Application of different methods for determination of the dynamic amplification factor (DAF) from moving loads on roadway RC bridges

Abstract

The dynamic effect of traffic loads on roadway bridges is usually introduced through the so-called dynamic amplification factor - DAF. This parameter shows how many times the impacts obtained from the load's static action are increased. One of the main goals of the dynamic tests of reinforced concrete bridges, with proof load, is to determine the DAF's actual value and compare it with the value taken into consideration in the design project. This research focuses on the possible methods for the determination of the DAF on roadway reinforced concrete bridges. For this purpose, results of dynamic tests performed on newly built bridges, with proof loading on various motorway sections in the Republic of North Macedonia, were used. Therefore, semi-prefabricated buildings with pre-stressed concrete beam girders and a static system - simple beam were analyzed. During the test, the main girders' vertical displacements were measured, through which the DAF was determined. For processing, analysis, and filtering of the measured signals' dynamic component, appropriate techniques have been used. After processing the signals, the DAF's value is determined by applying two proposed methods. With the processed results, a comparative analysis is performed between the DAF's determined values obtained from applying different methods. These analyses allow us to study the impact of using different measurement techniques and methods for processing the signals for calculating the dynamic effect of the moving loads. In this way, an attempt is made to suggest which methods for determining the DAF obtain more reliable results for its value.