I-465/I-65 South Interchange Modification
American Structurepoint provided project management and design services for reconstruction of one of the busiest interchanges in the state, I-465 and I-65 on the south side of Indianapolis. We also prepared an engineering assessment report, interchange justification study, conducted traffic management planning, and provided road design, bridge design, utility coordination, land acquisition services, cost estimation, and contract document preparation services. Traffic engineering as well as engineering assessment and design services were part of this project, which included value engineering for the proposed interchange modifications, performing necessary traffic operations analysis for the mainline freeway, ramp merge and diverges and weaving segments using HCS, preparing an interchange justification study and design of the interchange along with a new flyover ramp approximately 1,456 -foot long on a 784 -oot horizontal curve designed to carry 2 lanes of traffic.
A VISSIM simulation model was also prepared for the entire corridor including the complex interchange to evaluate the traffic capacities for all the movements and to visualize the operations for peak traffic conditions during the design year forecast.
Several superstructure types were investigated for the new flyover ramp bridge and ultimately alternate bid plans were developed for concrete and steel girder options. Additionally, a detailed economic analysis was explored using horizontally curved steel girders versus straight steel girders that were kinked at splice locations. The results indicated that although additional piers were necessary, there was substantial savings by not curving the girders and maintaining a shorter superstructure depth to lower the approach roadway profile. For the concrete beam alternate, a prestressed concrete, Indiana Bulb-T beam was chosen. Because of the complexities within the interchange, including several existing roadways to remain in service during construction, a large sewer line to remain, and numerous proposed roadway elements, placement and construction of substructure units was very limited. Temporary shoring and a detailed construction sequence, including maintenance of traffic, was developed to ensure the bridge could be built safely and effectively.