Behavior of Concrete Segmental Box Girder Bridges with Open Webs

The prestressed concrete (PC) box girder bridge with open webs, whose mechanical behavior is halfway between that of the traditional plain web and the lattice box girder bridges is a relatively new bridge form. The concept depends on new structural developments considering complex geometry that combines cast in situ and prefabricated elements. In this paper, the Abra Bridge (or Tavaro Viaduct) in France was measured and analyzed by using the so-called space frame lattice model. The paper discusses the advantages of this bridge type. The paper also presents the use of a space frame lattice computational method for structural analysis. Given the calculated results, to reduce the principal stresses in the webs, the shear stresses are reduced by the vertical preshear force provided by the external prestressed tendons along the whole bridge, which is proposed by the authors. At the same time, the vertical internal prestressed tendons in the webs can be designed to increase the vertical compressive stresses. The threaded bar can be designed along the hypotenuse side in each web. The space frame lattice model is an effective tool of calculation and analysis for PC box girder bridges with open webs. The reinforcements in webs can be designed according to the principal tensile stresses calculated by the model. (C) 2015 American Society of Civil Engineers.