Response Modal Nonlinear Time-History Dynamic Analyses of the Northridge Earthquake of a Two- Storied Steel Structure with Rubber Isolator and Fixed-base Systems

Four single-story single-span Gabled Frame Structures (GFSs) which included in China national Standard Design Drawing of Light-weight Steel Structure with Gabled Frame (02SG518-1) were studied and their longitudinal seismic performances were evaluated through extensive nonlinear time-history analysis using eight ground motions representing the Frequent Earthquake, DBE and the MCE hazard levels, the load-bearing performances, deformation capacities and the curves of displacement were studied. The analysis results showed that the longitudinal seismic action of all GFSs considered in this study is very little, the displacement at the top of the column can satisfy the demands of the Technical Specificationfor Steel Structure of Light-weight Building with Gabled Frames even in MCE. The GFSs designed followed the Specificaiton have the excellent longitudinal seismic performance.

Download Full-text

The Effect of Long Duration Earthquakes on the Overall Seismic Behavior of Steel Structures Designed According to Eurocode 8 Provisions

Vibration ◽

10.3390/vibration3040029 ◽

2020 ◽

Vol 3 (4) ◽

pp. 464-477

Author(s):

Panagiota Katsimpini ◽

Foteini Konstandakopoulou ◽

George A. Papagiannopoulos ◽

Nikos Pnevmatikos ◽

George D. Hatzigeorgiou

Keyword(s):

Seismic Performance ◽

Time History ◽

Steel Structures ◽

Eurocode 8 ◽

Steel Buildings ◽

Long Duration ◽

Base Steel ◽

Fixed Base ◽

Permanent Settlement ◽

Nonlinear Time History

Premature and simultaneous buckling of several steel braces in steel structures due to the prolonged duration of a seismic motion is one of the issues that must be addressed in the next version of Eurocode 8. In an effort to contribute towards the improvement of the seismic design provisions of Eurocode 8, an evaluation of the overall behavior of some steel building-foundation systems under the action of long duration seismic motions is performed herein by means of nonlinear time-history seismic analyses, taking into account soil–structure interaction (SSI) effects. In particular, the maximum seismic response results—in terms of permanent interstorey drifts, overturning moments and base shears of the steel buildings as well as of the permanent settlement and tilting of their foundations—are computed. It is found that the seismic performance of steel buildings when subjected to long duration seismic motions is: (i) acceptable for the two and five-storey fixed base steel buildings and for the two-storey steel buildings with SSI effects included; (ii) unacceptable for the eight-storey fixed base steel buildings and for the five and eight-storey steel buildings with SSI effects included. In all cases of steel buildings with SSI effects included, the seismic performance of the mat foundation, as expressed by the computed values of residual settlement and tilting, is always acceptable.

Download Full-text

Seismic Assessment Of Multi-Span Steel Railway Bridge In Turkey Base On The Nonlinear Time History Analyses

10.5194/nhess-2017-168 ◽

2017 ◽

Author(s):

Mehmet F. Yilmaz ◽

Barlas Ö. Çağlayan

Keyword(s):

Fragility Curves ◽

Time History ◽

Field Measurements ◽

Response Analysis ◽

Northridge Earthquake ◽

Railway Bridge ◽

Railway Line ◽

Damage Data ◽

Steel Railway Bridge ◽

Nonlinear Time History

Abstract. It has been seen that bridges are vulnerable to earthquakes by the research studies after important earthquakes like the San Fernando earthquake (1971 USA), the Northridge earthquake (1994 USA), Great Hanshin earthquake (1995 Japan), and Chi-Chi earthquake (1999 Taiwan). These studies show that to do the seismic risk assessments for bridges, fragility curves are useful tools. There are the most used two ways to generate the fragility curves; empirically or analytically. If the damage reports from past earthquakes are available then empirical fragility curves may be developed but otherwise seismic response analysis of structures may be used to develop analytical fragility curves. In Turkey, earthquake damage data are very limited so to develop the fragility curves for the Alasehir bridge, the analytical method is used in this study. The bridge that is studied on is lying on the Manisa-Afyon railway line that is very important for both transportation and freightage. As the most of the country land covers the seismically active zones it is a necessity to find out the vulnerability of the Alasehir bridge. The Alasehir bridge is consists of six 30 m length truss system span with a total span length of 189.43 m supported by 2 abutments and 5 truss piers with height of 12.5 m, 19 m, 26 m, 33 m and 40 m. Sap2000 is used for computer model of the Alaşehir bridge and the model is refined by using field measurements. Then selected 60 different real earthquake data are used for the analysis by using the refined model. Both material nonlinearity and Δ-δ are considered during the analysis. With this study, seismic behavior of Alasehir steel railway bridge is determined. Truss piers reaction and displacements are used to determine the seismic performance of the Alasehir bridge. Different IMs are compared in terms of efficiency, practicality, and sufficiency. Component and system fragility curve are derived for most proper IMs.

Download Full-text

Investigating the Performance of Viscoelastic Dampers (VED) Under Nearfield Earthquakes with Directivity Feature

Civil and Environmental Engineering ◽

10.2478/cee-2018-0003 ◽

2018 ◽

Vol 14 (1) ◽

pp. 21-27 ◽

Cited By ~ 1

Author(s):

Ali Vatanshenas ◽

Mohammad Sadegh Rohanimanesh ◽

Ehsan Mohammadiha

Keyword(s):

Short Distance ◽

Near Field ◽

Time History ◽

Steel Structure ◽

Nonlinear Time History Analysis ◽

Acceleration Response ◽

Viscoelastic Dampers ◽

Acceleration Time History ◽

History Analysis ◽

Nonlinear Time History

AbstractOne of the most important factors that make structures vulnerable to earthquakes is the short distance between structures and epicenter. Near-field earthquakes have special properties, such as increasing acceleration applied to the structure, which distinguishes them from far-field earthquakes. Therefore, the absorption of input energy for structures located near the faults is very important. Hence, by rotating the earthquake acceleration time history and comparing the resulting spectral acceleration response, the angle which applies the greatest force to the structure on the earthquake directivity side is obtained, and then the performance of a steel structure with viscoelastic dampers (VED) under near-field earthquakes with directivity feature is investigated. After analyzing the structure using nonlinear time history analysis, it was observed that the directivity phenomenon leads to significant increase in the force applied to the structure, but the viscoelastic dampers showed an acceptable performance in both states of with and without directivity.

Download Full-text

Evaluation of Out-of-Plane Wall Anchorage Force Provisions in Buildings with Rigid Walls and Flexible Roof Diaphragms

Earthquake Spectra ◽

10.1193/121915eqs186ep ◽

2017 ◽

Vol 33 (1) ◽

pp. 1-23 ◽

Cited By ~ 1

Author(s):

Maria Koliou ◽

John Lawson ◽

Andre Filiatrault ◽

Dominic J. Kelly

Keyword(s):

Model Building ◽

Ground Motions ◽

Time History ◽

Plane Wall ◽

Dynamic Analyses ◽

Out Of Plane ◽

Current Design ◽

Nonlinear Time History ◽

Rigid Walls ◽

Strong Ground

Heavy concrete and masonry walled buildings with lightweight steel or wood flexible roof diaphragms are a common type of construction in North America. Failures of the out-of-plane wall anchorage to these roof systems and the resulting partial roof collapses during past earthquakes have led to repeated revisions to the seismic design provisions in the U.S. model building codes. However, the force levels considered in the current design provisions have remained largely unchanged since their introduction in the 1997 Uniform Building Code, and these provisions have not been fully tested by strong ground motions in the field. Using a two dimensional numerical framework, a series of nonlinear time history dynamic analyses on various building archetypes were conducted to evaluate the validity of the current wall anchorage design force levels. The results of this study reveal that the current wall anchorage design forces are generally appropriate, but with some very significant exceptions.

Download Full-text

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 ◽

Nonlinear Time History

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.

Download Full-text

Study on Seismic Performance of Symmetrical Steel Framed Building that with and without ERB and FPS Isolators

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.204-208.2634 ◽

2012 ◽

Vol 204-208 ◽

pp. 2634-2640

Author(s):

Dong Zhou Xia

Keyword(s):

Base Isolation ◽

Linear Time ◽

Time History ◽

Cost Effective ◽

Design Guidelines ◽

Northridge Earthquake ◽

Base Shear ◽

Rubber Bearing ◽

History Analysis ◽

Fixed Base

As is known, base isolation can reduce earthquake energy that transferred from the ground motion to the structure by buffering it with a bearing layer at the foundation which has relatively low horizontal stiffness. The paper investigates the time history records of a two storied symmetrical steel framed isolated building with Elastomeric Rubber Bearing and Friction Pendulum Systems that under the Northridge earthquake, and the isolator parameters are calculated using the design guidelines of International Building Code (IBC2000) within the spirit of IS 1893–2002(7). And then, contrasting of the roof’s displacements, accelerations and base shear values of the steel framed building with and without isolators, and which studied from the Non-linear time history analysis using structural analysis software SAP2000. The results show that base isolation will provide a substitute technology for the conventional, fixed-base design of structures and cost-effective for new buildings in high seismic regions.

Download Full-text

Response control of structures under Seismic and Blast induced ground motions

E3S Web of Conferences ◽

10.1051/e3sconf/202130901137 ◽

2021 ◽

Vol 309 ◽

pp. 01137

Author(s):

Vamshisheela Siripuram ◽

Atulkumar Manchalwar

Keyword(s):

Base Isolation ◽

Ground Motions ◽

Time History ◽

Nonlinear Time History Analysis ◽

Base Shear ◽

Rubber Bearing ◽

Lead Rubber Bearing ◽

Fixed Base ◽

Isolation Device ◽

Nonlinear Time History

In the present paper an investigation is carried out to evaluate the efficiency of Base Isolation device in a building subjected to both seismic and blast induced ground motions. A 5-story building is modelled with different story stiffness and floor masses is considered in this study. In SAP 2000 software two buildings, one with fixed base and the other with isolated base are designed and nonlinear time history analysis is conducted. The structural responses of these two models subjected to four recorded earthquakes and four different blast ground accelerations is compared in this study. The base isolated device such as lead/rubber bearing have proved to be effective in reducing the base Shear and Top story acceleration, and also increase in Hysteresis energy in the base isolated structure subjected to seismic and blast vibrations.

Download Full-text

Effects of Soil-Structure Interaction on the Inelastic Seismic Response of Continuous Bridges on Piled Foundation

International Journal of Engineering and Advanced Technology - Regular Issue ◽

10.35940/ijeat.f8503.088619 ◽

2019 ◽

Vol 8 (6) ◽

pp. 1282-1290

Keyword(s):

Seismic Response ◽

Soil Structure ◽

Pushover Analysis ◽

Time History ◽

Fundamental Period ◽

Soil Structure Interaction ◽

Structure Interaction ◽

Fixed Base ◽

Ductility Capacity ◽

Nonlinear Time History

Effect of soil-structure interaction (SSI) on seismic response of bridges is not clearly understood, and in general practice, bridge design is carried out ignoring its effect. This is due to the general consensus that fixed base leads to a more conservative design despite the fact that many researchers indicate that ignoring soil-structure interaction may lead to underestimation of seismic response. The current paper aims to investigate the effect of SSI on the nonlinear seismic behavior of 9-span continuous bridge supported on pile foundation penetrating sandy soils. Three types of soils were investigated representing medium to stiff sandy soil. Both pushover analysis and nonlinear time history incremental dynamic analysis are carried out using Opensees to investigate the effect of SSI on the seismic response parameters (namely, fundamental period, pushover curves, foundation rigid body motions, global ductility capacity and demand, and maximum drift ratio) of the bridge and to compare it to fixed base assumption (i.e., SSI ignored). The results indicate that although SSI increases the flexibility of the structure (accordingly increasing fundamental period), the seismic demand of the bridge increases. This increase is more pronounced as the soil becomes softer.

Download Full-text

Analysis, Design, and Construction of a Base-Isolated Multiple Building Structure

Advances in Civil Engineering ◽

10.1155/2014/585429 ◽

2014 ◽

Vol 2014 ◽

pp. 1-13 ◽

Cited By ~ 13

Author(s):

Stefano Sorace ◽

Gloria Terenzi

Keyword(s):

Base Isolation ◽

Time History ◽

Residential Building ◽

Longitudinal Direction ◽

Isolation System ◽

Expansion Joints ◽

Analysis And Design ◽

Fixed Base ◽

Base Isolation System ◽

Nonlinear Time History

The analysis and design of a multiple residential building, seismically protected by a base isolation system incorporating double friction pendulum sliders as protective devices, are presented in the paper. The building, situated in the suburban area of Florence, is composed of four independent reinforced concrete framed structures, mutually separated by three thermal expansion joints. The plan is L-shaped, with dimensions of about 75 m in the longitudinal direction and about 30 m along the longest side of the transversal direction. These characteristics identify the structure as the largest example of a base-isolated “artificial ground” ever built in Italy. The base isolation solution guarantees lower costs, a much greater performance, and a finer architectural look, as compared to a conventional fixed-base antiseismic design. The characteristics of the building and the isolators, the mechanical properties and the experimental characterization campaign and preliminary sizing carried out on the latter, and the nonlinear time-history design and performance assessment analyses developed on the base isolated building are reported in this paper, along with details about the installation of the isolators and the plants and highlights of the construction works.

Download Full-text