A comparative study of the response of buried pipes under static and moving loads

The buried pipes should be designed properly to withstand the loads imposed by the backfill soil weight and traffic loads. However, a thorough literature review has shown differing opinions on the effect of static and moving traffic loads on buried pipes. Some studies have shown that moving loads produce higher displacement in buried pipes compared to static loads, while other studies have shown contradicting results. These differing opinions have created confusion among researchers who are studying the response of buried pipes under traffic loads, where most of the studies have been conducted using either static or moving loads without proper justification to the selection of the loading type. To clarify this confusion, this paper presents a rigorous study on the behaviour of buried pipes under static and moving traffic loads using a robust finite element analysis. The static and dynamic finite element models have been developed and validated using high-quality field data collected from the literature. The developed models were then used to investigate the effect of the truck speed, pipe stiffness and loading conditions on the maximum displacement of buried pipes. The results showed that the displacement of buried pipes due to static loads is always higher than the pipe displacement due to moving loads. In addition, it was found that the ratio of the static to dynamic pipe displacement decreases as the pipe stiffness increases and increases to a lesser extent as the truck speed increases. Hence, future studies should consider the static loads in designs as these are the most stringent loading condition. This is actually very helpful for designers if they are using numerical methods in their designs, because static analyses are much more straightforward to conduct and less computationally demanding compared to dynamic analyses.