高性能アンカーの外側耐震補強性能に関する基礎的研究

Abstract

本研究では、新旧接合面近傍のアンカ一筋に鋼管シアキーを固定して断面積を増大させた高性能アンカーの提案、並びにそのせん断抵抗性能を実験的に検討した。その結果、補強部の浮き上がり量は、鋼管シアキーの外径と埋込み深さの増大に従って増大すること、新旧接合部のせん断耐力は、鋼管シアキーの外径と埋込み深さの増大とともに直線的に増大すること、既存部モルタルの支圧強度によって決まる新旧接合部のせん断耐力は、本研究で提案した解析モデルを用いることで合理的に説明できること、高性能アンカーによるせん断抵抗性能を向上させるには、鋼管シアキーの埋込み深さをある値以上に設定する必要があること、などが明らかとなった。

In this study，the high performance anchor bar with the sectional area expanded by the steel tube was proposed for the improvement of shear carrying capacity of the placing joint by outside seismic reinforcement，and the abilities of high performance anchor bar were investigated. In this experiment，three diameters of steel tube with the wall thickness of 2mm (the diameters are 15，20 and 30mm) and four lengths of steel tube (the lengths are 20，40，60 and 60mm) were selected as shown in Table 1 and Fig. 2. The specimen，the loading method and measurement method as shown in Figs. 1 and 4 were used in this experiment. The results obtained by the experiments can be summarized as follows: 1) The uplift of the placing joint increases linearly with increasing the diameter of steel tube in the range under 20mm，but is little affected by the diameter of steel tube in the range over 20mm，and increases slightly with increasing the embedded depth of steel tube. 2) The shear strength of the placing joint reinforced by the high performance anchor bar increases linearly with the increase of the diameter and embedded depth of the steel tube. 3) In the case that the shear strength of the placing joint by outside seismic reinforcement is detennined by the bearing strength of the existing mortar with lower strength as compared to the reinforcing mortar，the effects of the diameter and embedded depth of the steel tube on the shear strength of the placing joint can be explained reasonably by using the analytical model proposed in this study. 4) In order to improve the shear carrying capacity of the high performance anchor bar，it is necessary to use the steel tube more than a certain embedded depth.