植筋增设底板T梁截面转换试验研究

Experimental study on cross-section transformation of T-beam with planting bar

预应力T梁由于结构简单、受力明确等诸多优点,目前在我国公路桥梁中被广泛采用。但早期的预应力T梁桥因受到局部设计不合理、施工工艺达不到设计要求等原因致使T梁桥出现下挠量过大、开裂等结构性病害,导致预应力T梁桥无法满足通行需求。本文提出植筋增设底板T梁截面转换加固技术,对比分析了加固前后预应力T梁的各项性能指标。试验表明:预应力T梁在植筋增设底板后,新增设底板与原T梁协同变形,共同承载,有效提高了抗弯刚度1.5倍,抗扭刚度3.5倍,提升了28%的极限承载能力,减少了30%的下挠量并延缓了开裂。该加固技术能有效提高预应力T梁的承载力和耐久性,值得推广应用。

Prestressed T-beam is widely used in highway bridges in China due to the simple structure and clear force.However,for the unreasonable local design and the failure of the construction process to meet the design requirements,the early prestressed T-beam bridges caused structural defects such as excessive deflection and cracking of the T-beam bridge,which caused the prestressed T-girder bridge to be unable to meet the requirements.In this paper,the T-beam section transformation and reinforcement technology of the base plate is proposed,and the performance indexes of the prestressed T-beam before and after reinforcement are compared and analyzed.The test shows that after the prestressed T-beam is added to the bottom of the planting bar,the newly added bottom plate and the original T-beam are co-deformed and jointly supported,which effectively increases the bending stiffness by 1.5 times,the torsional stiffness by 3.5 times,and improves the ultimate load carrying capacity by 28%,reduces the amount of deflection by 30%and delays cracking.The reinforcement technology can effectively improve the bearing capacity and durability of the prestressed T-beam,which is worthy of popularization and application.