PVC drainage connection approval memo, Apr 1985

NYC 9/11 Public Portal Document

lit: IlSy HANDBOOK OP PVC PIPE

Under most soil conditions, flexible PVC pipe tends to deflyi I II an elliptical shape and the horizontal and vertical deflections m-'. considered equal for small deflections (A). Since most PVC pipe'-'' scribed by either pipe stiffness (F/AY) or outside diameter to thief. ratio (DR), the Iowa Equation (24) can be transposed and rewritt-' follows: EQUATION 25 - EQUATION 26 ■ A D, KP{100) . - .7 < .△C y - . 3 D.KPdOO) : yi-_ ------ ------------------—___ . qz Jz. — _ _______ D 0.149 + 0.061 E' D ~ {2E/3 (DR -1)»1 + 2 ■ AY ' ... . o.O6ie Where: P = Prism Load (Soil Pressure), psi I The above equations maybe used in-conjunction with the vainest' the empirical constants E', and K. The following example illustu- their use„,^r - f- c .* ' ■ Exampier Whatris the deflection of S DR 18 PVC’ pipe if buried u? flaCbottom trench in a fine grained soil'with unit- weight of 120 lbs pertL and with liquid limit less than 50%jf the depth of burial is 10 feet? ’ Front Table 26, E' = 200 psi and incorporating a bedding constur; K = OJ; and the prism ■load.as assumed in the derivation of Table 27 alo-f with' a deflection la-g factor of D^ — 1.5 , the following results are derived I :.-AY? ; D/KP-dOO) P = wH^ . . ..... 7 ■ ■ ;■■■,.......- 7-

* : J2EZ3(DR-1)3L + O.a6ie V I: P - 120 ^3 X 10 ft X ,C'7' = 8.33 psi

; 2E 2(400,000) - . . 3{PR ~1)3 “ 3(18-1)3 “ 5^-28 ps. r. ■i V A - 1.5(0.1)(8.33)(100) . D 54.28 + 0.061(200) 1-9 percent

For the general case, Jive loads should be added to the earth load to determine the total load at the depth-being .considered, - , -' In Table 27, results of calculations oTdeflections of buried AWWA C900-DR~14, 18, and 25 PVC pipe are presented for cases’where either highway or railway loads are present, - 7 ; / '; , 144

I

■ NYC-WTC_OOO1 65054