Dynamic Performance of a Stayed Highway Bridge Under Traffic Loads: Design Predictions vs. Dynamic Test Results

MARCELO A. CEBALLOS; FDERICO PINTO; CARLOS A. PRATO; ANTONIO M. PRATO

Porto

Conferencia; 1st Iberic Conference on Theoretical and Experimental Mechanics and Materials; 2018

University of Porto

The dynamic performance of a highway bridge with precast pre-stressed concrete deck and stays made of solid section 47 mm diameter steel bars in lieu of typical strand cable systems is addressed by comparing design predictions with actual dynamic load tests performed at the end of construction. The design was based on the Spanish design code IAP-11 of 2011. Due to the particular selection of solid steel bars to serve as stays in a highway bridge, the dynamic performance of the bridge and their fatigue life prediction suggested at design stage the need to perform a series of tests of an existing smaller bridge with similar structural concept and materials, and upon completion of construction of the new bridge, to carry out dynamic tests.The tests consisted on recording vertical component of accelerations at the mid-span section of one of the main spans when the control vehicle prescribed in the IAP-11 Code rolled on at the allowed speed limit. In contrast to the case of the previous tests performed on a smaller bridge where measured accelerations for the control vehicle where significantly higher than those computed for the same loading, in the new bridge the measured and computed responses are found in acceptable agreement with Code-based predictions, even though the 60 m main spans of the bridge are beyond the 50 m maximum span limit prescribed by the IAP-11 Code for the simplified procedure based on a control vehicle.