Abstract:The pre-tensioned prestressed T-beam is gradually and widely used in bridge construction in China due to its outstanding advantages such as simple structure, convenient construction, good economy and good durability. The web is an important load-bearing part of the T-beam and an essential component that provides structural shear resistance. According to the stress characteristics of the structure, the traditional T-beams in China generally adopt a variable-thickness web form, and the thickness of the fulcrum web generally reaches 45 cm. However, the pre-tensioned polyline prestressed T-beam introduced in the United States adopts the form of equal thickness web, and the thickness of the web at the fulcrum is much smaller than that of T-beam webs in China. To investigate the impact of web thickness on the mechanical properties and economics of bridges, taking a 30 m-span pre-tensioned polyline prestressed equal-thickness web T-beam as an example, the spatial finite element analysis is carried out for three web thicknesses. The key mechanical indicators of bending resistance, shear resistance and crack resistance, and the the economics of prefabricated beams are analyzed. The research shows that the change of web thickness has little influence on the load effect, bearing capacity, stiffness and crack resistance, but significantly impact on the upper limit of section shear resistance, often controlling the design. There are significant differences in the restrictions on section dimensions among different design codes. The economy of precast T-beam is better by Code for Design of Highway Prefabricated Concrete Bridges (JTG/T 3365-05—2022) and Technical Standard for Precast Concrete Segment Bridges (CJJ/T 1—2023) during the design.
