## 6 Conclusions  
In this study, a new type of beam-column joint was designed, two full-scale new-type joints were tested under low cyclic loading, and the influence of bolt strength on the seismic performance of new-type joints was studied. The finite element model was established based on the experimental joint specimens, and the results were compared with the experimental results to verify the correctness of the finite element simulation results. Through the finite element software, the seismic resistance of new joints with different axial ratios was studied, and the influence of the axial compression ratio on the seismic performance of new joints was discussed. Based on the above research, a new type of improved joint is proposed, the numerical model of the improved joint is established by finite element software, and the seismic performance of the improved joint is compared with the experimental simulation results. The main conclusions are as follows:  
1. Under the action of low-cycle loading, bolts and precast beams are the main stress components of the new-type joints, and the failure modes are as follows: bolts yield, enlarged ends of precast beams are destroyed, and precast columns and the corbel can still bear the load. Under an earthquake, bolts and precast beams can be replaced to complete the joint repair work, which accords with the new joint design concept. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Specimen** & **Axial Pressure** & \multirow{2}{*}{\(V_{j}\)_Calculation (kN)_} & \multirow{2}{*}{\(V_{j}\)_Test (kN)_} & \multirow{2}{*}{\(V_{j}\)_Calculation/V\({}_{j}\)_Test_} \\
**Number** & **Ratio** & & & \\ \hline J1 & 0.05 & 1236 & 1126 & 1.28 \\ J2 & 0.05 & 1452 & 1238 & 1.17 \\ \hline \hline \end{tabular}
\end{table} 
Table 12: Comparison between the calculated values and test values of shear bearing capacity of joints. Figure 37: Stress diagram of the joint core. 2. The hysteresis curves of the two new joints are bow-shaped, and the hysteresis curves are generally smooth and full, with a large hysteresis loop area. The equivalent energy dissipation coefficient is 0.855-1.16, and the equivalent damping coefficient is 0.1-0.25, indicating that the new joints have a strong energy dissipation capacity. 3. The two new joints have obvious stiffness degradation, and the descending section is relatively gentle. The residual stiffness of J1 and J2 is 1.16 and 0.5, respectively, which indicates that the new joints still have a certain bearing capacity when they are damaged. At the same time, according to the stiffness degradation curve, the stiffness degradation speed of J2 in each displacement stage is slightly smaller than that of specimen J1, and the stiffness of J2 in each displacement stage is higher than that of specimen J1, which indicates that increasing the bolt strength reduces the degradation rate of joint stiffness. 4. The yield load \(P_{y}\) = 98 kN, the ultimate load \(P_{max}\) = 148 kN, and the ultimate failure load \(P_{u}\) = 151 kN of J1. The yield load \(P_{y}\) = 113 kN, the ultimate load \(P_{max}\) = 165 kN, and the ultimate failure load \(P_{u}\) = 178 kN of J2. Compared with J1, the yield load of J2 is increased by 39.4%, the ultimate load is increased by 11.5%, and the failure load is increased by 13.2%. This shows that when the strength grade of bolts increases, the yield bearing capacity and ultimate bearing capacity of joints will increase. It is suggested that the strength of connecting bolts can be appropriately increased to improve the bearing capacity of joints in practical engineering. 5. The finite element simulation results are in good agreement with the experimental results. The simulation results showed that the opening cross section of the column in the core of the joint mainly bears the compressive stress along the axial direction of the screw exerted by the bolt in the horizontal direction and forms local concentrated stress in the area of the hole opening but is not subjected to shear stress.