Combination rules and critical seismic response of steel buildings modeled as complex MDOF systems

2016 ◽  
Vol 10 (1) ◽  
pp. 211-238 ◽  
Author(s):  
Alfredo Reyes-Salazar ◽  
Federico Valenzuela-Beltran ◽  
David de Leon-Escobedo ◽  
Eden Bojorquez-Mora ◽  
Arturo Lopez Barraza
Keyword(s):  
Seismic Response ◽  
Steel Buildings ◽  
Combination Rules ◽  
Mdof Systems

Combination Rules and Maximum Response for Steel Buildings with PMRF Represented by Complex 3D MDOF Systems

2014 ◽  
Vol 595 ◽  
pp. 159-165
Author(s):  
Alfredo Reyes-Salazar ◽  
Eden Bojorquez ◽  
Federico Valenzuela-Beltran ◽  
Juan I. Velazquez-Dimas
Keyword(s):  
Principal Components ◽  
Incidence Angle ◽  
Accurate Estimation ◽  
Steel Buildings ◽  
Combination Rules ◽  
Critical Response ◽  
Mdof Systems ◽  
Individual Effects ◽  
The Individual ◽  
Correlated Components

The seismic responses of 3D steel buildings with perimeter moment resisting frames (PMRF), modeled as complex MDOF systems, are estimated and the accuracy of the commonly used rules to combine the individual effects of the seismic components, as well as the influence of the correlation of the components and the correlation of the individual effects on the accuracy of the rules, are studied. The responses are also estimated for several incidence angles of the horizontal components and the critical one is identified. It is observed that the rules underestimate the axial load but they reasonably overestimate the interstory and base shear. The effect of individual components may be highly correlated, not only for normal components, but also for totally uncorrelated components. Moreover, the rules are not always inaccurate in the estimation of the combined response for correlated components. On the other hand, totally uncorrelated components are not always related to an accurate estimation of the combined response. The critical response does not occur for principal components and the corresponding incidence angle of the seismic components varies from one earthquake to another. In the general case, the critical response can be estimated as 1.30 times that of the principal components.

scholarly journals Effect of Damping and Yielding on the Seismic Response of 3D Steel Buildings with PMRF

2014 ◽  
Vol 2014 ◽  
pp. 1-21 ◽  
Author(s):  
Alfredo Reyes-Salazar ◽  
Achintya Haldar ◽  
Ramon Eduardo Rodelo-López ◽  
Eden Bojórquez
Keyword(s):  
Seismic Response ◽  
Three Dimensional ◽  
Lateral Force ◽  
Viscous Damping ◽  
Steel Buildings ◽  
Local Response ◽  
Equivalent Viscous Damping ◽  
Response Parameter ◽  
Mdof Systems ◽  
Crude Approximation

The effect of viscous damping and yielding, on the reduction of the seismic responses of steel buildings modeled as three-dimensional (3D) complex multidegree of freedom (MDOF) systems, is studied. The reduction produced by damping may be larger or smaller than that of yielding. This reduction can significantly vary from one structural idealization to another and is smaller for global than for local response parameters, which in turn depends on the particular local response parameter. The uncertainty in the estimation is significantly larger for local response parameter and decreases as damping increases. The results show the limitations of the commonly used static equivalent lateral force procedure where local and global response parameters are reduced in the same proportion. It is concluded that estimating the effect of damping and yielding on the seismic response of steel buildings by using simplified models may be a very crude approximation. Moreover, the effect of yielding should be explicitly calculated by using complex 3D MDOF models instead of estimating it in terms of equivalent viscous damping. The findings of this paper are for the particular models used in the study. Much more research is needed to reach more general conclusions.

scholarly journals Investigating the Use of Natural and Artificial Records for Prediction of Seismic Response of Regular and Irregular RC Bridges Considering Displacement Directions

2021 ◽  
Vol 11 (3) ◽  
pp. 906
Author(s):  
Payam Tehrani ◽  
Denis Mitchell
Keyword(s):  
Seismic Response ◽  
Radial Displacement ◽  
Time History ◽  
Good Prediction ◽  
3D Analysis ◽  
Combination Rules ◽  
Principal Axes ◽  
Artificial Records ◽  
The Mean ◽  
Irregular Bridges

The seismic responses of continuous multi-span reinforced concrete (RC) bridges were predicted using inelastic time history analyses (ITHA) and incremental dynamic analysis (IDA). Some important issues in ITHA were studied in this research, including: the effects of using artificial and natural records on predictions of the mean seismic demands, effects of displacement directions on predictions of the mean seismic response, the use of 2D analysis with combination rules for prediction of the response obtained using 3D analysis, and prediction of the maximum radial displacement demands compared to the displacements obtained along the principal axes of the bridges. In addition, IDA was conducted and predictions were obtained at different damage states. These issues were investigated for the case of regular and irregular bridges using three different sets of natural and artificial records. The results indicated that the use of natural and artificial records typically resulted in similar predictions for the cases studied. The effect of displacement direction was important in predicting the mean seismic response. It was shown that 2D analyses with the combination rules resulted in good predictions of the radial displacement demands obtained from 3D analyses. The use of artificial records in IDA resulted in good prediction of the median collapse capacity.

Seismic response of complex 3D steel buildings with welded and post-tensioned connections

2016 ◽  
Vol 11 (2) ◽  
pp. 217-243 ◽  
Author(s):  
Alfredo Reyes-Salazar ◽  
Sonia E. Ruiz ◽  
Eden Bojorquez ◽  
Juan Bojorquez ◽  
Mario D. Llanes-Tizoc
Keyword(s):  
Seismic Response ◽  
Steel Buildings ◽  
Post Tensioned

Seismic response of 3D steel buildings with hybrid connections: PRC and FRC

2016 ◽  
Vol 22 (1) ◽  
pp. 113-139 ◽  
Author(s):  
Alfredo Reyes-Salazar ◽  
Jesus Alberto Cervantes-Lugo ◽  
Arturo Lopez Barraza ◽  
Eden Bojorquez ◽  
Juan Bojorquez
Keyword(s):  
Seismic Response ◽  
Steel Buildings

Ductility Reduction Factors for Steel Buildings Modeled as 2D and 3D Structures

2014 ◽  
Vol 595 ◽  
pp. 166-172
Author(s):  
Alfredo Reyes-Salazar ◽  
Eden Bojorquez ◽  
Achintya Haldar ◽  
Arturo Lopez-Barraza ◽  
J. Luz Rivera-Salas
Keyword(s):  
Lateral Force ◽  
Reduction Factor ◽  
Steel Buildings ◽  
Structural Representation ◽  
Global Response ◽  
A Value ◽  
Mdof Systems ◽  
Moment Resisting ◽  
2D And 3D ◽  
Reduction Factors

The global ductility parameter (μG), commonly used to represent the capacity of a structure to dissipate energy, and the associated ductility reduction factor (Rμ), are estimated for steel buildings with perimeter moment resisting frames (PMRF), which are modeled as 2D and 3D complex MDOF systems. Results indicate that the μG value of 4, commonly assumed for moment resisting steel frames, cannot be justified. A value of 3 is more reasonable. The values of μG and Rμ may be quite different for 2D and 3D structural representations or for local and global response parameters, showing the limitation of the commonly used Equivalent Lateral Force Procedure (ELFP). Thus, the ductility and ductility reduction factors obtained from simplified structural representation must be taken with caution.

Seismic Response of Steel Buildings with Different Structural Typology

2012 ◽  
Vol 256-259 ◽  
pp. 2234-2239
Author(s):  
Marco Valente
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Structural Damage ◽  
Numerical Models ◽  
Reference Structure ◽  
Steel Buildings ◽  
Seismic Excitations ◽  
Plastic Deformations ◽  
Torsionally Stiff ◽  
Torsionally Flexible

This study investigates the influence of the in-plan structural layout on the seismic response of symmetric and asymmetric steel structures. A five-storey steel frame building was used as reference structure and two different structural systems were employed to represent torsional stiff and torsional flexible structures. Accurate numerical models of the different typologies of structures were developed and both nonlinear static and dynamic analyses under bi-directional ground motion were carried out. The influence of axial force-bending moment interaction in columns in the two main directions and second order effects were taken into account in the numerical analyses. The results of the numerical investigations on symmetric structures showed that the reduction of the number of moment resisting connections may lead to an increase of the structural damage. Asymmetric variants of the investigated structures were created by assuming different mass eccentricities in each of the two main directions and extensive parametric studies were performed. For the torsionally flexible building, the influence of ground motion intensity was very strong. A transition from torsionally flexible to torsionally stiff behaviour in the weaker direction of the initially torsionally flexible structure was observed for severe seismic actions. The change of the stiffness of the structure in one direction due to high levels of plastic deformations affected the structural response in the orthogonal direction. Torsional effects decreased in case of severe seismic excitations and high levels of plastic deformations. The reduction of torsional effects observed for low seismic actions on the stiff side of torsionally stiff buildings disappeared under strong seismic excitations.

Design Approach Based on UAFR Spectra for Structures with Displacement-Dependent Dissipating Elements

2007 ◽  
Vol 23 (2) ◽  
pp. 417-439 ◽  
Author(s):  
J. Luz Rivera ◽  
Sonia E. Ruiz
Keyword(s):  
Seismic Response ◽  
Response Spectra ◽  
Design Criterion ◽  
Limit States ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Mdof Systems ◽  
Concrete Building ◽  
Hazard Curves ◽  
Ultimate Limit

In the first part of this paper an algorithm is proposed to obtain demand hazard curves and, from them, seismic-response spectra with uniform annual failure rates for single-degree-of-freedom (SDOF) systems with energy-dissipating devices (EDDs). In the second part, a performance-based dual-level approach is proposed for the design of buildings with EDDs. The criterion establishes acceptance conditions (related to serviceability—and to ultimate limit-states) that correspond to the main system and to the dissipating elements. The uncertainties implicit in the transformation between the response of SDOF and MDOF systems with EDDs are taken into account by means of their demand hazard curves. The reliability-based dual-level design criterion proposed is illustrated by means of a ten-story reinforced concrete building rehabilitated with steel energy-dissipating devices.

scholarly journals Combination rules for steel buildings under seismic loading: MDOF vs SDOF systems

2017 ◽  
Vol 11 ◽  
pp. 67-72 ◽  
Author(s):  
Alfredo Reyes-Salazar ◽  
Mario Llanes Tizoc ◽  
Eden Bojorquez ◽  
Juan Bojorquez ◽  
Federico Valenzuela-Beltran ◽  
...  
Keyword(s):  
Seismic Loading ◽  
Steel Buildings ◽  
Combination Rules
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