超高延性混凝土加固砖木结构抗震性能试验

Seismic performance of timber-framed masonry structure strengthened with ultra-high ductile concrete

摘要:

为研究超高延性混凝土（ultra-high ductile concrete, UHDC）面层加固立贴式砖木结构的可行性,以及探究UHDC面层对砖木结构抗震性能的影响,以一栋缩尺比为1/2的立贴式砖木结构模型为研究对象,进行了未加固和UHDC面层加固两种情况下的振动台试验,比较未加固结构和UHDC加固结构的动力特性、破坏模式、位移响应、扭转效应和基底剪力等抗震性能。结果表明:在选定台面激励下,未加固砖木结构不能满足现行规范的抗震设防要求,需要进行抗震加固后才可继续使用；UHDC面层显著提高了砖木结构的刚度,降低了结构的刚度退化,从而有效控制了大震作用下的结构损伤,提升了结构的抗震性能；9度罕遇地震作用下,UHDC加固砖木结构的x向层间位移角为3.96‰；UHDC面层减小了砖木结构由于结构不对称造成的扭转效应；UHDC面层加固结构比碳纤维布加固结构的抗震性能更好。UHDC面层加固砖木结构能够满足中国GB 50011—2010《建筑抗震设计规范》规定的8度抗震设防要求,初步证明了UHDC用于震损结构修复和现存建筑房屋加固是切实可行的。

Abstract:

To investigate the feasibility of timber-framed masonry structure reinforced with ultra-high ductile concrete (UHDC) layer and explore the influence of UHDC layer on the seismic performance of timber-framed masonry structure, shaking table tests were performed on 1/2 scaled timber-framed masonry structure model under conditions of original un-strengthened structure and UHDC strengthened structure. The seismic properties of un-strengthened structure and UHDC strengthened structure including dynamic characteristics, failure modes, displacement response, torsional effect, and base shear were compared and discussed. Test results show that the un-strengthened structure could not meet the seismic fortification requirements of the current code under the selected table excitation, and it could only be used after seismic reinforcement. The UHDC layer significantly improved the stiffness and reduced the stiffness degradation of the structure, so as to effectively control the structural damage under large earthquake and improve the seismic performance of the structure. Under rare earthquake of 9 degree, the x-direction inter-story drift of UHDC layer strengthened structure was 3.96‰. The UHDC layer reduced the torsional effect of the structure caused by structural asymmetry. The seismic performance of UHDC layer strengthened structure was better than that of CFRP strengthened structure. The structure strengthened with UHDC layer could meet the requirements of 8 degree seismic fortification intensity as stipulated in GB 50011—2010, which preliminarily proved that UHDC was feasible to repair the earthquake damaged structure and strengthen the existing buildings.