老旧预应力空心板梁非常规裂缝产生机理分析  

Mechanism Analysis of Unconventional Cracks in Old Prestressed Hollow Slab Beams

作　　者：王嘉祺 彭崇梅 赵辛玮 WANG Jiaqi;PENG Chongmei;ZHAO Xinwei

机构地区：[1]上海城建城市运营(集团)有限公司,上海200120

出　　处：《上海公路》2024年第1期56-61,M0005,共7页Shanghai Highways

摘　　要：混凝土开裂是老旧预应力空心板梁典型病害之一,通常表现为跨中底板弯曲裂缝和近支座腹板剪切裂缝。在多榀简支空心板梁的小剪跨比区段,发现了非常规的弯剪裂缝。利用空间杆系模型和精细化实体有限元模型,对先张预应力空心板梁的开裂机理进行分析。结果表明,设计缺陷和重载车辆是板梁底板和腹板贯通开裂的主要原因。其中,预应力端部应力集中,诱发了非常规弯剪裂缝产生;车辆荷载则加剧了薄弱截面裂缝的扩展。The concrete cracking is one of typical diseases of old prestressed hollow slab beams.The conventional cracks that have been observed include the bending cracks of bottom slabs in the mid span and the shear cracks of webs near the support.However,the unconventional flexural-shear cracks have been found at the beam ends with small shear span ratio in simply supported hollow slab beams.The cracking mechanism of pretensioned prestressed hollow slab beams was analyzed based on the spatial beam and the refined solid finite element analysis.The results indicate that the design defects and heavy vehicles are the main causes of the flexural-shear cracks.The stress concentration at the end of pretensioned prestressed strands induces unconventional flexural-shear cracks,and the vehicle load exacerbates the development of cracks in the weak section of beams.

关 键 词：桥梁工程 老旧桥梁 空心板梁 开裂机理 数值模拟 

分 类 号：U445.71[建筑科学—桥梁与隧道工程]