Confinement reinforcement for bridges in medium to high seismicity zone based on new CSA A23.3-04 approach

Recent advances in confinement reinforcement of building columns have resulted in changes in Canadian code for Design of Concrete Structures CSA A23.3-04. Bridge columns and piers may also take advantage of these advances. The purpose of this paper is to use a comparable approach to propose new equations to be introduced in future Canadian bridge design code. The adopted approach for transverse reinforcement is based on the recently developed uniaxial confinement model for concrete column at Sherbrooke University. Parametric studies have been carried out on some typical bridge columns and piers to develop equations for confinement reinforcement. An intermediate level of ductility (moderate ductility) for bridge columns and piers has been introduced, similar to that in CSA A23.3-04 building design code. Confinement reinforcement for this level of ductility has been found to be less stringent than that for ductile level. This level of ductility is suitable for regions of low to medium seismicity. The adopted approach is supported by experimental results and will provide the designer more flexibility but economical and safer seismic design of bridge columns and piers.