Experimental study on spatial mechanical properties of grout anchor lap joints

Abstract

To study the anchoring performance of non-concentric and multi-medium lap joints of grout anchors, pull-out experiments of 18 groups of specimens were implemented. The main focus of this study is the influence of steel bar diameter and anchorage length on the bond and anchorage performance when the diameter of metal bellows and spacing of spiral stirrups are fixed. Qualitative and quantitative analyses are conducted to experimentally ascertain the mechanical safety of structures. The finite element method is employed to replicate crack development and mechanically simulate the segment model. The simulation results are analyzed and compared with experimental data. When the anchorage length is 35d–40d (where d is the diameter of the embedded steel bar), no component is damaged, indicating that the anchorage length is stable and reliable. However, when the anchorage length is less than 15d, slip failure occurs. In this work, a comprehensive description of the mutual restriction and force transmission variation law of each component of the node under the action of stress based on the strain distribution analysis of the multi-media coupling model is provided. Moreover, optimization suggestions for the structure are proposed. The results of this study provide experimental support for the application of this type of joint in prefabricated building structures.