Details:

Creators:
Saber, Aziz ; Mothukuri, Ajay K. ; Arasangi, Prashant
Saber, Aziz ; Mothukuri, Ajay K. ; Arasangi, Prashant Less -
Corporate Creators:
Louisiana Transportation Research Center
Corporate Contributors:
Louisiana. Dept. of Transportation and Development
Subject/TRT Terms:
[+]
Continuous Bridges. Continuous Girder Bridges Diaphragms (Engineering) Diaphragms (Structural Engineering)--Testing Prestressed Concrete Bridges Prestressed Concrete Bridges--Testing Testing
Publication/ Report Number:
FHWA/LA.09/440
Resource Type:
Tech Report
Geographical Coverage:
Louisiana
Edition:
Final report; April 2006-March 2008.
Corporate Publisher:
Louisiana Transportation Research Center
Abstract:
The research presented herein describes the field verification for the effectiveness of continuity diaphragms for

skewed continuous precast, prestressed, concrete girder bridges. The objectives of this research are (1) to perform

field load testing on the Burlington Northern Santa Fe (BNSF) overpass and compare measured strains with those

determined through the theoretical analyses and (2) to study the effects of continuity diaphragms on stresses and

deflections from truck loading on bridge deck slab and bridge girders.

The current design concept of continuity diaphragms was examined to determine the effectiveness of the

diaphragms in skewed bridges. The bridge parameters that were considered include skew angle, length of the

span, beam spacing, the ratio of beam spacing to span (aspect ratio), and the ratio of girder stiffness to that of the

slab. A prestressed concrete bridge with continuity diaphragms and a skewed angle of 48° was selected by a team

of engineers from the Louisiana Department of Transportation and Development (LADOTD), the Louisiana

Transportation Research Center (LTRC), the Federal Highway Agency (FHWA).

The BNSF Overpass Bridge is located on US-90 in Jennings, Louisiana. The field verification was performed

using a comprehensive instrumentation plan and live load tests as described in this report. The field and

theoretical results from this study provided a fundamental understanding of the load transfer mechanism through

these diaphragms of skewed, continuous span bridges. The findings in this study on stresses, strains, and

deflections in the bridge deck and girders indicated that the effects of the continuity diaphragms on skewed

continuous span precast prestressed concrete girder bridges were negligible. The results presented in this report

also confirmed the theoretical findings published in LTRC Report 383 titled “Continuity Diaphragm for Skewed

Continuous Span Precast Prestressed Concrete Girder Bridges.” Continuity diaphragms used in prestressed

concrete girder bridges on skewed bents provided additional redundancy in the bridge but caused difficulties in

detailing and construction. As the skew angle increases or the girder spacing decreases, the construction becomes

more difficult and the effectiveness of the diaphragms becomes questionable. It is also recommended that the use

of continuity diaphragms be evaluated based on the need for the enhanced structural redundancy, the reduced

expansion joint installation and maintenance costs, and the associated construction difficulties and costs. The

outcome of this research will reduce the construction and maintenance costs of bridges throughout Louisiana and

the United States.


Format:
PDF
Funding:
LTRC Project No. 06-3ST ; State Project No. 736-99-1373
LTRC Project No. 06-3ST ; State Project No. 736-99-1373 Less -
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:b92c6b290ba0e63a67ae2342d51a99b2656506e3dbd5987dfc707c907bccdeb1
Download URL:
https://rosap.ntl.bts.gov/view/dot/18254/dot_18254_DS1.pdf
File Type:

Supporting Files

• No Additional Files

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