## 4 Conclusions  
Several high-intensity earthquakes have occurred worldwide and caused enormous economic losses or deaths in recent years. With the aim of mitigating the detrimental effects induced by earthquake disasters, LYP steel, with excellent ductility capacity, can be potentially adopted as an effective energy dissipation device in structural systems such as high-rise buildings, long-span structures, and railway bridges. However, the inelastic dynamic responses, with repeated cyclic out-of-plane buckling and yielding of the LYP steel energy absorbers subjected to the earthquake action, is highly complex and difficult to predict accurately by any conventionally analytical or numerical method. The goal of this paper is to clearly demonstrate, by a rigorous experimental program, that the benefits of using energy absorbers, which behave just like a \"fuse\" in buildings, can significantly improve the seismic performance of structures. The insight into the dynamic behaviors of the test structure will enable a better guideline for seismic design under strong earthquakes. In this study, a number of experiments were conducted to investigate the non-linear dynamic seismic responses of a quarter-scaled model of a steel frame retrofitted by LYP steel energy absorbers. The test specimens were subjected to a shaking table test with gradually increasing acceleration amplitudes, representing incremental earthquake intensities. The following main conclusions can be drawn from the experimental studies. 1. Incorporation of the energy absorbers into high-rise buildings can significantly enhance the seismic performance of the structure, which provides a low-cost alternative solution for structural designers. The low-yield-point steel with superior hysteretic behavior should be primarily adopted as the material used in the energy absorbers, which enter the yield stage prior to the main members of the frame in order to provide energy dissipation when subjected to the earthquake action. Attention should be paid to the shape of the plate when designing the energy absorbers. The cross-sectional width of the LYP plate varies with the height, which is smallest at the middle and largest at both ends. The arc transition adopted at the cross-sectional change is an effective way to improve the local stress concentration. 2. The measured initial fundamental natural frequency and initial damping ratio of the specimen were 15.68 Hz and 3.17% subjected to the first loading stage of 0.1 g, respectively, which remained essentially unchanged before PGA \(<\) 0.6 g. As the PGA increased from 0.7 g to 1.0 g, the natural frequency gradually decreased while the damping ratio slightly increased. These results indicated that structural stiffness degradation and slightly accumulated damage occurred. The results were in a good agreement with the experimental observations on the loosening of the high-strength bolts at column bases. 3. The acceleration amplification factors \(\beta\) under PGA = 1.0 g at the second floor were, respectively, 2.3, 2.42, and 2.63, subjected to the El Centro, Kobe, and Taft waves, while those at the first floor were 1.4, 1.32, and 1.78, respectively. The \(\beta\) value increased with the height and exhibited a sharp increase before a certain input acceleration level, and then it gradually decreased with a further increasing acceleration. 4. The maximum inter-story drift ratio of the test model was between 1/2310 and 1/1742 in the case of frequent earthquakes and was 1/233 in the case of rare earthquakes, which was significantly less than the allowable limit values given in China's seismic code. This clearly reveals that the structure possesses an extremely high safety reserve, to sufficiently satisfy the design requirements, and is remarkably suitable for applicability in high-intensity seismic fortification areas. 5.