Fatigue Analysis of Unconfined Concrete Columns

摘要

Current seismic design codes which aim at maximizing the overall ductility of a211u001estructural system are a result of extensive experimental and analytical research 211u001eover the past three decades. In seismic bridge engineering, the state-of-the-211u001epractice has lagged by some two decades the state-of-the-knowledge. Thus the vast 211u001emajority of the bridge structures in most countries, including the United States, 211u001ehave been built to non-seismic codes. Since it is not economically feasible to 211u001eabandon all of these existing structures, it is necessary to evaluate their 211u001eexpected seismic performance and then retrofit those structures, it is necessary 211u001eto evaluate their expected seismic performance and then retrofit those structures 211u001ethat are deemed to be be seismically deficient. This report is concerned with the 211u001efirst step in the seismic retrofit process-seismic evaluation. Using an energy 211u001ebased methodology it explores the various possible failure in non-seismically 211u001edesigned structures including: unconfined concrete fatigue; bond failure in 211u001eanchorages and lap splices; compression buckling of the longitudinal 211u001ereinforcement; fracture and fatigue of the longitudinal reinforcement; and shear 211u001efailure of the columns.