Time-Dependent Deformations of Prestressed and Prestressed Reinforced High Strength Concrete Members

预应力和预应力钢筋高强混凝土构件的随时间变形

基本信息

批准号：
08455204
负责人：
SATO Ryoichi
金额：
$ 2.24万
依托单位：
Utsunomiya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08455204/
关键词：
High Strength Concrete PC PRC Long-Term Deformation Creep Shrinkage Superposition Tension Stiffening 長期挙動自己収縮

项目摘要

This study presents the experimental investigation on creep and shrinkage of concrete with compressive strength of more than 100N/mm2 and the research on mechanics and numerical analysis of long-term deformations of prestressed concrete (PC) and prestressed reinforced concrete (PRC) members under sustained load after prestressing. The results obtained from the study executed in 1996 and 1997 are summarized as followings :(1) Based on the principle of superposition, drying, shrinkage strain increases in approximate proportion as 70% of autogenous shrinkage strain increment after drying start, and the proportion is independent of drying start time.(2) The empirical equations of CEB Model Code 1990 (MC90) were modified to predict creep and autogenous shrinkage strain of high strength concrete in accordance with the experimental results in which loading was carried out at various ages of concrete.(3) Based on the principle of superposition taking into account the effect of age concrete at … More loading and modeling the mechanical properties of high strength concrete, time-dependent strain of reinforcing bar due to autogenous shrinkage can be estimated with satisfactory accuracy.(4) When the maximum value of strain of reinforcing bar is 650-1000 (*10^<-6>), the tension stiffness of high strength concrete (105N/mm^2) members is 14-18% larger than that of normal strength concrete (45N/mm^2) members in case of steel ratio of 0.37-0.64%, which is defined as difference between maximum value and average value in strain of reinforcing bar.(5) Average curvature of high strength concrete members at 400 days after loading was 63% of normal strength concrete members. For evaluating curvature, MC90 for tension stiffening overestimats average curvature as the reinforcement stress becomes large.(6) The design equation of effective flexural stiffness in JSCE Standard Specification was valid for high strength concrete members.(7) Based on the principle of superposition for not only concrete but also bond, basic bond equations were formulated for analysis of time-dependent deformations of RC and PRC members subjected to bending moment. Less

这项研究介绍了对混凝土蠕变和收缩的实验研究，其抗压强度超过100N/mm2，以及关于在持久负载下负载下的预应力混凝土（PC）和预应种的钢筋混凝土（PC）的长期变形的力学和数值分析的研究。从1996年和1997年执行的研究获得的结果总结为以下内容：（1）基于叠加原理，干燥，收缩菌株的增加，大约是自体收缩率的70％，干燥开始开始后的70％，而在干燥时间开始后，与干燥时间的比例无关。高强度混凝土根据实验结果，在实验结果下，在混凝土的各个年龄进行负载。（3）基于叠加原理，考虑到年龄在……更大的负载和建模高强度混凝土的机械性能的效果……高强度混凝土的机械性能，高强度混凝土的机械性能，由加强型的加强限量估计的应变量可以估计最高的限制（4时），可以估计（4时）的精确性（4） 650-1000（*10^<-6>），高强度混凝土（105n/mm^2）成员的张力刚度比正常强度混凝土（45n/mm^2）成员大14-18％，如果钢的比率为0.37-0.64％，则在4.37-0.64％的情况下定义为4个平均值的均值和平均值的均值（5）构成量（5）均值（5）的平均值。负载占正常强度混凝土构件的63％。为了评估曲率，随着增强应力变得较大，张力僵硬的MC90平均曲率较大。（6）JSCE标准规范中有效弯曲刚度的设计方程对高强度混凝土成员有效。（7）基于叠加原理的叠加原理，不仅是键合键的键键键键键键合作，用于分析时间符合时间差异和依赖于时间差异，并具有依赖性的分析。较少的