Study On Design And Performance Of The Elliptic Steel Anchorage Devices

With the continuous development of construction technology in China,the node of the reinforced concrete structures reinforced hook anchorage problems increasingly prominent,the larger bending radius of 90° hooked steel is easy to cause node congestion reinforced,concrete placement difficult phenomenon,especially for large diameter bars is more outstanding.Shorten reinforced steel anchorage length and ease congestion,reduce steel consumption has become the developing direction of the mechanical anchoring reinforcement,the elliptic steel anchor device is follow the direction of a study.This paper introduced the design of the elliptic anchoring device,and completed the center pullout test and finite element analysis software of 30 specimens.Pullout tests using one-way loading method,by measuring the different bearing area and different diameter reinforced anchorage performance,and under the same conditions,the circular anchor plate and 900° hook steel compared draws the following conclusions:(1)Elliptic anchorage device is composed of elliptic bearing plate and the nut,and connected by a screw thread steel bar,including the design of nut tighten the anchor plate provides convenience for site construction personnel,the overall design are in line with the"regulations of technology of steel bar anchoring plate"(JGJ256-2011).(2)The damage form of specimens are reinforced snap in this test,which give full play to the ultimate strength of the reinforced.Under the same conditions,anchorage performance of the elliptical anchorage device is proportional to the area of bearing plate,and is inversely proportional to the diameter steel,but there is no obvious change.(3)Elliptic anchor device compared with 90° bend hook steel bar anchoring elliptic anchor shortens the anchorage length,improves the anchorage performance,reduce the steel consumption and the cost.Compared with circular anchor plate,the elliptic anchoring ability of anchor is high and improve the reinforced crowded phenomenon,improve the overall stability of the conponent.The anchorage performance of three is:the elliptic anchoring device is not less than the circular anchor plate,and the circular anchor plate is not less than the 900 hook steel And three of them have better anchoring performance.It is also proved that the elliptic anchoring device can be used to replace 90° hook steel.(4)The basic research data about steel bar anchoring by pull-out test and finite element analysis,which formed new methods and new measures to solve reinforced congestion,steel binding difficulty,concrete pouring uneven and reduce the anchorage length of steel bar.To establish and perfect our countrys steel mechanical anchoring technology to lay a certain foundation.