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

这项研究涉及在发展先进的钢筋混凝土建筑体系时出现的粘结和锚固问题，其中高强混凝土的使用高达100兆帕，高强钢筋的使用高达1000兆帕。本研究的主要成果可以分为四类，具体如下：1.钢筋表面变形对粘结性能的影响。将六种钢筋形状、三种混凝土强度水平和三种水平的抗裂钢筋侧向约束作为试验变量，进行了三倍肋间距短嵌套钢筋的拉拔试验。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关系。高强材料钢筋混凝土构件的粘结劈裂强度试验采用简支梁试件进行了粘结劈裂破坏试验，重点考察了混凝土强度、侧向配筋量和布置方式以及发展长度等因素对粘结劈裂破坏的影响。根据试验结果，可以推导出预测各种变量组合下粘结强度的经验公式。90度弯钩钢筋的锚固能力。对90ﾟ高强钢筋钩的锚固能力进行了大范围的研究。根据计算结果，提出了考虑多个变量的设计方程。提出了一种模拟节点中单根梁筋粘结性能的试验方法。在大量试验结果的基础上，提出了梁柱节点梁筋粘结设计公式。

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.