Performance-Based Design Approach for Seismic Rehabilitation of Buildings with Displacement-Dependent Dissipators

2001 ◽  
Vol 17 (3) ◽  
pp. 531-548 ◽  
Author(s):  
Sonia E. Ruiz ◽  
Hiram Badillo
Keyword(s):  
Time History ◽  
Seismic Intensity ◽  
Seismic Retrofitting ◽  
Performance Based Design ◽  
Preliminary Design ◽  
Single Degree Of Freedom ◽  
Ductility Demand ◽  
Seismic Rehabilitation ◽  
Structural Responses ◽  
History Approach

A performance-based approach for seismic retrofitting of buildings with energy dissipating devices is presented. The approach may be seen as an algorithm useful for converging to a preliminary design of a system to be analyzed according to the time history approach recommended in the NEHRP Guidelines for the Seismic Rehabilitation of Buildings (FEMA 273). The algorithm is based on the analysis of equivalent single-degree-of-freedom models with added parallel elements that represent the dissipating devices. The combined systems are analyzed under sets of accelerograms associated with different return intervals. The acceptance criteria are intended to control the peak drift of the rehabilitated structure and the maximum ductility demand of the dissipating devices. It is required that these maximum structural responses, for a given seismic intensity, be equal to or smaller than those associated with a given probability of exceedance. The approach is successfully applied to a ten-story, three-bay frame rehabilitated with U-shaped steel dissipators.

scholarly journals Seismic Strengthening Effects of Full-Size Reinforced Concrete Frame Retrofitted with Novel Concrete-Filled Tube Modular Frame by Pseudo-Dynamic Testing

2021 ◽  
Vol 11 (11) ◽  
pp. 4898
Author(s):  
Jin-Seon Kim ◽  
Ju-Seong Jung ◽  
Dong-Keun Jung ◽  
Eui-Yong Kim ◽  
Kang-Seok Lee
Keyword(s):  
Dynamic Analysis ◽  
Shear Failure ◽  
Dynamic Testing ◽  
Seismic Intensity ◽  
Seismic Retrofitting ◽  
Restoring Force ◽  
Rc Structures ◽  
Linear Dynamic ◽  
Non Linear ◽  
Force Characteristics

The present study proposes a new seismic retrofitting method using a concrete-filled tube modular frame (CFT-MF) system, a novel technique to overcome and improve the limitations of existing seismic strengthening methods. This CFT-MF seismic retrofitting method makes the most of the advantages of both concrete and steel pipes, thereby significantly improving constructability and increasing integration between the existing structure and the reinforcement joints. This method falls into the category of typical seismic retrofitting methods that focus on increasing strength, in which the required amount of seismic reinforcement can be easily estimated. Therefore, the method provides an easy solution to improving the strength of existing reinforced concrete (RC) structures with non-seismic details that are prone to shear failure. In the present study, a full-size two-story test frame modeled from existing domestic RC structures with non-seismic details was subjected to pseudo-dynamic testing. As a result, the effect of the CFT-MF system, when applied to existing RC structures, was examined and verified, especially as to its seismic retrofitting performance, i.e., restoring force characteristics, stiffness reinforcement, and seismic response control. In addition, based on the pseudo-dynamic testing results, a restoring force characteristics model was proposed to implement non-linear dynamic analysis of a structure retrofitted with the CFT-MF system (i.e., the test frame). Finally, based on the proposed restoring force characteristics, non-linear dynamic analysis was conducted, and the results were compared with those obtained by the pseudo-dynamic tests. The results showed that the RC frame (building) with no retrofitting measures applied underwent shear failure at a seismic intensity of 200 cm/s2, the threshold applied in seismic design in Korea. In contrast, in the frame (building) retrofitted with the CFT-MF system, only minor earthquake damage was observed, and even when the maximum seismic intensity (300 cm/s2) that may occur in Korean was applied, small-scale damage was observed. These results confirmed the validity of the seismic retrofitting method based on the CFT-MF system developed in the present study. The non-linear dynamic analysis and the pseudo-dynamic test showed similar results, with an average deviation of 10% or less in seismic response load and displacement.

Seismic Vulnerability Analysis of FRP Retrofitting Industrial Buildings

2015 ◽  
Vol 724 ◽  
pp. 353-357
Author(s):  
Jian Zhu ◽  
Ping Tan ◽  
Pei Ju Chang
Keyword(s):  
Seismic Vulnerability ◽  
Response Spectrum ◽  
Time History ◽  
Seismic Intensity ◽  
Fiber Reinforced Polymers ◽  
Infill Wall ◽  
Intensity Index ◽  
Industrial Buildings ◽  
Dynamic Time ◽  
Masonry Infill Wall

This study focus on derivation of such vulnerability curves using Fiber Reinforced Polymers technologies retrofitted conventional RC industrial frames with masonry infill wall. A set of stochastic earthquake waves which compatible with the response spectrum of China seismic code are created. Dynamic time history analysis is used to compute the random sample of structures. Stochastic damage scatter diagrams based different seismic intensity index are obtained. Seismic vulnerability of FRP-reinforced RC industrial frames is lower than unreinforced frames obviously, and seismic capability of frames using FRP technologies is enhanced especially under major earthquake.

Influence of High Mode Effects on Ductility Reduction Factors for MDOF Shear-Type Structures

2014 ◽  
Vol 578-579 ◽  
pp. 412-416
Author(s):  
Hui Ying Wang
Keyword(s):  
Time History ◽  
Degree Of Freedom ◽  
High Mode ◽  
Lumped Mass ◽  
Ductility Demand ◽  
Mdof Systems ◽  
Mode Effect ◽  
Modification Factor ◽  
Shear Type ◽  
Reduction Factors

The influences of high mode effect on ductility reduction factors for multi-degree-of-freedom (MDOF) systems are studied by modifying ductility reduction factors for equivalent single-degree-of-freedom (SDOF) systems. Based on MDOF lumped-mass shear-type models, nonlinear dynamic time history analysis are performed to investigate the influence of ductility demand increase owing to high mode effect on ductility reduction factors. An empirical estimating model of MDOF modification factor is proposed. The results demonstrate that ductility reduction factors for MDOF systems are clearly smaller than those for SDOF systems. The modification factor is mainly affected by the fundamental period and ductility.

Post-Yielding Behavior of Hinge-Supported Wall with Buckling-Restrained Braces in Base

2019 ◽  
Vol 13 (03n04) ◽  
pp. 1940003 ◽  
Author(s):  
Xiaoyan Yang ◽  
Jing Wu ◽  
Jian Zhang ◽  
Yulong Feng
Keyword(s):  
Response Spectrum ◽  
Time History ◽  
Shear Wall ◽  
Seismic Intensity ◽  
Nonlinear Time History Analysis ◽  
Wall Structure ◽  
Superposition Method ◽  
Structural Wall ◽  
Design Response Spectrum ◽  
Buckling Restrained Braces

A novel structural wall with hinge support and buckling restrained braces (BRBs) set in the base (HWBB) is studied. HWBB can be applied to precast manufacturing due to its considerable ductility and the separate loading mechanism in HWBB–frame structure. In elastic stage, BRBs play a brace role to make the hinged wall resist horizontal forces like a shear wall. BRBs dissipate seismic energy through plastic and hysteresis effects after yielding and the damage is only concentrated in BRBs. The performance of an HWBB is equivalent to a shear wall structure with excellent ductility and stable energy dissipation capacity. Numerical analysis indicates that the hinged wall body in the HWBB well controls the deformation mode of the structure, avoiding the concentration of story drifts, thereby protecting the remaining parts of the structure. It is revealed that the moments of the wall body will generate significant increments after BRBs yielding, and the Seismic Intensity Superposition Method is proposed to calculate the moments. In this method, nonlinear response of an HWBB can be regarded as the sum of the responses of two elastic corresponding structures excited with two parts of the seismic intensity, respectively. Modes and moments equations of the hinged wall with uniform distribution of stiffness and mass are derived, and calculation results coincide with that of the nonlinear time history analysis (NHA). For a more general case, the white noise scan method is proposed to solve the structure’s natural characteristics and to further calculate the response. Finally, the post-yielding moment calculation method and the process based on design response spectrum are proposed. It is proved that the moments from proposed Seismic Intensity Superposition Method can envelop most of the moments from NHA, and it is a good estimate of the response of HWBB in nonlinear stage.

System Identification of Jack-Up Platform by Spectral Analysis

2010 ◽  
Author(s):  
X. M. Wang ◽  
C. G. Koh ◽  
T. N. Thanh ◽  
J. Zhang
Keyword(s):  
Spectral Analysis ◽  
System Identification ◽  
Time Domain ◽  
Time History ◽  
Offshore Structures ◽  
Wave Load ◽  
History Of ◽  
Structural Responses ◽  
Jack Up ◽  
Numerical Strategy

For the purpose of structural health monitoring (SHM), it is beneficial to develop a robust and accurate numerical strategy so as to identify key parameters of offshore structures. In this regard, it is difficult to use time-domain methods as the time history of wave load is not available unless output-only methods can be developed. Alternatively, spectral analysis widely used in offshore engineering to predict structural responses due to random wave conditions can be used. Thus the power spectral density (PSD) of structural response may be more appropriate than time history of structural responses in defining the objective (fitness) function for system identification of offshore structures. By minimizing PSD differences between measurements and simulations, the proposed numerical strategy is completely carried out in frequency domain, which can avoid inherent problems rising from random phase angles and unknown initial conditions in time domain. A jack-up platform is studied in the numerical study. A search space reduction method (SSRM) incorporating the use of genetic algorithms (GA) as well as a substructure approach are adopted to improve the accuracy and efficiency of identification. As a result, the stiffness parameters of jack-up legs can be well identified even under fairly noisy conditions.

scholarly journals Comparison of Scaling Ground Motions Using Arithmetic with Logarithm Values for Spectral Matching Procedure

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Rui Zhang ◽  
Dong-sheng Wang ◽  
Xiao-yu Chen ◽  
Hong-nan Li
Keyword(s):  
Ground Motions ◽  
Time History ◽  
Response Spectra ◽  
Time History Analysis ◽  
Spectral Matching ◽  
Moment Resisting Frame ◽  
History Analysis ◽  
Moment Resisting ◽  
Structural Responses ◽  
Structural Time

In recent studies, spectral matching is the most commonly proposed method for selecting earthquake records for time-history analysis of structures. However, until now, there have been no serious investigations of the effects of coordinate values on the scaling of ground motions. This paper investigated the influence of using arithmetic and logarithmic values of response spectra in spectral matching procedures (i.e., ASM and LSM methods) on the results of nonlinear structural time-history analysis. Steel moment resisting frame structures of the 3-, 9-, and 20-stories, which represent low-, medium-, and high-rise buildings, respectively, were used as examples. Structural benchmark responses were determined by calculating the arithmetic mean and median of peak interstory drift ratio (PIDR) demands based on the three record sets developed by the American SAC Steel Project. The three record sets represent seismic hazard levels with 50%, 10%, and 2% probabilities exceeded in 50 years, and their average acceleration spectra were also taken as the target spectrum. Moreover, another 40 record components for selection were scaled both by ASM and LSM methods. The seven components whose spectra were best compatible with the target spectra were selected for the structural time-history analysis. The scale factors obtained by the LSM method are nearly larger than that of the ASM method, and their ranking and selection of records are different. The estimation accuracies of structural mean (median) responses by both methods can be controlled within an engineering acceptable range (±20%), but the LSM method may cause larger structural responses than the ASM method. The LSM method has a better capacity for reducing the variability of structural responses than the ASM method, and this advantage is more significant for longer-period structures (e.g., 20-story structure) with more severe nonlinear responses.

Evaluation of code torsional provisions by a time history approach

1987 ◽  
Vol 15 (4) ◽  
pp. 491-516 ◽  
Author(s):  
A. M. Chandler ◽  
G. L. Hutchinson
Keyword(s):  
Time History ◽  
History Approach

Effect of the orientation of records on displacement ductility demand

2012 ◽  
Vol 39 (4) ◽  
pp. 362-373 ◽  
Author(s):  
A.D. García-Soto ◽  
H.P. Hong ◽  
R. Gómez
Keyword(s):  
Degree Of Freedom ◽  
Single Degree Of Freedom ◽  
Ductility Demand ◽  
Displacement Ductility ◽  
Single Degree ◽  
Perfectly Plastic ◽  
Principal Axes ◽  
Hazard And Risk ◽  
Elastic Perfectly Plastic ◽  
Pseudo Spectral

Effects of the ground motion record orientation on the estimated pseudo-spectral acceleration (PSA) have been investigated and reported in the literature; the statistics of the PSA along the major and minor principal axes differ from that for a random orientation. This is true for California as well as for Mexican records. However, a statistical assessment of the effect of record orientation on the displacement ductility demand is lacking. Such an assessment could be important for gaining confidence in and understanding of using the ductility demand rules for seismic hazard and risk evaluations. The statistical analyses of the effect of orientation on the estimated displacement ductility demand for elastic-perfectly-plastic and bilinear hysteretic (single degree of freedom) systems is carried out in the present study using sets of records from Mexican inslab and interplate earthquakes, and California earthquakes. Based on the obtained statistics, it is suggested that the consideration that the ductility demand is independent of the orientation of the records can be adequate, especially for Tn greater than 0.3 s and elastic-perfectly-plastic hysteretic single degree of freedom systems.

Seismic Fragility Analysis of Mid-Story Isolation and Reduction Structures Based Two Directions

2013 ◽  
Vol 739 ◽  
pp. 309-313 ◽  
Author(s):  
Pei Ju Chang
Keyword(s):  
Fragility Curves ◽  
Response Spectrum ◽  
Time History ◽  
Longitudinal Axis ◽  
Seismic Intensity ◽  
Seismic Fragility ◽  
Infill Wall ◽  
Intensity Index ◽  
History Analysis ◽  
Masonry Infill Wall

This study focus on derivation of such fragility curves using classic mid-story isolation and reduction structures (MIRS) in China metropolis. This study focus on derivation of such fragility curves using conventional industrial frames with masonry infill wall. A set of stochastic earthquake waves compatible with the response spectrum of China seismic code selected to represent the variability in ground motion. Dynamic inelastic time history analysis was used to analyze the random sample of structures. MIRS seismic capability of longitudinal and transversal orientation is different. Stochastic damage scatter diagrams based different seismic intensity index are obtained. Seismic fragility of longitudinal axis (Y axis) is larger than transversal axis (X axis) of frames under major earthquake obviously.

Aseismic Structural Systems for Buildings

2006 ◽  
Vol 1 (3) ◽  
pp. 358-377 ◽  
Author(s):  
Makoto Watabe ◽  
Keyword(s):  
Simple Structure ◽  
Dynamic Properties ◽  
Time History ◽  
Structural Systems ◽  
Initial Displacement ◽  
Single Degree Of Freedom ◽  
Principal Factors ◽  
History Of ◽  
Circular Frequency ◽  
General Dynamic

When structures are subjected to earthquake motions, the principal factors controlling their behavior are i) dynamic characteristics of the structure ii) characteristics of the input earthquake motions. In this sense, it is essential, first of all, to be acquainted with general dynamic properties. Let the simple structure – single degree of freedom system – as illustrated in Fig. 1 be considered. Spring, mass, and damper are the three elements which characterize the system. If to this system, an initial displacement is applied, then set it free, the time history of the displacement, velocity and acceleration will be as shown in Fig. 2. In Fig. 2 the basic concepts of period, frequency and circular frequency of the system are also explained.

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