Advanced Materials Research Vols. 446-449

Abstract: Based on the limited demand of transfer beam sectional dimension of tall building structure with transfer story in Technical Specification for Concrete Structures of Tall Building, a high-level transfer frame-shear structure with steel-lead viscoelastic dampers is presented for simulating the mechanical behavior of the key components effect with consideration the transfer beam depth with 1/6, 1/8 and 1/10 calculation span. The analysis results indicate that the internal force of the transfer beam, frame-support column of transfer story, shear wall above transfer level and base shear wall is obviously reduced, with the reduction of the transfer beam depth. Comparison with the high-level transfer frame-shear structure, the internal force of the key components of the high-level transfer frame-shear structure with the steel-lead viscoelastic dampers also is reduced. Therefore, the limited demand of the transfer beam sectional dimension and the construction measure of the shear wall could be properly reduced in the high-level transfer frame-shear structure with the steel-lead viscoelastic dampers.

Abstract: In order to study the seismic performance, of macro-synthetic fiber-reinforced concrete ductile columns, specific used as the concrete energy absorption system placed in the structure, three concrete ductile columns were constructed and tested using low-frequency cyclic loading. The damage pattern, hysteresis curve, ductile factor and equivalent viscous damping coefficient of the columns were obtained. The results show that the macro-synthetic fiber-reinforced concrete ductile column has the good ductility and the high post-crack energy absorption ability.

Abstract: This paper presents a probabilistic seismic risk assessment methodology developed for Highway Bridge including models for transportation network analysis, hazard estimation, and seismic performance of highway components and evaluation of the economic impact to serve as a tool in the decision process for earthquake disaster management including pre-earthquake and post earthquake actions. This study is focused on the development of a procedure for seismic risk assessment, based on a probabilistic seismic hazard analysis.

Abstract: This paper carried out the seismic performance evaluation of a super-tall hybrid structure. The hybrid structure consists of steel reinforced concrete (SRC) frame and reinforced concrete (RC) core wall. Based on the characteristics of the structure, the structural system, seismic performance objectives and seismic measures are presented. Moreover, the elastic response spectrum analysis, elastic and elasto-plastic dynamic analysis are performed to evaluate the seismic behavior of the structure at different seismic hazard levels. The conclusion can be drawn that through the seismic measures taken in the paper, the super-tall structure could generally achieve the seismic performance objectives.

Abstract: Since 90s of last century, foreign scholars propose a floor response spectrum method for seismic analysis of pipeline system multiply supported on buildings, which is named as Cross-Oscillator Cross-Floor Response Spectrum (CCFS) method. The CCFS method is simple in calculation and its results are reliable. Firstly, basic assumptions in expression derivation of CCFS method are studied, such as not introducing support degrees of freedom of building, adopting displacement model and assuming white noise as earthquake excitation etc. All of these assumptions will lead to some shortcomings. Then, the defect root of CCFS method is explained by specific theoretical derivation process, and it is pointed out that utilizing CCFS method for calculating displacement of boundary degrees of freedom of pipeline system relative to building may lead to inaccuracy of results, and the white noise assumption for earthquake excitation will also certainly produce some errors. Finally, the defect of CCFS method is verified by numerical example. The conclusions can provide an important reference for reasonable application of CCFS method in seismic analysis of multiply supported pipeline system on buildings.

Abstract: The objective of this paper is to study the response characteristics of large span structures subjected to multiple vertical excitations by means of time history analyses. The spatial variation of ground motions are represented as the combined effect of wave-passage and incoherency. They are simulated by the method of conditional simulation based on the selected four series of typical recorded ground motions. Some important responses such as internal force, displacement are monitored and compared between different cases. These analytical simulations provide a tentative work for investigating destructive effects of the multiple vertical excitations which can be solidified by further study and post-earthquake survey.

Abstract: There are a large number of acceleration records obtained in the near fault strong motion of Wenchuan earthquake in 2008, which greatly enriched the database of strong motion. By the classification analysis to Sichuan records and comparison with the domestic and international earthquakes analysis, we draw the following conclusions: 1) whether parallel or perpendicular direction, the peaks of soil are greater than rock. With the fault distance increasing, the gap between the two gradually will minish.2) With the increase in the number of peaks obtained, the correlation coefficient of GPGA or LGPA is generally increasing.3) The mean of R is respectively 8.10(rock), 10.31(soil), 10.10(total) in the usual range.4). The average of λ is respectively 0.5862(rock), 0.5707(soil), 0.5722(total), they are between 1/2 and 2/3. The difference is not large.

Abstract: There are a large number of acceleration records obtained in the near fault strong motion of Wenchuan earthquake in 2008, which greatly enriched the database of strong motion. This article compares seismic records of Wenchuan earthquake with other domestic and international earthquakes, such as response spectrum, multi-peaks average and R. It also discussed a damage reason of fault zones in Wenchuan earthquake.

Abstract: By modifying the Random phase angle ,conventional method of ground motion simulation is improved .The simulated result that used conventional method have a good astringency on the limited site and more reasonable to accord with actual state of seismic. To make the simulated result with variability in space and time, simulated progress considered not only the traveling wave effect, but also the spatial coherence of the seismic ground motion and local site effect.

Abstract: Fourier transform and short-time Fourier transform are the main methods in signal analysis, which can reflect the spectrum signature of signals in the whole time domain; but they cannot be used in the multi-resolution analysis on the non-stationary signals. However, the wavelet transform overcome the limits of Fourier and short-time Fourier transform, which can be performed in accurate time-frequency analysis of signals. Furthermore, the diversity of wavelet functions makes the wavelet transform more adaptive and flexible. Applying the wavelet transform to seismic signal processing is the complement and improvement of existing processing methods. In this paper, the basic theory of the wavelet threshold denoising method and its application to the strong motion signal processing were mainly introduced. The high-frequency noises were removed, and simultaneously the high-frequency signals were effectively retained.