Project Description

The I.H. 635/LBJ Freeway Corridor Study encompasses approximately 21 miles of the LBJ Freeway extending west from I.H. 35E to U.S. 80. The study was undertaken to develop proposed solutions to the ever-worsening traffic congestion in the LBJ corridor, which would provide for public mobility and safety at current and future traffic levels; respond to changing traffic conditions and patterns; and reduce impacts on the arterial street network in the community.

Scope of Services

Working on a team lead by HNTB, LACHEL & Associates, Inc. provided geotechnical services, preliminary tunnel design services, constructibility analysis and cost estimating services for a feasibility level evaluation of the proposed tunnel alternatives. The proposed tunnel alternatives included a 50-foot wide mined tunnel (3 lanes, no shoulders) and a 62-foot wide mined tunnel (3 lanes with 2-foot and 10-foot shoulders).

As part of the services provided, LFA oversaw a limited geotechnical exploration and testing program, evaluated the results of that program and developed design loading and construction sequences for the various tunnel alternatives. LFA then developed preliminary ground support and final liner designs for both the 50-foot and 62-foot wide tunnel sections. LFA also provided constructibility analyses and cost estimates for the various tunnel configurations during the life of the study and provided recommendations for life safety issues such as tunnel ventilation, tunnel lighting, fire control measures and cross-passage locations for emergency egress and emergency personnel access.