DAMAGE INDEX ANALYSIS OF PREFABRICATED SEGMENTAL BRIDGE COLUMNS UNDER CYCLIC LOADING

Abstract

THE DAMAGE INDEX IS USUALLY APPLIED TO EVALUATE THE DAMAGE STATES OF BRIDGE STRUCTURES, WHICH IS THE BASIS OF STRUCTURAL FRAGILITY STUDY. THE PRESENT STUDY ANALYTICALLY INVESTIGATES THE SEISMIC DAMAGE INDEX OF THE PREFABRICATED SEGMENTAL BRIDGE COLUMNS (PSBC) UNDER CYCLIC LOADING, IN ORDER TO ANALYZE THE SEISMIC FRAGILITY OF THE BRIDGE STRUCTURES WITH PSBC. BASED ON THE PREVIOUS PSEUDO-STATIC EXPERIMENTS, DIFFERENT DAMAGE STATES CHARACTERISTICS OF THE MONOLITHIC CAST-IN-PLACE BRIDGE COLUMNS (MCBC) AND THE PSBC ARE DISCUSSED AND ANALYZED. THEN, THE LIMIT-STATE CAPACITIES FOR EACH DAMAGE STATE OF THE PSBC ARE PROPOSED BY TAKING FOUR PARAMETERS INTO CONSIDERATION, WHICH ARE THE COMPRESSIVE STRAIN OF CONCRETE, THE TENSILE STRAIN OF STEEL, THE TENSIONING LEVEL AND THE RESIDUAL DISPLACEMENT. THE NONLINEAR FINITE ELEMENT MODELS OF THE PSBC ARE DEVELOPED BY OPENSEES. A MODIFIED FORMULA FOR DAMAGE INDEX FOR THE PSBC IS ESTABLISHED BASED ON THE LIMIT-STATE CAPACITIES AND THE RESULTS OBTAINED FROM THE MODELS. THE DAMAGE INDEX FOR THE PSBC IS THEN OBTAINED. A SIMILAR EXPERIMENTAL BRIDGE COLUMN IS USED TO VERIFY THE DAMAGE INDEX WITH THE SAME ANALYTICAL METHOD. THE RESULTS INDICATE THAT THE DATA OBTAINED FROM THE COLUMNS NUMERICAL MODELS SHOW GOOD AGREEMENT WITH THE EXPERIMENTAL RESPONSE OF THE COLUMNS. THE DERIVED DAMAGE INDEX FORMULA OF THE PSBC IS REASONABLE AND CAN BE FURTHER APPLIED. THE MAXIMUM ERROR BETWEEN THE PROPOSED DAMAGE INDEX AND THAT OBTAINED IN THE VERIFIED CASE IS 20.3%. THE PROPOSED METHOD IN THIS PAPER FOR DEVELOPING THE DAMAGE INDEX OF THE PSBC CAN BE USED IN THE SEISMIC VULNERABILITY ANALYSIS ASSESSMENT OF THE BRIDGE STRUCTURES WITH PREFABRICATED SEGMENTAL COLUMNS.