Contract & risk management of underground works Wagner Harald Consulting Engineer & ITA EXCO Expert Online published on 26 June, 2013. Abstract The Tunnel Designer together with his client is deciding about the future success of the project at the very early project stage. He is the manager of the tunnel construction itself, as his choice of contract model and design is a management tool in construction. While keeping this in mind, Contract & Risk Management of Underground Works deals with the choice of tunnel contract model and construction management. It summarizes the state of the art of contracting for both conventional and mechanized tunnelling. Fundamental requirements for design and construction contract of tunnels are: Evaluation/classification of ground conditions and particular project requirements Design with subdivisions in stages, following the project and construction development Framework for a range of potential applications Construction Methods suitable for standard plant, equipment and material Risk Management Plan (RMP) in context with Geotechnical Baseline Report (GBR) Flexible Contractual Models for fair remuneration.
Demand for proper designed and contracted Underground Works is continuously growing. Conventional and TBM Tunnelling is both well suited for tunnelling in difficult, complex and rapidly changing geological and geotechnical conditions. It is paramount to maximise safety and to minimise construction cost by selecting optimum driving cross section, driving methods and lining during the design and construction phases. During tunnel excavation simultaneous and joint decision by the contract partners must be realized within predetermined limits to manage flexible response to changing ground and ground behaviour conditions. Tunnelling needs trained, qualified and experienced consultants, designers and contractors, it needs qualified and experienced engineers on site, and qualified and experienced workforce. It needs a suitable design as well as a suitable contract model. This goes hand in hand with a contract system which had to be developed for being able to cope with changes in ground behaviour based on GBR and RMP together with the character and scope of the works in a fair and objective way. In recent years it became more evident, that the most important feature of a tunnel project is the contract model applied. Though internationalization and globalization are melting cultures and continents together and advanced data highways make the world a global village, all of the contract models are based and do depend on the professional tradition of the country where the project gets implemented. Information exchange happens increasingly fast to the benefit of the projects and its stakeholders. The paper attempts to highlight in the tunneling community with special emphasis on the advantages provided by the International Tunnelling and Underground Space Association and beyond national borders on the most beneficial features of tunneling contracts under ITA auspices. Regardless the technology applied, any tunnel contract of today is benefitting from most carefully performed ground investigations resulting in the Geotechnical Baseline Report together with the Risk Management Plan accepted and supported by all project stakeholders. Top |