A Replacement for the 30%, 40%, and SRSS Rules for Multicomponent Seismic Analysis

1998 ◽  
Vol 14 (1) ◽  
pp. 153-163 ◽  
Author(s):  
Charles Menun ◽  
Armen Der Kiureghian
Keyword(s):  
Ground Motion ◽  
Simple Formula ◽  
Seismic Analysis ◽  
Response Spectrum ◽  
Structural Response ◽  
General Rule ◽  
Design Codes ◽  
Maximum Value ◽  
Special Cases ◽  
Orthogonal Components

A response spectrum rule for combining the contributions from three orthogonal components of ground motion to the maximum value of a response quantity is presented. This rule, denoted CQC3, is compared to the 30% and 40% rules and the square-root-of-sum-of-squares (SRSS) rule currently specified in many design codes. It is shown that these current rules are special cases of the CQC3 rule, when certain conditions regarding the nature of the ground motion or the structural response are satisfied. Because these conditions are not always satisfied, it is argued that the CQC3 rule should be adopted as a general rule for the multicomponent combination problem. The CQC3 rule additionally offers a simple formula for determining the most critical orientation of the ground motion components for each response quantity of interest. The CQC3 rule is computationally simple and easy to implement in standard dynamic analysis codes.

scholarly journals A Multi-Objective Ground Motion Selection Approach Matching the Acceleration and Displacement Response Spectra

2018 ◽  
Vol 10 (12) ◽  
pp. 4659 ◽  
Author(s):  
Yabin Chen ◽  
Longjun Xu ◽  
Xingji Zhu ◽  
Hao Liu
Keyword(s):  
Ground Motion ◽  
Response Spectrum ◽  
Structural Response ◽  
Response Spectra ◽  
Computationally Efficient ◽  
Ground Motion Selection ◽  
Displacement Response ◽  
Rc Frames ◽  
Selection Approach ◽  
Displacement Response Spectra

For seismic resilience-based design (RBD), a selection of recorded time histories for dynamic structural analysis is usually required. In order to make individual structures and communities regain their target functions as promptly as possible, uncertainty of the structural response estimates is in great need of reduction. The ground motion (GM) selection based on a single target response spectrum, such as acceleration or displacement response spectrum, would bias structural response estimates leading significant uncertainty, even though response spectrum variance is taken into account. In addition, resilience of an individual structure is not governed by its own performance, but depends severely on the performance of other systems in the same community. Thus, evaluation of resilience of a community using records matching target spectrum at whole periods would be reasonable because the fundamental periods of systems in the community may be varied. This paper presents a GM selection approach based on a probabilistic framework to find an optimal set of records to match multiple target spectra, including acceleration and displacement response spectra. Two major steps are included in that framework. Generation of multiple sub-spectra from target displacement response spectrum for selecting sets of GMs was proposed as the first step. Likewise, the process as genetic algorithm (GA), evolvement of individuals previously generated, is the second step, rather than using crossover and mutation techniques. A novel technique improving the match between acceleration response spectra of samples and targets is proposed as the second evolvement step. It is proved computationally efficient for the proposed algorithm by comparing with two developed GM selection algorithms. Finally, the proposed algorithm is applied to select GM records according to seismic codes for analysis of four archetype reinforced concrete (RC) frames aiming to evaluate the influence of GM selection considering two design response spectra on structural responses. The implications of design response spectra especially the displacement response spectrum and GM selection algorithm are summarized.

scholarly journals Effect of Shear Wall Location On Seismic Performance of High Raised Buildings

2021 ◽  
Vol 4 (1) ◽  
pp. 30-34
Author(s):  
Gajagantarao Sai Kumar ◽  
Purushotham Rao ◽  
Partheepan Ganesan
Keyword(s):  
Seismic Analysis ◽  
Response Spectrum ◽  
Structural Response ◽  
Shear Walls ◽  
Shear Wall ◽  
Existing Structures ◽  
Maximum Stiffness ◽  
Earthquake Resistant Structures ◽  
Minimum Displacement ◽  
Earthquake Zone

Multi-storey buildings tend to get damaged mainly during earthquake. Seismic analysis is a tool for the estimation of structural response in the process of designing earthquake resistant structures and/or retrofitting vulnerable existing structures. The principle purpose of this work is to analyze and design a building with a shear wall and also to find the appropriate position of shear wall that result in maximum resistance towards lateral forces and minimum displacement of the structure. In this study, a G+7 multi-storey building of 15 m ×20 m in plan area has been chosen and modelled using ETABS. The developed model was validated by solving manually and the results were validated in ETABS. Thereafter, 4 different new plans were modelled in ETABS located in the same earthquake zone area. These plans have shear wall concepts are implemented on the building at four different locations. Seismic, vibration and response spectrum analysis were performed on these structures. Salient parameters such as storey stiffness, storey displacement and storey drift were computed using the ETABS model. These were compared with that of the frame having no shear walls. By comparing the results obtained at different shear wall locations, the best plan with the shear wall having minimum lateral storey displacement and maximum stiffness is suggested for this location.

scholarly journals Effect of Frequency Content of Earthquake on the Seismic Response of Interconnected Electrical Equipment

CivilEng ◽  
2020 ◽  
Vol 1 (3) ◽  
pp. 198-215
Author(s):  
Kashif Salman ◽  
Sung Gook Cho
Keyword(s):  
Seismic Response ◽  
Natural Frequency ◽  
Ground Motion ◽  
High Frequency ◽  
Seismic Analysis ◽  
Response Spectrum ◽  
Low Frequency ◽  
Stable Operation ◽  
Design Spectrum ◽  
Standard Design

To ensure the stable operation of safety-related nuclear power plant (NPP) equipment, they are tested by following the seismic qualification procedures. The in-cabinet response spectrum (ICRS) is used to test the mounted components. However, the ICRS varies significantly with the number of uncertainties that include (1) loaded and unloaded condition of the cabinets, (2) the number of connected cabinets (grouping effects), and (3) higher frequency contents in the seismic inputs. This study focuses on the ICRS generation and alteration induced due to the listed uncertainties. A prototype of an electrical cabinet was experimentally examined. Followed by the numerical modeling of the cabinet, the seismic analysis for the group of cabinets was performed using artificial ground motion compatible with the standard design spectrum and the real accelerograms of high and low frequency contents. The seismic response using finite element (FE) analysis manifests (1) natural frequency of loaded cabinets reduced due to the in-cabinet components while for the unloaded cabinets it increased significantly, (2) a consistent reduction in ICRS due to the grouping effect was recorded when excited by the lower-frequency motion, while it was amplified dramatically due to high-frequency pulses. Interconnected cabinets under the low-frequency input motions have a significant reduction of 50% in the ICRS that corresponds to the higher stiffness of the cabinets, while a 100% increase under the high frequency of ground motion was obtained. High frequency of ground motion, usually above 10 Hz, can cause the interconnected cabinets to resonate as the natural frequency of these equipment lies in this range.

scholarly journals COMPARISON STUDY OF BRACING CONFIGURATION WITH SHEAR LINK IN ECCENTRICALLY BRACED FRAME STEEL STRUCTURE

2020 ◽  
Vol 1 (1) ◽  
pp. 7
Author(s):  
Jusuf Wilson Meynerd Rafael ◽  
Alva Yuventus Lukas
Keyword(s):  
Seismic Analysis ◽  
Response Spectrum ◽  
Structural Response ◽  
Steel Structure ◽  
Structure Design ◽  
System Structure ◽  
Structural Element ◽  
Braced Frame ◽  
Building Model ◽  
Best Response

The EBF structural system is identified by the use of bracing and link beams as components that work to receive lateral seismic loads. The position of the link beam makes the EBF system have several choices of bracing configuration; D-Braces, Split K-Braces, V-Braces, Split K & Inverted Split K-Braces, Inverted Y-Braces. Structural analysis was carried out on a 10-story building model for the EBF system with different type of bracing configurations using the ETABS software. All models analyzed according to Indonesian Code (SNI 1729:2015 and SNI 1726:2019) to obtain the structural element. Seismic analysis uses the response spectrum analysis method to obtain the structural response parameters in the EBF system. Result of the analysis for all of bracing configuration are shown that Split K-Braces model has the best response parameters when compared to the MRF system. The  lowest value for the parameter is owned by Inverted Y-Braces, although overall it is still larger than the MRF system. The bracing configuration greatly affects the response of EBF system due to the behavior that occurs in the link beam, therefore the selection for type of bracing configuration is also important in the EBF system structure design.

scholarly journals The Effect of Ground Motion Selection Methods for Seismic Design of Tall Buildings: A Case Study of Mandalay City

2020 ◽  
Vol 17 (12) ◽  
pp. 1348-1355
Author(s):  
Yan Naung KO ◽  
Teraphan ORNTHAMMARATH
Keyword(s):  
Ground Motion ◽  
Response Spectrum ◽  
Active Faults ◽  
Structural Response ◽  
Tall Buildings ◽  
Lateral Force ◽  
Far Field ◽  
Ground Motion Selection ◽  
Near Fault ◽  
Near Fault Earthquakes

The near-fault earthquakes ground motion usually observed a few kilometers away from the active faults generally contains high energetic velocity pulses as a consequence of directivity effects. Mandalay city is located 8 km away from the Sagaing fault, and the comparative study is conducted to evaluate the structural response of 3 different types of Reinforced Concrete buildings - 4-story, 10-story, and 16-story buildings, respectively. These buildings are subjected to bi-directional ground motions selected from both far-field and pulse-like near-fault earthquakes. The far-field earthquakes produce less seismic demand on the buildings when compared to the near-fault earthquakes, where the ratio of the fundamental period of the building to the pulse period is significant. Comparing 2 ground motion selection and scaling methods of Tall Building Initiative guidelines - TBI (2010) and TBI (2017), the latter approach provides a more meaningful definition of intensity measure and allows reducing some conservatism. The structural response obtained from the design Equivalent Lateral Force (ELF) and Response Spectrum Analysis (RSA) is compared with the code-based linear Response History Analysis (RHA) results.

scholarly journals Probabilistic Seismic Hazard Assessment for Amaravathi Region, Andhra Pradesh

2019 ◽  
Vol 8 (6S4) ◽  
pp. 279-283
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Seismic Analysis ◽  
Response Spectrum ◽  
Seismic Hazard Assessment ◽  
Prediction Equation ◽  
Probabilistic Seismic Hazard Assessment ◽  
Ground Acceleration ◽  
Uniform Hazard Response Spectrum ◽  
Seismic Hazard Map

This article explains an analytical attempt that estimates seismic hazard for Amaravathi city. The present study has been carried out contemplating the available faults and epicentral data within a radius of 300km of the Amaravathi region. The homogenous earthquake catalogue has been prepared for Amaravathi region by Steep’s method. The seismic hazard parameters ―a‖ and ―b‖ for Amaravathi city were evaluated by Gutenberg-Ritcher method. The ―a‖ and ―b‖ values obtained as 4.69, 0.6468 respectively. The total 353 epicenters and 31 faults were considered in this seismic analysis for the estimate of PSHA for Amaravathi. The ground motion produced by the faults at this site has been estimated by using the regionspecific Ground Motion Prediction Equation (GMPE) developed by the raghukanth and lyenger (2007). The probability of occurrence of different magnitude classes was estimated. The hazard curves and mean annual rate of exceedance for Peak Ground Acceleration were calculated by using ground motion estimated in this area. The Uniform Hazard Response Spectrum (UHRS) for the ranging time periods between 0.1 – 4 seconds was prepared. PGA values for Amaravati region was found to be in between 0.001g to 0.3g from seismic hazard map that was prepared in this study

scholarly journals A Computationally Efficient Ground-Motion Selection Algorithm for Matching a Target Response Spectrum Mean and Variance

2011 ◽  
Vol 27 (3) ◽  
pp. 797-815 ◽  
Author(s):  
Nirmal Jayaram ◽  
Ting Lin ◽  
Jack W. Baker
Keyword(s):  
Ground Motion ◽  
Response Spectrum ◽  
Ground Motions ◽  
Structural Response ◽  
Response Spectra ◽  
Selection Algorithm ◽  
Target Response ◽  
Computationally Efficient ◽  
Mean And Variance ◽  
The Impact

Dynamic structural analysis often requires the selection of input ground motions with a target mean response spectrum. The variance of the target response spectrum is usually ignored or accounted for in an ad hoc manner, which can bias the structural response estimates. This manuscript proposes a computationally efficient and theoretically consistent algorithm to select ground motions that match the target response spectrum mean and variance. The selection algorithm probabilistically generates multiple response spectra from a target distribution, and then selects recorded ground motions whose response spectra individually match the simulated response spectra. A greedy optimization technique further improves the match between the target and the sample means and variances. The proposed algorithm is used to select ground motions for the analysis of sample structures in order to assess the impact of considering ground-motion variance on the structural response estimates. The implications for code-based design and performance-based earthquake engineering are discussed.

On Ground Motion Intensity Indices

2007 ◽  
Vol 23 (1) ◽  
pp. 147-173 ◽  
Author(s):  
Rafael Riddell
Keyword(s):  
Ground Motion ◽  
Seismic Analysis ◽  
Structural Response ◽  
Frequency Range ◽  
Ground Acceleration ◽  
Essential Point ◽  
Sensitive Region ◽  
Peak Ground Motion ◽  
Degradation Models

The characterization of strength of earthquake demands for seismic analysis or design requires the specification of a level of intensity. Numerous ground motion intensity indices that have been proposed over the years are being used for normalizing or scaling earthquake records regardless of their efficiency. An essential point of this study is that a ground motion index is appropriate, or efficient, as long as it can predict the level of structural response. This study presents correlations between 23 ground motion intensity indices and four response variables: elastic and inelastic deformation demands, and input energy and hysteretic energy; nonlinear responses are computed using elastoplastic, bilinear, and bilinear with stiffness degradation models. As expected, no index is found to be satisfactory over the entire frequency range. Indeed, indices related to ground acceleration rank better in the acceleration-sensitive region of the spectrum; indices based on ground velocity are better in the velocity-sensitive region and, correspondingly, generally occur in the displacement-controlled region. Despite frequent criticism, the peak ground motion parameters passed the test successfully. A ranking of indices is presented, thus providing a choice of the most appropriate one for a particular application in the frequency range of interest.

scholarly journals Seismic Design of Steel Structures with Special Flexural Frame Based on Performance by Durability Method

2018 ◽  
Vol 4 (12) ◽  
pp. 2926
Author(s):  
Pouyan Ashrafzadeh ◽  
Arash Kheyrolahi
Keyword(s):  
Seismic Analysis ◽  
Response Spectrum ◽  
Structural Response ◽  
Time History ◽  
Steel Structures ◽  
Finite Element Software ◽  
Durability Analysis ◽  
History Analysis ◽  
Time Histories ◽  
Minimum Number

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%.

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