Diaphragm Damage of Precast Concrete T-Shape Girder Bridge: Analysis and Strengthening

For advantage of economical and practical construction, precast T-shape girder bridge is commmonly used in China. In recent years, damage of diaphragm became a serious problem in operation and maintenance. In this study, based on finite element (FE) analysis of an actual bridge, stress distribution and failure process of diaphragm is demonstrated. The result shows that the stress of middle diaphragms started to beyond the limit firstly, under heavey load of 1.5 times equivalent Grade highway-I live load. Then, method of Double-K brace to strengthen the transveral connnection of the exist bridges is proposed and applied on background bridge. Based on the field test, tensile stress of diaphragms concrete reduced 69.4% when Double-K brace were adopted, and the lateral integrity of precast T-beam bridge could be improved effectively.