NEHRP Clearinghouse
- Title
- Flexural Retrofit of Circular Reinforced Bridge Columns by Steel Jacketing. COLRET: A Computer Program for Strength and Ductility Calculation.
- File
- PB95263562.pdf
- Author(s)
- Chai, Y. H.; Priestley, M. J. N.; Seible, F.
- Source
- California State Dept. of Transportation, Sacramento. Office of Structures Design.; California State Business and Transportation Agency, Los Angeles.; Federal Highway Administration, Sacramento, CA. California Div.; National Science Foundation, Arlington, VA., October 1991, 152 p.
- Identifying Number(s)
- UCSD/SSRP-91/05
- Abstract
- This report presents the development of an analytical model, based on moment-curvature analysis at the critical section, for the prediction of flexural strength and ductility in prismatic circular bridge columns. Columns are treated as vertical cantilevers subjected to axial compression and lateral interial force. Passive confinement of the concrete core by the transverse steel is accounted for using a realistic model for confined concrete. Post-yield deformation of the column is predicted on the basis of an elasto-plastic idealization with plasticity concentrated in a localized hinged region. Failure modes such as that precipitated by sheer or bond-slip at the lap-splices of the longitudinal bars are not considered in the model. The analytical model is extended to columns with fully grouted steel jackets which are assumed to contribute to the ductility of the column by providing confinement to the column concrete without significant enhancement of the flexural strength. The increase in lateral stiffness of the column due to the steel jacketing is taken into account by considering the effective bond transfer between the jacket and column for composite action. Deformation beyond yield of the column is also considerd. The model is coded in a computer program to provide bridge engineers a simple and reliable means of assessing the performanc of existing bridge piers so that deficient peirs can be identified, and to allow an assessment of the improved column performance after retrofit. The reliability of the model is verified through experimental testing of large-scale column units.
- Keywords
- Reinforced concrete; Columns (Supports); COLRET computer program; Deflection; Bridge maintenance; Design analysis; Highway bridge; Ductility; Earthquake resistant structures; Retrofitting; Earthquake damage; Buckling; Circular bodies; Structural steels; Bridge design; Highway maintenance; Reinforcing materials; Flexural strength; Computer programs; Reinforcement (Structures)