Evaluation of Continuity Detail for Precast Prestressed Girders

[mahyarov]

Evaluation of Continuity Detail for Precast Prestressed Girders

Author: Okeil, Ayman M Louisiana State University, Baton Rouge Cai, Steve Chebole, Veeravenkata Hossain, Tanvir | Size: 7.10 MB | Format: PDF | Quality: Original preprint | Publisher: Louisiana State University, Baton Rouge | Year: 2011 | pages: 206

The construction of highway bridges using precast prestressed concrete (PSC) girders is considered one of the most economical construction alternatives because of the advantages they offer (e.g. reducing formwork and rapid construction). Constructing multi-simple span bridges is an easy alternative for precast PSC girder bridges. However, the existence of expansion joints often leads to a host of problems in their vicinity due to drainage leaks and debris accumulation. The maintenance of expansion joints is, therefore, an activity that bridge owners would rather avoid by eliminating these joints by building connections between precast elements that are capable of resisting the forces resulting from establishing continuity. Several continuity details have been used over the years for slab-on-girder bridges with the goal of avoiding the aforementioned maintenance issues and reaping the benefits of continuity without the drawbacks of introducing it in large structures such as bridges (e.g. thermal movements). A new continuity detail is adopted in the John James Audubon Bridge that differs from the current standard detail in Louisiana. The new detail is based on the recommendation of the National Cooperative Highway Research Program (NCHRP) Report 519 [1]. A 96-channel monitoring system was installed to provide information that can be used to assess the performance of the continuity detail. Embedded and surface-mounted sensors of different types were installed to measure strains, temperatures, rotations, and gap openings in critical locations in the monitored segment. Data from about 24 months of monitoring was collected. The data, its processing, and interpretation are presented in this report. Analyses based on NCHRP Report 519 model and finite element models were also conducted to further understand the behavior of the new detail. Results from the analyses were also used to recommend girder age at continuity to meet prespecified design criteria. A live load test was also conducted to assess the performance of the new detail. Recommendations based on the findings of the project are drawn. It can be said that the continuity detail is capable of transferring forces between girder ends. However, girder ends may be subjected to high localized strains, especially due to thermal variation, which can cause cracking. Such cracks are detrimental to the shear strength of PSC girders. Therefore, thermal gradients need to be considered in the design of this detail.

Code:

***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:

http://forum.civilea.com/thread-27464.html
***************************************

This post has been made by CivilEA Post-Generator ver 2.1.6