ABSTRACT
Driven by Qatar National Vision 2030 and catering to the 2022 FIFA World Cup, Qatar is undertaking an extraordinary and ambitious programme of infrastructure development to deliver a world-class new and upgraded road infrastructure network. Projects designed to improve highway capacity, connectivity, and safety through the urban and rural parts of Qatar and to meet current and future demands of population and economic growth. Underground highway structures form a major part in this modern and integrated road network posing a number of planning and design challenges due to the combination of complex ground conditions, high water table and the need for fast-track construction in congested urban areas with a dense network of existing utilities. In this paper, the authors discuss some of the most critical and challenging considerations in putting a planning and design process on a path to successfully deliver the projects, shifting occasionally from the traditional contracting method to a more collaborative approach. Case studies are presented with an insight in the modelling, numerical analysis, seismic design, temporary and final supports, waterproofing and value engineering. An array of structures are presented consisting of a road underpass built by top-down method to account for traffic constraints, a pedestrian underpass implementing a box-jacking method to ensure undisturbed traffic through soil/hard rock and high water table, and a Cut & Cover tunnel designed in an area of an existing junction including impact assessments of existing utilities and bridge foundations and an evaluation of its seismic performance applying the recommendation of U.S. Department of Transportation FHWA-NHI-10-034 Technical Manual for Design and Construction of Road Tunnels – Civil Elements.
