Strength rehabilitation of a pipeline system at the critical point by mechanical preloading

Computer modelling and numerical FEM analysis of buried preloaded (prestressed) piping of a compressor station is shortly discussed in the present paper. The aim of the preloading is to reduce the stress intensity at the critical point of the piping. The necessary preloading force was computed as a non-linear function of the effects of bearing and friction at the pipe/soil interface. The real magnitude of the force and the unloading bending moment were tensometrically measured during preloading. Paper also presents brief descriptions of the proposed preloading procedure to be applied as well as the tensometric checks of the preloading force and the necessary relieving bending moment. The comparison of the FEM results and the evaluation of measurement readings confirmed the efficiency of preloading under service conditions.