Quantitative study of the factors affecting the behavior of reinforced concrete bridge foundations against floods

Evaluating the vulnerability of bridges to flooding is essential for risk-informed planning of their maintenance. This paper aims to develop a systematic model for investigating the behavior of bridges at the time of flooding, in which structural, geotechnical, and hydraulic parameters are considered. A three-dimensional finite element model of reinforced concrete bridge piers was developed, in which the material nonlinearity and the interactions between the pier and the surrounding soil and the flood water were considered. The parameters used in the model were validated based on experimental data from a single pile and a reinforced concrete column under axial and lateral loading. The validated modeling approach was then used to simulate an existing bridge pier, for which the structural, geotechnical, and hydraulic parameters were varied to evaluate the effective parameters. The results showed that the presented modeling approach is capable of providing reliable predictions of the performance of bridge piers at the time of flooding, which makes it suitable for practical vulnerability assessment of bridges. Moreover, it was observed that the behavior of the bridge piers against floods was more sensitive to geotechnical and hydraulic parameters than structural parameters, to the level that by changing the soil type from medium sand to loose sand, the lateral displacement of the structure is 1.87 times. Also, by increasing the longitudinal slope from 0.004 to 0.005 and decreasing the roughness coefficient from 0.025 to 0.021, the lateral displacement of the structure will change to 2.57 and 6.55 times its initial value, respectively.