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The authors developed two types of block systems, consisting only of main and key blocks, without joint mortar, to improve the in- and out-of-plane seismic performances and enhance the workability. Two types of block systems have different key block shapes. One is the peanuts shape, and the other is the H shape. The proposed block systems have a half-height difference between the main and key blocks, to significantly improve seismic performance in in- and out-of-plane directions, compared to typical masonry wall with joint mortar. In this study, in order to evaluate the out-of-plane seismic performance of the proposed block systems, two types of block walls are experimentally investigated, including the typical block wall. Firstly, the shaking table tests are carried out to investigate the fundamental out-of-plane behaviors of three specimens. Next, four-point bending tests are planned to evaluate the out-of-plane seismic performance, since all specimens do not occur the out-of-plane collapse in the shaking table tests from the preliminary calculation. In this paper, the development of predominant period, profiles of acceleration and displacement, and maximum tensile strength of each specimen are discussed in detail. As a result, the maximum loads of the proposed block walls were about three to four times that of the typical block wall. This result means that the proposed block system has significantly improved seismic performance in the out-of-plane direction.

There have been several studies on analyses using finely meshed finite‐element ( FE ) models to understand in detail the behaviors of buildings during severe earthquakes. The accuracy of such analyses is often validated by comparing the results to the corresponding full‐scale shaking‐table test. While this approach is highly successful in terms of accuracy, no studies have considered the effect of fractures of members. In this study, numerical analyses are conducted for a steel structure subjected to multiple series of excitations in a full‐scale shaking‐table test considering fractures. The structure is modeled with planar and solid finite elements, and the fracture is treated by the mandatory deletion of elements at the time at which the fracture is observed in the experiment. The results show that by considering the fracture of steel members with the deletion of elements, the history of input excitations, and the resulting damages, the behaviors can be simulated analytically with a much higher accuracy.

In this study, a new type of tank roof form is suggested to reduce the high impact forces caused by sloshing. Using this roof allows the tank designers to consider less freeboard, which is economically valuable. For this purpose, an experimental investigation has been implemented to evaluate the efficacy of the proposed roof to distribute the contained liquid impact forces in several time stages. In these experimental measurements, a series of shaking table tests are conducted for a partially filled tank under harmonic and various earthquake excitations for both typical and proposed tank roof forms. The liquid impact forces are reasonably evaluated and compared for both types of tank roof. The efficacy of the proposed roof design is validated by experimental results and it is shown that the sloshing loads can significantly be reduced up to an average of 50% for the dimensions considered in the experiments.

To investigate the seismic performance of a wind turbine that is influenced by both the ice load and the seismic load, the research proposes a numerical approach for simulating the seismic behavior of a wind turbine on a monopile foundation. First, the fluid-solid coupled equation for the water-ice-wind turbine is simplified by assigning reasonable boundary conditions and solving the motion equation, and the seismic motion equation of the wind turbine is developed. Then, on this basis, we propose a simplified 3D numerical model that can simulate the interactions among the wind turbine, water and sea ice. By conducting shaking table tests, the results demonstrate that the established numerical model is effective. Finally, we investigate the effect of the boundary range and ice thickness on the seismic performance of a turbine under near-field and far-field seismic actions. Research results illustrate that ice changes the distribution form of the hydrodynamic pressure. Moreover, the thickness of the ice greatly influences the seismic behavior, while the influence of the ice boundary range is only within a certain range. Additionally, the ice load decreases the energy-dissipating capacity of the wind turbine, so the earthquake resilience of the wind turbine is significantly decreased.

Soil slopes located in more rainfall region have been damaged significantly in the previous earthquakes due to the earthquake-induced excess pore water pressure (EPWP), which is among primary factors causing slope failure. For the purpose of evaluating seismic behaviors of an unsaturated soil slope at various groundwater levels, we established a simple approach for calculating earthquake-induced EPWP, which is importable to the numerical simulation software through the custom interface. Based on this, we investigate the seismic performance of the unsaturated soil slope. It is observed that the seismic performance of the slope has much difference at various groundwater levels; the slope deformation at a high groundwater level increases greatly while the groundwater reduced the vibration of the slope. Also, it was found that the slope shows different failure processes with the groundwater influence: the failure of slope with high groundwater is mainly the flow slide and tensile crack around the slope toe while the slope presents the collapse and slip failure without the groundwater influence. Moreover, by strict similarity law formula derivation, the shaking table test of two slope models, one without groundwater and one with groundwater, was performed, and the test results show that our calculation results are accurate and reasonable, and our establishment calculation method of EPWP is practical and convenient.

Qinghai-Tibet Plateau is one of the most seismically active aeras of China and rock mass structures or geological structure are also complex here. Earthquake-induced geological disasters are occurred frequently in this region. Among them, plane failure is often generated on bedding rock slope especially in destructive area of the Wenchuan earthquake which caused numerous casualties and serious economic loss. To reveal failure mechanism of bedding rock slope, this paper studied the seismic response and investigated progressive failure characteristics of the bedding rock slope through a large-scale shaking table test. A bedding rock slope of 45° contained an unfilled joint set with spacing of 0.1 m that dipped at an angle of 34° out of the surface, was conducted in a rigid model box, with a length of 3.47 m, width of 0.68 m, and height of 1.2 m, respectively. A series of tests results show that acceleration amplification factor in horizontal direction (AAF-X) increases with the increase of the slope elevation and acceleration amplification factor in vertical direction (AAF-Z) amplifies at lower part of the slope. When the shaking intensities are over 0.2 g, the slope crest and its vicinity start to show nonlinear dynamic response. Existence of bedding planes let the isoline morphology of AAF-X redistribute and dominate the seismic amplification at the crest. The progressive failure progress of the model under earthquake can be divided into four stages. This novel experiment offers some important insights to mechanism of bedding plane landslides triggered by earthquakes, evaluation stability of slopes under earthquake, and disaster prevention and mitigation.

Base-isolated structures are extensively used in critical infrastructure and lifeline projects. Current response spectrum methodology for determining seismic actions has limitations in designing long-period base-isolated structures. Based on a two-degree-of-freedom (2DOF) model that accounts for the non-proportional damping characteristics of isolation bearings, this study analyzes the filtering characteristics of the isolation layers through spectral analysis of both original and attenuated ground motions. Theoretical and experimental results demonstrate that designing the superstructure using the \"filtered response spectrum(FRS)\" is more rational compared to conventional design response spectra(DRS). Shaking table tests under white noise and seismic excitations verify the filtering effect of isolation bearings: filtered acceleration time-history are reduced to 1/3–1/2 of the original peak values, with the FRS exhibiting decreased peaks, rightward shifts, and significantly shortened platform segments. The filtering principle, rather than period elongation alone, better explains the isolation layer’s effectiveness, particularly for structures with inherently long natural periods.Current code-based design spectra inadequately capture the filtered seismic input, necessitating revisions to incorporate isolation-specific filtered spectra for rational and resource-efficient designs.

To improve the safety and functional retention of masonry structures under moderate to severe earthquakes, a systematic study of the mechanical properties of lead rubber bearings (LRBs) and shaking table tests of seismic isolation masonry models was conducted. Firstly, based on the characteristics of low-rise masonry structure houses and common wall sizes, five small-diameter lead-rubber isolation bearings were designed, and vertical performance and horizontal stiffness tests were carried out. The mechanical performance parameters such as equivalent horizontal stiffness, post-yield stiffness, equivalent damping ratio, and vertical stiffness were obtained. The relationship curve and fitting formula between horizontal displacement, shock absorption coefficient and their influencing factors were calculated. Subsequently, a typical two-story brick structure house without structural columns in a village was selected as the test prototype. A vibration table comparison test with and without seismic isolation layer was designed at a 1:2 scale and full counterweight. Using response spectrum analysis and numerical simulation, three seismic waves were selected for both isolated and non-isolated structures, and sensor placement and loading schemes were designed. Based on the comparison of isolation and non-isolation test phenomena, especially the structural damage of the isolation layer, combined with the dynamic characteristics of white noise sweep frequency, acceleration, displacement, interlayer shear force and interlayer displacement angle, the isolation effect is analyzed and the isolation layer model design is verified. The results show that the vertical compression stiffness of LRB No. 4 is relatively stable, the hysteresis curve is full, the horizontal displacement is less than 60.5 mm, the damping coefficient is less than 0.4, the post-yield stiffness is 149.7 N/mm-167.8 N/mm, and the equivalent horizontal stiffness is 193.9 N/mm-218.65 N/mm. The first two periods of the isolation model are longer and the natural frequency is low, about 25% of the non-isolation model. When the peak acceleration is 0.4 g, the reduction rate of the top layer increases to about 48%, and the reduction rate of the first layer increases to about 40%. The displacement reduction rate of the top floor is about 24% under the action of Tangshan waves, about 36% under the action of Jiangyou waves, and up to 40% under the action of artificial waves. The test results verified the rationality of the low masonry isolation model structure and the isolation effect of lead core rubber bearing(LRB) + Frictionless sliding bearing(FSB).

A large-scale shaking table test of an anti-dip rock slope at the tunnel entrance with retaining structures was designed and conducted, and the dynamic responses of the slope and the surrounding rock were analyzed. To investigate the damage evolution law in the surrounding rock, dynamic parameters of the rock mass and marginal spectra were used to study the dissipation law of seismic energy and the distribution characteristics of seismic energy across different frequency bands, respectively. The research findings indicate that the retaining structure effectively inhibits toppling failure at the tunnel entrance; however, considerable toppling deformation persists in the slope, and a through-going crack has developed at the invert section of the tunnel lining. The acceleration amplification effect in the shallow buried section of the tunnel is stronger than that in the deep buried section. Under vertical seismic action, the acceleration amplification effect at the tunnel entrance is significant. The damage analysis based on dynamic parameter changes shows that, with increasing input acceleration, the damaged area is mainly concentrated in the surrounding rock at the lower part of the lining and gradually extends deeper into the slope. Marginal spectrum analysis shows that, under vertical seismic action, the damage to the surrounding rock at the lower part of the lining can be identified according to the energy distribution characteristics in the 9–12 Hz frequency band. The failure state of the lining can be effectively identified through changes in the dynamic parameters and attenuation of the marginal spectrum amplitude of the surrounding rock. For the seismic design of anti-dip rock slopes at tunnel entrances, the seismic performance of the inverted arch in the lining should be improved, and reinforcement measures for the surrounding rock beneath the lining should be intensified. Greater attention should be given to the low-frequency components of vertical seismic waves.

A set of benchmark, medium scale, shaking table tests on corroded reinforced concrete (RC) columns is conducted with the aim of investigating the effects of corrosion damage on the nonlinear dynamic behaviour of RC bridge piers. The experimental programme consists of an uncorroded control specimen and two corroded RC column specimens, with identical structural details. An accelerated corrosion procedure is used to corrode the RC columns. The uncorroded and corroded specimens are subjected to far-field long duration ground motion excitations. The two corroded columns had 51% and 65% average mass loss ratios. The testing sequence includes slight, extensive, and complete damage levels, followed by an aftershock to examine the cascade effect on the nonlinear dynamic response of the proposed RC columns. The experimental results show that corrosion changes the failure mode of the RC columns, and has a significant negative impact on the residual strength (about 50% mass loss results in about 80% strength reduction) and drift capacity of RC columns.