Abstract:
Rapid development in urban areas raises the demands for higher capacity, more efficient and safer transportation systems while increasingly emphasizing limited environmental impact. Many present geometric and operational characteristics of the transportation facilities constructed decades ago cannot meet the current or anticipated future needs. The challenges facing the designers are to improve functionality of transportation system and preserve environment especially when it is located in a city with interchange configuration. This paper presents the actual geometric solutions of a practical project involving multiple tasks and substantial constraints in an environmentally sensitive area. With defined and desired project scopes, geometric designs of this project are optimized to provide best solutions while having minimal environmental impact. It shows how three dimensional configuration and detailed geometric designs are applied using design flexibility to fit in an urban area surrounded by business, schools, churches, and residential houses. It covers hook ramps geometry, the profile design of the overcrossing bridge, highway widening and realigning, spiral pedestrian bridge design and special superelevation handling for lane reduction in a area with substantial elevation differences and restriction. Sight distances, design speeds, environment impact, safety, drainage and driving performance are factors considered in the design. This paper recommends that for a given area impacted by the project, comprehensive optimization and innovative exploration in designs shall be on the checklist of project delivery to achieve the quality and maximum functional benefit especially in an urban city with interchange configuration.
