Abstract:
A TENTATIVE METHOD WAS SUGGESTED FOR RATING CULVERT PIPES. THE RATING EQUATION SUGGESTED IS BASED ON THE DEPRECIATION AND DETERIORATION OF THE BARREL DUE TO THE PRINCIPAL DESTRUCTIVE FORCES AND MODIFIED BY THE EXTERNAL CONDITION OF INSTALLATION. IT SEEMS THE RATING SCHEME SHOULD BE DESIGNED SO AS TO TAKE INTO CONSIDERATION RATINGS TAKEN FROM ALL DESTRUCTIVE FORCES. CULVERT PIPE EXPERIMENTS ARE UNDERWAY TO OBTAIN ACTUAL PRESSURES ON THESE PIPES. REALIZING THAT IN ACCORDANCE WITH THE THEORY ON CULVERT PIPES, PRESSURES ARE FUNCTIONS OF THE RELATIVE DEFLECTION OF PIPE AND EARTH ALONGSIDE THE LEVEL OF TOP OF PIPE, PROVISIONS FOR ASCERTAINING THE PRESSURE ON PIPES AT VARIOUS FLEXIBILITIES WERE MADE. SIX DIFFERENT KINDS OF PIPE OF VARYING FLEXIBILITY EACH HAVING A DIAMETER OF 30 INCHES AND A LENGTH OF TWO FEET SIX INCHES WERE USED. THE DATA HAVE SHOWN THAT THE RELATIVE DEFLECTIONS MUST BE TAKEN INTO CONSIDERATION WHEN ATTEMPTING TO ESTIMATE OR COMPUTE THE CULVERT PIPE PRESSURES BY ANY THEORETICAL FORMULA. TESTS INDICATED THAT THIS IS TRUE, ALTHOUGH UNIT INTENSITIES OF PRESSURES WERE OBTAINED BY MEANS OF SOIL-PRESSURE CELLS. THE EARTH PRESSURES ON CULVERT PIPES THAT WERE DETERMINED APPLIED ONLY TO BODIES COMPARABLE TO SOLID CYLINDRICAL BODIES PRACTICALLY FREE FROM DEFORMATION OR DEFLECTION. NO THEORETICAL EARTH PRESSURE FORMULA FOR DETERMINING RELIABLE PRESSURES ON CULVERT PIPE CAN BE SET UP WITHOUT INCLUDING A FACTOR WHICH WOULD VARY WITH THE FLEXIBILITY OF THE PIPE.
Supplemental Notes:
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