1925 (#1403-1607) - Laserfiche WebLink

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The te~t~n~ machine shall be substantial and rigid throngho~t, so that the distribution of the load will not be affected by the deformation or yielding of any p~rt. The bearings and the specimen shall be accurately centered so as to socure a symmetrJ= cai distribution of the loading on each side of the center of the pipe in every direction. The pipe to be tested shall be carefully bedded above and below in sand, for one-fourth (]~) of the circumference of the pipe measured o~ the middle line of the shell. The det~h of heddip~ above and below the pipe at the thinnest points shall he one-half (~) the radius of ~e middle llne of the shell. The sand used shall be clean, and shall be such as will pass a one-fourth (~) inch The top beating frame shall not be allowed to come in contact with the pipe nor with the top bearing plate. The upper surface of the sand in the top bearing shall be struck level with a straight edge, and shall be covered with a rigid top bearing plate, the Iongth of which plate shall be the total len~h of the pipe, and the width of which plate shall be not less than one-half inch less than the inside width of the top bearing frame* The lower surface of the top bearing plate shall be a true plane, made of heavy' timbers or other rigid nmterlal, capable of distributing the test load oniformly without bonding. The teat load shall be applied at thc exact center of this top bearing plate, in such a manner as to permit free motinn of the plate in all directions. For this purpose a spherical bearing is preferred, but two rollers at right angles may be used. The test may be made without the use of a testing machine, by piling weights directly on a platform resting on the to~ bearing plate provided, however, that the weights shall be piled symmetrically al)out a vertical llne through the center of the pipe, and that the platform shall not be allowed to touch the top bearing frame. The frames of the top and bottom bearings shall be made of timbers so heavy as to avoid betiding 5y the side pressure of the sand. The interior surfaces of the frames shall be dressed. No frame shall come in contact with the pipe during the test. A strip of cloth may be at~ched to the inside of the upper frame on each side, along the lower edge, to prevent the upper frame on each side, along the lower edge, to prevent the escape of sand bet'~reen the ~rame and the pipe. The inad shall be applied to each specimen until the amount specified in the following table, for the minimum crushing strength, has been reached. No additional pressure is required but may be applied for record purposes. The various sizes of pipe shall withstand the following pressures: Minimum (~rushing Strength 8ise (pomul~ per ~ foot). 6" 14~0 14~0 ~0" 1710 I$'* 21' 24" The net inside length of the pipe from the bottom of the socket to the spigot end of the pipe is to he used as the divisor in obtaining the aomunt of the crushing strength per linear foot, (2) X~¥DROSTATIC PRESSUF~ TF~ST. Sound full size pipe in each size shall be tested for leakage under internal hydrostatic pressure. When subjected to an internal hydrostatic pressure of ten (10) pounds per square ~ch during a period of five (5) minutes, the exterior surface of the p~pe shall not show