scholarly journals Accuracy of Advanced Methods for Nonlinear Static Analysis of Steel Moment-Resisting Frames

2014 ◽  
Vol 8 (1) ◽  
pp. 310-323 ◽  
Author(s):  
Massimiliano Ferraioli ◽  
Alberto M. Avossa ◽  
Angelo Lavino ◽  
Alberto Mandara
Keyword(s):  
Pushover Analysis ◽  
Nonlinear Static Analysis ◽  
Seismic Demands ◽  
Steel Moment Resisting Frames ◽  
Moment Resisting Frames ◽  
Capacity Spectrum ◽  
History Analysis ◽  
Moment Resisting ◽  
Response History Analysis ◽  
Nonlinear Static

The reliability of advanced nonlinear static procedures to estimate deformation demands of steel momentresisting frames under seismic loads is investigated. The advantages of refined adaptive and multimodal pushover procedures over conventional methods based on invariant lateral load patterns are evaluated. In particular, their computational attractiveness and capability of providing satisfactory predictions of seismic demands in comparison with those obtained by conventional force-based methods are examined. The results obtained by the static advanced methods, used in the form of different variants of the original Capacity Spectrum Method and Modal Pushover Analysis, are compared with the results of nonlinear response history analysis. Both effectiveness and accuracy of these approximated methods are verified through an extensive comparative study involving both regular and irregular steel moment resisting frames subjected to different acceleration records.

scholarly journals Evaluation of p-delta effect in structural seismic response

2018 ◽  
Vol 162 ◽  
pp. 04019 ◽  
Author(s):  
Sardasht Sardar ◽  
Ako Hama
Keyword(s):  
Seismic Response ◽  
Pushover Analysis ◽  
Nonlinear Dynamic Analysis ◽  
Time History ◽  
Steel Structure ◽  
Nonlinear Static Analysis ◽  
Structural Behavior ◽  
Finite Element Software ◽  
History Analysis ◽  
Nonlinear Static

Numerous recent studies have assessed the effect of P-Delta on the structures. This paper investigates the effect of P-Delta in seismic response of structures with different heights. For indicating the effect of P-Delta, nonlinear static analysis (pushover analysis) and nonlinear dynamic analysis (Time history analysis) were conducted by using finite element software. The results showing that the P-Delta has a significant impact on the structural behavior mainly on the peak amplitude of building when the height of the structures increased. In addition, comparison has been made between concrete and steel structure.

scholarly journals Evaluation of a Modified MPA Procedure Assuming Higher Modes as Elastic to Estimate Seismic Demands

2004 ◽  
Vol 20 (3) ◽  
pp. 757-778 ◽  
Author(s):  
Anil K. Chopra ◽  
Rakesh K. Goel ◽  
Chatpan Chintanapakdee
Keyword(s):  
Structural Engineering ◽  
Pushover Analysis ◽  
Computational Effort ◽  
Attractive Alternative ◽  
Engineering Practice ◽  
Seismic Demands ◽  
History Analysis ◽  
Modes Of Vibration ◽  
Response History Analysis ◽  
Damped Systems

The modal pushover analysis (MPA) procedure, which includes the contributions of all significant modes of vibration, estimates seismic demands much more accurately than current pushover procedures used in structural engineering practice. Outlined in this paper is a modified MPA (MMPA) procedure wherein the response contributions of higher vibration modes are computed by assuming the building to be linearly elastic, thus reducing the computational effort. After outlining such a modified procedure, its accuracy is evaluated for a variety of frame buildings and ground motion ensembles. Although it is not necessarily more accurate than the MPA procedure, the MMPA procedure is an attractive alternative for practical application because it leads to a larger estimate of seismic demands, improving the accuracy of the MPA results in some cases (relative to nonlinear response history analysis) and increasing their conservatism in others. However, such conservatism is unacceptably large for lightly damped systems, with damping significantly less than 5%. Thus the MMPA procedure is not recommended for such systems.

scholarly journals Application of Nonlinear Static Procedures for the Seismic Assessment of Regular RC Moment Frame Buildings

2014 ◽  
Vol 30 (2) ◽  
pp. 767-794 ◽  
Author(s):  
Michalis Fragiadakis ◽  
Dimitrios Vamvatsikos ◽  
Mark Aschheim
Keyword(s):  
Pushover Analysis ◽  
Nonlinear Dynamic Analysis ◽  
Single Mode ◽  
Moment Frame ◽  
Seismic Demands ◽  
Frame Buildings ◽  
Moment Resisting ◽  
Nonlinear Static ◽  
Global And Local ◽  
Modal Pushover

The applicability of nonlinear static procedures for estimating the seismic demands of typical regular RC moment-resisting frames is evaluated. This work, conducted within the framework of the ATC-76-6 project, shows the degree to which nonlinear static methods can characterize global and local response demands vis-à–vis those determined by nonlinear dynamic analysis for three RC moment-frame buildings. The response quantities (engineering demand parameters) considered are peak story displacements, story drifts, story shears, and floor overturning moments. The single-mode pushover methods evaluated include the N2 and the ASCE-41 coefficient methods. Multi-modal pushover methods, such as modal pushover analysis and the consecutive modal pushover method, were also evaluated. The results indicate that the relatively good performance of the single-mode methods observed for low-rise buildings rapidly deteriorates as the number of stories increases. The multi-modal techniques generally extend the range of applicability of pushover methods, but at the cost of additional computation and without ensuring the reliability of the results.

scholarly journals Plastic hinge assessment of RC moment-resisting frames

2020 ◽  
Vol 1 (3) ◽  
pp. 37-41
Author(s):  
Mahmoud Alhassan ◽  
Mohamad Abdelrahim
Keyword(s):  
Plastic Hinge ◽  
Pushover Analysis ◽  
Computer Software ◽  
Elastic Stiffness ◽  
Frame Structure ◽  
Nonlinear Static Analysis ◽  
Rc Structures ◽  
Moment Resisting Frames ◽  
Moment Resisting ◽  
Fundamental Reason

This paper gives a short introduction about various kinds of analysis, plastic hinges, moment-resisting frames (MRFs) in RC Structures. It likewise gives computer software ETABS displaying and an investigation of structures concerning Pushover Analysis. The fundamental reason for this examination is to apply a push to all models, analyse and get a reasonable thought regarding their behaviour. The behaviour of these structures likewise was evaluated considering various variables such as the changes in the number of floors, spans length, reinforcements' yield strength and characteristic strength of concrete. This investigation incorporates the moment-resisting frames (MRFs) having 4, 7, and 10 storeys and a relative report for all models' outcomes. Pushover analysis is a nonlinear static analysis used to determine the relationship between strength and displacement in order to evaluate the performance of the RC frame structure. It was found that the plastic hinge may be assessed using parameters such as span lengths and the number of storeys. When the number of storeys increases, the elastic stiffness value decreases and when the span length increases the elastic stiffness also decreases. The collapse of members happens only when there is a formation of 3 hinge mechanisms. Plastic hinge colours have been given, and each colour has its significance to permit a good design.

scholarly journals Optimum Performance-Based Design Of Unsymmetrical 2D Steel Moment Frame

2021 ◽  
Author(s):  
Arezoo Asaad Samani ◽  
Seyed Rohollah Hoseini Vaez ◽  
Mohammad Ali Fathali
Keyword(s):  
Lateral Loading ◽  
Performance Based Design ◽  
Nonlinear Static Analysis ◽  
Second Step ◽  
Analysis Method ◽  
Moment Frame ◽  
Steel Moment Frame ◽  
Steel Moment Resisting Frames ◽  
Moment Resisting ◽  
Nonlinear Static

Abstract The most commonly used analysis method in performance-based design (PBD) is the nonlinear static analysis (NSA). In unsymmetrical 2D frames, unlike its symmetrical state, NSA should be performed in two lateral loading directions, which complicates the process of achieving a feasible optimal design in addition to increasing the volume of calculations. In this study, a two-step approach is proposed for the design of unsymmetrical 2D steel moment-resisting frames (SMRF). In this approach, in two independent steps, the structure is analyzed with lateral loading pattern based on the first mode shape in positive and negative direction, respectively. The implementation of the second step is conditional on the satisfactory completion of the first step. The objective function takes into account the differences between successful and unsuccessful steps. The constraints considered are based on the acceptance criteria for SMRFs according to FEMA-356 at each performance level. The effectiveness of the proposed approach has been investigated by employing four meta-heuristic optimization algorithms to determine the optimum design for case studies of SMRF structures having three and nine stories.

scholarly journals Adaptive Pushover Analysis of Irregular RC Moment Resisting Frames

10.29007/pbdr ◽  
2018 ◽  
Author(s):  
Rutvik Sheth ◽  
Devesh Soni ◽  
Minoli Shah
Keyword(s):  
Static Analysis ◽  
Pushover Analysis ◽  
Time History ◽  
Nonlinear Static Analysis ◽  
Seismic Zone ◽  
Fundamental Vibration ◽  
Moment Resisting ◽  
Nonlinear Static ◽  
Adaptive Pushover ◽  
Nonlinear Time History

Researchers and engineers certainly prefer to use nonlinear static methods over complicated nonlinear time-history methods. However, in nonlinear static procedure both predetermined target displacement and force distribution pattern are based on a false assumption that the structural behavior and its responses are dominated by the fundamental vibration modes. Therefore, over the past decades, there have been a great number of studies on considering higher mode contribution in nonlinear static results. The Displacement-based Adaptive Pushover Analysis (DAP) is one of the performance assessments tool for improving the accuracy of the obtained results of nonlinear static analysis in estimating the seismic demands of the structures. In this paper, 5 storey L- shaped RC frame is analyzed for seismic Zone IV and designed as per provisions of IS codes. Performance evaluation is carried out by nonlinear static analysis as well as adaptive pushover analysis and results are compared.

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