Corrugated Polyethylene Drainage Pipe AASHTO std M252-09 (part 2)
7.4. Perforation-When perforated pipe is specified, the perforations shall conform to the requirements of Class 2 perforations are for pipe intended to be used for subsurface drainage only. The perforations shall be cleanly cut so as not to restrict the inflow of water. Where circular perforations are preferred, the drill shall not penetrate the side walls of the corrugations. Pipe connected by couplings or bands may be unperforated within 100mm of each length of pipe.
Note 3-Pipe ordered under Class 1 perforations has no requirement as to inlet area because it specifies size, number, and location of holes. alternate perforation patterns should be agreed to between the purchaser and manufacturer.
7.4.1. Class 1 Perforations-The perforations shall be approximately circular and shall have nominal diameters of not more than 5mm for 100-and 150-mm diameter pipe and not greater than 10mm for 200- and 250-mm diameter pipe. The joles shall be arranged in rows parallel to the axis of the pipe. The location of the perforations shall be in valley of the outside corrugateion and in each corrugation. The rows of perforations shall be arrange in two equal group placed symmetrically on either side of the lower unperforated segment corresponding to the flow line of the pipe. The spacing of the rows shall be uniform. The distance of the centerlines of the uppermost rows above the bottom of the invert, and the inside chord lengths of the unperforated segment illustrated in Figure 1 shall be as specified in Table 1. All measurements shall be made in accordance with measure dimensions of perforations on a straight specimen with no external forces applied. Make linear measurements with instruments accurate to 0.2mm.
Table 1-Rows of perforations, Height H of the Centerline of the Uppermost Rows Above the Invert, and Chord Length L of Unperforated Segment, for Class 1 Perforations
7.4.2. Class 2 Perforations-Circular and slotted perforations shall conform to the maximum dimensions as shown in Table 2. Perforations shall be placed in the outside valleys of the corrugations. The water inlet area shall be a minimum of 20cm²/m of pipe. All measurements shall be made in accordance measure dimensions of perforations on straight spacimen with no external forces applied. Make linear measurements with instruments accurate to 0.2mm.
Table2-Maximum Perforation Dimension
7.5. Pipe Stiffness– Type C pipe, as described in Sction 4.1.1 (read post part 1), shall have a minimum pipe stiffness (PS) of 240kPa at five percent deflection, and Type S pipe, as described in Section 4.1.2 (read post part 1), shall have a minimum pipe stiffness (PS) of 340kPa at 5% deflection when tested in accordance with a pipe specimen and test for pipe stiffness (PS) as described in ASTM D 2412, with the following exceptions.
7.6. Pipe Flattening-There shall be no evidance of wall buckling, cracking, spliting, delamination, or decrease or downward deviation in the load-deflection curve when the pipe is tested in accordance with described in ASTM D 2412 until the vertical inside diameter is reduced by 20%. The rate of loading shall be the same as in ASTM D 2412. The specimen shall fail if wall buckling, cracking, spliting, or delamination is observed with the unaided eye or if there is a decrease or downward deviation in load-deflection curve at 20% or less deflection. The load-deflection curve shall be carried beyond 20% deflection so that shape of the curve at 20% deflection can be determind.
7.7. Environmental Stress Cracking-There shall be no cracking of the pipe when tested in accordance with ASTM D 1693.
7.8. Brittleness-There shall be no cracking of the pipe wall when tested in accordance with test two samples of pipe at an impact of 45 joules between two flat parallel plates using the apparatus depicted in Figure 2.
sources : AASHTO Designation M252-09.pdf
Edited by : Andreas PT Shuanglin Pipe Indonesia
Upload by : Andreas PT Shuanglin Pipe Indonesia