【作者】 李增志；

【导师】 丁红岩；

【作者基本信息】 天津大学 ， 建筑工程技术与管理， 2012， 博士

【摘要】 预制混凝土管柱,即在预制的混凝土管中浇注混凝土,二者共同承担荷载,用作建筑物、构筑物的受力构件,预制混凝土管既做模板又做受力构件。具有标准化生产、质量可靠,采用高强混凝土、承载力高,拼装施工、施工效率高,柱外表采用清水混凝土、避免二次装修,节省模板、节约钢材,耐高温,耐腐蚀、造价低、用途广泛等特点。本文在混凝土本构关系、钢筋本构关系及二者相互作用关系现有研究成果基础上,根据箍筋约束混凝土基本理论、混凝土损伤理论等,建立了混凝土弹塑性损伤模型,用ABAQUS软件,对预制混凝土管短柱的承载力和变形进行了非线性有限元研究。提出了预制混凝土管短柱极限承载力计算公式和简化计算公式;提出了预制混凝土管约束管芯混凝土抗压强度、相应峰值应变计算公式和应力-应变全曲线方程;指出承载力简化提高系数在1.05~1.3之间;管壁厚、配箍特征值、箍筋间距三个主要影响因素中,配箍特征值影响承载力和管芯混凝土抗压强度、相应峰值应变最大,壁厚、箍筋间距其次;短柱随管芯混凝土强度提高、体积配箍率增大、壁厚增厚、箍筋间距变小,极限承载力分别提高10%~40%、10%~30%、10%~20%、10%~30%左右,增加的幅值逐渐变小;约束混凝土抗压强度随体积配箍率增大、壁厚增厚、箍筋间距变小分别提高20%~60%、20%~50%、5%左右,增加的幅值逐渐变小;峰值应变随着体积配箍率增大、壁厚增厚逐渐增大,幅值在0.002~0.004之间;预制混凝土管约束管芯混凝土应力-应变全曲线与现有研究结论和特征相符。中长柱承载力和变形研究中指出,理想轴压中长柱(长细比小于20)承载力与短柱相同,柱中无侧向位移即无挠度,柱中横向应变为纵向应变的0.3~0.5倍,即计算泊松比为0.3~0.5,随管芯混凝土强度提高、壁厚增大、体积配箍率增大,逐渐变小。轴向极限承载力受偏心距影响较大,承载力-弯矩关系符合混凝土构件弯压破坏的规律和特征。中长柱弯压受力,存在二次弯矩效应,影响因素多,弯矩效应比较复杂。根据拟静力实验方法、引入损伤因子,单向水平加载,短柱柱顶最大位移、承载力在轴压比为0、0.2时,分别为30-40mm、60-80mm,60-70kN、135-145kN,与预制混凝土空心管相比,分别提高20%、25%,25%、30%左右,延性系数均大于6;反复加载时,滞回曲线饱满,骨架曲线良好,承载力退化系数在0.95~0.98之间。更多还原

【Abstract】 Precast concrete pipe column is constructed by pouring concrete into precast pipe column, which acts as mould as well as resists loads with concrete pouring in site. Precast concrete pipe column, as a kind of resistance member of buildings, is a kind of standardized production with high quality, and has a high bearing capacity as the utility of high strength concrete. Its construction process is effective under assembly process, and without secondary decoration by adopted as cast finish concrete. It can be widely used and has a low cost as low quantity of mould and steel is applied.On the basis of current research on constitutive model of concrete and reinforcement and their interaction, taking into account of theory concerning constrain on concrete by reinforcement and concrete damage, numerical model concerning elastoplastic damage model and nonlinear behavior was developed using FEM software ABAQUS, in order to study on the resistance capacity and deflection of precast concrete pipe short column. Formulation and its simplified vision concerning ultimate resistance capacity of precast concrete pipe short column were developed. The compressive strength and corresponding ultimate strain and stress-strain diagram of core concrete was proposed. It is concluded that the value of the simplified enhanced coefficient of resistance capability is between 1.05and 1.3. Among the three factors of wall thickness, stirrup characterize value, stirrup spacing that affect resistance capability, stirrup characterize value has the most significant impact, and wall thickness, stirrup spacing have the secondary impact. The ultimate resistance capability of short column increases by 10%~40%、10%~30%、10%~20%、10%~30% as the increase of core concrete strength ,the increase of stirrup ratio, the increase of wall thickness ,and the decrease of stirrup spacing separately. The compressive strength of the core concrete increases by 20%~60%、20%~50%、5% as the increase of stirrup ratio ,the increase of wall thickness and the decrease of stirrup spacing separately, but the increment decreases gradually. The ultimate strain increases as the increase of stirrup ratio, the increase of wall thickness, and the value was between 0.002and 0.004. The stress-strain diagram of core concrete obtained was in accordance with current research result.It is indicated that from the research the resistance capability of medium long column (the slenderness ratio is less than 20) is similar to that of short column, and there is no lateral deflection in the column. The transverse stain was 0.3~0.5 times of longitude stain, that is to say the calculation Passion’s ratio is 0.3~0.5. The resistance capability-moment relationship of beam-column was in accordance with the axial force-moment diagram obtained by current calculation method, but the resistance capability increases by 20%. The initial eccentric was taken into account when the slenderness ratio is 30, and the effect of second-order effects is notable.Taking into account of quasi-static experiment method and damage factor, the ultimate displacement of short column is 30~40mm, 60~80mm, and the resistance capability of short column is 30~40kN, 135~145kN when axial compression ratio of short column is 0, 0.2 separately under monotonous transvers loads. The data above are 20%, 25%, 25%, and 30% larger than that corresponding data of precast concrete hollow pipe separately. And the ductility factors are all bigger than 6 under different conditions. Under cyclic loadings, the hysteresis loop obtained is full and spine curve is in good condition, and the ratio of strength degradation is between 0.95~0.98.更多还原