ABSTRACT
The proposed Orange Line project is a 32.2 km light rail transit corridor that will serve downtown Austin in Texas, USA. The project includes 5.2 km of 10.4 m excavation diameter single bore double track TBM tunnel. A hybrid TBM will be used to bore through the limestone and shale rock and alluvium soil of downtown Austin crossing under the Colorado River. Orange Line has four underground stations in downtown Austin. The project also includes two emergency egress buildings, one storage track facility, and the two approach structures. Precast tunnel segments are to be made of fiber-reinforced concrete (FRC). FRC segments are superior for crack control and more cost effective overall and are therefore the preferred solution for this project. This paper presents the details of the design of tunnel, stations, and other underground structures of this major project.
