Sep 16, 2011 the response spectrum of an earthquake is the most favored seismic input for earthquake engineers. Study of earthquake response spectra submitted in partial fulfillment of the requirements of bits c421t. It allows a clear understanding of the contributions of different modes of vibration. This script calculates the elastic response spectra based on eurocode 8 part1 en 19981. It offers a simplified method for finding the design forces for structural members for. This function generates elastic response spectrum for seismic design of buildings. For an entertaining and enlightening history of the toolbox, i encourage you to read this post from celsos blog. Locate and describe an earthquakes magnitude using matlab. The following matlab project contains the source code and matlab examples used for response spectra. The vrs uses pointbypoint multiplication of the transmissibility function times the base input psd.
A displacement response spectrum is the plot of maximum displacement of a single degree of freedom system sdof to a particular ground motion as a function of the natural frequency and damping ratio of the sdof. It provides a technique for performing an equivalent static lateral load analysis. Statistical earthquake ground motion models gavin and. After an estimation is made of the linear viscous damping properties of the structure, a specific response spectrum curve is selected. The response spectrum rather than seismological parameters ubc 1997 and ibc 2000 maximumstructural response if threerecords used averagestructural response if sevenrecords used srss of the two horizontal components should not be less than 1. Therefore, it enables the user to calculate the peak ground acceleration pga and pseudo velocity.
In the context of seismic analysis of structures, various earthquake inputs may be required depending upon the nature of analysis being carried out. Shock response spectrum srs in matlab mathworks, inc. Simulation of uniform hazard earthquake ground motions, journal of structural engineering, vol. We are interested in the maximum relative displacement, velocity, and total accelerations. Spectrum intensity is defined as the integral of pseudovelocity spectrum of 5% damping level between 0. It is apparent that all response spectrum curves represent the properties of the earthquake at a specific site and are not a function of the properties of the structural system. Ground motion estimation during strong seismic events using matlab. Earthquake response spectrum analysis of 4 story shear. There are a number of response spectra that are defined for representing the ground motion, such as, displacement response spectrum, pseudo velocity response spectrum, absolute acceleration response spectrum, and energy spectrum. The user can change the input parameters to construct a sitespecific response spectrum considering different hazard conditions.
The main reasons for the widespread use of this method are. Constant ductility response spectrum for elcentro earthquake california, may 18, 1940, ns component chopra 2012. Earthquake ground motion and response spectra springerlink. The method presented in this course is widely used and is applicable to any structure or equipment that can be modeled as a singledegreeoffreedom sdof system. Sgs s eismic data g eneration s ystem extracts and plots graphs of earthquake history records, seismic response spectrums and design response spectrums using the midas family programs builtin earthquake database. Seismic response spectrum gui file exchange matlab central. Response spectra file exchange matlab central mathworks. Figure 3 shows the lower half of the earthquake acceleration response spectrum that we will use for the analysis. This spectrum were done taking as a start point normalized version of the response spectra obtained from different accelerograms recorded for the following earthquakes. I have more of these types of programs for shock and vibration, so please let me know if there is an interest.
A verysmall matlab package that implements the empirical earthquake sourcescaling relations to enable monte carlo approach to predict the source parameters, i. In the 1982 eeri monograph on earthquake design and spectra, newmark and hall describe how they developed an idealized seismic response spectrum based on a range of response spectra generated for available earthquake records. The first data reported from an earthquake record is generally the peak ground acceleration pga which expresses the tip of the maximum spike of the acceleration ground motion figure 1. An algorithm developed in matlab for the automatic selection of cut. Its origin probably dates from civil engineering and the problem of seismic excitations, i. Elastic response spectrum file exchange matlab central. Response spectra in matlab download free open source matlab. Construction of design response spectrum the chilean way. Software to download usgs earthquake hazard program. This online engineering pdh course presents the response spectrum method of earthquake response analysis of simple structures and mechanicalelectrical equipment. Sep 10, 20 response spectrum method is favoured by earthquake engineering community because of. An artificial accelerogram generator code written in matlab ferreira. Gismo is a matlab toolbox for seismic data analysis built on a common platform.
The chapter presents probabilistic methods for evaluating seismic risk at a site and development of seismic maps used in codes and provisions. Earthquake response spectrum free software download. The acceleration response spectra is represented as piecewise linear segments, whose endpoints are defined by a time, acceleration coordinate. To do so, first, natural frequencies or period should be obtained by means of modal analysis of desired structure. Sep 28, 2015 a new computerbased platform has been proposed whose novelty consists in modeling the local site effects of the ground motion propagation using a hybrid approach based on an equivalent linear model. This can be accomplished quickly by using broadband data from the iris dmc data management center and some coding in matlab.
Response spectra are calculated for five damping periods 0, 2, 5, 10 and 20%. This script aims to offer the shock response spectrum of an acceleration time history of an earthquake which is known. The method presented in the course is widely used and is applicable to any structure or equipment that can be modeled as a singledegreeoffreedom sdof system. Vibration response spectrum file exchange matlab central. Response spectrum method of analysis with simplified. The base input psd must be in terms of acceleration. Therefore, we can generate a response spectrum for that earthquake. Aug 24, 2006 this program calculates the shock response spectrum for a base input, where the base input is in the form of an acceleration time history. Jennings abstract a numerical method for computing response spectra from strongmotion earthquake records is developed, based on the exact solution to the governing differential equation. Selection, scaling and simulation of input ground motion for. Strong motion recordings are the key in many earthquake. Response spectrum is an important concept for the analysis of the dynamic effect of earthquake events.
A new opensource software for strong ground motion data processing. Project seizmo is a matlab and gnu octave based toolbox encompassing a collection of over 700 functions that provide a framework for seismic data preparation, quality control, and analysis akin to that of seismic analysis code with a focus on passive source seismology at regional and global scales where earthquakes and ambient noise are the. Aug 24, 2006 this program calculates the vibration response spectrum vrs for a base input power spectral density psd. This function generates elastic response specra including displacement spectrum, pseudo acceleration spectrum, and pseudo velocity spectrum which are needed in a response spectrum analysis of structures. The course presents the response spectrum method of earthquake response analysis of simple structures and mechanicalelectrical equipment. It determines the response spectrum of accelerations, pseudoaccelerations, displacements, velocities and pseudovelocities, for an accelerogram, by means of matlab program with input file in. In particular, gismo provides a framework that speeds the development time for building research codes around seismic waveformtrace data, event catalog data and instrument responses.
During an earthquake, violent shaking is transmitted into a structure at the points where it is attached to the ground. A computerbased environment for processing and selection of. He defined the srs shock response spectrum as the maximum response motion from a set of single dof oscillators covering the frequency range. A displacement response spectrum is the plot of maximum. T he response spectrum of an earthquake is the most favored seismic input for earthquake engineers. It also discusses some related issues, such as the response spectrum calculations, the statistical dependence between the three earthquake components, the duration of the time history, the.
Engineers use response spectrum modal superposition analysis to determine the structural response to sudden forces or shocks such as an earthquake. Locate and describe an earthquakes magnitude using matlab lets say a big earthquake occurs somewhere in the world and you want to know a bit about it. To solve the equation of motions for different periods, the newmark linear method was used. The response spectrum of an earthquake is the most favored seismic input for earthquake engineers. An improved algorithm for selecting ground motions to match a. Factors that influence earthquake ground motion such as source distance, site geology, earthquake magnitude, source characteristics, and directivity are examined. The shock response spectrum srs allows to estimate transient acceleration signals in terms of a maximum response of a dynamic vibration system. Response spectrum analysis is the dominant contemporary method for dynamic analysis of building structures under seismic loading. To design a structure against earthquake, one of the most recommended methods by design specifications is response spectrum analysis in which rather than time history analysis, maximum responses are estimated by this method. Nonlinear response spectra of artificial earthquake waves. It also plots the solution and stores them in a file allowing certain changes such as the acceleration unit.
The soil behavior is modeled assuming that both the shear modulus and the damping ratio vary with the shear strain amplitude. Ground motion estimation during strong seismic events using. Elastic response spectrum for elcentro earthquake california, may 18, 1940, ns component. Response spectrum analysis 7 the maximum ground acceleration, for the earthquake defined by figure 15. Gismo toolbox seismic data analysis in matlab file. Shock response spectrum file exchange matlab central. Gupta group leader, civil engineering group birla institute of technology and science pilani, rajasthan333031. From this, you can see how the toolbox starts life as a collection of useful stuff from a small group, into a mature, wellthought out collection of tools meant for use by a broader audience. Pdf this report is the development of response spectrum analysis for mdof structure in matlab. Computer programs for calculating and optimization linear 1d.
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