Ambient vibration tests of a seven-story reinforced concrete building in Van Nuys, California, damaged by the 1994 Northridge earthquake

2000 ◽  
Vol 19 (6) ◽  
pp. 391-411 ◽  
Author(s):  
S.S Ivanović ◽  
M.D Trifunac ◽  
E.I Novikova ◽  
A.A Gladkov ◽  
M.I Todorovska
Keyword(s):  
Reinforced Concrete ◽  
Ambient Vibration ◽  
Northridge Earthquake ◽  
Reinforced Concrete Building ◽  
Ambient Vibration Tests ◽  
Concrete Building ◽  
Vibration Tests ◽  
1994 Northridge Earthquake

scholarly journals Numerical Modeling of Masonry Infilled Reinforced Concrete Building during Construction Stages Using ABAQUS Software

Buildings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 181 ◽  
Author(s):  
Boudjamaa Roudane ◽  
Süleyman Adanur ◽  
Ahmet Can Altunışık
Keyword(s):  
Reinforced Concrete ◽  
Natural Frequencies ◽  
Ambient Vibration ◽  
Mode Shapes ◽  
Analysis Model ◽  
Reinforced Concrete Building ◽  
Finite Element Software ◽  
Comparison Results ◽  
Concrete Building ◽  
Abaqus Software

The effects of seismic actions on reinforced concrete (RC) structures are strongly influenced by the dynamic behavior of their materials. It is crucial to find a simple definition of the natural frequencies of reinforced concrete buildings, particularly in relation to both principal and secondary elements constructing the reinforced concrete building type. This paper firstly presents a comparison with the ambient vibration surveys. An analysis model of different stages of construction of the reinforced concrete masonry wall was compared using the finite element software. In the second step, structural responses of the model were investigated by means of static analysis. Three main types were examined: Bare frame for one, two and three storeys; brick-walled; and coated cases. Modal analysis is carried out by ABAQUS software starting from the deformed building, to provide the natural frequencies and mode shapes. For the natural frequencies, a good agreement is obtained between analytical and experimental results. Furthermore, the comparison results between different cases show that the application of the plaster work increases the lateral stiffness and has significant effects on the dynamic response of the buildings.

scholarly journals Steady state vibration tests of a six-storey reinforced concrete building

1971 ◽  
Vol 4 (1) ◽  
pp. 94-107
Author(s):  
A. M. Reay ◽  
R. Shepherd
Keyword(s):  
Steady State ◽  
Reinforced Concrete ◽  
Fold Increase ◽  
Longitudinal Direction ◽  
Torsional Mode ◽  
Reinforced Concrete Building ◽  
Concrete Building ◽  
Modes Of Vibration ◽  
Vibration Tests ◽  
Free Beam

Five modes of vibration of a six-storey reinforced concrete building were excited by steady-state resonance testing. Good correlation between predicted and measured frequencies was obtained. In the lateral translation tests, two translation modes and the vibration of the roof as a free-free beam were excited. Damping measured in the fundamental mode was 4.1% critical and the average contribution of foundation compliance to the top-storey deflection was 32%. Damping in the second translation mode was 6.6% and of the free-free beam vibration, 3.6%. The first torsional mode of the building was excited, and for an eight-fold increase in excitation force, the natural frequency reduced by 1.2%, indicating a slight degree of non-linearity in the response. Damping in this mode was 6.9% , no change being noted for the eight-fold force increase. In the longitudinal direction, two modes were excited, the first torsional mode and the first longitudinal translation mode. Properties of the former were similar to those determined from the torsional response test. Damping in the translation mode was 10.1% and the foundation compliance contributed 24% of the top-storey deflection.

scholarly journals Study of the Seismic Response on the Infill Masonry Walls of a 15-Storey Reinforced Concrete Structure in Nepal

Buildings ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 39 ◽  
Author(s):  
André Furtado ◽  
Nelson Vila-Pouca ◽  
Humberto Varum ◽  
António Arêde
Keyword(s):  
Reinforced Concrete ◽  
Seismic Response ◽  
Concrete Structure ◽  
Numerical Study ◽  
Numerical Models ◽  
Ambient Vibration ◽  
Reinforced Concrete Structure ◽  
Infill Walls ◽  
Ambient Vibration Tests ◽  
Vibration Tests

Following the strong earthquake on April 25, 2015 in Nepal, a team from the University of Porto, in collaboration with other international institutions, made a field study on some of the most affected areas in the capital region of Kathmandu. One of the tasks was the study of a high-rise settle of buildings that were damaged following the earthquake sequence. A survey damage assessment was performed to a 15-storey infilled reinforced concrete structure, which will be detailed in the manuscript. Moreover, ambient vibration tests were carried out to determine the natural frequencies and corresponding vibration modes of the structure. The main aim of this manuscript is to present a numerical study concerning the influence of the masonry infill walls in the structure seismic response. For this, three numerical models were built discriminating the situations with and without damage and nondamaged infill walls. Validation and calibration of the numerical model was ensured by comparing the numerical frequencies with those obtained from ambient vibration tests. In addition, linear elastic analyses were carried out, using real accelerograms from the Gorkha earthquake to assess and quantify the major differences between the models in terms of inter-storey drifts ratios, inter-storey shear forces and seismic loadings.

scholarly journals Forced Vibration Testing of a Four-Story Reinforced Concrete Building Utilizing the nees@UCLA Mobile Field Laboratory

2008 ◽  
Vol 24 (4) ◽  
pp. 969-995 ◽  
Author(s):  
Eunjong Yu ◽  
Derek Skolnik ◽  
Daniel H. Whang ◽  
John W. Wallace
Keyword(s):  
Reinforced Concrete ◽  
Harmonic Excitation ◽  
Ambient Vibration ◽  
Mode Shapes ◽  
Northridge Earthquake ◽  
Vibration Data ◽  
Field Laboratory ◽  
Concrete Building ◽  
Rc Building ◽  
Low Amplitude

The nees@UCLA mobile field laboratory was utilized to collect forced and ambient vibration data from a four-story reinforced concrete (RC) building damaged in the 1994 Northridge earthquake. Both low amplitude broadband and moderate amplitude harmonic excitation were applied using a linear shaker and two eccentric mass shakers, respectively. Floor accelerations, interstory displacements, and column and slab curvature distributions were monitored during the tests using accelerometers, linear variable differential transformers (LVDTs) and concrete strain gauges. The use of dense instrumentation enabled verification of common modeling assumptions related to rigid diaphragms and soil-structure-interaction. The first six or seven natural frequencies, mode shapes, and damping ratios were identified. Significant decreases in frequency corresponded to increases in shaking amplitude, most notably in the N-S direction of the building, most likely due to preexisting diagonal joint cracks that formed during the Northridge earthquake.

scholarly journals Ambient Vibration Test of a 18-Story Reinforced Concrete Building

2018 ◽  
Vol 53 ◽  
pp. 03077
Author(s):  
Jun Ma ◽  
Jie Ge
Keyword(s):  
Reinforced Concrete ◽  
Domain Decomposition ◽  
Frequency Domain ◽  
Dynamic Properties ◽  
Ambient Vibration ◽  
Vibration Test ◽  
Ambient Vibration Test ◽  
Reinforced Concrete Building ◽  
Concrete Building ◽  
Frequency Domain Decomposition

Ambient vibration analysis of a 18-story reinforced concrete building was carried out to investigate its dynamic properties. Ambient vibration test was conducted on the building, and modal parameters including natural frequencies and damping ratios were identified using the Frequency domain decomposition (FDD) method and the Enhanced frequency domain decomposition (EFDD) method. The results demonstrate that ambient vibration test is a feasible and efficient technique to excite structures, and that FDD and EFDD methods are reliable and efficient techniques for ambient vibration data.

A dynamic test of a four-story reinforced concrete building*

1953 ◽  
Vol 43 (1) ◽  
pp. 7-16
Author(s):  
J. L. Alford ◽  
G. W. Housner
Keyword(s):  
Reinforced Concrete ◽  
Forced Vibration ◽  
Dynamic Test ◽  
Strong Motion ◽  
Reinforced Concrete Building ◽  
Concrete Building ◽  
Resonance Curves ◽  
Vibration Tests

abstract Forced vibration tests were conducted on a four-story reinforced concrete building. Deflections and accelerations were produced which approached the magnitude of those which occur during strong-motion earthquakes. Damping values were calculated from the resonance curves obtained. The results show that the total damping in the structure is small and that the damping apparently increases with increasing amplitude of motion. Within the accuracy of the measurements the damping was independent of the frequency of the motion.

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