# Anchor Design of a Ring Joint Based on Reliability in a Precast Shear Wall Structure
## 1 Introduction  
The industrialisation of buildings is the future direction for the development of the construction industry, and this transformation will allow for sustainable development of the construction industry. Prefabricated shear wall structure systems are widely used in high-rise buildings, which can reduce resource consumption and facilitate environmental protection. In prefabricated buildings, the connections are critical for the mechanical performance of the structure in meizoseismal areas [1], particularly the vertical connection of the components, the quality and reliability of the connection are crucial to the architecture.  
Various precast building connection methods have been proposed by scholars, and their tensile properties have been evaluated, including grouted sleeve connections, etc. [2; 3; 4]. The grouted sleeve has been developed [5; 6], and its uniaxial tensile properties have been extensively studied [7; 8; 9; 10]. Research has shown that the bearing capacity is affected by the grouted sleeve strength, grout strength, rebar diameter, and bond strength [11]. The bond strength of the grout and rebar plays a key role in determining the bearing capacity, and has thus attracted the attention of researchers. In addition, a novel grouted rolling pipe splice has been proposed and its mechanical performance has been tested [12; 13]. A plug-in filling hole for lap-joint steel bars, was tested considering the rebar diameter, anchor length, and concrete strength, and the results indicated that the connection was reliable [14]. In design theory, the anchoring test was carried out and the calculation formula of the lap lengthdesign was given based on the reliability analysis [15], including straight reinforcement and mechanical anchoring. [PERSON] [16] carried out the pull-out test on grouted-filled lap splice, and established the formula for calculating the ultimate overlap length, and carried out reliability analysis based on the central point method. Both had given the anchor length with reliability guarantee. In the above connections, the complicated joining processes and expensive connecting equipment greatly increases the cost, and the research also indicated that the connection had anchor failure due to the poor interval quality of the connection. Therefore, the concealed operation of the above connection method has a certain degree of security risks in application.  
A new connection called ring joint comprising interlocked ring rebar and inserted horizontal rebar has been proposed. The connection area is poured on-site, and a continuous beam is then formed, which strengthens the joining area significantly, as shown in Figure 1a. This connection saves the sleeve consumption, and there are no concealed operations, which can guarantee the quality and reliability under reasonable design conditions. In research, [PERSON] [17] conducted cyclic tests considering the height-width ratio and the joining height with the connecting area in the middle of the walls, and the results indicated that the connection was safe. To evaluate the mechanical performance, cyclic in-plane tests [18] and the flexural out-of-plane tests [19] were conducted when the connection was applied to the bottom of the shear wall. The above experimental research indicates that the joint can meet the relevant specifications in China. There is still a lack of research on mechanical mechanism and application of anchor design, so further research is necessary.  
In this paper, the pull-out test was carried out to evaluate the anchoring performance. The mechanism was clear and the bearing capacity model could predict the bearing capacity well. Anchor length was determined based on reliability analysis and design suggestions were proposed, which could promote the application of the connection technology.