Water-Structure Interaction Analysis of a Segmental Bridge Using Ambient Vibration Testing at Different Water Levels

Abstract

Updating the FEM numerical model using experimental dynamic properties requires considering the environmental conditions present during the execution of the tests. An experimental program aimed at studying the fluid-structure interaction in the dynamic response of a concrete segmental bridge with partially submerged piers in an artificial reservoir was carried out through the execution of two experimental campaigns at different water levels. The bridge is located on the Bucaramanga - San Vicente de Chucurí road (Santander, Colombia) with a length of 558 m, spans of 93 and 180 m and pile heights of 57, 90 and 109 m, variable box girder section from 9 to 3 m; the piers of the bridge are partially submerged leaving a minimum clearance of 28 m. The experimental campaigns were developed using two triaxial accelerometers placing the accelerometers every 18 m with measurements of 20 min per location. The obtained signals were processed using the EFDD technique identifying 11 modal shapes in transverse direction, vertical and transverse rotation. Different parameters were considered for the numerical modeling in which several cases of water level were established, based on measurements of the water level during the execution of the ambient vibration test, masses concentrated in the piles. The calibration of the numerical models from the identified dynamic properties detect percentage reductions in the natural frequencies related to the water level of the reservoir. The research provides a better insight into the incidence of fluid-structure interaction on the dynamic response of deepwater bridges and considerations during dynamic characterization tests.