Synthesis of Information Related to Highway Problems. Topic 39-01. Adjacent Precast Box Beam Bridges: Connection Details

<strong><p align="left"> </p><p class="MsoNormal" style="MARGIN: 0in 0in 0pt; LINE-HEIGHT: 150%" align="left"><span style="COLOR: black"><font size="3"><font face="Times New Roman">Bridges built with adjacent precast, prestressed concrete box beams are a popular and economical solution in many states because they can be constructed rapidly, and deck forming is eliminated. There is a new thrust to use these bridges for rapid construction under the Highways for LIFE program. According to recent National Bridge Inventory data, adjacent concrete box beams constitute about 17 percent of bridges built annually on public roads. </font></font></span><span style="COLOR: black"><font size="3"><font face="Times New Roman">The box beams are generally connected by grout placed in a key between each of the units, and usually with transverse ties. Partial depth or full depth keys are typically used, incorporating grouts using various mixes. Transverse ties, grouted or un-grouted, vary from a limited number of threaded rods with finger tight nuts to several high strength tendons post-tensioned in multiple stages.<span style="mso-spacerun: yes">  </span>In some cases, no topping is applied to the structure while in other cases a non-composite topping or a composite structural slab is added. </font></font></span><span style="COLOR: black"><font size="3"><font face="Times New Roman">Bridges constructed using box beams have been in service for many years and have generally performed well. However, a recurring problem is cracking in the grouted joints between adjacent units, resulting in reflective cracks forming in the wearing surface. In most cases, the cracking leads to leakage which allows chloride laden water to saturate the sides and bottom of the beams, eventually causing corrosion of the non-prestressed and prestressed reinforcement. In severe cases, the joints crack completely and load transfer is lost. There is no design method for shear keys in the AASHTO Standard Specifications for <st1:place w:st="on"><st1:placename w:st="on">Highway</st1:placename> <st1:placetype w:st="on">Bridges</st1:placetype></st1:place> or the AASHTO LRFD Bridge Design Specifications. Most shear key details in use are regional standard details of uncertain origin, and there is no information on the magnitude of forces induced in the shear keys and the ability of a given detail to resist these forces. </font></font></span><span style="COLOR: black"><font size="3"><font face="Times New Roman">This synthesis study will document the different types of grout key configurations, grouts, and transverse tie systems that are currently being used in the <st1:country-region w:st="on">U.S.</st1:country-region> and <st1:country-region w:st="on"><st1:place w:st="on">Canada</st1:place></st1:country-region>, and how each type has performed. </font></font></span></p></strong>


  • English


  • Status: Completed
  • Contract Numbers:

    Project 20-05, Topic

  • 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:

    Williams, Jon

  • Performing Organizations:

    Henry G. Russell, Incorporated

  • Principal Investigators:

    Russell, Henry

  • Start Date: 20071101
  • Expected Completion Date: 0
  • Actual Completion Date: 20090115
  • Source Data: RiP Project 16912

Subject/Index Terms

Filing Info

  • Accession Number: 01543766
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 20-05, Topic
  • Files: TRB, RiP
  • Created Date: Nov 21 2014 1:04AM