Mike O Callaghan Pat Tillman Memorial Bridge Case Study

Hoover Dam Bypass:
The Mike O’Callaghan-Pat Tillman Memorial Bridge The bridge was built to be take the traffic away from the Hoover Dam which had just turned 75 years old and cannot hold the traffic anymore. The Hoover Dam was not able to hold the 14,000 thousand cars that drive across the dam every day. To help preserve the dam Arizona and Nevada built The Mike O’Callaghan-Pat Tillman Memorial Bridge. This was a huge project between both states that would end up cost them $240 million. The project started in 1998 after President Bill Clinton sign the tea 91 into law and delegated money to support new construction for roadways. Nevada and Arizona both contributed $20 million each and got $130 million from bond funds. Other funds came from different
areas and different organizations like US DOT, and Federal Highway High Priority Projects. The Mike O’Callaghan-Pat Tillman Memorial Bridge what a lot of different types of challenges that it had to overcome.
Some were the shear height of the bridge and make the bridge reach across the canyon. The bridge was cast in place and had all the concrete shipped to the site and poured on site. The site used a lot of steel, concrete and cable. The bridge was a twin rib arch bridges and the arch was 1050 feet that reached from one side of the canyon to the other. These arches were Concrete-Steel Composite Arches and are the only kind of this in the United States. It is also the 2nd highest bridge in the United States. They also use some interesting techniques to support the bridge and to hoist up some of the material. They used a Cable Stay system that was used to support the arches as the where being put together. They also used a high line crane system that help move the bigger equipment around the bridge and help set material in place. Most of the projects were done during the same time of each other and didn’t have to wait for one another. They had the Arizona approach and the Nevada Approach being constructed by two different companies and the bridge itself was constructed by two other
companies.

By the end of the construction the bridge was built but it was over budget by about $42 million and was 3 year over the completion date. But with all the different problems that accrued on the site it was done in good time

Citation
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