Study on normalization of residual displacements for single-degree-of-freedom systems

Intermediate Step ◽

Residual Displacement ◽

Inelastic Displacement ◽

Residual Displacements ◽

Constant Strength ◽

Residual displacement spectrum is one of the most important means to predict the permanent deformation of structures after the earthquake, and various normalizations of residual displacements have generally been used for construction of the spectrum. However, the issue regarding the merits and drawbacks of each normalization has not yet been investigated thoroughly. A comparison between two normalizations that relate the residual displacements to the elastic and inelastic displacements is made in terms of the effect of ground motion and structural characteristics by means of the results of nonlinear time history analysis. The statistical results reveal that the residual-to-peak-inelastic displacement ratios have the advantages of small dispersion, samples without any outliers, and relatively symmetric distribution, which benefits from the strong correlation between residual and peak inelastic displacements. Moreover, the residual-to-peak-inelastic displacement ratios are almost independent of site conditions, significant duration, and natural periods. Consequently, the peak inelastic displacements are superior to the elastic ones as an intermediate step for residual displacements estimation, provided that the peak inelastic displacements are estimated with a low uncertainty. For providing alternatives to estimate residual displacement demands, the constant-strength residual displacement spectra are developed for both normalizations.

Nonlinear Time-History Analysis for Validation of the Displacement-Based Seismic Assessment of the RC Upper Bridge of a Dam

Advances in Civil Engineering ◽

10.1155/2018/9879101 ◽

2018 ◽

Vol 2018 ◽

pp. 1-13 ◽

Cited By ~ 2

Author(s):

P. Lestuzzi ◽

H. Charif ◽

S. Rossier ◽

M. Ferrière ◽

J.-P. Person

Keyword(s):

Structural Characteristics ◽

Time History ◽

Seismic Assessment ◽

Soil Conditions ◽

Acceleration Time Histories ◽

Nonlinear Time History Analyses ◽

Displacement Demand ◽

Displacement Based ◽

The seismic assessment of a secondary structure of the Chancy-Pougny dam, namely, the upper bridge, is discussed in this paper. A first seismic assessment, performed according to classical force-based methodology, concluded the necessity of an extensive retrofitting for the upper bridge. By contrast, the application of the displacement-based approach showed that the current situation is already satisfactory, and therefore, practically no retrofitting is needed. The paper focuses on the nonlinear time-history analyses which were achieved in order to check the accuracy of the results obtained using the displacement-based method. The structural characteristics of the reinforced concrete upper bridge are similar to those of conventional bridges. However, the piers were built with very little reinforcement and consequently they will exhibit a rocking behavior in case of earthquake loading. Rocking is rather a favorable failure mechanism and is related to a certain amount of displacement capacity. However, this behavior is not linked to plastic energy dissipation which may significantly increase the related displacement demand. In order to determine the real displacement demand, nonlinear time-history analyses were achieved with SDOF systems defined by an “S” shape hysteretic model. Spectrum compatible stationary synthetic accelerograms and slightly modified recorded earthquakes were both used for acceleration time-histories. The results showed that the displacement demand corresponds well with the one determined by usual push-over analysis. The results show a very favorable seismic situation, related to a relatively stiff structure associated to rock soil conditions with an A class soil. The seismic safety of the upper bridge is already satisfactory for the current state (without retrofitting). Consequently, the proposed costly reinforcement for the upper bridge could be significantly reduced.

Dynamic P-Δ Effect on Probabilistic Residual Displacement of Bridge Structures

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.405-408.1678 ◽

2013 ◽

Vol 405-408 ◽

pp. 1678-1681

Author(s):

Bo Yu ◽

Di Liu ◽

Lu Feng Yang

Keyword(s):

Time History ◽

Dynamic Responses ◽

Stability Factor ◽

Bridge Structure ◽

Residual Displacement ◽

Sdof System ◽

History Analysis ◽

Bridge Structures ◽

Residual displacement has been identified as one of the most important parameter to assess the reparability and usability of bridge structures after strong earthquake, which is significantly impacted by the P-Δ effect. In this study, the influence of the P-Δ effect on the probabilistic characteristics of residual displacement of bridge structure was quantificationally investigated based on a series of nonlinear time-history analysis. The bridge structure was idealized as the single-degree-of-freedom (SDOF) system and the hysteretic behaviour was represented by the improved Bouc-Wen model. The statistic analysis was implemented based on the inelastic dynamic responses of the SDOF system under 69 selected earthquake records. The results show that the P-Δ effect has significant impact on the residual displacement, especially for systems with large stability factor and/or small post-yield stiffness ratio and yield strength.

Displacement Demand for Nonlinear Static Analyses of Masonry Structures: Critical Review and Improved Formulations

Buildings ◽

10.3390/buildings11030118 ◽

2021 ◽

Vol 11 (3) ◽

pp. 118

Author(s):

Gabriele Guerrini ◽

Stylianos Kallioras ◽

Stefano Bracchi ◽

Francesco Graziotti ◽

Andrea Penna

Keyword(s):

Time History ◽

Nonlinear Static Analysis ◽

Equivalent Linearization ◽

Eurocode 8 ◽

Masonry Structures ◽

Equivalent Viscous Damping ◽

Inelastic Displacement ◽

N2 Method ◽

Nonlinear Static ◽

This paper discusses different formulations for calculating earthquake-induced displacement demands to be associated with nonlinear static analysis procedures for the assessment of masonry structures. Focus is placed on systems with fundamental periods between 0.1 and 0.5 s, for which the inelastic displacement amplification is usually more pronounced. The accuracy of the predictive equations is assessed based on the results from nonlinear time-history analyses, carried out on single-degree-of-freedom oscillators with hysteretic force–displacement relationships representative of masonry structures. First, the study demonstrates some limitations of two established approaches based on the equivalent linearization concept: the capacity spectrum method of the Dutch guidelines NPR 9998-18, and its version outlined in FEMA 440, both of which overpredict maximum displacements. Two codified formulations relying on inelastic displacement spectra are also evaluated, namely the N2 method of Eurocode 8 and the displacement coefficient method of ASCE 41-17: the former proves to be significantly unconservative, while the latter is affected by excessive dispersion. A non-iterative procedure, using an equivalent linear system with calibrated optimal stiffness and equivalent viscous damping, is then proposed to overcome some of the problems identified earlier. A recently developed modified N2 formulation is shown to improve accuracy while limiting the dispersion of the predictions.

Seismic Ratchetting of Single-Degree-of-Freedom Steel Bridge Columns

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.763.295 ◽

2018 ◽

Vol 763 ◽

pp. 295-300 ◽

Cited By ~ 1

Author(s):

Khaled Saif ◽

Chin Long Lee ◽

Trevor Yeow ◽

Gregory A. MacRae

Keyword(s):

Time History ◽

Steel Structures ◽

Bridge Columns ◽

Steel Bridge ◽

Axial Loads ◽

Maximum Displacement ◽

Residual Displacements ◽

Average Maximum ◽

Force Reduction ◽

Nonlinear time history analyses of SDOF bridge columns with elasto-plastic flexural behaviour which are subject to eccentric gravity loading are conducted to quantify the effect of ratchetting. Peak and residual displacements were used as indicators of the degree of ratchetting. The effects of member axial loads and design force reduction factors were also investigated. It was shown that displacement demands increased with increasing eccentric moment. For eccentric moment of 30% of the yield moment, the average maximum and residual displacements increase by 4.2 and 3.8 times the maximum displacement, respectively, which the engineers calculate using static methods without considering ratchetting effect. Design curves for estimating the displacement demands for different eccentric moments are also developed. The current NZ1170.5 (2016) provisions were found to be inadequate in estimating the maximum displacement for steel structures, and hence, new provisions for steel structures should be presented.

Probabilistic Peak Displacement Analysis of Bridge Structures with P-Δ Effect

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.405-408.1674 ◽

2013 ◽

Vol 405-408 ◽

pp. 1674-1677

Author(s):

Bo Yu ◽

Di Liu ◽

Lu Feng Yang

Keyword(s):

Time History ◽

Dynamic Responses ◽

Bridge Structure ◽

Vibration Period ◽

Peak Displacement ◽

Sdof System ◽

Bridge Structures ◽

Performance Based Seismic Design ◽

Peak displacement is one of the most important parameters for the performance based seismic design of bridge structure, while the peak displacement is often significantly impacted by the P-Δ effect. In this study, the influence of the P-Δ effect on the statistics of peak displacement of bridge structure was quantificationally investigated based on a series of nonlinear time-history analysis. The bridge structure was idealized as the single degree of freedom (SDOF) system and the hysteretic behaviour was represented by the improved Bouc-Wen model. The statistic analysis was implemented based on the inelastic dynamic responses of the SDOF system under 69 selected earthquake records. The results show that the P-Δ effect has significant impact on the mean and dispersion of peak displacement of bridge structures, especially if the normalized yield strength and the natural vibration period are small.

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

Civil Engineering Dimension ◽

10.9744/ced.20.1.35-40 ◽

2018 ◽

Vol 20 (1) ◽

pp. 35

Author(s):

Pamuda Pudjisuryadi ◽

Benjamin Lumantarna ◽

Ryan Setiawan ◽

Christian Handoko

Keyword(s):

Plastic Hinge ◽

Time History ◽

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.

Nonlinear Analysis of a RC Frame Structure with Semi-Interlayers Damaged during Wenchuan Earthquake

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.156-157.467 ◽

2010 ◽

Vol 156-157 ◽

pp. 467-472

Author(s):

Peng Tao Yu ◽

Jing Jiang Sun

Keyword(s):

Nonlinear Analysis ◽

Wenchuan Earthquake ◽

Time History ◽

Large Earthquake ◽

Frame Structure ◽

Frame Structures ◽

Rc Frame ◽

Rc Frame Structures ◽

Under the excitation of large earthquake, structures enter into high nonlinear stage. Currently, Opensees, Perform-3d and Canny are used as the most popular nonlinear analysis procedures. The fiber model will be introduced firstly and the nonlinear analysis models in Canny are explained in detail. Then Canny2007 is used to conduct nonlinear time history analysis on a heavily damaged frame structure with interlayer in Dujiangyan during Wenchuan Earthquake. Analysis shows that the maximum inter-story drift appears between the interlayer and its upper layer, and the heavy damage agrees well with the results of damage investigation. By comparing the damage extent of frame structures with or without interlayer, it reveals that the seismic performance of RC frame structures without interlayer is obviously better than that of ones with interlayer.

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.

Seismic Performance Analysis of the Special-Shaped Frame Column Structure on Multi-Dimensional Seismic

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.90-93.1644 ◽

2011 ◽

Vol 90-93 ◽

pp. 1644-1648

Author(s):

Dong Qiang Xu ◽

Mei Mei He

Keyword(s):

Ground Motion ◽

Time History ◽

Regular Structure ◽

Frame Structure ◽

Weak Links ◽

Column Structure ◽

Structure Torsion ◽

Torsional Component ◽

The article considers the two horizontal components of ground motion and torsional component, to do nonlinear time history analysis both on regular and irregular shaped column frame structure models. The results show that torsional component of ground motion haves some impact on torsion reaction of structures, stiffness of irregular shaped column frame structure is uneven, and angle of columns are greater than that of the regular structure; torsion haves some impact on the torque of structure, the torque increases of corner columns is maximum, so corner columns are weak links in shaped column structure, considered fully during the seismic design.