USE OF BACKWATER IN DESIGNING BRIDGE WATERWAYS
HOW IS THE LENGTH OF A BRIDGE OVER A STREAM DETERMINED? THIS QUESTION HAS MANY ANSWERS SINCE BRIDGE ENGINEERS, RESPONSIBLE FOR SUCH DECISIONS, HAVE HAD TO RELY PRINCIPALLY ON PERSONAL OBSERVATION AND EXPERIENCE FOR THE ANSWERS. IN SHORT, NO GENERALLY ACCEPTED METHOD FOR BRIDGE WATERWAY DESIGN HAS EXISTED. A COMPARISON OF THE SMALL NUMBER OF BRIDGE FAILURES TO THE TOTAL NUMBER OF BRIDGES THROUGHOUT THE COUNTRY ATTEST TO THE COMMENDABLE JOB BRIDGE DESIGNERS HAVE PERFORMED WITH THE LIMITED DESIGN TOOLS AVAILABLE. THEIR RECORD IS MOST CERTAINLY IMPRESSIVE. WHAT PROPORTION OF EXISTING BRIDGES ARE UNDER-DESIGNED AND WHAT PROPORTION ARE OVER-DESIGNED FROM THE STANDPOINT OF LENGTH AND CLEARANCE? WITH MANY NEW BRIDGES SCHEDULED TO BE CONSTRUCTED UNDER THE ACCELERATED HIGHWAY PROGRAM, THE ABOVE QUESTION DESERVES SERIOUS THOUGHT FROM THE STANDPOINT OF SAFETY AND ECONOMY. UNDER-DESIGNED BRIDGES USALLY SPEAK FOR THEMSELVES, GIVEN SUFFICIENT TIME. IN THE CASE OF OVER DESIGN, NO RELIABLE STANDARDS EXIST AT THE PRESENT TIME BY WHICH THESE STRUCTURES CAN BE JUDGED IMPARTIALLY. /AUTHOR/
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Supplemental Notes:
- No 242, pp 57-68 5 FIG, 2 TAB, 4 REF Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
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Authors:
- Bradley, Joseph N
- Publication Date: 1960
Media Info
- Media Type: Digital/other
- Pagination: 12p
- Monograph Title: Bridges: bearing pads, foundations, scour and waterways
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Serial:
- Highway Research Board Bulletin
- Issue Number: 242
- Publisher: Highway Research Board
Subject/Index Terms
- TRT Terms: Bridge design; Bridge waterways; Bridges; Clearances (Navigation); Economics; Failure; Knowledge; Methodology; Safety; Structural design
- Uncontrolled Terms: Experience; Observation
- Old TRIS Terms: Bridge clearance
- Subject Areas: Bridges and other structures; Economics; Highways; Safety and Human Factors;
Filing Info
- Accession Number: 00208823
- Record Type: Publication
- Files: TRIS, TRB
- Created Date: Sep 16 1994 12:00AM