Comparison SIA – ITA on contractual practices

This paper presents the result of a semester study carried out by the master students in geotechnical engineering at the ETH Zurich. The article gives an overview of the internationally most common types of contracts used in underground construction and compares the ITA contractual framework checklist to the SIA-standards. More specifically, the comparison focuses on the risk allocation between client and contractor in underground construction projects. The conclusion of the study is that although it is not possible to assign the responsibility of hazard scenarios directly to either client or contractor one can allocate the risk of the potential causes. The comparison shows that the SIA-standards fulfil the recommendations according to the ITA contractual framework checklist for underground construction. As a final step, the paper presents a theoretical application example of risk allocation according to the Swiss standards (SIA 118/198) on the tunnel section of the new cross-city rail-link in Zurich.