Today: “Behavior of Buried Composite Arch Bridges,” Ph.D. Defense Presentation by Harold Walton
Department of Civil and Environmental Engineering
Ph.D. Defense Presentation By: Harold J. Walton
Advisors: Bill Davids and Melissa Landon
BEHAVIOR OF BURIED COMPOSITE ARCH BRIDGES
Monday November 16, 2015 at 11:15 am
Barrows Hall, Arthur St. John Hill Auditorium
This investigation focuses on soil-structure interaction of concrete-filled fiber reinforced polymer (FRP) tube arches (CFFTs) used as the main structural members in a bridge system. The presented research covers efforts to expand understanding beyond isolated arches and to account for the role of soil experimentally and numerically. Soil plays several roles for a bridge: weight on the structure, restraining arch movement, and dissipating surficial truck loads. Four bridge systems were constructed with two different span-to-rise ratios (5:1 and 2.67:1) and two different materials (steel and CFFT). Scaled arches were placed in a self-reacting timber soil box and were backfilled with compacted granular fill in alternating lifts to simulate field construction. Surface live loads were applied at seven locations across the middle 60% of the span of the arches, replicating truck loading. Bridges were loaded at the apex until failure to find the capacity of the buried arch system. This discussion includes improvements to the soil-spring model currently used to design CFFT arch bridges and the development of a soil-continuum model that added insight on the behavior of buried arch bridges. Both analyses model backfilling, live load, and ultimate load, and are compared with experimental results. The coil-continuum model is not a practical design tool because it is computationally and financially expensive. The soil-spring model was conservative but accurate for predicting peak positive moment in steel arches for different live load positions and accurately captured total moment for loads above the previous maximum applied load indicating that it may be a useful tool for design or load rating.