scholarly journals Simplified Method for the Seismic Design of Low-Rise, Shear Wall Base- Isolated Buildings

2014 ◽  
Vol 8 (1) ◽  
pp. 22-33
Author(s):  
Arturo Tena-Colunga
Keyword(s):  
Seismic Design ◽  
Hybrid Method ◽  
Base Isolation ◽  
Shear Wall ◽  
Static Method ◽  
Isolation System ◽  
Strong Earthquakes ◽  
Wall Structures ◽  
Simplified Method ◽  
Isolated Structures

A simplified method for the seismic design of low-rise, base-isolated shear wall structures is proposed in MOC-2012. This simplified method is basically a hybrid method, where the design of the isolation system is a simpler version for the static method available in US guidelines for the design of base-isolated structures and the design of the superstructure essentially is an improved version of the simplified method for the seismic design of conventional low-rise shear wall structures of Mexican seismic codes. The application of this method and its effectiveness to obtain safe designs is illustrated with a practical example. It is anticipated this simple methodology would help promote the use of base isolation in low-rise shear wall structures and reduce their vulnerability when subjected to strong earthquakes.

Mechanism of the Frame-Supported Masonry Shear-Wall Structure with Inter-Story Isolation

2013 ◽  
Vol 351-352 ◽  
pp. 765-770
Author(s):  
Lei Lu ◽  
Ying Zhou
Keyword(s):  
Numerical Analysis ◽  
Shear Wall ◽  
Mixed System ◽  
Wall Structure ◽  
Stiffness Ratio ◽  
Mass Ratio ◽  
Isolation System ◽  
Wall Structures ◽  
Theoretical And Numerical Analysis ◽  
Masonry Shear Wall

Many frame-supported masonry shear-wall structures were observed severely damage in Wenchuan Earthquake. In this paper, an inter-story isolation system is implemented in such structures to mitigate the hazard of the earthquake. The mechanism of the mixed system is demonstrated by theoretical and numerical analysis. And it is concluded that the mass ratio, the below-stiffness ratio, the yield shear of isolated layer and the up-stiffness ratio are the main parameters whose effects are discussed separately. For the design convenience, a set of fitting equations of these parameters are provided.

scholarly journals Base isolation

1978 ◽  
Vol 11 (4) ◽  
pp. 219-233
Author(s):  
D. M. Lee ◽  
I. C. Medland
Keyword(s):  
Base Isolation ◽  
Shear Forces ◽  
Isolation System ◽  
Higher Mode Effects ◽  
Mode Effects ◽  
Effective Form ◽  
Base Isolation System ◽  
Standard Set ◽  
Isolated Structures

In this paper the evolution of a technique for protecting a structure from earthquake attack is traced from its beginning through to its currently most effective form, and this form, the Base Isolation System, is compared to other currently available techniques. The influence of higher mode effects in base isolated multi-storey structures is investigated and shown to be of considerable significance in determining the shear forces in the upper levels of a structure. Because of these higher mode effects the responses of appendages on isolated structures, while still being less than those for appendages on unisolated structures, can be significantly larger than previous 1-D analyses had suggested. A standard set of distributions of inter-storey shear up a multi-storey structure is presented with each distribution being defined by a parameter which varies from zero to unity.

A Study on the Response Instability of Seismically Isolated Structures Affected by Ground Inclination During Earthquakes Part 1 : Estimation of Ground Inclination During Earthquakes and the Influence of Static Ground Inclination

2011 ◽  
Vol 6 (3) ◽  
pp. 281-298 ◽  
Author(s):  
Mitsuo Miyazaki ◽  
◽  
Yukihiro Nishimura
Keyword(s):  
Seismic Isolation ◽  
Dynamic Performance ◽  
Restoring Force ◽  
Isolation System ◽  
Strong Earthquakes ◽  
Response Characteristics ◽  
Building Safety ◽  
Isolated Structures ◽  
Isolation Systems ◽  
Ground Motion Records

Seismic isolation can provide superior building safety and dynamic performance during strong earthquakes, however, it is known that some near-source ground motions produce excessive response deformations, which may be larger than the allowable capacity of the isolation devices. Isolation systems with longer periods and higher damping are more capable of resisting such deformations, and the author proposed new isolation systems with periods of 10 sec, or even longer. Longer isolation periods, however, mean less resistance and restoring force in the isolation systems, which may cause concerns about unstable response characteristics during strong earthquakes. One such unstable behavior is the possibility of excessive horizontal displacements of the isolation system resulting from ground inclination. Based on numerical analyses using existing vertical ground motion records, this paper estimates the ground inclination during earthquakes and studies the anticipated horizontal deformation of isolated structures that might be induced by such ground inclination.

Seismic design of base-isolated highway bridges utilizing lead–rubber bearings

1990 ◽  
Vol 17 (3) ◽  
pp. 413-422 ◽  
Author(s):  
A. Ghobarah ◽  
H. M. Ali
Keyword(s):  
Seismic Design ◽  
Base Isolation ◽  
Time History ◽  
Highway Bridges ◽  
Response Spectra ◽  
Design Guidelines ◽  
Design Parameters ◽  
Seismic Behaviour ◽  
Isolation System ◽  
Design Procedures

A study is made of the seismic behaviour of base-isolated highway bridges with the objective of developing design procedures in the form of code-type approach. The recommendations of current codes concerning the use of energy dissipation mechanisms for the seismic design of bridges are reviewed. A model representing the bridge deck, piers, and the base-isolation system is used to evaluate the response of the bridge to a selected earthquake time history record and to evaluate the effects of various design parameters on the dynamic response. The results of this analysis are used in the development of design guidelines for the isolated bridge system. It was found that base isolation affects the design forces on piers and abutments as well as the deck displacements. An optimum design should provide a reasonable balance between the shear forces on supports and tolerable displacements. Two design procedures are proposed based on the time history and inelastic response spectra approaches. Simplified charts are presented which aid in the seismic design of new bridges as well as in the upgrading of existing ones. Key words: dynamic, seismic, design, highway, bridges, earthquake, base isolation.

Statistical Analysis of Fundamental Periods of Frame-Shear Wall Structures

2012 ◽  
Vol 174-177 ◽  
pp. 2071-2078 ◽  
Author(s):  
Yan Qiang Gao ◽  
Wen Feng Liu
Keyword(s):  
Seismic Design ◽  
Exponential Type ◽  
Empirical Formula ◽  
Shear Wall ◽  
Fundamental Period ◽  
Single Variable ◽  
Empirical Formulas ◽  
Linear Type ◽  
Wall Structures ◽  
Non Linear

The differences of empirical formulas of China, United States, Japan, and Europe for estimating the fundamental periods of frame-shear wall structures are investigated. Summing up paradigms of the empirical formulas from the above representation countries, the paradigm formulas expressed as single-variable exponential type, single-variable linear type, and multi-variable non-linear type. Using statistical data of 88 groups of the measured fundamental period for least-squares regression analysis, and the effect of fitting regression formula is judged by the norm of relative error‖δ‖2 , the norm of root mean square error‖RMSE‖2 , and the norm of residual mass‖CRM‖2Italic textb> . The results show that: the single-variable exponential type has wide application and gets closer with measured fundamental period; the single-variable linear type is briefly, and the single-variable based on structural height has smaller error than the single-variable of stories; the multi-variable non-linear type is very complex and larger error compared with the measured fundamental period. Considering the formula in the form of simple, practical and consistent with the codes, this paper gives single-variable exponential type as recommended empirical formula for estimating the fundamental periods of frame-shear wall structures .The proposed empirical formula can serve as a reference for revision of the seismic design code, frame-shear wall structure seismic design and related studies.

Displacement-Based Seismic Design for Reinforced Masonry Shear-Wall Structures, Part 1: Background and Trial Application

2015 ◽  
Vol 31 (2) ◽  
pp. 969-998 ◽  
Author(s):  
Farhad Ahmadi ◽  
Marios Mavros ◽  
Richard E. Klingner ◽  
Benson Shing ◽  
David McLean
Keyword(s):  
Seismic Design ◽  
Design Procedure ◽  
Shear Wall ◽  
Local Deformation ◽  
Wall Structures ◽  
Reinforced Masonry ◽  
Plastic Mechanism ◽  
Displacement Based ◽  
Masonry Shear Wall ◽  
Displacement Based Seismic Design

In this paper, a displacement-based seismic design procedure is presented for reinforced masonry shear-wall structures, with the objective of being more consistent, transparent, and practical than current force-based seismic design procedures. The procedure anticipates the formation of a plastic mechanism at specified target displacements, calculates the local deformation demands associated with that mechanism, and ensures that those local deformation demands remain below deformation capacities for flexure-dominated and shear-dominated wall segments. Guidelines to determine the target displacements and effective damping properties for reinforced masonry wall structures are provided. The proposed procedure and guidelines are used in a trial application to design a full-scale, two-story reinforced masonry shear-wall system.

scholarly journals Analysis of a Frame-Shear Wall Concrete Structure by Using Base Isolation and Evaluation of Structure-Soil Interaction

2017 ◽  
Vol 7 (6) ◽  
pp. 2282-2287
Author(s):  
H. I. Polat
Keyword(s):  
Cross Sections ◽  
Base Isolation ◽  
Shear Wall ◽  
Structure Design ◽  
Mode Shapes ◽  
Earthquake Response ◽  
Response Analysis ◽  
Seismic Load ◽  
Isolation System ◽  
Base Isolation System

A base isolation system is a type of earthquake-resistant structure design approach based on the principle of reducing a structure’s earthquake response rather than increasing the structure’s earthquake resistance capacity. Seismic base isolated structures have the ability to make large displacements relative to the level of insulation elements. This means that a large structure performs very small displacements between floors during an earthquake and exhibits a rigid body behavior. At this point, the earthquake forces acting on the structure decrease along with the floors. In this article a school building composed of frame-shear wall is resolved primarily with the traditional fixed base structure system, mode shapes are found and periods are obtained. For earthquake response analysis, earthquake loads are distributed to the floors using the equivalent seismic load method and structural elements experiencing capacity problems are found. Then, using the earthquake record, larger failure of cross sections and capacity problems are obtained compared to the first method. In the second stage, the same structure is dissolved again by placing the lead core rubber base isolators between the base and the vertical structural members. The periods of structures under earthquake load have increased significantly by utilizing base isolation, as a result of that spectral accelerations decreased. Thus, large decreases in the shear forces acting to the structure are determined and failures of cross sections are removed.

scholarly journals Experimental Study on Behaviors of Adaptive-slit Shear Walls

2013 ◽  
Vol 7 (1) ◽  
pp. 189-195 ◽  
Author(s):  
Zhijuan Sun ◽  
Jiliang Liu ◽  
Mingjin Chu
Keyword(s):  
Experimental Study ◽  
Seismic Design ◽  
Mechanical Characteristics ◽  
Shear Walls ◽  
Shear Wall ◽  
Seismic Damage ◽  
Wall Structures ◽  
Performance Based Seismic Design ◽  
Damage Process ◽  
New Type

In order to meet the needs of performance-based seismic design, a new type of adaptive-slit shear wall that is easy to construct and behaves well under cyclic loading is introduced to improve the seismic performance of conventional shear wall structures. The seismic damage of an adaptive-slit shear wall develops gradually and it transforms from integral wall into slit wall. The mechanical characteristics of adaptive-slit shear walls suggest that such walls are adaptive to various seismic requirements under earthquakes of different intensities. Compared with conventional shear walls, the new wall is highly ductile and is advantageous in controlling the seismic damage process.

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