Journal Article

Performance-based seismic assessment of skewed bridges with and without considering soil-foundation interaction effects for various site classes

Abdoul R. Ghotbi

2014

Overview

The seismic behavior of skewed bridges has not been well studied compared to straight bridges. Skewed bridges have shown extensive damage, especially due to deck rotation, shear keys failure, abutment unseating and column- bent drift. This research, therefore, aims to study the behavior of skewed and straight highway overpass bridges both with and without taking into account the effects of Soil-Structure Interaction （SSI） due to near-fault ground motions. Due to several sources of uncertainty associated with the ground motions, soil and structure, a probabilistic approach is needed. Thus, a probabilistic methodology similar to the one developed by the Pacific Earthquake Engineering Research Center （PEER） has been utilized to assess the probability of damage due to various levels of shaking using appropriate intensity measures with minimum dispersions. The probabilistic analyses were performed for various bridge configurations and site conditions, including sand ranging from loose to dense and clay ranging from soft to stiff, in order to evaluate the effects. The results proved a considerable susceptibility of skewed bridges to deck rotation and shear keys displacement. It was also found that SSI had a decreasing effect on the damage probability for various demands compared to the fixed-base model without including SSI. However, deck rotation for all types of the soil and also abutment unseating for very loose sand and soft clay showed an increase in damage probability compared to the fixed-base model. The damage probability for various demands has also been found to decrease with an increase of soil strength for both sandy and clayey sites. With respect to the variations in the skew angle, an increase in skew angle has had an increasing effect on the amplitude of the seismic response for various demands. Deck rotation has been very sensitive to the increase in the skew angle; therefore, as the skew angle increased, the deck rotation responded accordingly. Furthermore, abutment unseating showed an increasing trend due to an increase in skew angle for both fixed-base and SSI models.

• Publisher: Institute of Engineering Mechanics, China Earthquake Administration,Springer Nature B.V
• Subject: Bridges / Bridges (structures) / Civil Engineering / Clay / Control / Damage / Decks / Demand / Dynamical Systems / Earth and Environmental Science / Earth Sciences / Earthquake damage / Earthquake engineering / Earthquakes / Geotechnical Engineering & Applied Earth Sciences / Ground motion / Probability / Sand / Seismic activity / Seismic engineering / Seismic phenomena / Seismic response / Skew angle / Soil (material) / Soil strength / Soil types / Structural engineering / Vibration / 倾斜角度 / 土-结构相互作用 / 场地 / 强地面运动 / 性能评价 / 抗震性能 / 斜梁桥 / 概率分析