scholarly journals Nonlinear Inelastic Earthquake Analysis of 2D Steel Frames

2020 ◽  
Vol 10 (6) ◽  
pp. 6393-6398
Author(s):  
P. C. Nguyen
Keyword(s):  
Residual Stresses ◽  
Plastic Hinge ◽  
Steel Frames ◽  
Time History ◽  
Stability Functions ◽  
Fiber Plastic ◽  
Inelastic Responses ◽  
Displacement Based ◽  
Nonlinear Time History ◽  
Plastic Hinge Method

In this work, a new method for nonlinear time-history earthquake analysis of 2D steel frames by a fiber plastic hinge method is presented. The beam-column element based on the displacement-based finite element method is established and formulated in detail using a fiber plastic hinge approach and stability functions. Geometric nonlinearities are taken into accounting by stability functions and the geometric stiffness matrix. A nonlinear dynamic algorithm is established based on the combination of the Newmark integration method and the Newton-Raphson iterative algorithm for solving dynamic equations. The proposed program predicts the nonlinear inelastic responses of 2D steel frames subjected to earthquakes as efficiently and accurately as commercial software. This study also shows that the initial residual stresses of steel should be considered in nonlinear inelastic time-history earthquake analysis of 2D steel frames while SAP2000 does not consider the effects of residual stresses.

scholarly journals Nonlinear Inelastic Analysis of 2D Steel Frames

2020 ◽  
Vol 10 (4) ◽  
pp. 5974-5978 ◽  
Author(s):  
P. C. Nguyen ◽  
B. Le-Van ◽  
S. D. T. V. Thanh
Keyword(s):  
Residual Stresses ◽  
Plastic Hinge ◽  
Steel Frames ◽  
Nonlinear Problems ◽  
Zone Method ◽  
Stability Functions ◽  
Inelastic Analysis ◽  
Fiber Plastic ◽  
And Behavior ◽  
Plastic Hinge Method

In this study, a new method for nonlinear analysis of 2D steel frames, by improving the conventional plastic hinge method, is presented. The beam-column element is established and formulated in detail using a fiber plastic hinge approach. Residual stresses of I-shape sections are declared at the two ends through fibers. Gradual yielding by residual stresses along the member length due to axial force is accounted for by the tangent elastic modulus concept. The P-δ effect is captured by stability functions, whereas the P-Δ effect is estimated by the geometric stiffness matrix. A nonlinear algorithm is established for solving nonlinear problems. The present study predicts the strength and behavior of 2D steel frames as efficiently and accurately as the plastic zone method did.

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

2014 ◽  
Vol 30 (4) ◽  
pp. 1601-1618 ◽  
Author(s):  
Arash Sahraei ◽  
Farhad Behnamfar
Keyword(s):  
Lateral Displacement ◽  
Plastic Hinge ◽  
Pushover Analysis ◽  
Time History ◽  
Relative Displacement ◽  
Analysis Procedure ◽  
New Method ◽  
Nonlinear Time History Analysis ◽  
Displacement Based ◽  
Nonlinear Time History

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.

scholarly journals Nonlinear time-history earthquake analysis for steel frames

Heliyon ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. e06832
Author(s):  
Phu-Cuong Nguyen ◽  
Thanh-Tuan Tran ◽  
Trong Nghia-Nguyen
Keyword(s):  
Steel Frames ◽  
Time History ◽  
Nonlinear Time History

scholarly journals Performance of an Existing Reinforced Concrete Building Designed in Accordance to Older Indonesian Seismic Code: A Case Study for a Hotel in Kupang, Indonesia

2018 ◽  
Vol 20 (1) ◽  
pp. 35
Author(s):  
Pamuda Pudjisuryadi ◽  
Benjamin Lumantarna ◽  
Ryan Setiawan ◽  
Christian Handoko
Keyword(s):  
Plastic Hinge ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Seismic Load ◽  
Ground Acceleration ◽  
Seismic Code ◽  
Damage Level ◽  
History Analysis ◽  
Nonlinear Time History ◽  
Seismic Hazard Map

The recent seismic code SNI 1726-2012 is significantly different compared to the older code SNI 1726-2002. The seismic hazard map was significantly changed and the level of maximum considered earthquake was significantly increased. Therefore, buildings designed according to outdated code may not resist the higher demand required by newer code. In this study, seismic performance of Hotel X in Kupang, Indonesia which was designed based on SNI-1726-2002 is investigated. The structure was analyzed using Nonlinear Time History Analysis. The seismic load used was a spectrum consistent ground acceleration generated from El-Centro 18 May 1940 North-South component in accordance to SNI 1726-2012. The results show that Hotel X can resist maximum considered earthquake required by SNI 1726-2012. The maximum drift ratio is 0.81% which is lower than the limit set by FEMA 356-2000 (2%). Plastic hinge damage level is also lower than the allowance in ACMC 2001.

Seismic Isolation Devices Based on Sliding between Surfaces with Variable Friction Coefficient

2016 ◽  
Vol 32 (4) ◽  
pp. 2291-2315 ◽  
Author(s):  
Paolo M. Calvi ◽  
Matteo Moratti ◽  
Gian Michele Calvi
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Time History ◽  
Absorption Capacity ◽  
Sliding Isolation ◽  
Variable Friction ◽  
Displacement Based ◽  
Nonlinear Time History ◽  
High Level ◽  
Base Isolators

Base isolators are effective tools to favor a high level of building performance under lateral load, providing protection to both structural and nonstructural elements. In this context, this paper discusses the possibility of employing materials with different frictional properties to enhance the response of flat and curved-surface base isolators. Two innovative devices, referred to as “BowTie” and “BowC,” are introduced and discussed in some detail. A series of nonlinear time history analyses are then conducted using a customized computer program and considering a number of case study structures, designed applying a displacement-based approach. The results of the analyses are used to discuss the key differences between variable friction and constant friction sliding isolation devices. It is shown that the newly proposed isolators may represent an improvement on classic base-isolation solutions, in light of their higher energy absorption capacity, which contributes to significantly enhance their performance.

A Novel Incremental Iterative Force Recovery Method for Second-Order Beam-Column Elements in Plastic Hinge Analysis of Steel Frames

2021 ◽  
Author(s):  
Yi-Qun Tang ◽  
He Zhu ◽  
Er-Feng Du
Keyword(s):  
Plastic Hinge ◽  
Steel Frames ◽  
Direct Analysis ◽  
High Accuracy ◽  
Second Order ◽  
Single Element ◽  
Recovery Method ◽  
Inelastic Analysis ◽  
Force Recovery ◽  
Plastic Hinge Method

This paper is concerned with an incremental iterative force recovery method in the second-order plastic hinge analysis of steel frames mainly modelled by a single element per member. Second-order beam-column elements are preferred in the direct analysis of steel frames due to their high accuracy and efficiency. However, formulations of these elements are complicated, and therefore they may have a problem of getting element force recovery in inelastic analysis. To overcome this difficulty, a novel incremental iterative force recovery method for second-order beam-column elements is proposed to perform plastic hinge analysis. The proposed method is derived more strictly and has good performance. Also, the section assemblage approach and the refined plastic hinge method are adopted in this study to consider the gradual degradation of section stiffness in the plastic hinge analysis. To verify the accuracy, efficiency and robustness of the proposed method, several benchmark examples are analyzed by the proposed method and compared with solutions reported by early researchers.

scholarly journals FRP Composite in Mitigating Seismic Risk of RC Structures in Near-Fault Regions with/without Aftershocks

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Vui Van Cao ◽  
Son Quang Pham
Keyword(s):  
Plastic Hinge ◽  
Time History ◽  
Damage State ◽  
Rc Structures ◽  
Seismic Sequences ◽  
Near Fault ◽  
Damage Indices ◽  
Aftershock Sequences ◽  
Nonlinear Time History ◽  
Original Frame

The literature related to earthquakes and fibre reinforced polymer (FRP) retrofitting can be divided into two main categories: (1) the applications of FRP to retrofit structures subjected to single traditional earthquakes and (2) the effects of mainshock-aftershock sequences on original structures (without FRP retrofitting). Research on using FRP to mitigate the risk of pulse-type mainshock-aftershock sequences for reinforced concrete (RC) structures located in near-fault regions is hardly found in the literature and is thus the aim of this study. To achieve this aim, a four-storey RC frame, near-fault mainshocks, and seismic sequences were selected. The frame was retrofitted using FRP wraps at plastic hinge locations. Nonlinear time history and damage analyses of the original and FRP-retrofitted frames subjected to these near-fault mainshocks and seismic sequences were conducted. The results showed that aftershocks significantly increase the damage indices of the frames, shifting the damage state of the original frame from severe damage to collapse and the damage state of the FRP-retrofitted frame from light damage to moderate damage. FRP retrofitting successfully reduced the risk of seismic sequences by reducing the damage two levels, shifting the damage state of the original frame from collapse to moderate damage.

Correlation between Damage Indexes in Knee Bracing Frames Subjected to Earthquakes

2011 ◽  
Vol 255-260 ◽  
pp. 2350-2354
Author(s):  
Kamran Faraji ◽  
Mahmoud Miri
Keyword(s):  
Structural Damage ◽  
Steel Frames ◽  
Time History ◽  
Deformation Energy ◽  
Hysteretic Behavior ◽  
Nonlinear Time History Analysis ◽  
Damage Level ◽  
History Analysis ◽  
Nonlinear Time History ◽  
Earthquake Accelerograms

For vulnerability assessment of structures, different damage indexes have been established by researchers that estimate the structural damage level. In these indexes different parameters have been used for calculating structural damage level. In this paper, damage indexes based on deformation, energy and cycle hysteretic behavior are investigated in order to find a correlation between their numerical values. The selected damage indexes are calculated and compared by applying them in nonlinear time history analysis of low and intermediate rise knee braced steel frames subjected to a set of seven earthquake accelerograms. Correlations between various indexes have been presented graphically and approximate conversion formulas are also provided.

scholarly journals AN INVESTIGATION ABOUT EFFECTS OF FLUID-STRUCTURE-SOIL INTERACTION ON RESPONSE MODIFICATION COEFFICIENT OF ELEVATED CONCRETE TANKS

2016 ◽  
Vol 8 (1) ◽  
pp. 1-7
Author(s):  
Mirtaha Hashemi ◽  
Khosrow Bargi
Keyword(s):  
Plastic Hinge ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
History Analysis ◽  
Elevated Tanks ◽  
Recent Earthquakes ◽  
Nonlinear Time History ◽  
Seismic Forces

This paper aims to observe effects of fluid-structure-soil interactions on the response modification coefficient of elevated concrete tanks with frame and shaft supporting systems. Because of weaknesses and failures of elevated tanks that have been reported in recent earthquakes and importance of optimum and resistant design and also better seismic performance of these structures, it is essential to investigate on the response modification coefficient of elevated concrete tanks. In this paper, the response modification coefficient has been evaluated by using the numerical modeling. The method of research is a case study. The models have been subjected to an ensemble of important earthquake ground motions. The effects of soilstructure interactions and fluid-structure interactions on seismic behavior of the elevated concrete tanks have been modeled by the equivalent springs and Housner’s method, respectively. Dynamic response of the elevated tanks has been considered by using the nonlinear time history analysis and the discrete plastic hinge approach. Finally, the effects of fluid-structure-soil interactions on the response modification coefficient of the elevated concrete tanks have been discussed by considering results of the analyses. It has been concluded that the codes may underestimate base seismic forces for some seismic regions and some subsoil classes.

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