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Constitutive Laws of Consisting Materials and Load-Deformation Mechanism of Pre-stressed Concrete Members

预应力混凝土构件的材料本构规律及荷载变形机理

基本信息

批准号：
11650584
负责人：
NAKATSUKA Tadashi
金额：
$ 2.37万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

For predicting load-deformation relations of pre-stressed concrete flexural members, stress-strain relations of pre-stressing (PC) steels under cyclic loading, stress-strain characteristics of confined concrete subjected to shear force and flexural moment, and effects of bond between grout and PC steel on flexural performance of PC flexural members are investigated. Following main conclusions are obtained.1) The cyclic stress-strain models for PC steels using Menegotto-Pinto expression with variable of strain are proposed. The models estimate satisfactorily hysteretic curve of PC strand, stretched and low temperature annealed (blueing) PC bars and induction heating quenched PC bars of different strength and size under various type of cyclic loading, such as gradual increase strain cyclic loadings, random cyclic loadings etc..2) Uni-axial stress-strain characteristics of confined concrete subjected to constant shear force show smaller tangent modulus, smaller compressive strength and smaller strain at the strength, in the case of higher shear force level. Shear strain of confined concrete under constant shear force increase according to axial stress increment in the case of high compression force level.3) The equations to evaluate F value ( strain compatibility factor) for calculating accurately ultimate flexural strength of pre-stressed concrete members are proposed analytically. The F values are investigated with consideration of bond-slip characteristics between pre-stressing steel and grout, on block elements obtained by dividing the members along longitudinal direction. Employed parameters in the analysis are shape and diameter of pre-stressing steel, strength of grout and so on.

为了预测预应力混凝土受弯构件的荷载-变形关系，研究了循环荷载作用下预应力钢筋的应力-应变关系、约束混凝土在剪力和弯矩作用下的应力-应变特性以及浆液与预应力钢筋之间的粘结对预应力混凝土受弯构件抗弯性能的影响。主要结论如下：1）提出了以应变为变量的基于Menegotto-Pinto公式的PC钢循环应力-应变模型。该模型对不同强度和尺寸的预应力混凝土绞线、拉伸和低温退火（发蓝）预应力混凝土棒以及感应加热淬火预应力混凝土棒在各种类型的循环荷载（如逐渐增加的应变循环荷载、随机循环荷载等）下的滞回曲线进行了满意的估算。2)在恒定剪切力作用下，约束混凝土的单轴应力-应变特性表现为剪切力水平越高，切线模量越小，抗压强度越小，强度处的应变越小。在较高的压力水平下，约束混凝土在恒定剪力作用下的剪应变随轴向应力的增加而增加。3）解析地提出了精确计算预应力混凝土受弯构件极限承载力的F值（应变协调系数）计算公式。在考虑预应力筋与水泥浆粘结滑移特性的情况下，对沿构件沿着纵向剖分得到的块体单元的F值进行了研究。分析中采用的参数有预应力筋的形状、直径、灌浆强度等。