A NUMERICAL STUDY ON SEISMIC RESPONSE OF SELF-CENTRING PRECAST SEGMENTAL COLUMNS

Abstract

THIS STUDY ANALYTICALLY INVESTIGATES THE BEHAVIOUR OF SELF-CENTRING PRECAST SEGMENTAL BRIDGE COLUMNS UNDER NONLINEAR-STATIC AND PSEUDO-DYNAMIC LOADING AT DIFFERENT PRESTRESSING STRAND LEVELS. FOR THIS PURPOSE A 3D NONLINEAR FINITE ELEMENT MODEL FOR HYBRID POST-TENSIONED PRECAST SEGMENTAL BRIDGE COLUMNS IS DEVELOPED. FIRSTLY, THE HYSTERETIC PERFORMANCE OF HYBRID UNBONDED AND BONDED POST-TENSIONED SEGMENTAL BRIDGE COLUMNS ARE COMPARED, THEN BONDED POST-TENSIONED SEGMENTAL COLUMNS AT 25%, 40% AND 70% PRESTRESSING STRAND STRESS LEVELS ARE ANALYSED AND COMPARED WITH AN EMULATIVE MONOLITHIC CONVENTIONAL COLUMN. IN THE TIME-HISTORY ANALYSIS, THE COLUMN SAMPLES ARE SUBJECTED TO DIFFERENT EARTHQUAKE RECORDS TO INVESTIGATE THE INFLUENCE OF POST-TENSIONING (PT) FORCE LEVELS ON LATERAL SEISMIC RESPONSE OF PRECAST SELF-CENTRING COLUMNS IN LOW AND HIGHER SEISMICITY ZONES. THE RESULTS INDICATE THAT FOR LOW SEISMICITY ZONES, BRIDGE COLUMNS AT A HIGHER INITIAL STRESS LEVEL DEFLECT MORE APPROPRIATELY WITH LOWER LATERAL PEAK DISPLACEMENT. HOWEVER, IN HIGHER SEISMICITY ZONES, APPLYING A HIGH INITIAL STRESS LEVEL SHOULD BE AVOIDED FOR PRECAST SEGMENTAL SELF-CENTRING COLUMNS WITH INHERENT LOW ENERGY DISSIPATION CAPACITY.