CIVIL ENGINEERING 365 ALL ABOUT CIVIL ENGINEERING



AbstractTo promote accelerated bridge construction (ABC), precast bridge columns are now being more widely used in engineering applications. Researchers have often studied the seismic performance of precast bridge columns, but the study of shear performance is quite limited. The main purpose of this study is to investigate shear behavior of low-aspect-ratio precast columns with grouted sleeve connections considering the effect of axial load ratios. Cyclic quasistatic tests of four 1/4-scaled reinforced concrete precast column specimens were conducted to investigate their seismic performance. The experimental results showed that large axial load reduced ductility factor of columns, but increased lateral force capacity. A predicting method for lateral force capacity of precast bridge columns based on a strut-and-tie model in the sleeve region was developed. The method can realistically predict the lateral force capacity and take into the influence of axial load on lateral force capacity of precast columns with grouted sleeve connection.Practical ApplicationsGrouted sleeve connections have been one of the most effective connections for precast columns in prefabricated bridge construction. For urban expressway bridge engineering, there are many columns with low aspect ratio. Lack of corresponding performance evaluation methods of the short columns with grouted sleeve connection restricts its application in medium- and high-intensity earthquake zones. This study revealed damage mechanisms of precast column under cyclic load, such as shear crack, shear slip of joint, and failure modes of joint connection. In addition, a strut-and-tie model was proposed to accurately predict lateral bearing force for precast columns with grouted sleeves under various axial load ratios. The achievement of this study can provide theoretical support for seismic design of short columns (aspect ratio less than 2.5), and the related research results have been applied to the engineering construction of urban bridges in medium- to high-intensity areas such as Jingxiong Expressway, Zunqin Expressway, and Shanghai S26 Expressway.



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