Abstract
In this paper, a discussion is presented about the impact-induced damage suffered by bridge pier columns during rockfall events through model tests and impact force, column top displacement, stress-strain response, and other parameters in relation to the process of impact. On this basis, the following conclusions are drawn. Firstly, the impact force, as well as the displacement and strain of the column top, increases rapidly after taking a hit, while the displacement is reduced after reaching its maximum. Secondly, at the same falling height, the higher the impact position, the smaller the peak of impact force and the longer the attenuation period. Thirdly, at the same impact height, the impact energy, the displacement of the column top, and the peak of the impact force increase as the falling height of the pendulum ball is on the rise, but the attenuation period remains unchanged. Fourthly, the failure mode of column impacted by the swing ball conforms to shear-flexural failure. Fifthly, it is recommended to strengthen the preventative measures for those weak positions like 1/2 height and 1/4 height of bridge pier, so as to minimize the potential damage caused by rockfalls. Besides, a theoretical formula used to estimate the maximum impact force is proposed. Lastly, under the axial load of bridge deck, the performance of the pier in impact resistance under rockfall is better and the damage is less severe than in the experimental impact test. The axial load applied by the deck imposes some constraints on the pier, thus reducing concrete damage. The research results can contribute to the research on addressing the rockfall-bridge pier collision problem. The experimental research demonstrates its theoretical significance to engineering for the prevention of rockfall.
Highlights
In recent years, with the rapid expansion of transportation network across China, the earthquake-prone areas distributed in mountainous regions provide favorable conditions for the occurrence of rockfall incidents [1,2,3,4]
In order to promote the development of bridge construction in China and reduce the detrimental effects caused by rockfall disasters, it is of much practical significance to figure out the dynamic response mechanism and pier damage caused by rockfall-bridge pier collision, which is conducive to mitigating the risk of rockfall
By listing the conditions with the most severe damage of different impact heights, it can be known that the maximum number of concrete spalling grids and maximum displacement of column top occurred at the height of 1/2 of the column, and the maximum impact force occurred at the height of 1/4 of the column. erefore, in actual engineering, these weak parts should be strengthened locally to reduce the damage
Summary
With the rapid expansion of transportation network across China, the earthquake-prone areas distributed in mountainous regions provide favorable conditions for the occurrence of rockfall incidents [1,2,3,4]. In order to calculate the impact force, collision frequency, and bending shear wave velocity of the hull, [11] analyzed and summarized the empirical expressions When it comes to numerical solution, finite element software LS-DYNA is commonly applied to conduct mechanical analysis and simulation for the dynamic response of structures under impact loads [12]. A 56 kg pendulum ball device is designed to impact on a 1/4 scale concrete model column, which is purposed to simulate a rockfall impacting a bridge pier On this basis, a discussion is conducted about the dynamic response and damage mode of rockfall-bridge pier collision through the time-history curves of impact force, velocity, acceleration, pier top displacement, stress-strain, and other parameters related to the process of impingement, along with the crack condition of the column
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