[Truncated abstract] A growing number of large span bridges are built across navigable waterways all around the world in the past decades. These bridges are under the threats of accidental impact loads generated by vehicles, winds and passing vessels. Among these accidents, vessel collisions are deemed to be an important issue as such accidents can result in bridge closure for inspection and repair before they are put into use again, cause severe casualties and huge financial losses. Therefore it is of vital importance to prevent and protect bridges from vessel impact damages. The primary objective of the study is to accurately quantify impact load and structural response of bridge piers subjected to barge impact. Empirical equations and simplified impact models are proposed for design practice. Methodologies for quick and reliable bridge condition assessment after barge impact, as well as impact damage mitigation techniques are also investigated in the study. In this research, barge impact loads on square and circular bridge piers are first investigated. Nonlinear finite element (FE) models that take into consideration nonlinear response and damage of both barge and pier structures are developed and calibrated with previous work and scaled impact tests. With the validated FE models, extensive numerical simulations are conducted to calculate barge impact force and pier response. Based on these simulation results, empirical equations are proposed to predict barge impact load as a function of barge velocity, barge mass and pier dimension and geometry. To simplify the analysis of bridge responses to barge impact, an equivalent nonlinear single degree of freedom (SDOF) system is proposed to predict pier responses to barge impact. The proposed SDOF model is validated with the 3D numerical simulations. The results show the proposed method can efficiently and accurately predict bridge responses to barge impact load and can be used in the design practice.
|Qualification||Doctor of Philosophy|
|Publication status||Unpublished - 2013|