00216760

Component

http://onlinepubs.trb.org...rbbulletin/102/102-001.pdf

THE THREE-EDGE BEARING TEST IS THE STANDARD TEST IN GENERAL USE FOR CONCRETE PIPE OF ALL SIZES TO DETERMINE THE LOAD TO PRODUCE A 0.01-INCH-CRACK AND THE LOAD TO PRODUCE ULTIMATE FAILURE. RELATIVELY FEW SUCH TESTS HAVE BEEN PERFORMED ON PIPE LARGER THAN 72 INCHES IN DIAMETER, PARTLY DUE TO THE LACK OF EQUIPMENT WITH CAPACITY TO HANDLE THE LARGE PIPE, AS WELL AS THE COST OF MANUFACTURING AND TESTING THE PIPE TO DESTRUCTION. TESTS ON 84-INCH REINFORCED- CONCRETE PIPE INDICATE THAT SOME TYPE OF REINFORCEMENT IS NEEDED TO PREVENT A SHEAR FAILURE IN THE LARGER SIZES OF PIPE IF THE FULL STRENGTH OF THE PIPE IS TO BE DEVELOPED. VARIOUS SYSTEMS FOR REINFORCING THE PIPES WERE USED INCLUDING STANDARD TYPES. TEST RESULTS INDICATE THAT A MAJOR FACTOR CAUSING THE DISCREPANCY BETWEEN TEST RESULTS AND EXPECTED THEORETICAL RESULTS HAS BEEN THE FAILURE TO CONSIDER SHEARING STRESSES SET UP IN WALL OF THE PIPE. FAILURE DUE TO SHEARING STRESS OCCURS BEFORE THE TENSION REINFORCEMENT HAS BEGUN TO CARRY ITS DESIGN LOAD, PARTICULARLY IN HEAVILY REINFORCED PIPE. IF SPECIAL REINFORCEMENT IS PROVIDED TO TAKE CARE OF SHEARING STRESSES, THE STRENGTH OF THE TENSION REINFORCEMENT CAN BE USED MORE EFFICIENTLY. IT IS POSSIBLE TO GRADE THE INCREASED ENCROACHING STRENGTH OF LARGE DIAMETER PIPE WITHOUT AN INCREASE IN THE WALL THICKNESS. IT IS CONCLUDED THAT BETTER METHODS OF SHEAR REINFORCEMENT SHOULD BE DEVELOPED.

No 102, pp 1-11, 9 FIG, 2 TAB, 7 PHOT, 6 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.

01410506

11p

1955

Highway Research Board Bulletin

Digital/other

Bearing capacity; Bearing tests; Diameter; Failure; Material reinforcement; Reinforced concrete pipe; Shear stress

Geotechnology; Highways; Materials

TRIS, TRB

Apr 21 1994 12:00AM

• DEFLECTIONS OF TIMBER-STRUTTED CORRUGATED-METAL-PIPE CULVERTS UNDER EARTH FILLS