Surface Impact Loads for Buried pipeline

1. Maximum impact load The impact loads described in this section are those resulting from large weights falling from significant heights. In this case, the use of an impact factor F , as applied in Section 4, is not sufficient to estimate the effect of the impact load on the buried pipe. The surface impact load due to the weight W of a fallen object 2.Penetration and PPV For impact near the pipe location, the increased pressure transmitted to the pipe can be evaluated as described in Section 4 where Pmax is the applied surface load. This evaluation considers the ovality, through-wall bending, side wall crushing, and ring buckling. In addition, the burial depth should be sufficient to guard against ground penetration by falling objects. Example problem see the link http://www.4shared.com/document/pfUVB8pb/Example_problem_for_Maximum_Im.html

Vertical Earth Load for buried pipeline

Applied Load Vertical earth load is primarily a consideration for non-operating conditions of buried steel pipe when the pipeline is under no internal pressure. Under most operating conditions, the external earth pressure can be neglected since it is insignificant in comparison to the internal pipe pressure. Vertical earth load is an important consideration when designing piping casings used for rail and road crossings. For the purpose of calculating earth loads on a buried pipe, a steel pipe is considered flexible and design procedures for flexible pipes apply. For flexible pipes placed in a trench and covered with backfill, the earth dead load applied to the pipe is the weight of a prism of soil with a width equal to that of the pipe and a height equal to the depth of fill over the pipe refer : Guidelines for the design of buried steel pipe