Papers by Keyword: Shaking Table Test

Abstract: Currently, theoretical and experimental studies on the overall behavior of semi-precast reinforced concrete high-rise buildings subjected to the earthquake are limited. These studies have mostly focused on the behavior of either joints or frames. To study the overall behavior of a structure under an earthquake, one of the best methods is to do the seismic shaking table test. This paper presents the results of an experimental study on the overall behavior of a semi-precast reinforced concrete multi-story building, which uses new design and construction technology, by using the seismic shaking table test method. These buildings are constructing in series in Vietnam. This research carried out both the linear and nonlinear behavior of the structure until the stage of near collapse. The study consists of three main steps: designing the simulating model; establishing a process to generate artificial accelerograms which are in accordance with the seismic characteristics in Vietnam; testing the 12-story semi-precast model to verify theoretical predictions.

Abstract: To investigate the seismic performance of the traditional Chinese timber structure, a one-fifth scale model of a seven-story pavilion-style wooden pagoda was tested on a shaking table. An artificial wave and two natural earthquake waves were used. Different excitation intensities ranging from frequent-met level to rare-met level of 7 degree as specified in Chinese code were mainly considered. White noise excitations were applied to obtain the change of the dynamic characteristics of the model. The identification results of dynamic characteristics indicated that the model’s damping ratio was more than 0.1, and the first natural frequency decreased by 17% with the corresponding damping ratio increased by 46% after the earthquake excitations. Typical components which including ludous and sandous were observed with splitting perpendicular- to-wood-grain under rare-met earthquake excitations, but other structural members were not found noticeable damage. The maximum acceleration amplification coefficient of the top point was 2.46, and the maximum displacement was 239 mm. Small residual deformation was detected under the rare-met earthquake excitations. The experiment implied the extraordinary seismic performance of such kind of structures.

Abstract: Pile foundation equipped with a low-cost frictional type seismic isolation device is investigated. The frictional mechanism results from a contact between two surfaces of a half steel sphere mounted on the pile cap and the corresponding inner steel sphere embedded in the footing of upper structure. To verify the mechanical behaviors of the pile with frictional type seismic isolation device, tests, and its numerical simulations have been performed. The rotational friction device is found to be very effective in releasing the internal energy transferred from the pile foundation to the upper structure. The behavior of the friction-type device was studied by modeling using the nonlinear time history dynamic analysis. It was observed that the responses of the structures with devices can be approximated by using springs and dampers model.

Abstract: This study is aimed to investigate the seismic behavior of the freestanding dry storage cask for spent fuel, several shaking table tests were conducted using a scaled cask model for a real assessment of the characteristics of the seismic response of the cask. First, the harmonic excitation test on the pedestal of the cask was performed to estimate the friction coefficient at the interface between the cask and the pad according to the sliding acceleration response of the pedestal. Then, tests for the seismic response of the cask were conducted for two different setups, the vertical cylindrical concrete cask (VCC) and the concrete cask with an add-on shield which has a square pedestal (VCC+AOS), respectively, using the artificial earthquakes compatible to the design spectrum. In order to verify the often-used analysis method for the seismic response of the cask in engineering practice, the explicit finite element software LS-DYNA was adopted to generate the finite element model of the scale cask with the cask/pad interface modeled by Coulomb’s law of friction and to simulate the shaking table tests. Results indicate that the utilized method gave reasonable cask responses if the variation of the friction coefficient at the cask/pad interface was small during the sliding process.

Abstract: This study is aim to evaluate the dynamic response variation of the scale-down reinforced concrete frame specimen under accelerated corrosion conditions. The specimens achieved the accelerated corrosion test by immersing in the accelerated corrosion test. Open circuit potential, corrosion rate, natural frequencies, displacements, accelerations and response spectral curves were tested and discussed. Test results presented that the corroded reinforced concrete specimens presented the changes in the dynamic response especially natural frequencies and response spectrum. This study provided further insight on the variation of seismic response behaviors in the deteriorated reinforced concrete structures and hoped to useful for structural assessments and appraisals applied to full-scale structures.

Abstract: A 1/25 scale-down specimen was constructed of a reinforced concrete reactor building used in the nuclear power plant. The non-demoulding technology and self-consolidating concrete were used to cast the specimen with a length of 2.9 m, width of 2.9 m, height of 2.9 m and weight of 28 tons. The entirety struc-ture was composed of a primary containment (thickness of 10 cm), a secondary containment (thickness of 7.5 cm) and three floors (thickness of 30 and 15 cm). Shaking table tests were conducted on it in the National Center for Research on Earthquake Engineering. Testing results indicated that the scale-down specimen kept the structural integrity under a 0.6 g specific seismic wave hit. In addition, the ETABS model accurately represented the dynamic characteristics of the scale-down specimen by numerical method obtained the conservative results.

Abstract: Shaking table test is an important means of simulated earthquake in laboratory, slope shaking table test data provide a scientific basis for analysis of dynamic stability and instability mechanism of slopes. Sine vibration table test data processing is different from general frequency domain analysis method, need real-time data processing in time domain. Taking the sine sweep test conditions, which is one of the conditions in "Earthquake landslide and slope prevention and control technology research on shaking table test", as an example. Describes the layout of sensors in shaking table test and the reasons; Sine sweep test load and aim; and listed the steps and methods of the sine sweep test in data processing; Through the processing and analysis of test data identified the vibration frequency of model and shaking table system is 30Hz, damping ratio is 2.06%; Analysis and calculation of the different sections of the slope and position of the amplification coefficient. A methodological guidance for shaking table test and dynamic response analysis of the slope is provided.

Abstract: The applicability of seismic waves for the seismic performance estimation of 750 kV post insulator has been investigated in full-scale shaking table test. the input seismic waves comprise El Centro seismic wave, Landers seismic wave, sine beat wave and artificial standard wave. The testing results indicate that, high dynamic responses of the equipment can be obtained under artificial standard wave condition. In addition, due to comprehensive enveloping ability and gentle spectral curve, artificial standard wave is ideal for the seismic performance evaluation of 750 kV post insulator in the test. An finite element model has been developed and numerical seismic analysis has been performed. Satisfactory match between the simulated and measured results reveals the reliability of the test. The achievements obtained in this paper are helpful in choosing reasonable input wave for shaking table test, and also provide technical support on determining seismic capacity of high voltage electrical equipment.

Abstract: As a key component of power transmission and distribution systems, HV reactor bushing made of porcelain have suffered serious damage in previous earthquakes. In order to enhance seismic ability, the new type bushing made of composite material have been used in high seismic fortify-cation intensity projects. The test requirement in this analysis included: the selection of dynamic magnification factor、the selection of excited wave、the control of tolerance between input peak acceleration and output peak acceleration. During the shaking test, the dynamic characteristics, including frequency and damping ratio, and the seismic response of the composite bushing was obtained. Based on the analysis results of the bushing, the judgment of the seismic capacity was achieved.

Abstract: In order to establish the virtual design method of shaking table test of structure in sine-swept vibration, the accurate sine-swept function in logarithmic variety is proposed by theoretic derivation. According to the numerical simulation, the dynamic response of structure in sine-swept vibration by multi-support excitation is acquired. And the maximum amplitude is less than that of structure in sine-swept vibration by single-support excitation based on the comparison with each other. However, several orders vibration mode are excited by the sine-swept vibration in multi-support excitation, and the structure resonates many times, which will increase the damage probability of structure. In other words, the load case of sine-swept vibration by multi-support excitation is worse than the case of sine-swept vibration by single support excitation. The conclusions above can provide basis for design and dynamic time-domain analysis of aerospace products of shaking table test in sine-swept excitation.