Advanced Materials Research Vols. 594-597

Abstract: Three primary nuclear technique of RCCM, ASME and the GB50267-97 code of China, have the similar classification of nuclear facility in nuclear power plant, including the code class and security class. The class 2 pressure pipeline design clauses in the 3 codes are similar, but are not identical. The earthquake input and the clauses about the class 2 pressure pipeline are compared. The results show that, when use the alternative damping values for response spectra analysis, GB and ASME are somewhat safer than RCCM in level B criteria, RCCM is somewhat safer than GB and ASME in level D criteria. In class 2 piping design code, RCCM stress assessment focuses more on the pressure, the GB and ASME is more focuses on considering the weight and occasional loads, in the lower pressure and the same stress intensification factor conditions, GB and ASME criteria are conservative than RCCM.

Abstract: With vigorous development of hydroelectric source in west China, the anti-seismic security issue of dam engineering attracted particular attention. This paper presented the principle of dynamic time-history analysis method and established the model with the assistance of finite element method and combined with practical engineering for further analysis on the dynamic response of displacement and stress of dam’s dynamic time-history analysis to the time history. According to the result, it is feasible and necessary to apply the dynamic time-history analysis method to study the anti-seismic performance of the dam. Furthermore, it pointed out the weak part of the dam in anti-seismic function as well as the area concentrated with critical stress, providing reference for future anti-seismic engineering and shock resistance.

Abstract: The boiler steel structure is the main parts of the boiler, its stability directly determines the normal operation of the boiler and the security of the surrounding environment. For analyzing the boiler steel structure, first respectively using matrix displacement method, energy method and the empirical formula method to calculate the periodic of the boiler steel structure; then using the bottom shear method and the mode-superposition response spectrum method to calculate the shear and the axial force of the boiler steel structure in same situation, and through comparing the results to gain the correction coefficient of the mode-superposition response spectrum for the engineering practice and discussing the calculation of the boiler steel structure under earthquake using mode-superposition response spectrum method. Providing the theoretical basis for the seismic design, the reinforcement and the maintenance of the boiler steel structure.

Abstract: Seismic subsidence of loess is a kind of disaster induced by strong ground motion in loess area, while seldom example of this subsidence was found in long time study, usually instead of laboratory test. An explosion ground motion in a typical loess field was designed to verify seismic subsidence of loess with natural condition and laboratory test of loess seismic subsidence was conducted in China. The result proved seismic subsidence of loess could be induced by explosion ground motion, while the maxmuim settlement of 3.3cm in the case of experiment is much less than 53cm with a moderate or strong dynamic stress in laboratory due to an incomplete seismic subsidence of loess in this field. The seismic subsidence of toper loess layers is less than the below in the field test although it is opposite to in laboratory test due to closer distance between the below layers and explosion shots.

Abstract: Based on mobile strong motion array observation, borehole exploration and site seismic response analysis, the site effects of mountainous topography in southeastern Gansu and the topography of loess tableland on ground motion were investigated in details. The analysis on acceleration records of aftershocks showed that the peak ground acceleration at top of the mountain is nearly 2 times of that at the foot of it. The seismic response analysis of sites shows that the loess tableland may amplify PGA by 1.44-2.0 times. Therefore, site effects of mountains and loess topography on ground motion should been taken account into seismic design.

Abstract: Loess is widely distributed in China and the Loess Plateau is one of the major areas where strong earthquakes often take place. From the field investigation on earthquake damages caused by Wenchuan Ms 8.0 of 12 May. 2008, the seismic amplification effects were observed. In order to analyze the mechanism of the seismic amplification effects, microtremor surveys were carried out to detect the ground condition and the predominant frequency of the different sites of the same mountain was obtained. Moreover, the typical mesa of loess plateau is studied applying the dynamic finite element analysis method of two dimensions linearly equivalent for dynamic response numerical calculation, with different loess thickness and different slope grades. The magnifications of peak acceleration at the mountaintop and mountainside are obtained under different conditions. It is found that the magnification is related to the loess thickness and slope grades, which is in accordance with the earthquake damages, and the results show that the loess thickness and slope grade are important factors influencing earthquake damage.

Abstract: The assembled monolithic compound spiral reinforced concrete column in this paper is a kind of concrete column reinforced by high-strength compound spiral stirrups and jointed by local steel tubular and bolt reinforcement. Experiments of four specimens under low cyclic loading and different axial compressive loads are carried out, and the result testifies that the anti-seismic property of these measures is not worse than the integral compound spiral hoop columns under the same load.

Abstract: Reinforced concrete ( RC) frame structure is one type of building structure which is widely used in China. Damage of some reinforced concrete frame structures under the earthquake is caused by the damage of RC beams, So RC beams are an essential seismic members. The paper introduces the design of RC beam specimen, mechanical properties of materials, production of RC beam specimen, test method, loading device, loading system, the contents of measurement and data acquisition in detail. From the above analysis, it is obvious that the test is the most effective means of studying the seismic performance of beam.

Abstract: Three level seismic fortification theory is seismic design theory of the bearing capacity,which can not really realize that no damage under minor earthquake, repairable under moderate earthquake and no collapsing under strong earthquake. In order to overcome this deficiency, American earthquake engineering and structural engineering experts have profound conclusion after the previous earthquakes, improved bearing capacity design method, put forward the theory of performance-based design.Firstly,the origin of performance-based design theory is introduced in the paper.Secondly,the main content of performance-based design theory is illustrated,which include Earthquake Hazard Levels,performance levels of building structure,target building performance levels and performance- based design methods.Finally,the paper pointes out that performance-based design theory has attracted extensive attention of Chinese researchers and engineering designer,a series of research work has been carried on,and some achievement has been made.

Abstract: during the process of fitting or synthesizing near-fault ground motion，parameters of the equivalent velocity pulse need to be decided based on seismic records．Thus, it is a key problem that how to identify these parameters from the records．Pulse period and pulse peak velocity are important parameters in the equivalent velocity pulse models．In this study，various methods on identifying these parameters are reviewed．It is shown that all the existing methods have limitations，especially for the irregular seismic records．Finally，problems need to be further studied is pointed out.