Determination of Period of RC Buildings by the Ambient Vibration Method

Determining the dynamic properties of structures is important for understanding their seismic behaviour. Ambient vibration signal measurement is one of the approaches used to determine the period of structures. Advantages of this method include the possibility of taking real-time records and presenting nondestructive and rapid solutions. In this study, natural vibration periods are calculated by taking ambient vibration signal records from 40 buildings. The height of the building, infill wall effect, presence of seismic retrofit, and presence of damage are taken into consideration, and their effects on natural vibration periods are investigated. Moreover, the results are compared with the analytical methods to reveal the differences. A significant correlation between the period and height of the building is observed. It is seen that the natural vibration periods of the buildings decrease by 7% to 30% (15% on average) due to infill wall contribution. However, the efficiency of infill walls decreases as the building height increases. Another significant result is that adding shear walls substantially decreases the vibration period values by 23% to 33% with respect to the shear wall ratio. When the analytical estimates and measured building period results are compared, it is seen that analytical models have closer period estimates before infill walls are implemented. The limited data in scope of the study suggest that significant differences may present in the analytical and measured periods of the buildings due to infill wall contributions.

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Structural Behavior of the General Archive of the Nation (AGN) Building, Mexico

Infrastructures ◽

10.3390/infrastructures3030039 ◽

2018 ◽

Vol 3 (3) ◽

pp. 39

Author(s):

Marcos Chávez ◽

Fernando Peña ◽

Claudia Cruz ◽

Gustavo Monroy

Keyword(s):

Dynamic Properties ◽

Ambient Vibration ◽

Structural Behavior ◽

High Plasticity ◽

Fundamental Vibration ◽

Vibration Period ◽

Ambient Vibration Tests ◽

Smeared Crack ◽

The Government ◽

Vibration Tests

This article presents a study on the structural behavior of the Government Building that is part of the old Lecumberri Palace and which currently houses the Mexican General Archive of the Nation. This building was inaugurated in 1900 and closed in 1976, after serving as a prison for 76 years. It was reopened in 1982 after it had undergone several remodeling works. The construction is made of brick masonry with lime mortar. It is supported by a deposit of overly compressible high-plasticity clays. The main problems of this building are the appearance of cracks in both interior and exterior walls, and moisture in the ground floor, caused by differential settlements. The study entailed a geometric and a damage survey as well as ambient vibration tests in order to determine the dynamic properties of the construction. The data obtained was used for the making of a model that, using the finite element method, was analyzed under different load conditions. This study has focused on the overall response with the assumption of smeared crack damage. According to the results, the building’s safety was deemed as acceptable. It has the capability to withstand seismic actions as established by the Mexican Building Code due to the high density of its walls and the resulting stiffness, which infer that the fundamental vibration period of the building would be distant from the predominant vibration period of the soil. This highlights the idea that the building’s critical condition is constituted by the differential settlements, which cause damage in the construction.

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Analysis of a damaged 12-storey frame-wall concrete building during the 2010 Haiti earthquake — Part II: Nonlinear numerical simulations

Canadian Journal of Civil Engineering ◽

10.1139/cjce-2012-0099 ◽

2013 ◽

Vol 40 (8) ◽

pp. 803-814 ◽

Cited By ~ 5

Author(s):

Benoit Boulanger ◽

Patrick Paultre ◽

Charles-Philippe Lamarche

Keyword(s):

Structural Damage ◽

Numerical Models ◽

Dynamic Properties ◽

Shear Walls ◽

Element Model ◽

Companion Paper ◽

Ambient Vibration ◽

Wall Structure ◽

Haiti Earthquake ◽

Concrete Building

After the 2010 Haiti earthquake, which destroyed a significant part of the seismically vulnerable city of Port-au-Prince, the country’s capital, a 12-storey reinforced concrete building that behaved well was investigated to understand its dynamic response. This paper completes the experimental work presented in a companion paper, in which the dynamic properties of the building were obtained from ambient vibration tests, and from which a finite-element model was updated. This paper’s main objectives are: (i) to understand the causes that led to the observed structural damage; and (ii) to estimate the likely seismic excitation at the site of the building. Several nonlinear analyses involving various ground motion intensities were conducted and the results were compared with the damage reported during the on-site survey. The numerical models reproduced the observed damages well and helped to explain them. The overall response of the mixed stiff frame–wall structure was clearly dominated by the high stiffness of the shear walls, showing that this type of structural system helps in keeping reasonable interstorey drift levels. Overall, the building’s structure seems to have responded linearly to all the ground motions investigated, but deformation demands imposed to the frame by the shear walls lead to local damages.

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Seismic Analysis of a Residential Building Considering Different Types of Opening Arrangement in the Infill Wall

International Journal for Research in Applied Science and Engineering Technology ◽

10.22214/ijraset.2021.38473 ◽

2021 ◽

Vol 9 (10) ◽

pp. 649-656

Author(s):

Kapil Shankar Soni

Keyword(s):

Failure Modes ◽

Seismic Analysis ◽

Response Spectrum ◽

Residential Building ◽

Base Shear ◽

Seismic Behaviour ◽

Infill Wall ◽

Infill Walls ◽

Time Period ◽

Natural Time

Abstract: Infill walls are inevitable components of any structure to create dispassion between interior space and external condition. In general, there are some prevalent openings inside the infill walls because of practical needs, architectural observations or aesthetic inspections. In current design practice, strength and inflexibility contribution of infill walls aren't thought of. However, the presence of infill walls may impact the seismic reaction of structures exposed to earthquake loads and cause a conduct which is not the same as that estimated for a bare frame. Additionally, partial openings inside infill walls are significant parameter prompting the seismic behaviour of infilled frames in this manner retreating lateral stiffness and strength. In this study is proposed to compare various models of buildings considering the openings (10% of surface area) at different locations in the infill walls for the seismic behaviour. A G+13 residential building is considered in Zone III with soil type II and analysis is carried out by Response Spectrum Method. Various parameters are considered such as Natural Time period, Base shear, Storey displacement, Storey drift and Storey stiffness were studied. The comparative study could simplify designers and code developers in selecting and recommending appropriate analytical models for estimating strength, stiffness, failure modes and other properties of infill frames with openings. Keywords: Residential Building, Openings Infill Wall, ETAB Software, Natural Time Period, Base Shear, Storey Shear, Storey Displacement, Storey Drift, Storey Stiffness.

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Evaluation of the period and soft story conditions of reinforced concrete buildings with and without infill walls

Challenge Journal of Structural Mechanics ◽

10.20528/cjsmec.2021.03.004 ◽

2021 ◽

Vol 7 (3) ◽

pp. 151

Author(s):

Başak Zengin

Keyword(s):

Reinforced Concrete ◽

Shear Walls ◽

Structural System ◽

Infill Wall ◽

Infill Walls ◽

Earthquake Energy ◽

Ground Floor ◽

Earthquake Loads ◽

Soft Storey ◽

Soft Story

Since the ground floor of most of the buildings in our country is designed as a shop or ground floor (in the buildings created as a workplace), there is very little infill wall ratio on the ground floors due to architectural and functional reasons, and some of them do not even exist at all. However, infill walls significantly increase the horizontal rigidity and strength of the structure, thus causing a decrease in the period value that determines the earthquake loads that will affect the structure. However, the infill wall meets the first destructive forces of the earthquake, and during this time, it cracks and absorbs some of the earthquake energy. The structural system elements of the building (columns and shear walls) start to meet the earthquake forces only when the infill walls are damaged and fail. In this direction, the aim of this study is to investigate to what extent the amount of infill wall on the ground floor affects the period of the building, and whether there are soft storey irregularities in the building according to the change in the amount of infill wall on the ground floor. In this study, while there are infill walls on all floors and all axes of buildings of various heights (3, 6, 9 and 11 floors), the amount of infill walls in the x and y directions on the ground floors is reduced to a certain extent, and many models are created until the ground floor is completely without infill walls. All these models created were analyzed with the support of the SAP2000 program, and the period values were determined and examined according to the soft storey problems and compared with the case of the entire building with and without infill walls. In addition, it was examined whether the period formulas determined as a result of the studies and taking into account the infill wall give realistic results for the situation examined in this study.

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Developing a Feature Extraction of Existing Structures Using an Ambient Vibration Test

10.31224/osf.io/hg94n ◽

2020 ◽

Author(s):

Hamed Sarmast ◽

Hassan Haji Kazemi

Keyword(s):

Dynamic Properties ◽

Analytical Models ◽

Ambient Vibration ◽

Vibration Test ◽

Vibration Testing ◽

Destructive Testing ◽

Ambient Vibration Test ◽

Existing Structures ◽

Ambient Vibration Testing ◽

Using Data

The paper aims to extract the dynamic properties of existing structures without utilizing the analytical models. The ambient vibration testing could be used on any type of frame such as concrete, steel and masonry to investigate the structural vulnerability. The method could be the first stage and necessarily for the retrofit process. To achieve this aim, the ambient vibration testing can also be employed. The experimental data obtained from the method can be used to monitor the health, evaluating, and damage detection structures at present. The achieved data can be compared in future with the recorded signals at different times. So, the ambient vibration test was carried out on the building of Imam Hossein Hospital at Mashhad. Then, its dynamic characteristics of the acceleration records are obtained by using Data Acquisition System with three accelerometers in two perpendicular coordinates. The method is more accurate and practical compare with analytical models of the existing buildings. The ambient vibration test prevents of several points such as destructive testing or may irreparable damage to the building as well as high cost. Even, the ambient vibration test maybe required for every couple of decayed, when noticed of any changes in the condition of buildings after construction. These type of changes could be quality of concrete or welding or some changes in the location of walls that can be affected the dynamic specifications of the building. The method provides real lateral load pattern and actual modes that can evaluate existing condition of the building compare with the time of construction.

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Dynamic Analysis of Buildings with Coupled Shear Walls under Seismic Loading: Simplified Method to Estimate Natural Vibration Period of Buildings

Proceedings of the Eleventh International Conference on Civil, Structural and Environmental Engineering Computing ◽

10.4203/ccp.86.210 ◽

2009 ◽

Author(s):

M. Rahman ◽

M. Hassanen

Keyword(s):

Dynamic Analysis ◽

Natural Vibration ◽

Shear Walls ◽

Seismic Loading ◽

Vibration Period ◽

Simplified Method

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Performance of RC Cast-in-Place Buildings During The November 26, 2019 Albania Earthquake

10.21203/rs.3.rs-1027850/v1 ◽

2021 ◽

Author(s):

Marko Marinković ◽

Markel Baballëku ◽

Brisid Isufi ◽

Nikola Blagojević ◽

Ivan Milićević ◽

...

Keyword(s):

Structural Damage ◽

Shear Walls ◽

Seismic Assessment ◽

Rc Buildings ◽

Physical Damage ◽

Seismic Behaviour ◽

Infill Walls ◽

Masonry Infill ◽

Masonry Infill Walls

Abstract This paper documents performance of cast-in-place reinforced concrete (RC) buildings in the Durrës during Albania earthquake of 26th of November 2019 (MW 6.4). Both mid- and high-rise RC buildings were affected by the earthquake, experiencing structural and/or non-structural damage and even collapse in some cases. The authors performed a reconnaissance study after the earthquake and were involved in seismic assessment of buildings in the affected area. Besides the observations related to physical damage related to RC buildings, the paper also presents results of a statistical analysis of damaged RC buildings in the Durrës city. The discussion in the paper is focused on damage patterns and failure mechanisms that are relevant for the seismic response of RC structures. Most common damage pattern is related to masonry infill walls, which experienced damage and failure in some cases, and affected the performance of adjacent RC columns due to the infill/frame interaction. Taller RC framed buildings (10 storeys and higher) were expected to have RC shear walls; however, these walls were reportedly absent in the damaged buildings of this type. In some cases, masonry infill walls (instead of RC shear walls) were used in the elevator shaft areas, which resulted in inadequate seismic performance. Two case study buildings were presented in detail to illustrate seismic behaviour of cast-in-place RC buildings. The case study is based on field observations after the earthquake and a detailed seismic assessment study. Finally, relevant lessons and recommendations are presented in light of the observed performance of RC buildings.

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Developing a Feature Extraction of Existing Structures Using an Ambient Vibration Test

10.31224/osf.io/wsm69 ◽

2020 ◽

Author(s):

Hamed Sarmast

Keyword(s):

Experimental Data ◽

Feature Extraction ◽

Dynamic Properties ◽

Analytical Models ◽

Ambient Vibration ◽

Vibration Test ◽

Vibration Testing ◽

Ambient Vibration Test ◽

Existing Structures ◽

Ambient Vibration Testing

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THE EFFECT OF PLACEMENT OF L-TYPE SHEAR WALLS IN RC STRUCTURES ON STRUCTURAL BEHAVIOR

INTERNATIONAL REFEREED JOURNAL OF ENGINEERING AND SCIENCES ◽

10.17366/uhmfd.2021.15.4 ◽

2021 ◽

Vol 0 (15) ◽

pp. 0-0

Author(s):

Muhammet Zeki ÖZYURT

Keyword(s):

Reinforced Concrete ◽

Natural Vibration ◽

Shear Walls ◽

Shear Wall ◽

Structural Behavior ◽

Structural System ◽

Reinforced Concrete Structure ◽

Vibration Period ◽

Peak Displacement ◽

Ground Floor

Aim: In this study; In this study, it was investigated how the symmetrical and different positions of the L-type shear walls on the floor plan affect the structural behavior in the reinforced concrete residential and office buildings with a symmetrical structural system. Method: In the study, three different carrier system types were created for a symmetrical reinforced concrete structure with 5 floors (ground floor + 4 normal floors), according to the shear wall layouts, and on a total of 12 different models (ground floor heights of 2.5 m, 3.0 m, 4.0 m and 5 m) was examined. Results: It was determined that as the ground floor height increased, the natural vibration period, soft floor irregularity coefficient and peak displacement value also increased in all models examined in the study. It has been observed that the natural vibration period is greater when the shear walls are located at the corners of the outer axles than if they are located in the middle of the outer axles and in the inner axles. It has been observed that in all cases of ground floor height, the number of soft floor irregularities in the corner shear wall layout model on the outer axes is approximately 0.2% higher than in the Type 2 situation. Conclusion: In this study, for the 5-storey reinforced concrete structures used for workplace and residential purposes, whose structural system is determined symmetrically so that torsional irregularity does not occur, the results obtained by changing the placement of L-section shear walls in the plan, drew attention to the fact that the position of the shear wall affects the structural behavior. For buildings with a ground floor height less than or equal to the normal floors, the most appropriate shear wall placement is when the shear walls are on the outer axes and in the corner. For buildings with a ground floor height higher than normal floors, the most appropriate shear wall placement takes place on the inner axes of the building.

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Natural Vibration Period Analysis of Multi-Storey Reinforced Concrete Frame Structure

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.226-228.351 ◽

2012 ◽

Vol 226-228 ◽

pp. 351-354

Author(s):

Li Na Hao ◽

Yong Sheng Zhang

Keyword(s):

Reinforced Concrete ◽

Frame Structure ◽

Ambient Vibration ◽

Reinforced Concrete Frame ◽

Natural Period ◽

Test Technique ◽

Infill Walls ◽

Vibration Period ◽

Concrete Frame ◽

Reinforced Concrete Frame Structure

Field measurements of dynamic characteristics of the multi-storey reinforced concrete frame structure buildings were carried out, by using the ambient vibration test technique, and structural modal parameters were extracted. The measured results and calculated results in accordance with current design specifications were compared. Results show that for multi-storey reinforced concrete frame structure, the measured vibration period of structure is close to the natural period calculated in accordance with the empirical formula of the “Load Code for the Design of Building Structures”. In the actual project, when the designer calculate the natural period if considering only the quality of the infill walls, without considering the stiffness of the infill walls, the period should be shortened. In this paper, the recommended period shortening factor for the multi-storey reinforced concrete frame structure is gave 0.4~0.5.

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