Connection Details of Adjacent Precast Concrete Box Beam Bridges

Bridges constructed with adjacent precast prestressed concrete box beams have been in service for many years and provide an economical solution for short and medium span bridges. A recurring problem is cracking in the longitudinal grouted joints between adjacent beams, resulting in reflective cracks forming in the asphalt wearing surface or concrete deck. The cracking appears to be initiated by stresses caused by temperature gradients, live loads, transverse post-tensioning, or a combination. Once the cracking has occurred, chloride-laden water can penetrate the cracks and cause corrosion of the reinforcement and prestressing strand. National Cooperative Highway Research Program (NCHRP) Synthesis 39: Adjacent Precast Concrete Box Beam Bridges: Connection Details reported a wide variety of practices used by state highway agencies for the connection details between adjacent box beams. These practices include partial depth or full depth grouted keyways, keyways grouted before or after transverse post-tensioning, prepackaged or non-prepackaged grout materials, post-tensioned or non-tensioned transverse ties, a wide range of applied transverse post-tensioning forces, and cast-in-place concrete decks or no decks. A few states reported that their methods had reduced the longitudinal cracking, whereas others had not been successful using similar methods. Research to evaluate those practices at the design and construction phases can lead to connection details that prevent cracking and leakage at the joints and extend the service life of the adjacent box beam bridges. The objective of this research is to develop guidelines for the design and construction of connection details for adjacent precast concrete box beam bridges to eliminate cracking and leakage in the longitudinal joints between adjacent boxes. The research will produce proposed design and construction specifications with commentary in the format of the American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) Bridge Specifications. Accomplishment of the project objective will require at least the following tasks. PHASE I--Planning - (1). Conduct a critical review of relevant specifications, technical literature, and owner and industry experiences. The review should cover research findings from both domestic and foreign sources. (2). Propose analytical and testing programs to investigate cracking in the longitudinal grouted joints between adjacent beams. As a minimum, the following factors should be considered: (i) design methodology; (ii) effect of span length; (iii) bridge width; (iv) skew angle; (v) number and location (both vertically and horizontally) of transverse post-tensioning ties; (vi) differential camber; (vii) optimum keyway shape and configuration; (viii) keyway preparation; (ix) keyway grout type and curing methods; and (x) grouting and post-tensioning sequence for two-stage construction. The testing program should cover the design of laboratory specimens to be tested in Phase III. The design should consider the scale effect and testing configurations on the accuracy of the results. (3). Prepare Interim Report No. 1 that documents Tasks 1 and 2 and provides an updated work plan for the remainder of the project. This report is due no later than 3 months after the contract award. The updated plan must describe the process and rationale for the work proposed for Phases II through V. PHASE II--Analytical Program - (4). Execute the approved work plan for the analytical program. (5). Identify proposed areas of the AASHTO LRFD Bridge Specifications that may require modification. (6). Finalize the testing program to validate the findings of the analytical program. (7). Prepare Interim Report No. 2 that documents Tasks 4 through 6 and provides an updated work plan for the remainder of the project. This report is due no later than 9 months after approval of Phase I. The updated plan must describe the work proposed for Phases III through V. PHASE III--Testing Program and Analytical Program Validation - (8). Execute the testing program according to the approved work plan.( 9). Validate and finalize the analytical program based on test results.(10). Prepare Interim Report No. 3 that documents Tasks 8 and 9 of Phase III no later than 12 months after approval of Phase II. PHASE IV-- Proposed Modifications to AASHTO LRFD Bridge Specifications - (11). Based on the analytical and testing investigations, develop specification and commentary language for proposed changes to the AASHTO LRFD Bridge Specifications supported with examples. (12). Quantify the potential economic impact of the proposed revisions.(13). Prepare Interim Report No. 4 that documents Tasks 11 and 12 of Phase IV no later than 6 months after approval of Phase III. PHASE V--Final Products - (14). Update proposed modifications to the AASHTO LRFD Bridge Specifications after consideration of review comments and prepare ballot items for AASHTO Highway Subcommittee on Bridges and Structures consideration.(15). Prepare a final report that documents the entire research effort.

Language

  • English

Project

  • Status: Completed
  • Funding: $450000.00
  • Contract Numbers:

    Project 12-95

  • Sponsor Organizations:

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    American Association of State Highway & Transportation Officials (AASHTO)

    444 North Capitol Street, NW, Suite 225
    Washington, DC  United States  20001

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Project Managers:

    Dekelbab, Waseem

  • Performing Organizations:

    Iowa State University, Ames

    Ames, IA  United States  50011
  • Principal Investigators:

    Phares, Brent

  • Start Date: 20130805
  • Expected Completion Date: 0
  • Actual Completion Date: 20161104
  • Source Data: RiP Project 38350

Subject/Index Terms

Filing Info

  • Accession Number: 01547694
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 12-95
  • Files: TRB, RiP
  • Created Date: Dec 13 2014 1:01AM