The application of semi-continuous post-tension pre-stressing box girder bridges in Africa

Abstract

With the rapid development of Africa, more and more bridges are to be built, a bridge type with characteristics of safety, stability, convenient of construction and less cost now is in huge demand. The paper presents an advanced bridge type with semi-continuous post-tension pre-stressing box girder, and introduces the design principles, construction procedures, and actual applications of the bridge type in Africa highway projects, such as the Addis Ababa-Adama Expressway of which is the first expressway in east Africa, and Kampala to Entebbe Expressway of which is the first expressway in Uganda. In the paper, the design principles and construction procedures will be presented, girders of the bridge type can be precast in factory with post-tension pre-stressing concrete, and structural system can be transferred from simple supported system to semi-continuous system during construction. To simulate the mechanical behaviour of the bridge before and after structural system transformation, a numerical modelling is also built on the basis of finite element software. Based on the theoretical derivation, finite element analysis and actual project application, the presented bridge type is proven to be safe, advanced and less cost, meet the corresponding specifications, the presented bridge type can be generalized to more Africa highway projects