Analysis of RMS Acceleration Response Spectrum for Random Pedestrian Loads

2011 ◽  
Vol 261-263 ◽  
pp. 292-298 ◽  
Author(s):  
Jie Song ◽  
Zhi Gang Song ◽  
Yi Jie Shen

Pedestrian loads are affected by such uncertain parameters as walking step frequency, step length, dynamic load factors and phases of harmonic components, which lead to the uncertainties of structural response. A new method for calculation random response spectrum based on uniform design is introduced to reduce calculation work. A few representative samples of loads time histories are simulated using uniform design, and then the RMS acceleration response spectrums are obtained by dynamic time-history analysis of beam structures with different spans and damping ratios. The RMS acceleration response spectrums which have certain percentiles are obtained by reliability analysis based on response surface. Ultimately the general forms of RMS acceleration response spectrums are deduced from the analyses of sensitivities for damping ratio and span.

2018 ◽  
Vol 34 (4) ◽  
pp. 1913-1930 ◽  
Author(s):  
Irmela Zentner

The random vibration theory offers a framework for the conversion of response spectra into power spectral densities (PSDs) and vice versa. The PSD is a mathematically more suitable quantity for structural dynamics analysis and can be straightforwardly used to compute structural response in the frequency domain. This allows for the computation of in-structure floor response spectra and peak responses by conducting only one structural analysis. In particular, there is no need to select or generate spectrum-compatible time histories to conduct the analysis. Peak response quantities and confidence intervals can be computed without any further simplifications such as currently used in the response spectrum method, where modal combination rules have to be derived. In contrast to many former studies, the Arias intensity-based definition of strong-motion duration is adopted here. This paper shows that, if the same definitions of strong-motion duration and modeling assumptions are used for time history and RVT computations, then the same result can be expected. This is illustrated by application to a simplified model of a reactor building.


2018 ◽  
Vol 4 (12) ◽  
pp. 2926
Author(s):  
Pouyan Ashrafzadeh ◽  
Arash Kheyrolahi

Equivalent static, response spectrum and time history analysis are the well-known analysis methods that traditionally proposed. These methods are highly accurate but requires a great deal of time to match accelerations and the number of analyses, in the other words these methods are time consuming methods. Hence recently the structures are investigated using the durability time method, which plays an essential role in reducing the number of analyses that needs to be created; In fact, the durability time method is a new method of seismic analysis that is presented with a minimum number of time histories analysis. In this method the structure is placed under the influence of an increasing dynamic stimulation, structural response has been investigated over time and evaluated according to the corresponding response to different levels of stimulation intensity, strengths and weaknesses, and structural performance. In this study, steel folding frameworks with 5, 10 and 15 floors were investigated under two analytical methods (Time durability and Time histories methods). At first, the frameworks will be exposed under history of Imperial Governor, Kobe and Lumaprita earthquakes and analysis by finite element software ABAQUS. Then, based on the three analytical functions, the durability is investigated and the results are compared with each other. Finally, the behavior of the structures discussion and conclusion. The results show that the durability analysis method for earthquakes with higher intensity and time is more efficient, and for the Time-less earthquakes by time history method parametrically have a parametrical difference of 5%.


2011 ◽  
Vol 71-78 ◽  
pp. 1444-1450
Author(s):  
Wen Zheng Zhu ◽  
Zhong Gen Xu

The process and thought for the approach bridge of Suiwei bridge design using the method of isolation and energy dissipation were proposed in this paper. The concept of protecting a bridge from the damaging effects of an earthquake by introducing isolating bearings to isolate it from the moving ground is an attractive one. Firstly, the sizes of the laminated rubber bearings and the dia- meters of lead plugs are calculated with static analysis. Then the internal forces of the piers and the damping ratio of the isolated bridge needed to restrict the seismic deformation to 8cm during earth- quakes with seldom intensity were calculated using the Response Spectrum Method, and the result verified with dynamic time history method demonstrates that the Response Spectrum Design Method can restrict the girder displacement to 8cm during large earthquake and reach the goal of 25 percent shock reduction. The design process can be of reference to the bridge design with isolation and energy dissipation.


2011 ◽  
Vol 138-139 ◽  
pp. 217-222
Author(s):  
Fei Wang ◽  
Jie Mei Ma ◽  
Chun Lian Li ◽  
Yun Hui Chen

Deeply studying vibration and seismic response characteristics of Beijing Yin-tai Center provided information reflecting its anti-seismic performance based on which seismic response observation array was to be deployed. Time-historic analytical methods on the basis of modal analysis were applied to carry out structural seismic response. Two load cases were mentioned including the responses under minor earthquakes and moderate earthquakes. El-Centro wave, Northridge wave and synthetized time-histories were adopted with contrast analysis under Beijing Hotel time-history recorded in Tangshan Earthquake. Peak inter-story shift ratios and peak accelerations are obtained and analyzed. The inter-story shift ratio determines elastic state of structure under minor earthquakes and elastic-plastic state under moderate earthquakes. Predominant inter-story displacement and acceleration response provides the floors with more remarkable seismic response, which are vulnerable floors for monitoring in earthquakes.


2017 ◽  
Vol 33 (4) ◽  
pp. 1495-1512
Author(s):  
Clinton P. Carlson ◽  
Dimitrios Zekkos

Ground motion modification is extensively used in practice to modify a seed acceleration time history in intensity and frequency content until its acceleration response spectrum matches a target spectrum. However, the decision to accept or reject a modified motion commonly relies on a subjective process where the time histories of the modified motion are visually compared to those of the seed motion. Various metrics were used to quantify the similarity between the modified time histories and their scaled counterparts for hundreds of modified ground motions from three different earthquake scenarios. Of the metrics considered, the inverse modified RMSE metric for time histories ( imRMSE t) was found most appropriate as it resulted in the least amount of dispersion in the goodness-of-fit values with respect to spectral mismatch. The imRMSE t was then found to be correlated to qualitative rankings assigned to the modified time histories through a visual assessment. The correlation between the quantitative imRMSE t values and qualitative rankings is used to establish threshold values to screen modified velocity and displacement time histories that are likely acceptable or likely unacceptable.


2013 ◽  
Vol 353-356 ◽  
pp. 979-983
Author(s):  
Dong Zhang ◽  
Jing Bo Su ◽  
Hui De Zhao ◽  
Hai Yan Wang

Due to the upgrade and reconstruct of a high-piled wharf, the piling construction may cause the damage of the large diameter underground pipe of a power plant nearby. For this problem, a dynamic time-history analysis model was established using MIDAS/GTS program. Based on the analysis of the pile driving vibration and its propagation law, some parameters, such as the modulus of the soil, the Poissons ratio of soil, the action time of vibration load and the damping ratio of the soil that may have an effect on the response law of the soil, were studied. The study results not only serve as an important inference to the construction of this case, but also accumulate experience and data for other similar engineering practices.


2015 ◽  
Vol 724 ◽  
pp. 353-357
Author(s):  
Jian Zhu ◽  
Ping Tan ◽  
Pei Ju Chang

This study focus on derivation of such vulnerability curves using Fiber Reinforced Polymers technologies retrofitted conventional RC industrial frames with masonry infill wall. A set of stochastic earthquake waves which compatible with the response spectrum of China seismic code are created. Dynamic time history analysis is used to compute the random sample of structures. Stochastic damage scatter diagrams based different seismic intensity index are obtained. Seismic vulnerability of FRP-reinforced RC industrial frames is lower than unreinforced frames obviously, and seismic capability of frames using FRP technologies is enhanced especially under major earthquake.


2013 ◽  
Vol 756-759 ◽  
pp. 4482-4486
Author(s):  
Chun Gan ◽  
Xue Song Luo

In recent years, frequent earthquakes have caused great casualties and economic losses in China. And in the earthquake, damage of buildings and the collapse is the main reason causing casualties. Therefore, in the design of constructional engineering, a seismicity of architectural structure is the pressing task at issue. Through time history analysis method, this paper analyzes the time history of building structural response and then it predicts the peak response of mode by response spectrum analysis. Based on this, this paper constructs a numerical simulation model for the architecture by using finite element analysis software SATWE. At the same time, this paper also calculates the structure seismic so as to determine the design of each function structure in architectural engineering design and then provides reference for the realization of earthquake-resistant building.


2020 ◽  
Vol 156 ◽  
pp. 05026
Author(s):  
Fauzan ◽  
Afdhalul Ihsan ◽  
Mutia Putri Monika ◽  
Zev Al Jauhari

The amount of potential investment in Padang City, Indonesia since 2017 attracted many investors to contribute to the city. One of the investments is a 12-story hotel that will be constructed in By Pass Street of the city. The hotel is located in a high seismic zone area, so the seismic base isolation has been proposed to be used in the hotel building. The main aim of using a seismic base isolation device is to reduce the inertia forces introduced in the structure due to earthquakes by shifting the fundamental period of the structure out of dangerous resonance range and concentration of the deformation demand at the isolation system. An analytical study on the Reinforced Concrete (RC) hotel building with and without rubber bearing (RB) base isolation is carried out using the response spectrum and time history analysis methods. The results show that internal forces and inter-story drift of the building with high damping rubber bearing (HDRB) are lower than that of the fixed base with a remarkable margin. From this study, it is recommended to use the HDRB base isolation for medium and high rise buildings with soft soil in Padang City, Indonesia.


2016 ◽  
Vol 845 ◽  
pp. 274-282
Author(s):  
Fauzan ◽  
Febrin Anas Ismail ◽  
Zev Al Jauhari

Keywords: Earthquake, Internal Forces, Displacement, Response Spectrum Analysis, Time History Analysis, PoundingAbstract. Teaching Hospital is an educational facilitiy for students in the Faculty of Medicine and also as a health services for the general public. The hospital building must be built in accordance with earthquake-safe building standards, so that buildings are not damaged in an earthquake. Andalas University Hospital was built at Padang in 2014 which was designed using Indonesian Seismic Code SNI 03-1726-2002 with quakes zone 6. Since 2012, a new Seismic Code, SNI 1726-2012, was issued and all the buildings should be designed by using the new code. Therefore, the authors are interested in analyzing the structural response of the hospital building by using new seismic code SNI 1726-2012. The results, then, were compared with the responses of the structure which calculated by using SNI 03-1726-2002.The results of analysis show that the structural responses in the internal forces and displacement by using SNI 1726-2012 was higher than those using SNI 03-1726-2002. In this study, an analysis of potential Pounding was also conducted by using dynamic analysis Time History method. The analytical result shows that there is no pounding between adjacent buildings at Andalas University Hospital Buildings.


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