Modal Superposition Technique to Predict the Seismic-Pushover Load for Jacket-Type Structures

Elastic Response ◽

Preliminary Evaluation ◽

Inelastic Behavior ◽

Linear Superposition ◽

Linear Elastic ◽

Two novel methods namely the Dominant Modes method and the All Modes method to predict the seismic-pushover load for the jacket-type structures are presented. Both of these methods are based on the linear superposition of the modal reactions. As a preliminary evaluation, the linear elastic response of a jacket structure subjected to seismic-pushover loads is compared with that obtained from the response spectrum analysis. Furthermore, the nonlinear inelastic behavior obtained from the seismic-pushover analysis is compared with that obtained from the nonlinear time-history analysis, for a portal frame subjected to El Centro earthquake motion. When more than one mode is dominant in an excitation direction, both the linear elastic and the nonlinear inelastic responses obtained using the loads generated from the All Modes method are representative of the reference solutions.

Effect of bidirectional excitation on seismic performance of regular RC frame buildings designed for modern codes

Earthquake Spectra ◽

10.1177/87552930211047879 ◽

2021 ◽

pp. 875529302110478

Author(s):

Payal Gwalani ◽

Yogendra Singh ◽

Humberto Varum

Keyword(s):

Seismic Performance ◽

Time History ◽

Inelastic Behavior ◽

Moment Frame ◽

Frame Buildings ◽

Bidirectional Excitation ◽

Rc Frame Buildings ◽

Nonlinear Time History ◽

Hinge Model

The existing practice to estimate seismic performance of a regular building is to carry out nonlinear time history analysis using two-dimensional models subjected to unidirectional excitations, even though the multiple components of ground motion can affect the seismic response, significantly. During seismic shaking, columns are invariably subjected to bending in two orthogonal vertical planes, which leads to a complex interaction of axial force with the biaxial bending moments. This article compares the seismic performance of regular and symmetric RC moment frame buildings for unidirectional and bidirectional ground motions. The buildings are designed and detailed according to the Indian codes, which are at par with the other modern seismic codes. A fiber-hinge model, duly calibrated with the biaxial experimental results, is utilized to simulate the inelastic behavior of columns under bidirectional bending. A comparison of the estimated seismic collapse capacity is presented, illustrating the importance of considering the bidirectional effects. The results from fragility analysis indicate that the failure probabilities of buildings under the bidirectional excitation are significantly higher as compared to those obtained under the unidirectional excitation.

Direct Displacement Procedure for Performance-Based Seismic Design of Mid-Rise Wood-Framed Structures

Earthquake Spectra ◽

10.1193/1.3158932 ◽

2009 ◽

Vol 25 (3) ◽

pp. 583-605 ◽

Cited By ~ 18

Author(s):

Wei Chiang Pang ◽

David V. Rosowsky

Keyword(s):

Seismic Design ◽

Response Spectrum ◽

Design Procedure ◽

Time History ◽

Time History Analysis ◽

Framed Structures ◽

History Analysis ◽

Performance Based Seismic Design ◽

This paper presents a direct displacement design (DDD) procedure that can be used for seismic design of multistory wood-framed structures. The proposed procedure is applicable to any pure shear deforming system. The design procedure is a promising design tool for performance-based seismic design since it allows consideration of multiple performance objectives (e.g., damage limitation, safety requirements) without requiring the engineer to perform a complex finite element or nonlinear time-history analysis of the complete structure. A simple procedure based on normalized modal analysis is used to convert the code-specified acceleration response spectrum into a set of interstory drift spectra. These spectra can be used to determine the minimum stiffness required for each floor based on the drift limit requirements. Specific shear walls can then be directly selected from a database of backbone curves. The procedure is illustrated on the design of two three-story ATC-63 archetype buildings, and the results are validated using nonlinear time-history analysis.

Strengthening Research in the Longitudinal Frames of Prefabricated Structures with Viscous Dampers

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.671-674.782 ◽

2013 ◽

Vol 671-674 ◽

pp. 782-785

Author(s):

Bin He ◽

Jin Lai Pang ◽

Cheng Qing Liu

Keyword(s):

Seismic Performance ◽

Pushover Analysis ◽

Vertical Direction ◽

Time History ◽

Viscous Dampers ◽

Existing Building ◽

Concrete Frame ◽

Uniform Drift ◽

For the lack of research in the longitudinal frame of prefabricated structure for its weak lateral stiffness, pushover analysis is conducted to evaluate the seismic performance of a fabricated concrete frame. Based on case study, the strengthening strategies with viscous dampers are analyzed. In view of the undesirable drift distribution and failure mode in the existing building, it is believed that arrangement of dampers should be designed to attain a uniform drift distribution. Based on the nonlinear time history analysis method, the strategy of damper allocation in vertical direction of the structure is investigated .Results indicate that a proper design might be attained based on the property of existing system, leading to a uniform drift distribution and better seismic performance.

Analisis Kinerja Bangunan Rangka Baja dengan Bresing Tahan Tekuk terhadap Beban Gempa

RekaRacana: Jurnal Teknil Sipil ◽

10.26760/rekaracana.v6i2.98 ◽

2021 ◽

Vol 6 (2) ◽

pp. 98

Author(s):

Ilham Ilham

Keyword(s):

Pushover Analysis ◽

Time History ◽

Steel Structures ◽

Time History Analysis ◽

Structural Performance ◽

History Analysis ◽

Immediate Occupancy ◽

Nonlinear Time History ◽

Modal Pushover

ABSTRAKPenggunaan bresing tahan tekuk dapat menjadi solusi atas kebutuhan struktur tahan gempa di Indonesia. Disipasi energi pada elemen bresing tahan tekuk dilakukan melalui kinerja plastifikasi bagian inti bresing akibat beban tarik dan tekan. Penelitian ini berisi kajian kinerja dari bangunan rangka baja beraturan dengan bresing tahan tekuk (BRB) dengan variasi level ketinggian lantai yaitu 3 lantai, 8 lantai dan 15 lantai. Analisis struktur 3D dilakukan dengan dua prosedur analisis yaitu modal pushover dan nonlinear time history pada program ETABS. Hasil analisis menunjukkan bahwa pemilihan elemen BRB sangat mempengaruhi kinerja struktur, yang terlihat dari pola drift yang terjadi. Untuk struktur beraturan dengan berbagai ketinggian, tingkat kinerja struktur dengan BRB cukup baik, yaitu Immediate Occupancy (IO) akibat beban gempa rencana. Plastifikasi hanya terjadi pada BRB, dan kelelehan pada balok mulai terbentuk sampai mekanisme keruntuhan terjadi. Hasil modal pushover dengan nonlinear time history pada bangunan 15 lantai yang cukup mirip menunjukkan bahwa modal pushover dapat digunakan untuk memprediksi kinerja struktur BRB yang beraturan.Kata kunci: kinerja struktur, bresing tahan tekuk, immediate occupancy, modal pushover, nonlinear time history ABSTRACTBuckling restrained braces (BRB) can be an alternative solution for earthquake resistant steel structure in Indonesia. The energy dissipation for buckling restrained elements is conducted through yielding of the core due to tension or compression forces. This study presents an evaluation of the structural performance of steel structures with BRB varying in heights, 3-story, 8-story and 15-story. The 3D structural analysis was carried out with ETABS software using 2 methods, Modal Pushover and Nonlinear Time History. The results shows that the selection of BRB elements greatly affected the structural performance, showed by the drift pattern. For regular structures with variation in heights, structures with BRB behaved satisfactory under the design load with the performance level of Immediate Occupancy (IO). Yielding was limited to BRB members, and afterwards the yielding occurred on beams until collapse. The results of modal pushover and time history analysis for 15-story structure are similar, thus modal pushover can be used to predict the performance of regular structural system with BRB.Keywords: structural performance, buckling restrained brace, immediate occupancy, modal pushover analysis, nonlinear time history analysis

A Drift Pushover Analysis Procedure for Estimating the Seismic Demands of Buildings

Earthquake Spectra ◽

10.1193/030811eqs038m ◽

2014 ◽

Vol 30 (4) ◽

pp. 1601-1618 ◽

Cited By ~ 4

Author(s):

Arash Sahraei ◽

Farhad Behnamfar

Keyword(s):

Lateral Displacement ◽

Plastic Hinge ◽

Pushover Analysis ◽

Time History ◽

Relative Displacement ◽

Analysis Procedure ◽

New Method ◽

Displacement Based ◽

Relative displacement is a parameter that has a very high correlation with damage. The objective of this article is to develop an analysis procedure founded on the displacement-based seismic design methodology. Generalized interstory drift spectrum is applied as an essential tool in this new method called drift pushover analysis. In order to evaluate the behavior of structures, three demand parameters—lateral displacement, story shear, and plastic hinge rotation—are computed with conventional pushover analysis (CPA), modal pushover analysis (MPA), and drift pushover analysis (DPA), and are compared with those of the nonlinear time history analysis (NTA). It is observed that the new method, DPA, predicts the peak response measures more precisely and with less effort than the other nonlinear pushover procedures investigated in this study.

Adaptive Spectra-Based Pushover Procedure for Seismic Evaluation of Structures

Earthquake Spectra ◽

10.1193/1.1586117 ◽

2000 ◽

Vol 16 (2) ◽

pp. 367-391 ◽

Cited By ~ 197

Author(s):

Balram Gupta ◽

Sashi K. Kunnath

Keyword(s):

Response Spectrum ◽

Pushover Analysis ◽

Nonlinear Dynamic Analysis ◽

Time History ◽

Northridge Earthquake ◽

Seismic Evaluation ◽

Seismic Demands ◽

Ground Shaking ◽

Motion Characteristics ◽

The estimation of inelastic seismic demands using nonlinear static procedures, or pushover analyses, are inevitably going to be favored by practicing engineers over nonlinear time-history methods. While there has been some concern over the reliability of static procedures to predict inelastic seismic demands, improved procedures overcoming these drawbacks are still forthcoming. In this paper, the potential limitations of static procedures, such as those recommended in FEMA 273, are highlighted through an evaluation of the response of instrumented buildings that experienced strong ground shaking in the 1994 Northridge earthquake. A new enhanced adaptive “modal” site-specific spectra-based pushover analysis is proposed, which accounts for the effect of higher modes and overcomes the shortcomings of the FEMA procedure. Features of the proposed procedure include its similarity to traditional response spectrum-based analysis and the explicit consideration of ground motion characteristics during the analysis. It is demonstrated that the proposed procedure is able to reasonably capture important response attributes, such as interstory drift and failure mechanisms, even for structures with discontinuities in strength and/or stiffness that only a detailed nonlinear dynamic analysis could predict.

International Journal of Advanced Research in Science, Communication and Technology ◽

Special Moment Resistant Steel Buildings

10.48175/ijarsct-2214 ◽

2021 ◽

pp. 444-448

Author(s):

Deepan Dev B ◽

Dr V Selvan

Keyword(s):

Pushover Analysis ◽

Time History ◽

Building Structures ◽

Braced Frames ◽

Steel Buildings ◽

Braced Frame ◽

Moment Resisting ◽

Frame Systems ◽

The seismic response of special moment-resisting frames (SMRF), buckling restrained braced (BRB) frames and self-centering energy dissipating (SCED) braced frames is compared when used in building structures many stories in height. The study involves pushover analysis as well as 2D and 3D nonlinear time history analysis for two ground motion hazard levels. The SCED and BRB braced frames generally experienced similar peak interstory drifts. The SMRF system had larger interstory drifts than both braced frames, especially for the shortest structures. The SCED system exhibited a more uniform distribution of the drift demand along the building height and was less prone to the biasing of the response in one direction due to P-Delta effects. The SCED frames also had significantly smaller residual lateral deformations. The two braced frame systems experienced similar interstory drift demand when used in torsional irregular structures.

Prediction of the Maximum Seismic Member Force in a Superstructure of a Base-Isolated Frame Building by using Pushover Analysis

Buildings ◽

10.3390/buildings9090201 ◽

2019 ◽

Vol 9 (9) ◽

pp. 201 ◽

Cited By ~ 1

Author(s):

Fujii

Keyword(s):

Pushover Analysis ◽

Time History ◽

Time History Analysis ◽

Second Stage ◽

Frame Building ◽

History Analysis ◽

Frame Buildings ◽

Dynamic Time ◽

It is essential for the seismic design of a base-isolated building that the seismic response of the superstructure remains within the elastic range. The evaluation of the maximum seismic member force in a superstructure is thus an important issue. The present study predicts the maximum seismic member force of five- and fourteen-story reinforced concrete base-isolated frame buildings adopting pushover analysis. In the first stage of the study, the nonlinear dynamic (time-history) analysis of the base-isolated frame buildings is carried out, and the nonlinear modal responses of the first and second modes are calculated from pushover analysis results. In the second stage, a set of pushover analyses is proposed considering the combination of the first and second modal responses, and predicted maximum member forces are compared with the nonlinear time-history analysis results. Results show that the maximum member forces predicted in the proposed set of pushover analyses are satisfactorily accurate, while the results predicted considering only the first mode are inaccurate.

Research on Seismic Design and Modeling of City Viaduct

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.608-609.134 ◽

2014 ◽

Vol 608-609 ◽

pp. 134-138

Author(s):

Tian Ming Miao ◽

Ying Zhou

Keyword(s):

Spectrum Analysis ◽

Response Spectrum ◽

Statistical Significance ◽

Time History ◽

Practical Method ◽

Plastic Response ◽

Elastic Plastic ◽

History Analysis ◽

This paper gives the basic methods for the analysis of the seismic response of viaduct based on elastic-plastic response spectrum method, and established indicators correspond with the method of strength, deformation, basic displacement and other performance. Practical example shows that the elastic-plastic response spectrum analysis response can be careful examining structure of each target in strong earthquake action value, and compare with the nonlinear time-history analysis, the method is concise, efficient, stable, and has the statistical significance of spectrum analysis, that can be used as a city track traffic high bridge and practical method.

IABSE Symposium, Guimarães 2019: Towards a Resilient Built Environment Risk and Asset Management ◽

Development of Fragility Curves for Multi-Span RC Bridges using Generalized Pushover Analysis

10.2749/guimaraes.2019.0548 ◽

2019 ◽

Author(s):

Camilo Perdomo ◽

Ricardo Monteiro ◽

Halûk Sucuoğlu

Keyword(s):

Seismic Vulnerability ◽

Fragility Curves ◽

Pushover Analysis ◽

Time History ◽

Engineering Practice ◽

Nonlinear Analyses ◽

History Analysis ◽

Nonlinear Time History ◽

Existing Bridges

<p>Over the past few decades, fragility curves became a powerful tool for the seismic vulnerability assessment of structures. There are several available analytical procedures for calculating fragility curves, using both static and dynamic nonlinear analyses. In this study, a nonlinear static method, based on Generalized Pushover Analysis (GPA), is implemented for the development of analytical fragility curves of reinforced concrete (RC) bridges. The relative accuracy of the GPA algorithm, when applied to a large number of existing bridges, is evaluated through the comparison with the results from Nonlinear Time History Analysis (NTHA). Results indicate that GPA provides a good estimation of the fragility curves with respect to NTHA. The added computational demand of the GPA algorithm in terms of the number of analyses pays off in terms of accuracy while keeping the simplicity of a non-adaptive conventional pushover algorithm, which is desirable in engineering practice.</p>