Guoliang Bai

Seven groups of long-period ground motions (LPGMs) and three groups of ordinary ground motions (OGMs) were selected and bidirectionally input into a high-rise structure; the energy distribution and dissipation characteristics of the structure were studied comparatively. The results show that at the same seismic level, the input energy of the structure under LPGMs is significantly greater than that under OGMs. Under OGMs, the structure mainly dissipates energy through damping energy, while under LPGMs, hysteretic energy becomes the main way of energy dissipation. During an 8-degree frequent earthquake, coupling beams are the main energy dissipation members, the floors below 2/3 of the structural height mainly dissipate hysteresis energy by coupling beams, with the hysteretic energy ratio ranging from 61% to 99.9%, and the floors above 2/3 of the structural height mainly dissipate hysteretic energy by frame beams. During 8-degree design and rare earthquakes, the hysteretic energy ratio of coupling beams significantly decreases, and frame beams are the main energy-dissipating members; the hysteresis energy on the first to second floors is mainly dissipated by shear walls, while on floors above the third floor, the hysteresis energy is mainly borne by frame beams, the hysteretic energy ratio from the fifth to the twelfth accounts for 56% to 89%, and above the twelfth floor accounts for more than 85% to 90% on that floor.

To accurately assess the seismic damage of high-rise structures under long-period ground motions (LPGMs), a 36-story SRC frame-RC core tube high-rise structure was designed. Twelve groups of LPGMs and twelve groups of ordinary ground motions (OGMs) were selected and bidirectionally input into the structure. The spectral acceleration S_90c considering the effect of higher-order modes was adopted as the intensity measure (IM) of ground motions, and the maximum inter-story drift angle θ_max under bidirectional ground motions was taken as the engineering demand parameter (EDP). Structural Incremental Dynamic Analysis (IDA) was conducted, the structural vulnerability was investigated, and seismic vulnerability curves, damage state probability curves, vulnerability index curves, as well as the probabilities of exceeding performance levels and vulnerability index of the structure during 8-degree frequent, design, and rare earthquakes were obtained, respectively. The results indicate that structural damage is significantly aggravated under LPGMs, and the exceeding probabilities for all performance levels are greater than those under OGMs, failing to meet the seismic fortification target specified in the code. When encountering an 8-degree frequent earthquake, the structure is in a moderate or severe damage state under LPGMs and is basically intact or in a slight damage state under OGMs. When encountering an 8-degree design earthquake, the structure is in a severe damage or near-collapse state under LPGMs and is in a moderate damage state under OGMs. When encountering an 8-degree rare earthquake, the structure is in a near-collapse state under LPGMs and in a severe damage state under OGMs.

Irregularity in the plane layout of a building structure and the vertical discontinuity of lateral resistance components could lead to torsion and result in the brittle failure of a structure. According to the characteristics of the conventional island main building of nuclear power plants, this paper focuses on the conventional island main building of the CAP1400 nuclear power plant (NPP) in Shidaowan as the research object. A prototype structure model of the main building was developed using ABAQUS software. The seismic response of the structure under multidimensional ground motion was studied by inputting the X-direction and Y-direction translational and torsional components of ground motion in ABAQUS. The results demonstrate that the overall transverse displacement of the structure under bidirectional ground motion was significantly higher than that under unidirectional earthquakes, which was about 20%. Under a multidimensional frequent earthquake, the transverse displacement of the structure increased by about 13% on average compared with that under a bidirectional earthquake; the longitudinal increase was the largest, at about 28%. Finally, the lateral displacement of each layer of the steel-reinforced concrete (SRC) frame-bent main building structure with few walls proposed in this article decreased by an average of about 17% compared to the traditional SRC frame-bent main building structure. The longitudinal displacement was reduced by about 14% compared to the traditional SRC frame-bent main building structure.

Equivalent cast-in-site" is the current consensus on the seismic performance of fabricated buildings from home and overseas, that is, through reliable construction and connection measures, the macroscopic seismic performance of fabricated buildings is not lower than that of cast-in-place reinforced concrete structure. However, the research shows that the failure mechanism, damage forms and seismic performance indexes of prefabricated structures are different from those of cast-in-site structures, and the theory of "non-equivalent cast-in-site" is more consistent with the characteristics of stress, force transmission and connection deterioration of prefabricated structures. In this paper, a macroscopic "non-equivalent" numerical calculation method is proposed for the fabricated shear wall connected by grouting sleeve. First, a numerical calculation model of shear wall without considering the influence of sleeve connection and one that can consider the influence of sleeve connection are established, respectively, and the difference in carrying capacity between the two models is compared and analyzed. Furthermore, the strain values of concrete, reinforcement and joints in the calculation model of "non-equivalent" shear wall under nonlinear push over analysis are obtained, and the material properties and failure mechanism are analyzed. It is hoped that the research results can be valuable for the calculation and analysis of assembled walls.

Concentrated solar towers are commonly designed as high-rise hybrid structures, which exhibit properties of non-uniform mass and rigidity along the height of the tower, and consequently are vulnerable to strong seismic ground motions. This study presents a comprehensive analysis of the seismic performance of a hybrid solar tower, which is one of the tallest hybrid solar towers in the world. The hybrid solar tower includes a reinforced concrete tube at the bottom and a steel-truss tube at the top and is subjected to near-fault pulse-like ground motions. A simulation technique that utilizes the stochastic point-source model and a velocity pulse model was introduced to generate stochastic pulse-like ground motions. The stochastic response of the hybrid solar tower to near-fault pulse-like ground motions was computed to estimate the tower’s reliability. To enhance the efficiency of reliability estimation, an algorithm combining the Kriging surrogate and subset simulation (K-SS) was presented. The aggregate response of the tower was found to be significantly more damaging over the border of the reinforced concrete tube and the steel-truss tube than below the border. The study found that the hybrid solar tower has a reliability of 90.53% when subjected to stochastic near-fault pulse-like ground motions with a peak ground acceleration of 0.62 g. The findings of this study contribute to the understanding of the seismic performance of high-rise hybrid solar towers under near-fault pulse-like ground motions.

Coal gangue is the rock discharged from coal mining. Using coal gangue as coarse aggregate is one of the solutions for the sustainable development of construction engineering. Five one-half scaled coal gangue concrete (CGC) frame columns with different coal gangue coarse aggregate replacement ratios were designed, and the effect of coal gangue coarse aggregate on seismic behavior of columns under cyclic loading was studied. The test results show that the failure of coal gangue coarse aggregate under cyclic loading is the main reason for the reduction in hysteretic performance of CGC specimens. Compared with natural aggregate concrete (NAC) specimen, the hysteretic behavior, deformation performance, and energy consumption of CGC columns were reduced. However, the seismic performance of CGC specimens with higher replacement ratio was better than that of CGC specimens with a lower replacement ratio. Compared with NAC specimen, the ductility and total energy dissipation of CGC specimen with r = 100% were only reduced by 8.2% and 12.8%. In addition, the test results also found that the higher the replacement ratio, the greater the shear deformation of the specimen. It is recommended to appropriately increase the stirrup ratio of CGC specimens in seismic design.

In this paper, the compressive strength experiment for three groups of recycled aggregate concrete (RAC) specimens with different replacement ratios of recycled aggregate (0%, 50%, 100%) was carried out. The mechanism of the block and mortar properties on the compressive strength of block masonry was investigated by means of a static loading test. The formula for calculating the compressive strength of a recycled concrete block was obtained based on experimental data. Moreover, the global warming potential (GWP) of recycled aggregate concrete (RAC) block masonry was evaluated by life cycle assessment (LCA) methodology. The feasibility for application of RAC block masonry was discussed combined with environmental impact data analysis. The results show that the strength of RAC blocks is the principal element affecting the compressive strength of block masonry, and the strength of mortar also has a certain impact for the compressive of RAC block masonry; the sub-coefficient of material performance should be enhancive appropriately for ensuring the construction quality of RAC block masonry; the total GWP of RAC block is lower than that of natural aggregate concrete (NAC) block. The environmental benefits of the promotion and application of RAC block masonry are inspiring.