scholarly journals Earthquake Response Control of Ground Soft Storey

2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Sakshi A Manchalwar
Keyword(s):  
Time History ◽  
Nonlinear Time History Analysis ◽  
Friction Damper ◽  
Infill Wall ◽  
Soft Storey ◽  
Open Ground ◽  
Interstorey Drift ◽  
Masonry Infill Wall ◽  
Bracing System ◽  
Nonlinear Time History

In the present study, friction damper an energy dissipating passive device is explored to reduce the response of open ground storey building under lateral loading due to earthquake. This damper is installed in the selected bays of open ground storey so that the response is reduced. The masonry infill wall is macro-modeled in the form of compression only diagonal members. Three different types of bracing system were installed along with Pall friction damper – single diagonal tension – compression brace with friction damper, tension only cross brace with friction damper and chevron brace with friction damper were modeled using Wen’s plastic link element in SAP2000. G+4 storey buildings were analyzed using nonlinear time history analysis. The storey displacement and interstorey drift for all the cases were compared in the study.

scholarly journals Earthquake response control of ground soft storey

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Sakshi A Manchalwar
Keyword(s):  
Time History ◽  
Nonlinear Time History Analysis ◽  
Friction Damper ◽  
Infill Wall ◽  
Soft Storey ◽  
History Analysis ◽  
Open Ground ◽  
Masonry Infill Wall ◽  
Bracing System ◽  
Nonlinear Time History

In the present study, friction damper, an energy dissipating passive device is explored to reduce the response of open ground storey building under lateral loading due to earthquake. This damper is installed in the selected bays of open ground storey so that the response is reduced. The masonry infill wall is macro-modeled in the form of compression only diagonal members. Three different types of bracing system were installed along with Pall friction damper – single diagonal tension – compression brace with friction damper, tension only cross brace with friction damper and chevron brace with friction damper were modeled using Wen’s plastic link element in SAP2000. G+4 storey buildings were analyzed using nonlinear time history analysis. The storey displacement and inter-storey drift for all the cases were compared in the study.

scholarly journals Mitigation of Seismic Risks to Soft-Storey Structures Using Toggle-Brace-Damper Systems

2012 ◽  
Vol 238 ◽  
pp. 833-837 ◽  
Author(s):  
Ricky W.K. Chan ◽  
Zhe Fei Zhao
Keyword(s):  
Time History ◽  
Ground Level ◽  
Nonlinear Time History Analysis ◽  
Lateral Stiffness ◽  
Governing Equations ◽  
Magnification Factor ◽  
Soft Storey ◽  
History Analysis ◽  
Nonlinear Time History ◽  
Sudden Reduction

Soft-storey mechanism is characterized by a sudden reduction of lateral stiffness in one or more levels of a structure. Soft-storey is often observed in the ground level due to the absence of wall or cladding. With recent develop of energy dissipation systems, soft-storey mechanism can be corrected by addition of a damper-brace assembly. In particular, this paper investigates the effect of toggle-damper-brace systems on such situations. Governing equations including the magnification factor and lateral stiffness contributed by a toggle-damper-brace are formulated. It was found that a toggle-damper-brace system, if proportioned correctly, will significantly increase the travel in the damper and overall stiffness of structure can be enhanced. An illustrative example is presented using nonlinear time history analysis implemented on MATLAB.

Seismic performance of ribbed bracing system in passive control of structures

2015 ◽  
Vol 23 (18) ◽  
pp. 2926-2941 ◽  
Author(s):  
Ali Arzeytoon ◽  
Ali Akbar Golafshani ◽  
Vahab Toufigh ◽  
Hossein Mohammadi
Keyword(s):  
Passive Control ◽  
Compressive Force ◽  
Time History ◽  
Seismic Intensity ◽  
Nonlinear Time History Analysis ◽  
Concentrically Braced Frames ◽  
Maximum Displacement ◽  
Hysteretic Energy ◽  
Bracing System ◽  
Nonlinear Time History

In this article, a novel passive control system, ribbed bracing system (RBS), has been proposed to deal with the buckling problem. RBS is a bracing system with a simple mechanism that can be installed in braces as a supplemental part. The behavior of RBS is similar to that of conventional braces under tensile loading. However, under compressive force, it endures an insignificant force and prevents the braces from buckling through length reduction. In addition, seismic damage is concentrated in the bracing system of the structures equipped with RBS, decreasing the dissipated hysteretic energy in other structural members. There are two different mechanisms for RBS: 1) completely-closed RBS (CC-RBS) and 2) self-centering RBS (SC-RBS). The concept and mechanics of RBS have been verified by the results obtained from cyclic testing and numerical analysis of RBS specimens. In this research, after describing the mechanical configuration of RBS, nonlinear time history analysis has been conducted on 3-story and 6-story concentrically braced frames subjected to different seismic intensity levels, design basis earthquakes (DBE), and maximum considered earthquakes (MCE). The analyses have been performed on different types of bracing systems as follows: SC-RBS, CC-RBS, and Buckling Restrained Braces (BRB). The results show that SC-RBS frames have negligible residual story drifts, and maximum displacement in CC-RBS is slightly lower than that of BRB. Additionally, distribution of input energy into the structure was considered and showed that RBS frames demonstrate a high hysteretic energy dissipation, which results in lower demands in other structural elements.

Seismic assessment and upgrade of Type 2 construction steel moment-resisting frames built in Canada between the 1960s and 1980s using passive supplemental damping

2013 ◽  
Vol 40 (7) ◽  
pp. 644-654 ◽  
Author(s):  
Nikolas Kyriakopoulos ◽  
Constantin Christopoulos
Keyword(s):  
Time History ◽  
Nonlinear Time History Analysis ◽  
Experimental Program ◽  
Steel Moment Resisting Frames ◽  
Construction Steel ◽  
Moment Resisting ◽  
Interstorey Drift ◽  
Supplemental Damping ◽  
Nonlinear Time History

The seismic performance of a typical 1960s Type 2 construction steel moment-resisting frame hospital structure designed only for lateral wind loads was investigated. The structure was found to have a soft first storey and displayed large P–Δ sensitivities. An experimental program determined that the connections had considerable inherent ductility and were stable up to 2.0% interstorey drift, despite not having been designed for a ductile cyclic response. The structure was numerically modelled using advanced strength degradation considerations. A nonlinear time-history analysis was conducted using Montreal and Vancouver ground motions and the structure’s performance was found to be inadequate under the considered design hazard levels. Retrofits were proposed for the two orthogonal frames using a performance-based approach and supplemental damping, rather than local interventions to increase the ductility of these connections, and the performance of the final retrofit designs were investigated numerically to confirm that the desired performance levels were achieved.

scholarly journals Effect of a Near Fault on the Seismic Response of a Base-Isolated Structure with a Soft Storey

2017 ◽  
Vol 25 (4) ◽  
pp. 34-46
Author(s):  
B. Athamnia ◽  
A. Ounis ◽  
M. Abdeddaim
Keyword(s):  
Seismic Isolation ◽  
Seismic Analysis ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Base Shear ◽  
Rc Structures ◽  
Soft Storey ◽  
Near Fault ◽  
Nonlinear Time History ◽  
Far Fault

AbstractThis study focuses on the soft-storey behavior of RC structures with lead core rubber bearing (LRB) isolation systems under near and far-fault motions. Under near-fault ground motions, seismic isolation devices might perform poorly because of large isolator displacements caused by large velocity and displacement pulses associated with such strong motions. In this study, four different structural models have been designed to study the effect of soft-storey behavior under near-fault and far-fault motions. The seismic analysis for isolated reinforced concrete buildings is carried out using a nonlinear time history analysis method. Inter-story drifts, absolute acceleration, displacement, base shear forces, hysteretic loops and the distribution of plastic hinges are examined as a result of the analysis. These results show that the performance of a base isolated RC structure is more affected by increasing the height of a story under nearfault motion than under far-fault motion.

scholarly journals Seismic assessment of tall RC frames with hybrid friction damper and SMA designed by PBPD method

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
F. Norouzi ◽  
H. Nasebaradi ◽  
M. Jamshidi
Keyword(s):  
Design Method ◽  
Time History ◽  
Hysteretic Behavior ◽  
Nonlinear Time History Analysis ◽  
Friction Damper ◽  
High Rise ◽  
Rc Frames ◽  
Lateral Strength ◽  
Residual Deformations ◽  
Nonlinear Time History

In this study, a new lateral load resisting system for high-rise (Reinforced Concrete) RC frames is proposed, which includes friction damper-superelastic SMA wires. The proposed SMA-friction damper can not only regulate the mechanism of frictional energy dissipation components with its self-centering SMA wires according to the design method based on the proposed performance, which is able to provide a hysteretic behavior and high self-centering capacity with the lowest SMA consumption but also has some advantages such as simple configuration and economic application. In this paper, two high-rise 18 and 22-story RC frames were designed in two design modes of common and with the proposed damper. The nonlinear time history analysis subjected to 10 far-field earthquakes performed in Opensees software. The results of the analyses showed that using the proposed SMA-friction damper, in addition to the effective increase in ductility, lateral stiffness and lateral strength, provided an excellent self-centering capacity, which resulted to the significant reduction in the maximum drift and the residual deformations in the structure.

Seismic Vibration Control Using Superelastic Shape Memory Alloys

2006 ◽  
Vol 128 (3) ◽  
pp. 294-301 ◽  
Author(s):  
Jason McCormick ◽  
Reginald DesRoches ◽  
Davide Fugazza ◽  
Ferdinando Auricchio
Keyword(s):  
Shape Memory ◽  
Structural Control ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Small Scale ◽  
Niti Shape Memory Alloy ◽  
Braced Frames ◽  
History Analysis ◽  
Bracing System ◽  
Nonlinear Time History

Superelastic NiTi shape memory alloy (SMA) wires and bars are studied to determine their damping and recentering capability for applications in the structural control of buildings subjected to earthquake loadings. These studies improve the knowledge base in regard to the use of SMAs in seismic design and retrofit of structures. The results show that the damping properties of austenitic SMAs are generally low. However, the residual strain obtained after loading to 6% strain is typically <0.75%. In general, it is shown that large diameters bars perform as well as wire specimens used in non-civil-engineering applications. The results of a small-scale shake table test are then presented as a proof of concept study of a SMA cross-bracing system. These results are verified through analytical nonlinear time history analysis. Finally, a three-story steel frame implementing either a traditional steel buckling-allowed bracing system or a SMA bracing system is analyzed analytically to determine if there is an advantage to using a SMA bracing system. The results show that the SMA braces improve the response of the braced frames.

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.

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

2013 ◽  
Vol 405-408 ◽  
pp. 1674-1677
Author(s):  
Bo Yu ◽  
Di Liu ◽  
Lu Feng Yang
Keyword(s):  
Time History ◽  
Dynamic Responses ◽  
Nonlinear Time History Analysis ◽  
Bridge Structure ◽  
Vibration Period ◽  
Peak Displacement ◽  
Sdof System ◽  
Bridge Structures ◽  
Performance Based Seismic Design ◽  
Nonlinear Time History

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.

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