The shock response spectrum is a useful tool for estimating the damage potential of a shock pulse, as well as for test level specification. This paper describes seismic analysis of highrise building using program in staadpro. Abbass department of civil engineering, abu dhabi university, uae abstract modal response spectrum analysis mrsa is one of the most commonly used methods for determination of seismic response in building structures. It provides a technique for performing an equivalent static lateral load analysis. Specifically, it is important to have a good grasp of the relationships between frequency response functions and their individual modal parameters illustrated in figure 1. Knowing the various forms and trends of frequency response.
Adding a static load in a rs analysis doesnt make sense for me as the response spectrum analysis is a dynamic analysis or are you talking about prestressing a. Since the response spectra give only maximum response, only the maximum values for each. Seismic analysis of high rise building with is code 18932002 and is code 18932016 narayan malviya1. Cascaded analysis of secondary systems using response spectrum method. Useful elearning website will also be shown to give idea about topic clearly. Channel provide you knowledge about all competitive exam including computer proficiency test and current affairs too. In cases where structures are either too irregular, too tall or of significance to a community in the disaster response, the response spectrum approach is no longer appropriate, and more complex analysis is often. Modal response spectrum analysis earthquake resistance eurocode. Earthquake engineering, reliability analysis, earthquake engineering, fragility curves, shear wall system, flat slab structures. This cumulative modal weight criterion is for identifying the modes that will be.
Johnson department of earth and environmental science, new mexico tech 1. Tutorial for response spectrum analysis using caepipe. Read online ansys response spectrum analysis tutorial. Sep 10, 20 response spectrum method is favoured by earthquake engineering community because of. The opinions and conclusions stated are those of the author and may or may not be those of the laboratory. The response is calculated for each direction separately. Response spectrum method of analysis seismic analysis of. Response spectrum method is favoured by earthquake engineering community because of. Highlights from chapter 12 of asce 716 provisions for linear.
We recommend that you register using the same email address you use to maintain your asce member account. Response spectra can also be used in assessing the response of linear systems with multiple modes of oscillation multidegree of freedom systems, although they are only accurate for low levels of damping. In the present study, the response spectrum analysis rsa of regular rc building frames is compare with response spectrum analysis of regular building and carry out the ductility based design. Average interstorey drift and floor torsion responses, obtained from a set of time history analyses are compared with those of the modal. There is also a requirement that the cumulative modal weight of all modes within the cutoff frequency range must be greater than a specified value, with the navsea 3010 default being 80%. The method is only approximate, but it is often a useful, inexpensive method for preliminary design studies. Responsespectrum analysis provides insight into dynamic behavior by measuring pseudospectral acceleration, velocity, or displacement as a function of. The response can be measured as displacement, velocity or acceleration. I do not think it would be reasonable to consider pdelta analysis with response spectrum load cases the basic reason behind this is that the results of response spectrum would loose signs as soon as the modal combination is done using methods. Implementation of modal combination rules for response spectrum analysis using gemini phani k. I do not think it would be reasonable to consider pdelta analysis with response spectrum load cases the basic reason behind this is that the results of response spectrum would loose signs as soon as the modal combination is done using methods like srss, cqc etc. Some models are prepared that is bare frame, brace frame and shear wall frame. Comparative study of equivalent lateral force method and. Divide only t 1 response by r other modes respond elastically.
Modal response spectrum analysis earthquake resistance. Response spectrum analysis of structures subjected to seismic actions chapter pdf available january 20 with 4,654 reads how we measure reads. Pdf response spectrum analysis of structures subjected to. Modal and response spectrum analyses of an iter divertor. Similarly, several definitions for the shock response spectrum are. So i will apply response spectrum function per ibc 2006 in u1 direction by a scale factor. Mechanical vibrations overview of experimental modal analysis. The purpose of this report is to explain the shock response spectrum and to give a. Nukala june 1999 this is an informal report intended primarily for internal or limited external 7 distribution. Theory of response spectrum analysis earth and environmental. Response spectrum analysis can be used to estimate the peak response displacement, stress, etc.
The results from the mrs analysis are compared with the results obtained from an equivalent lateral force elf analysis of the same frame. Modal analysis is performed to identify the modes, and the response in that mode can be picked from the response spectrum. Introduction the basis of engineering seismology is the need to quantify how a given structure will respond to. Aug 31, 2018 channel provide you knowledge about all competitive exam including computer proficiency test and current affairs too.
Topic 6 structural dynamics iii analysis of elastic mdof systems. Nuregcr6645 reevaluation of regulatory guidance on. Topic 6 structural dynamics iii analysis of elastic mdof systems equations of motion for mdof systems uncoupling of equations through use of natural mode shapes solution of uncoupled equations recombination of computed response modal response spectrum analysis by example use of reduced number of modes. The shock response spectrum is a graphical representation of an arbitrary transient acceleration input, such as shock in terms of how a single degree of freedom sdof system like a mass on a spring responds to that input. Responsespectrum analysis technical knowledge base. Note that milstd1540c and milstd810e require this format for certain shock environments. Table 2 summarizes representative modal analysis results obtained from the 2 and 3layered model. Pdf multi modal response spectrum analysis implemented in.
Describeperform steps common to all analysis types. It offers a simplified method for finding the design forces for structural members for. This understanding is of value in both the measurement and analysis phases of the survey. Modal response may be combined using srss, cqc, abs, or gmc. Pdf response spectrum analysis of frame structures. Topic 6 structural dynamics iii analysis of elastic mdof. The maximum modal response associated with period tn is given by. Structural testing part 2, modal analysis and simulation br0507. As a result, when modal response spectrum analysis is used, a threedimensional model is required for all structures, including those with diaphragms that can be designated as flexible.
Design response spectrum required for the analysis to be used. Consideration of torsional irregularity in modal response. The motivation for moving linear response history lrh analysis from chapter 16 to chapter. My question is why we dont apply u2 and u3 in the same load case. Obtaining joint accelerations for response spectrum analysis of multidof structure. The objective of this project was to reevaluate the current regdatory guidance for combining modal responses in response spectrum analysis, evaluate recent technical developments, and recommend revisions to the regulatory guidance. Modifications to modal response spectrum analysis method modified to require 100% of the mass introduces rigid body mode concept for t modal analysis jimin he and zhifang fu. Implementation of modal combination rules for response. Jamestown, california 95327 abstract experimental modal analysis has grown steadily in popularity since the advent of the digital fft spectrum analyzer in the early 1970s. Analytical modal analysis modal analysis is the process of characterizing the dynamic response of a system in terms of its modes of vibration.
Multi modal response spectrum analysis implemented in opensees. Jun 23, 2012 so i will apply response spectrum function per ibc 2006 in u1 direction by a scale factor. Introduction to structural dynamics and earthquake engineering module 9 response spectrum modal analysis prof. This project did not specifically analyze the modal response combination methods applied to highly. Approximate modal response spectrum method of analysis. Response spectrum analysis provides insight into dynamic behavior by measuring pseudospectral acceleration. Consideration of torsional irregularity in modal response spectrum analysis o. Pdf multi modal response spectrum analysis implemented. Dynamic design analysis method ddam response spectrum.
The structural analysis of high rise multistory storey reinforced concrete symmetrical and asymmetrical frame building is done with the help of sap software. Responsespectrum analysis rsa is a lineardynamic statistical analysis method which measures the contribution from each natural mode of vibration to indicate the likely maximum seismic response of an essentially elastic structure. The frequency response function is very simply the ratio of the output response of a structure due to an applied force. Mar 04, 2014 module 9 response spectrum modal analysis 1. Responsespectrum analysis etabs computers and structures. Responsespectrum analysis rsa is a lineardynamic statistical. Today, this task can be performed very reliably and efficiently by many computer programs dedicated to seismic response analysis for the purposes of earthquakeresistant design.
Responsespectrum analysis provides insight into dynamic behavior by measuring pseudospectral acceleration, velocity, or displacement as a function of structural. This chapter uses the modal response spectrum mrs method of analysis to examine a sixstory momentresisting frame. Response spectrum method of analysis with simplified. Reevaluation of regulatory guidance on modal response. We measure both the applied force and the response of the structure due to the applied force simultaneously. Dynamic analysis using response spectrum seismic loading before the existence of inexpensive personal computers, the response spectrum method was the standard approach for linear seismic analysis 15. Response spectrum analysis with ansys workbench for response spectrum analysis you need to fulfill one requirement. The first step in a modal response spectrum analysis is the determination of the 3d modal shapes and natural frequencies of vibration eigenmodes and eigenvalues. Comparison of some code provisions prescribed by different earthquake codes. In the present study, the response spectrum analysis rsa of regular rc building frames is compare with response. Response spectrum analysis and nonlinear properties.
Highlights from chapter 12 of asce 716 provisions for. Jamestown, california 95327 abstract experimental modal analysis has grown steadily in popularity since the advent of the digital fft spectrum analyzer in. Response spectrum analysis rsa is a lineardynamic statistical analysis method which measures the contribution from each natural mode of vibration to indicate the likely maximum seismic response of an essentially elastic structure. Number of modes used in the response spectrum analysis has to cover that the missing mass is less than 10% of the total system mass. Nuregcr6645 reevaluation of regulatory guidance on modal. Structural testing part 2, modal analysis and simulation.
Response spectrum analysis which way is forward article pdf available october 2014 with 5,719 reads how we measure reads. Pdf response spectrum analysis of structures subjected. Mar 25, 2010 cascaded analysis of secondary systems using response spectrum method. Selection of case study building, its response spectrum analysis and design of the full structure is presented here. In practical applications, modal peak response can be appropriately estimated through inelastic displacement spectrum fema, 2000. Therefore, the purpose of this study is to develop a seismic. Fea for all frequency response analysis is an extension of modal analysis in some way. Analytical modal analysis depends on the generation of the equations of motion of a system through a finite element model. From a set of frf measurements made at defined points on a structure, we can begin to build up a picture of its response. The response spectrum method rsm was introduced in 1932 in the doctoral.