Bond And Anchor Behavior Of HRB500 Bundled Bars

In engineering concrete structure, steel bars are often allocated intensive in transfer beam or civil defence fortifications with large loads. It is difficult to position steel bars and to cast concrete. It not only decreases quality of members, but the whole structure. An effective way to handle this problem is to use bundled bars. With the popularity of high-strength reinforcements, such as HRB500, bond and anchor property of high-strength bundled bars has to be paid attention. This article attempts to provide reference for anchorage design, through the bond and anchor behavior of HRB500 bundled bars.According to the experiment of 24 HRB500 bond and anchor specimens, this article analyzes the effect of reinforcement numbers, thickness of concrete cover and anchorage length on bond-anchorage of HRB500 reinforcement. Through the results, load-slip curve of bundled bar are drawn. Studying bond-anchoring mechanism of bundled bar. Comparing code data by calculating with equivalent diameter of HRB500 reinforcement with experimental data, studying bonding strength of HRB500 bundled bar.The experimental results indicate that there are two failure patterns of HRB500 bundled bar which are pulling-out failure and splitting failure. Loading stages of pulling-out failure specimens can be divided into five parts which are minimal slipping segment, slipping segment, splitting segment, decreasing segment and retained segment. Loading stages of splitting failure specimens can be divided into three parts which are minimal slipping segment, slipping segment and splitting segment. It is same as normal reinforcement. HRB500 reinforcement can fit china code proposed by the group of bond-anchorage and it can calculate with equivalent diameter. Average bond-anchoring strength can decrease with increasing of number of reinforcement and anchorage length, but increase with increasing of thickness of concrete cover.