【作者】 鲁国昌；

【导师】 叶列平；

【作者基本信息】 清华大学 ， 土木工程， 2005， 硕士

【摘要】 近年来,FRP 布缠绕加固柱在实际工程中得到广泛应用,而 FRP 管约束混凝土做为新建结构构件也有望在将来得到应用。同时,与 FRP 约束混凝土相关的研究近年来也广泛开展起来。但目前对 FRP 约束混凝土模型大都仅仅把 FRP做为单纯的约束材料,没有考虑到 FRP 管在轴向受力情况下会造成环向约束作用的降低以及在双向受力情况对 FRP 强度的影响。本文首先总结了国内外有关 FRP 约束混凝土的研究情况,列举了 9种 FRP 布约束混凝土轴压本构模型和 3 种针对 FRP 管约束混凝土的轴压本构模型。本文通过对 FRP 管和核心混凝土的受力分析,考虑了 FRP 管承受轴向压力造成约束模量降低的影响,在借鉴 Huang 轴压本构模型基础上,提出一种考虑 FRP 管在双向受力情况下的轴压受力分析方法。该方法通过逐步增量法来计算 FRP 管约束混凝土的在轴心受压时的应力—应变关系,并根据 FRP 材料的破坏准则来确定 FRP 管极限强度。通过与国内外和本文的 FRP 管约束混凝土轴压试验数据的对比,表明所建议方法的计算结果与试验结果吻合较好。通过该模型,还进行了参数分析,如研究 FRP 管与混凝土间隙、FRP 管的铺层等对 FRP 管约束混凝土的轴压应力—应变关系的影响。本文还进行了 FRP 管约束混凝土和 CFRP 布约束混凝土的轴心受压试验研究,分别对不同厚度、不同纤维铺层、不同受力条件的 FRP 管约束混凝土试件以及混杂 FRP 管约束混凝土试件进行了对比分析。本文还对CFRP 布约束混凝土轴心受压试件的强度与极限应变的理论值和试验值、应力—应变关系的理论曲线与试验曲线进行了对比分析,此外对 CFRP 布与箍筋共同约束轴心受压试件进行了试验分析。更多还原

【Abstract】 Recently, the technique of reinforced concrete columns strengthened withwrapped the FRP sheets is becoming popular in the civil engineering, andconcrete-filled FRP tubes are expected to be used in new constructions ofcolumns. At the same time, studies on concrete confined with FRP have beenwildly carried out, but most models consider FRP under uniaxially loadedproviding confinement only in the hoop direction. The fact that the FRP tubesare usually bi-axially loaded will reduce the confinement modulus and tensilestrength in the hoop direction.In this thesis, stress-strain models of FRP-confined concrete under axialloading are summarized firstly, including nine models for concrete confinedwith FRP sheets and three models for concrete-filled FRP tubes.By studying the mechanical behavior of FRP tubes and core concreteunder axial compression, this thesis presents an analytic stress-strain modelwhich considers that FRP tube is subjected to both axial compression andhoop tension, and the axial strain-lateral strain relationship proposed byHuang is used in the model. The stress-strain relation is determined by using astep-by-step strain increment technique, and the failure theory of FRP isadopted in the model to determine the strength of the concrete-filled FRP tube.The proposed model is shown to compare well with test results conducted inthis thesis and other researchers.The experimental studies on the concrete-filled FRP tubes and concreteconfined with CFRP sheets have been carried out. The concrete filled in tubesof different thickness, different stacking angle and different load-carryingconditions are contrasted, and the concrete-filled in hybrid FRP tubes areanalyzed. The experimental results of the strength, the ultimate strain and thestress-strain curves of the concrete confined by CFRPS are compared with themodels, and the concrete confined by both stirrup and CFRPS are analyzed.By using the suggested model, the parametric study is presented.更多还原