Bond and anchorage problems in advanced reinforced concrete systems with the use of high-strength materials

本研究处理了在使用高达约100mpa的高强度混凝土和高达约1000mpa的高强度钢筋的先进钢筋混凝土建筑体系的发展中出现的粘结和锚固问题。本研究的主要成果可分为以下四类：1.研究结果：钢筋表面变形对粘结特性的影响。将6种钢筋配置、3级混凝土强度和3级钢筋抗劈裂侧向约束作为试验变量，进行了3倍肋距短预埋杆拉拔试验。根据这些试验结果，可以建立考虑侧向应力和纵向裂缝宽度影响的粘结滑移本构规律。高强度材料R/C构件的键裂强度。采用简支梁试件进行了粘结劈裂破坏试验，重点研究了混凝土强度、侧配筋的数量和布置以及发展长度对粘结劈裂破坏的影响。根据试验结果，可以推导出预测多种变量组合下粘结强度的实验方程。90度钩杆的锚固能力。对90种高强度棒材的锚固能力进行了广泛的研究。根据结果，提出了一个考虑多种变量的设计方程。通过节理区域的梁杆粘结劣化。提出了一种模拟节点中单梁杆粘结性能的试验方法。在大量试验结果的基础上，提出了周梁和强柱框架节点中豆杆的粘结设计方程。

This research deals with the bond and anchorage problems which arise in the development of advanced reinforced concrete building system with the use of high-strength concrete up to roughly 100 Mpa and high-strength reinforcing steel up to roughly 1000 Mpa. The main results of this research can be divided into four categories as in the followings.1. The influence of surface deformation of rebars on bond characteristics.Six types of configuration of rebars, three levels of concrete strength and three levels of lateral confinement against splitting action of rebars were combined as the test variables in pull-out tests of test bars having short embedded length of three times rib pitch. From these test results, the constitutive law of bond-slip including the effect of lateral stress and longitudinal crack width could be established.2. Bond splitting strength in R/C members with high-strength materials.Bond splitting failure tests were performed by the use of simply supported beam specimens with the emphasis on the effects of concrete strength, amount and arrangement of lateral rein-forcement, and development length. From the test results, the experimental equation which predicted the bond strength for extensive combinations of variables could be derived.3. Anchorage capacities of 90 degree hooked bars.Anchorage capacities of 90ﾟ hooks of high-strength bars were studied for a wide range of variables. A design equation which provided for many variables was proposed from the results.4. Bond deterioration of beam bars passing through joint region.A new test method which simulated the bond behavior of single beam bar in a joint was developed. From extensive test results, a bond design equation of bean bars in joints of week-beam and strong-column frames was proposed.