Modal mass coefficient and modal participation factor in sap2000. A physical approach with emphasis on earthquake engineering. As you said in sap2000 display tables, it gives the participation factors which is true but it. Sap2000 pdf csi analysis and reference manual for sap2000, etabs and safe 2. Export the joint masses table to excel by selecting analysis results.
An overview of the tuned mass damper and guidelines for modeling the device. Anchorage design for an equipment supported on vibration isolator 18 9. Why is modal participation ratio table not getting generated in sap2000. Mass technical knowledge base computers and structures. Export the joint masses table to excel by selecting analysis results joint output joint masses. This email is an invitation for the participation in the first south asia conference on earthquake engineering sacee2019 which will be held on 2122 february 2019 in karachi, pakist. The fixed mass participation ratio may be calculated as follows. Modal mass coefficient and modal participation factor in. For the love of physics walter lewin may 16, 2011 duration. Interpreting the modal mass participating ratios table.
Square the participation factor table and divide this value. How to increase the modal mass participation ratio slickdeals structural 2 sep 11 23. But to generate table with mass participation ratio, the system shows processing symbol and remains so for long time. Mass participation ratio and their summation along the degrees of freedom x, y and rotational z for the first 5 modes. This allows the same link property to be used for multiple link objects that may, for example, represent different size tributary regions supported by the link objects. Jun 08, 2011 34 videos play all sap2000 computers and structures, inc. Mini sap 2000 tutorial for an example beam hands on exercise. Participating mass ratio for the higher modes is very high. Modal analysis mass participation autodesk community. Dynamics check modal participating mass ratios youtube. Sap2000 manual sap2000 is a program developed by the company csi, computer and structures, inc. Modal mass k modal stiffness k g modal geometric stiffness f,f force or force vector f frequency z angular frequency participation factor p effective mass a dynamic amplification d,e rayleigh damping coefficients damping ratio in general scalar quantities are denoted by italics e.
Learn about the sap2000 structural analysis and design program. In addition, chapter 19 on viscous damping has been expanded to illustrate the physical effects of modal damping on the results of a dynamic analysis. Sap90, sap2000, safe, floor and etabs are trademarks of. Mass values are calculated for structural elements according to volume and material density. Locations, products and other master data business objects.
After analysis is run, check joint mass by selecting display show tables analysis results joint output. Using sap2000 software package in earthquake engineering. Effects of plastic hinge properties in nonlinear analysis. Example i general modeling techniques 2d shear wall analysis. Why is modal participation ratio table not getting generated. Dynamics check modal participating mass ratios engineering for all. Theoretical basis of methods used during structure dynamic. Note that no mass is assigned to joints 22 and 26 at the roof. Modal analysis of a 3d bridge model reveals that it has many closelyspaced modes. Description and users guide, university of california, berkeley, ca. Sap2000 is the latest and most powerful version of the wellknown sap series of structural analysis programs. During dynamic analysis, mass translation along each of the three joint displacement degreesoffreedom dof correlates with acceleration to create inertial forces. Table b1 defines the joint masses used in the model. Hello, how can i obtain modal masses from the results of a modal analysis in sap2000.
Interpreting the modal mass participating ratios table from etabs posted on october 8, 2018 march 14, 2019 by engr dennis mercado i have not been modelling extensively in etabs this recently so this query from a former had my technical engine humming once more. It has even been codified in many of the codes of record. Tech tip determine the number of modes for linear dynamic using mass participation. Sap2000 is a registered trademark of computers and structures, inc. The substructure mass participation of 72 selected bridges table 1, table 2 in sdof model is obtained from the finite element models. Threedimensional static and dynamic analysis of structures. Mini sap 2000 tutorial for an example beam hands on. Pushover analysis of steel structure using staad tn ram. Sap2000 will do the stress checks automatically when a member is designed.
How to calculate the relative contribution of each mode in. But to generate table with mass participation ratio, the system shows. Effects of plastic hinge properties in nonlinear analysis of. Effects of substructure mass participation on natural. Also can anyone share the pdf file regarding information on manders model. Bridges extends horizontally with its two ends restrained and that makes the dynamic characteristics of bridges different from building.
G other properties for steel material minimum yield stress. Turkish ts 5002000 r2018, mexican rcdf 2017, australian as 36002018 and korean kbc 2016. The mass participation factors reported on the frequencies spreadsheet reflect how much each mode participated in the response spectra analysis solution. The bottom portion of the table defines the masses, the top portion of the table defines which joints are referred to as the center, corner and edge joints. Period s mass ratio x mass ratio y sum mass ratio x sum mass ratio y mass ratio rz sum mass ratio rz 1 0. A new nonlinear multistep static load case type has been added. A description of the modeling details is provided in the following. Modal mass participation for first natural mode and relates base shear pf 1 modal participation factor for first natural mode and relates displacement to sdof. This should give you consistent modal participation factors. Mass per unit volume isotropic property dat modulus of elasticity.
Lateral force distribution as per torsion provisions of is 18932002 part i 12 6. Use this transaction very carefully as it updates master data tables directly. Demand spectrum curve is a plot of spectral acceleration s a vs spectral displacement s d. Effects of substructure mass participation on natural period. The corresponding mass participation values are given in the table. The computer program sap2000 and all associated documentation are proprietary and. Because the default number of mode shapes entered in sap2000 are 12. Optimized modeling and design of structures using sap2000 presented by.
Jul 29, 20 this email is an invitation for the participation in the first south asia conference on earthquake engineering sacee2019 which will be held on 2122 february 2019 in karachi, pakist. Start up screen of sap2000, select working unit to be tonm at dropdown menu. I know values for mass participation ratios and factors as well as modal stiffness can be easily found in the output but i do not know if these are even related to modal mass. Mass participation zthe force participation of each mode can be gauged by the mass participation factor. My doubt is that modal mass coefficient and participation factor as per atc 40 are unitless values. Csi analysis reference manual for sap2000, etabs and safe free ebook download as pdf file. Fourth, the 90 percent mass participation rule, intended to assure accuracy of the analysis, does not. Pushover analysis of steel structure using staad tn.
Csi analysis and reference manual for sap2000, etabs and safe 2. This conference is the inaugural event in this series of conferences which has been constituted under the auspices of south asia earthquake network shake. Find the section titled modal participating mass ratios as shown in. Remember that the rsa involves calculating separately the response for each mode to the applied base excitation represented by the spectra. Mass participation ratio technical knowledge base computers. Click on displayshow tables and tick modal participating mass ratios under. The third part of this volume, the sap2000 introductory tutorial manual, is intended to provide firsttime users with handson experience using the modeling, analysis and design features of sap2000.
In this study, sap2000 nonlinear version 8 has been used. Eccentricity values in etabs software issues structural. And the software will limit it to that many number of modal r. How do i calculate the fixedmass participation ratio of the model.
It is strongly recommended that you read this manual and work the tutorial before attempting a real project using sap2000. Why does sap2000 divide the responses of structures into. As you said in sap2000 display tables, it gives the participation factors which is true. In addition, static and dynamic participation factors have been defined that allow the structural engineer to minimize the errors associated with displacement type loading. Mass is then automatically concentrated at joint locations. Go into define load cases modal cases define modal case change the number of mode shapes you want to consider. Column dimensions and the amount and arrangement of longitudinal reinforcement are provided in fig. Ive modeled a simple 2 dof structure in etabs then manually computed the modal analysis. Local modes may disrupt the modal mass participation mode shapes. Export the joint masses table to excel by selecting analysis results joint output joint masses sum all joint masses to find the total mass square the participation factor table and divide this value by total mass.
How do i calculate the fixed mass participation ratio of the model. The earthquake analysis capabilities of sap2000 are demonstrated using a. As you said in sap2000 display tables, it gives the participation factors which is. The fixedmass participation ratio may be calculated as follows. Bridges extends horizontally with its two ends restrained and that makes the dynamic characteristics of bridges different from. It is observed that smp depends on the ratio of the total stiffness of the isolators to those of the piers. How to increase the modal mass participation ratio. Structural analysis of cultural heritage assisted by 3d. Massd is a sap basis tool used for mass update of certain objects data eg. The dead and participating live loads 30% of live load on the frame are 197. Linear analysis procedures linear modeling, assuming forcedeformation relationship is linear. The modal mass participation ratio is widely used as the metric to determine the relative significance of modes in a modal response spectrum analysis. Fue ass2fy50 modifysh01,v notes 41 72011 79211 10298.
Lateral force distribution as per new torsion provisions 14 7. About this manual this manual describes the basic and most commonly used modeling and analysis features offered by the sap2000 structural analysis program. Before doing some modifications, the mass participation would reach 90 % from the 2nd mode. Advanced applied load options have been added for multistep static load cases. Why is modal participation ratio table not getting generated in. No matter what i do, tha mass participation ratio reaches a certain percentage 56% and stops increasing. Why is modal participation ratio table not getting. For example, asce 705 710 is at home, sorry, section 12.
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