摘要
针对碳纤维板加固多边形古砖塔时预应力沿板带和砌体分布不均匀的情况,提出了在碳纤维板下加设微弯曲板和两端张拉的加固方案。制作了古砖塔缩尺模型并采用两种矢跨比(1∶15和1∶10)的微弯曲板进行加固,分别对试验模型进行超张拉试验,并维持50%预应力度进行长期持荷试验,以分析微弯曲板及其矢跨比改善应力分布效果。研究结果表明:加设微弯曲板和两端张拉的加固方案使作用在砌体上的围箍应力分布更加均匀,靠近和远离张拉端、转角和中面部位的应变差值明显减小;在长期荷载状态下,碳纤维板和砌体上应变逐渐均匀且变化符合对数规律,持荷30 d后应变基本稳定,仍对砖砌体保持一定的围箍应力;采用大矢跨比微弯曲板加固对改善应力集中有较好的作用,而采用小矢跨比微弯曲板加固则有利于塔体的开槽和复原,鉴于两者长期荷载效应差异不大,实际施工时可优先采用小矢跨比微弯曲板进行加固。
Recognizing the non-uniform distribution of strain along the strengthening plate and the brick masonry when the pre-stressed CFRP plate hoop is used to strengthen the ancient polygon pagoda,this paper proposes a new strengthening scheme with slightly bended plate put under CFRP plate and extended.A specimen of ancient brick pagoda was made and strengthened with plates of two rise span ratios(1∶15 and 1∶10).Over-tension tests were firstly carried out to the specimen,and then long-term loading tests with pre-stress degree of 50%,so that to investigate the impact of slightly bended plate and rise span ratio on stress distribution improvement.The results show that the hoop stress on the brick masonry is more uniformly distributed after improving the strengthening scheme,and the strain difference decreases obviously between the near and far tension ends,and the corner and middle of brick masonry.Under long-term pre-stressing force,the strains of CFRP plate and brick masonry tend to be uniform and the change with time follows logarithmic law,the strain is basically stable after 30 days and the hoop stress maintains at an acceptable level.The plate with a large rise span ratio is more efficient to relieve stress concentration,but the plate with a small rise span ratio is helpful to the slotting and recovery of the pagoda.Since the difference is insignificant between the load effect of the two rise span ratio under long-term pre-stressing force,the small rise span ratio plate is suggested in actual construction.
作者
陈良
袁建力
CHEN Liang;YUAN Jianli(Jiangsu Urban and Rural Construction College,Changzhou 213147,China;Architectural Science and Engineering College,Yangzhou University,Yangzhou 225009,China)
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2019年第11期64-72,共9页
Journal of Building Structures
基金
国家自然科学基金面上项目(51078323)
2017年度江苏省建设系统科技指导项目(2017ZD037)
关键词
古砖塔
预应力围箍
碳纤维板
微弯曲板
模型试验
应力分布
ancient brick pagoda
prestressed hoop
CFRP plate
slightly curvature plate
model test
stress distribution
