A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology

Thesis (M.Eng.) - Asian Institute of Technology, 1985

A rational study of the design and the as-built construction of the New Memorial bridge in Bangkok is presented. A detailed study of the design of the prestressed concrete box girder superstructure of the bridge system is carried out considering the balanced cantilever method of construction. The usual beam theory is used for the preliminary analysis and design of the longitudinal flexural and shear stresses. A rigorous finite element method using shell elements is applied for the final detailed analysis. The design includes specifying the dimensions of the cross-section before the analysis. The bridge system was built by two different construction methods, the main bridge was built by the balanced cantilever method, using cast-in-place segments whereas the approach viaducts were built by the conventional method, where the formwork is supported on the hardened ground. A detailed study of the balanced cantilever method using cast-in-place segments and the as-built construction steps of the main bridge is carried out. This method is advantageous and competitive when long spans over unusual topography, with large and heavy segments are encountered. It avoids the interference with traffic during construction. Finally the design and construction details are discussed and conclusions are made.