This paper numerically studied the collapse capacity of high-rise steel moment-resisting frames (SMRFs) using various width-to-thickness members subjected to successive earthquakes. It was found that the long-period component of earthquakes obviously correlates with the first-mode period of high-rises controlled by the total number of stories. A higher building tends to produce more significant component deterioration to enlarge the maximum story drift angle at lower stories. The width-to-thickness ratio of beam and column components overtly affects the collapse capacity when the plastic deformation extensively develops. The ratio of residual to maximum story drift angle is significantly sensitive to the collapse capacity of various building models. A thin-walled concrete filled steel tubular (CFST) column is proposed as one efficient alternative to enhance the overall stiffness and deformation capacity of the high-rise SMRFs with fragile collapse performance. With the equivalent flexural stiffness, CFST-MRF buildings with thin-walled members demonstrate higher capacity to avoid collapse, and the greater collapse margin indicates that CFST-MRFs are a reasonable system for high-rises in seismic prone regions.

To evaluate the fatigue behaviour of glass-fiber-reinforced polymers (GFRP), an experimental study was firstly carried out based on the up-downmethod. Then, the different predictionmodels, including linear model, nonlinear model and accumulated model, were utilized to modelling the fatigue life of GFRP composite materials, where the genetic algorithm (GA) was combined in the modelling procedure. The result reveals that the bond connecting the specimen with the clamp is the weakness under fatigue loading, thus the bond connecting the constructionmember in lattice tower with the fitting part in nodal points is the essential part that must be paid close attention to; the simulation results show that these three models whose parameters are assigned by using GA are satisfied well with the experimental data.

For the dynamic fatigue problem of transmission tower cross arms caused by the strong wind load, an experimental study on low-cycle fatigue behavior of a new type full-scale glass-fiber-reinforced polymers (GFRP) cross arm with steel sleeves was carried out. A total of six specimens were subjected to cyclic loading for simulating low-cycle fatigue. The stress state was monitored. The variety of load-displacement-time curve, energy dissipation and dynamic strain were analyzed. The ultimate bearing capacity of the specimens without significant fatigue failure was examined to derive residual bearing capacity. Based on the residual strength theory, the cumulative damage was evaluated to predict the fatigue life. It is shown that the GFRP cross arms demonstrated favourable anti-fatigue performance, and can be expected to provide important reference for wind res istance design in transmission tower line system.