This document is the 101E Trench Installation Alternate (HP Storm) Detail. Pipe detail, charts and notes provide descriptions and measurements.

The detail shows the maximum cover, final backfill, select native clean 6” above top of pipe, springline, Class I material to springline of pipe, bedding, suitable foundation and minimum trench width.

Table 1 is the recommended minimum trench width with pipe diameter sizes and minimum trench width measurements.

Table 3 clarifies the maximum cover for ADS HP storm pipe for each pipe diameter and Class I, Class II, Class III & Class IV values.

Note 1 states that measures should be taken to prevent migration of native fines into backfill material. Note 2 says soil classification are per ASTM D2321. Note 3 explains that the foundation is based on where the trench bottom is unstable. Per the engineer, the trench bottom may be stabilized using a geotextile material. Note 4 is about bedding and suitable material, minimum bedding thickness shall be 4” for 4”-24” or 6” for 30”-60”. Note 5 clarifies that for pipes outside of pavement, Class I material to be used for backfill up to the springline of the pipe. Note 6 states that minimum cover for non-traffic applications is 12” from the top of pipe to ground surface. Additional cover may be required to prevent flotation. Note 7 suggests to use clean backfill that is placed moderately compacted with no foreign debris. Note 8 states that HP Storm alternate trench detail only applies to backfill installations in non-traffic applications.