241. ACCELERATING BRIDGE CONSTRUCTION IN EARTHQUAKE COUNTRY
Name: Matthew Joseph Tobolski
Grad Year: 2009
Currently in the United States there is a great number of bridges which are rated as either structurally deficient of functionally obsolete. For many of these structures the only viable solution to resolve these deficiencies is total bridge replacement. With many of these bridges located in urban regions or serving as the only practical transportation route, rapid replacement is highly desirable. However, many of these structures are located in regions subjected to moderate to high seismic demands. Significant difficulties have historically arisen with bridges which can be constructed quickly and also provide significant seismic resistance. In an attempt to overcome these hurdles, the National Cooperative Highway Research Program (NCHRP) is funding Project 12-74, ?Development of Precast Bent Cap Systems for Seismic Regions.?
For concrete bridges, one clear solution to accelerate bridge construction is to move the casting off-site and off the critical path. The major concern with precasting members for bridges subjected to moderate to high seismic demands is the connections between elements. A total of five bent cap-to-column connections have been developed in conjunction with one bent cap-to-superstructure connection. This paper will focus on three innovative column connections and one innovative bridge system with a new superstructure connection. The bent cap connections are pioneering in that the manner in which the column is constructed and connected produces a system which can resist seismic demands with little damage and self-center following even a large earthquake. For the superstructure connection, the key feature relates to the permitting of the joint to open during an earthquake to utilize the system more efficiently.