Research On Mechanical Properties Of Bridge Deck Pavement Of Concrete Bridge Under Random Dynamic Load

In order to study dynamic response of concrete bridge deck pavement under vehicle random load, 3-D finite vehicle-bridge-deck pavement coupling vibration model was built, and the vehicle random load simulated by MATLAB/SIMULINK software based on 2-DOF 1/4vehicle model was applied on deck pavement through ANSYS software to analyze the effect of pavement roughness and velocity on dynamic response of control stress of deck pavement. The change regularity of dynamic response of pavement is studied under coefficient effect of roughness and velocity. The effects of elastic modal and thickness of pavement, concrete cushion layer thickness and transverse slope on control stress of pavement are analyzed under fixed constant load, moving constant load and random dynamic load respectively. The results indicate that:Firstly, the additional dynamic load of wheel increase with deck pavement roughness deepening; the response curves of stress extremum under dynamic random load are very close to those under moving constant load, but the damage effects of former are larger;Secondly, results from the moving constant load cannot meet the actual stress state of pavement layer; the magnification coefficients of maximum value of each control stress are very close and show some regularity; compared with the stress time history analysis at one fixed position, the distribution of extreme value of control stress can reflect stochastic character of vehicle load better; considering deck pavement roughness, each extreme values of control stress are larger than that of ideally smooth pavement.Thirdly, the peak stress of good deck pavement increase first and then decrease with the increase of vehicle speed, however, the response curve of stress extremum has a maximum point and a minimum point when the roughness is deep, and it is detrimental to the force status of pavement when the standard vehicle’s speed is too slow.Last but not least, under vehicle loads, stresses of deck pavement increase mainly linearly with the growth of elastic modal of asphalt pavement, while the thickness of asphalt layer varies, the change regularity of different control stress shows disparity, under comprehensive analysis, thickness of asphalt layer should not be too thick or thin and should better be controlled about 10cm; enlarging transverse slope will contribute to decreasing control stress of deck pavement.