Doha, the capital of Qatar, has been facing phenomenal growth of vehicular traffic owing to rapid development which has resulted in traffic congestion causing significant rise in travelling time in some areas. To mitigate these problems, upgrading existing intersections and consequently retrofitting the contained structures along significant corridors is a strategy implemented by the Public Works Authority in some cases. A case study presented herewith, is a project awarded as a Design & Build Contract by the PWA to upgrade the infrastructure at the junction of a major corridor (Junction 101 - Industrial Interchange). This paper covers the tender stage and the final design solutions, outlining the simulation models, assessment of the existing structures, the design analysis and the construction methodology adopted to address the operation and maintenance conditions as well as the project specific requirements and constraints.