Nonlinear finite element analyses of concrete bridge joint systems subjected to seismic actions

Following widespread damage to bridge joints in the San Francisco region fr om the 1989 Loma Prieta earthquake, the necessity for establishing an alter native method for seismic design of bridge joints was identified. Recognizi ng that conventional joint design practice based directly on shear forces r esults in congested reinforcement details, which are difficult to implement in practice, a rational design procedure was sought through large-scale te sting of bridge joint systems and subsequent finite element and strut-and-t ie analyses. The finite element part of the study is presented in this pape r, which focuses on (a) identification of compression force flow and thus t he load path across the joint, (b) examination of an efficient joint force transfer model, and (c) influence of cap beam prestressing. Combining the e xperimental and analytical results, a joint design method has been establis hed in which reduction of joint reinforcement was achieved by treating join t shear as part of the complete force transfer across the joint, rather tha n as an independent action. The proposed design approach has been validated in a laboratory test on a full-scale multiple-column bridge bent, (C) 2000 Elsevier Science B.V. All rights reserved.