On distress in pipe-arches

Abstract

Cracking of bolt holes is a very common form of distress in pipe-arch type of soil–steel structures, the conduit walls of which are subjected to very large radial soil pressures in their lower haunches. This paper, in discussing the mechanics of this form of distress, concludes that the cracks are formed mainly due to the inability of the soil in the haunch areas to sustain the very high pressures. It also contains methods to alleviate these problems, both at the design and at the construction stage. Guidelines for proper bolt arrangements are given, and use of low-strength concrete around and under the haunches is recommended. Pouring of concrete in segments is suggested to avoid potential flotation of the pipe during construction. A case history incorporating this measure is given to demonstrate its feasibility. Key words: soil–steel structure, pipe-arch, culvert, highway bridges, bolt-hole tears.