  • Concrete bridges
  • Live loads
  • Weigh in motion
  • Gross vehicle weight
• Publication/ Report Number:
  FHWA/LA.13/509 ; LTRC Project Number: 10-1ST ; State Project Number: 736-99-1662
• Resource Type:
  Tech Report
• Geographical Coverage:
  Louisiana
• Corporate Publisher:
  Louisiana. Dept. of Transportation and Development ; Louisiana Transportation Research Center
• Abstract:
  The bridge in this study was evaluated and a monitoring system was installed to investigate the effects of heavy loads and ; the cost of fatigue for bridges on state highways in Louisiana. Also, this study is used to respond to Louisiana Senate ; Concurrent Resolution 35 (SCR-35). The superstructure of the bridge in this study was evaluated for safety and reliability ; under four different kinds of truck configuration and loads hauling sugarcane. The bridge model was verified by performing ; live load tests using 3S3 trucks with a gross vehicular weight (GVW) of 100,000 lb. on the structure. The bridge finite ; element model was analyzed under the different kinds of loading and the effects were listed and compared. The results of ; the analyses show that the pattern of response of the bridge under the different cases follows the same trend. Among the ; four different cases of loading configurations, case 4, which was GVW =148,000 lb. and a vehicle length of 92 ft., produced ; the largest tensile and compressive stresses in the members. The results from the bridge deck analyses confirm that the ; bridge deck is under a stable stress state, whether the stresses are in the tension zone or the compression zone. The heavy ; load as indicated in SCR-35 will cause damage to bridges. ; The data from the monitoring system indicates that the average number of heavy loads during October, November, and ; December is 3.5 times higher than the rest of the year. The bridges are exposed to high cycles of repetition of heavy loads ; that will reduce the life span of the bridges by about 50%. The bridges that are built to last 75 years will be replaced after ; about 40 years in service. This seasonal impact is due to the sugarcane harvest and confirms the cost of fatigue, $0.9 per ; truck per trip per bridge, as determined in the previous study. ; Based on the results of the studies presented in this report, increasing the gross vehicle weight of sugarcane trucks is not ; recommended. The heavy loads indicated in SCR-35 will cause premature fatigue damage to the main structural members ; and could cause their eventual structural failure. In addition, the majority of the Louisiana bridges currently in service were ; designed to accommodate lower loads than the bridge tested on this project. Therefore, based on the test results, one should ; expect that the proposed trucks to significantly shorten the remaining life span of Louisiana bridges. All these bridges ; should be rehabilitated prior to implementing SCR 35. The data from the monitoring system will provide a good source of ; information to review the current serviceability criteria used by the Louisiana Department of Transportation and ; Development (LADOTD) for the design of prestressed concrete bridge girders.
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• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/27124/dot_27124_DS1.pdf
• File Type:
  [PDF - 5.15 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:72207dab2eac8ef75d4263bd0a487406b3e7f12cde7d265454d7de6513be8891