Seismic Evaluation of Low-Rise Reinforced Masonry Buildings with Flexible Diaphragms: III. Synthesis and Application

2006 ◽  
Vol 22 (2) ◽  
pp. 329-347 ◽  
Author(s):  
Gregory L. Cohen ◽  
Richard E. Klingner ◽  
John R. Hayes ◽  
Steven C. Sweeney
Keyword(s):  
Earthquake Engineering ◽  
Analytical Modeling ◽  
Seismic Analysis ◽  
Experimental Testing ◽  
Evaluation Methodology ◽  
Masonry Buildings ◽  
Seismic Evaluation ◽  
Reinforced Masonry ◽  
Shaking Table Testing ◽  
Flexible Diaphragms

This paper outlines the last two phases of a joint research study performed by the University of Texas at Austin and the U.S. Army Corp of Engineers, Construction Engineering Research Laboratory, Engineer Research and Development Center (CERL). The study coordinates and synthesizes experimental testing, analytical modeling, practical implementation, and real-world application to enhance FEMA-310, the predominant seismic evaluation methodology for low-rise reinforced masonry buildings with flexible diaphragms. In earlier phases of study, conclusions from shaking-table testing, quasi-static testing, and analytical modeling were used to develop a simple tool for the seismic analysis of these types of buildings. In this paper, the tool is developed in the context of performance-based earthquake engineering into a supplementary evaluation methodology intended to fill a gap in FEMA-310. The tool is applied to four existing buildings and ultimately shown to be simple, useful, and necessary.

Seismic Evaluation of Low-Rise Reinforced Masonry Buildings with Flexible Diaphragms: II. Analytical Modeling

2004 ◽  
Vol 20 (3) ◽  
pp. 803-824 ◽  
Author(s):  
Gregory L. Cohen ◽  
Richard E. Klingner ◽  
John R. Hayes ◽  
Steven C. Sweeney
Keyword(s):  
Analytical Modeling ◽  
Companion Paper ◽  
Design Tool ◽  
Shaking Table ◽  
Masonry Buildings ◽  
Seismic Evaluation ◽  
Static Testing ◽  
Reinforced Masonry ◽  
Shaking Table Testing ◽  
Flexible Diaphragms

This and a companion paper compare the results from shaking-table testing, quasi-static testing, and analytical predictions to provide a coherent description of the seismic response of low-rise reinforced masonry buildings with flexible roof diaphragms. This paper presents the development, implementation, and results of coordinated analytical modeling intended to corroborate and extend the results of experimental work discussed in a companion paper, Part I: Seismic and Quasi-Static Testing, and more important, examine the efficacy and accuracy of different analytical modeling approaches. Specifically, linear elastic finite-element models, simplified two-degree-of-freedom models, and nonlinear lumped-parameter models are created and all agree well with measured responses. Based on these, a simple design tool for the analysis of low-rise reinforced masonry buildings with flexible diaphragms is developed and verified.

Seismic Evaluation of Low-Rise Reinforced Masonry Buildings with Flexible Diaphragms

Masonry ◽  
2009 ◽  
pp. 109-109-38
Author(s):  
Gregory L. Cohen ◽  
Richard E. Klingner ◽  
John R. Hayes ◽  
Steven C. Sweeney
Keyword(s):  
Masonry Buildings ◽  
Seismic Evaluation ◽  
Reinforced Masonry ◽  
Flexible Diaphragms

Seismic Evaluation of Low-Rise Reinforced Masonry Buildings with Flexible Diaphragms

2006 ◽  
Vol 3 (7) ◽  
pp. 13661
Author(s):  
GL Cohen ◽  
RE Klingner ◽  
JR Hayes ◽  
SC Sweeney ◽  
SW Dean
Keyword(s):  
Masonry Buildings ◽  
Seismic Evaluation ◽  
Reinforced Masonry ◽  
Flexible Diaphragms

Seismic Evaluation of Low-Rise Reinforced Masonry Buildings with Flexible Diaphragms: I. Seismic and Quasi-Static Testing

2004 ◽  
Vol 20 (3) ◽  
pp. 779-801 ◽  
Author(s):  
Gregory L. Cohen ◽  
Richard E. Klingner ◽  
John R. Hayes ◽  
Steven C. Sweeney
Keyword(s):  
Experimental Testing ◽  
Shear Walls ◽  
The United States ◽  
Companion Paper ◽  
Degree Of Freedom ◽  
Shaking Table ◽  
Masonry Buildings ◽  
Static Testing ◽  
Reinforced Masonry ◽  
Shaking Table Testing

This and a companion paper compare the results from shaking-table testing, quasi-static testing, and analytical predictions, to provide a coherent description of the seismic response of low-rise reinforced masonry buildings with flexible roof diaphragms. Two half-scale, low-rise reinforced masonry buildings with flexible roof diaphragms are subjected to earthquake ground motions on the Tri-axial Earthquake and Shock Simulator at the United States Army Construction Engineering Research Laboratory, Engineer Research and Development Center. Following the shaking-table tests, diaphragms and top four courses of attached masonry walls are salvaged from the half-scale structures and tested quasi-statically in their own plane. In contrast to what is usually assumed in design, the half-scale specimens do not behave as systems with a single degree of freedom associated with the in-plane response of the shear walls, but rather a system with a dominant degree of freedom associated with the in-plane response of the roof diaphragm. A new index describing the potential for diaphragm damage is introduced, the diaphragm drift ratio. A companion paper, Part II: Analytical Modeling, presents analytical work intended to corroborate and extend results from experimental testing.

scholarly journals Seismic analysis of in-plane loaded walls in unreinforced masonry buildings with flexible diaphragms

2014 ◽  
Vol 47 (4) ◽  
pp. 275-289
Author(s):  
Yasuto Nakamura ◽  
Hossein Derakhshan ◽  
Jason M. Ingham ◽  
Michael C. Griffith
Keyword(s):  
Seismic Analysis ◽  
Unreinforced Masonry ◽  
Mode Analysis ◽  
Analysis Approach ◽  
Masonry Buildings ◽  
Alternative Analysis ◽  
Response Modification Factor ◽  
Seismic Demands ◽  
Flexible Diaphragms ◽  
Modification Factor

It is well recognised that the dynamic response of unreinforced masonry buildings with flexible timber diaphragms typically contains multiple dominant modes associated with the excitations of the diaphragms and the in-plane walls. Existing linear analysis methods for this type of structure commonly account for the multi-mode behaviour by assuming the independent vibrations of the in-plane loaded walls (in-plane walls) and the diaphragms. Specifically, the in-plane walls are considered to be rigid and the unmodified ground motion is assumed to be transmitted up the walls to the diaphragm ends. While this assumption may be appropriate for many low-rise unreinforced masonry buildings, neglecting the dynamic interaction between the diaphragms and the in-plane walls can lead to unreliable predictions of seismic demands. An alternative analysis approach is proposed in this paper, based on the mode properties of a system in which (1) the mass ratios between the diaphragms and the in-plane wall are the same at all levels, and (2) the periods of the diaphragms are the same at all levels. It is proposed that under these conditions, two modes are typically sufficient to obtain the peak seismic demands of the in-plane walls in elastically responding low-rise regular buildings. The applicability of the two-mode analysis approach is assessed for more general diaphragm configurations by sensitivity analysis, and the limitations are identified. The two-mode approach is then used to derive a response modification factor, which may be used in conjunction with a linear static procedure in the seismic assessment of buildings with flexible diaphragms.

scholarly journals Seismic Effect on Multi Storey Building with Different Positioning Of Floating Column

2019 ◽  
Vol 8 (11) ◽  
pp. 2807-2811
Keyword(s):  
Earthquake Engineering ◽  
Seismic Analysis ◽  
Response Spectrum ◽  
Seismic Effect ◽  
Masonry Buildings ◽  
Seismic Excitations ◽  
Utility Value ◽  
Response Spectrum Analysis ◽  
The World ◽  
Storey Building

Modern multi storied buildings are being constructed with floating column at the ground floor to meet the requirements of parking or other aesthetic or utility value. Masonry buildings have proved to be most vulnerable when earthquakes strike in any part of the world. The damage caused by the earthquake cannot be eliminated but it could be mitigated by taking extra precaution. Floating columns can be constructed at any level or storey, at any point in the construction area. Seismic analysis is a major tool in earthquake engineering; this is used to understand the response of buildings due to seismic excitations in a simpler manner. Response Spectrum Analysis was used. Assumptions were made to study the seismic effect on different position of floating column for a six storied RC framed building.

Performance of masonry structures during the 1994 Northridge (Los Angeles) earthquake

1995 ◽  
Vol 22 (2) ◽  
pp. 378-402 ◽  
Author(s):  
Michel Bruneau
Keyword(s):  
Los Angeles ◽  
Unreinforced Masonry ◽  
Masonry Building ◽  
Masonry Buildings ◽  
Masonry Structures ◽  
Northridge Earthquake ◽  
Seismic Evaluation ◽  
Masonry Construction ◽  
Reinforced Masonry ◽  
The Impact

The surface magnitude 6.8 Northridge earthquake which struck the Los Angeles area on January 17, 1994, damaged a large number of engineered buildings, of nearly all construction types. As earthquakes of at least similar strength are expected to occur in most of eastern and western Canada, the study of the effects of this earthquake is of particular significance to Canada. This paper, as part of a concerted multi-paper reporting effort, concentrates on the damage suffered by masonry buildings during this earthquake, and explains why the various types of observed failures occurred. The seismic performance of all masonry construction similar to that commonly found in Canada is reviewed, but a particular emphasis is placed on providing an overview of damage to unreinforced masonry structures which had been rehabilitated before this earthquake. To provide a better appreciation of the impact of this earthquake on masonry buildings, and a better assessment of the engineering significance of their damage in a Canadian perspective, this paper first reviews the evolution of building code requirements for unreinforced masonry buildings up to the seismic retrofit ordinances enacted prior to this earthquake. Examples of various damage types, as observed by the author during his reconnaissance visit to the stricken area, are then presented, along with technically substantiated descriptions of the causes for this damage, and cross-references to relevant clauses from Canadian standards and codes, as well as the recently published Canadian Guidelines for the Seismic Evaluation of Existing Buildings, whenever appropriate. Key words: earthquake, unreinforced masonry, seismic rehabilitation, retrofit, retrofitted masonry building, reinforced masonry, buildings, failure, collapse, heritage buildings.

Conditioned Simulation of Ground-Motion Time Series at Uninstrumented Sites Using Gaussian Process Regression

2021 ◽  
Author(s):  
Aidin Tamhidi ◽  
Nicolas Kuehn ◽  
S. Farid Ghahari ◽  
Arthur J. Rodgers ◽  
Monica D. Kohler ◽  
...  
Keyword(s):  
Time Series ◽  
Gaussian Process ◽  
Ground Motion ◽  
San Francisco ◽  
Earthquake Engineering ◽  
Seismic Analysis ◽  
Ground Motions ◽  
Free Field ◽  
Gaussian Process Regression ◽  
Motion Time

ABSTRACT Ground-motion time series are essential input data in seismic analysis and performance assessment of the built environment. Because instruments to record free-field ground motions are generally sparse, methods are needed to estimate motions at locations with no available ground-motion recording instrumentation. In this study, given a set of observed motions, ground-motion time series at target sites are constructed using a Gaussian process regression (GPR) approach, which treats the real and imaginary parts of the Fourier spectrum as random Gaussian variables. Model training, verification, and applicability studies are carried out using the physics-based simulated ground motions of the 1906 Mw 7.9 San Francisco earthquake and Mw 7.0 Hayward fault scenario earthquake in northern California. The method’s performance is further evaluated using the 2019 Mw 7.1 Ridgecrest earthquake ground motions recorded by the Community Seismic Network stations located in southern California. These evaluations indicate that the trained GPR model is able to adequately estimate the ground-motion time series for frequency ranges that are pertinent for most earthquake engineering applications. The trained GPR model exhibits proper performance in predicting the long-period content of the ground motions as well as directivity pulses.

scholarly journals Performance of the CGS six DOF Shaking Table on the Harmonic Signal Reproduction

2017 ◽  
Vol 62 (1) ◽  
pp. 102-111
Author(s):  
Abdelhalim Airouche ◽  
Hassan Aknouche ◽  
Hakim Bechtoula ◽  
Nourredine Mezouer ◽  
Abderrahmane Kibboua
Keyword(s):  
Adaptive Control ◽  
Earthquake Engineering ◽  
Harmonic Signal ◽  
Shaking Table ◽  
Experimental Procedure ◽  
Signal Tracking ◽  
Engineering Research ◽  
Control Techniques ◽  
Shaking Table Testing ◽  
Six Dof

Shaking table testing continues to play an important role in earthquake engineering research. It has been recognized as a powerful testing method to evaluate structural components and systems under realistic dynamic loads. Although it represents a very attractive experimental procedure, many technical challenges, which require attention and consideration, still remain. High fidelity in signal reproduction is the focus of the work presented in this paper. The main objective of this paper is to investigate the capabilities of adaptive control techniques based on Amplitude Phase Control (APC) and Adaptive Harmonic Cancellation (AHC) on the harmonic signal tracking performance of the shaking table. A series of 232 sinusoidal command waveforms with various frequencies and amplitudes were conducted on the shaking table of the laboratory of the National Earthquake Engineering Applied Research Center (CGS, Algeria). Experimental results are reported and recommendations on the use of these adaptive control techniques are discussed.

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