A practical case study on assessment and rehabilitation of a pipe rack

Abstract

A pipe rack was subjected to deterioration being the result of many years of use. The structure required assessment of damages and rehabilitation. During evaluation of the pipe rack structure several factors had to be taken into consideration, such as lack of technical documentation, increased loading, and changing design code requirements. A site inspection allowed for identification of numerous damages and their origin. It was concluded that an inadequate coating of paint, an aggressive environment, and leakage from installations in the pipe rack resulted in advanced corrosion, especially at the connection zones. Increased loading without adequate strengthening of the steel truss led to deformation of some structural members. The rehabilitation was supposed to bring the pipe rack back to a suitable condition for service, although it was required to limit the intervention to the structure and maintain the heating pipelines under service. Since the structure was originally designed according to the Polish design code from the 1960’s using the permissible stress method and nowadays it should fulfil requirements of the Eurocodes, the state of the pipe rack was assessed based on static strength analyses performed for both codes. The results of calculations are shown, compared, and analyzed. The selected solution for strengthening in the form of steel profiles welded to the most stressed members of the existing structure are presented.