Study of mode shapes of multistoried buildings with rooftop water tanks considering with and without infill wall panel stiffness

2016 ◽  
pp. 105-109
Author(s):  
Sangram Nirmale
Keyword(s):  
Mode Shapes ◽  
Wall Panel ◽  
Infill Wall ◽  
Panel Stiffness ◽  
Water Tanks

scholarly journals Operational Modal Analysis, Testing and Modelling of Prefabricated Steel Modules with Different LSF Composite Walls

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5816
Author(s):  
Maria Rashidi ◽  
Pejman Sharafi ◽  
Mohammad Alembagheri ◽  
Ali Bigdeli ◽  
Bijan Samali
Keyword(s):  
Modal Analysis ◽  
Dynamic Characteristics ◽  
Operational Modal Analysis ◽  
Mode Shapes ◽  
Infill Wall ◽  
Modular Systems ◽  
Modal Properties ◽  
Modular Units ◽  
Composite Walls ◽  
Modular Structures

The modal properties of modular structures, such as their natural frequencies, damping ratios and mode shapes, are different than those of conventional structures, mainly due to different structural systems being used for assembling prefabricated modular units onsite. To study the dynamic characteristics of modular systems and define a dynamic model, both the modal properties of the individual units and their connections need to be considered. This study is focused on the former aspect. A full-scale prefabricated volumetric steel module was experimentally tested using operational modal analysis technique under pure ambient vibrations and randomly generated artificial hammer impacts. It was tested in different situations: [a] bare (frame only) condition, and [b] infilled condition with different configurations of gypsum and cement-boards light-steel framed composite walls. The coupled module-wall system was instrumented with sensitive accelerometers, and its pure and free vibration responses were synchronously recorded through a data acquisition system. The main dynamic characteristics of the module were extracted using output-only algorithms, and the effects of the presence of infill wall panels and their material are discussed. Then, the module’s numerical micromodel for bare and infilled states is generated and calibrated against experimental results. Finally, an equivalent linear strut macro-model is proposed based on the calibrated data. The contribution of this study is assessing the effects of different infill wall materials on the dynamic characteristics of modular steel units, and proposing simple models for macro-analysis of infilled module assemblies.

scholarly journals Use ofIn-SituDynamic Measurements to Calibrate Analytical Models of RC-Elevated Water Tanks

2012 ◽  
Vol 19 (5) ◽  
pp. 903-914
Author(s):  
H.M. Lopes ◽  
C.S. Oliveira
Keyword(s):  
Water Supply ◽  
Analytical Models ◽  
Ambient Vibration ◽  
Mode Shapes ◽  
Water Supply Systems ◽  
Water Tank ◽  
Analysis And Design ◽  
Elevated Water ◽  
Water Tanks

Before establishing the priority settings for the reduction of seismic risk of water supply infrastructures, it is necessary to understand the dynamic behavior of elevated water tanks, which are components of those infrastructures. Among other information, the main frequencies of vibration of these structures must be estimated and the analytical models used in their analysis and design should reproduce the frequency values obtained by in-situ dynamic tests. This work focuses exclusively on reinforced concrete (RC) elevated water tanks (200–750 m^3 of water at heights of 30–40 m), which are very common structures in the water supply systems in Portugal since the mid XXth century. This type of structures can also be seen in many regions around the world. First, a nationwide survey was conducted to determine the most common typologies in the country in terms of structural layout. Second, an in-situ campaign using ambient vibration as input was performed for a group of selected structures to determine the main frequencies of vibration and to identify modal shapes and damping values. Third, a finite element model of several different typologies was developed using the water simply as a concentrated mass at the top; the elastic properties of the model of the structure including the foundation were calibrated, so that the frequencies of various mode shapes obtained by the analytical model would match the frequencies of the real structure. Finally, an expression was derived to estimate the fundamental frequency of a group of elevated water tank typologies based on the total mass at the top of the supporting structure, which include the water, the global lateral stiffness, and the height of the tank. This study, providing important information on the frequencies of vibration of RC-elevated water tanks, contributes in a definite way to the analysis and design of such water tanks.

scholarly journals Seismic Protection of RC Buildings by Polymeric Infill Wall-Frame Interface

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1577
Author(s):  
Ahmet Tugrul Akyildiz ◽  
Alicja Kowalska-Koczwara ◽  
Łukasz Hojdys
Keyword(s):  
Three Dimensional ◽  
Mode Shapes ◽  
Dimensional Structure ◽  
Seismic Loads ◽  
Rc Buildings ◽  
Infill Wall ◽  
Infill Walls ◽  
Rc Frames ◽  
Out Of Plane ◽  
Real Size

This paper is aimed at investigating the usage of flexible joints in masonry infilled walls surrounded by reinforced concrete (RC) frames. For this purpose, a real-size specimen was numerically created and exposed to the seismic loads. In order to evaluate both in-plane and out-of-plane performances of the infill walls, the system was chosen as a box shaped three-dimensional structure. In total, three different one-story constructions, which have single bays in two perpendicular directions, were modeled. The first type is the bare-frame without the infill walls, which was determined as a reference system. The second and third types of buildings are conventional mortar joint and PolyUrethane Flexible Joint (PUFJ) implemented ones, respectively. The influence of these joints on the material level are investigated in detail. Furthermore, general building dynamic characteristics were extracted by means of acceleration and displacement results as well as frequency domain mode shapes. Analyses revealed that PUFJ implementation on such buildings has promising outcomes and helps to sustain structural stability against the detrimental effects of earthquakes.

scholarly journals Mechanical Behavior of the Reinforced Retaining Wall Subjected to Static Load

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Yong Liu ◽  
Zhanyong Yao ◽  
Hongzhe Liu ◽  
Mingxia Shao ◽  
Yulong Zhao
Keyword(s):  
Mechanical Behavior ◽  
Static Load ◽  
Retaining Wall ◽  
Influence Factors ◽  
Horizontal Displacement ◽  
Maximum Tensile Stress ◽  
Wall Panel ◽  
Element Analysis ◽  
Panel Stiffness ◽  
Reinforced Retaining Wall

To study the mechanical behavior and influence factors of the reinforced retaining wall under the static load, numerical simulation of the reinforced retaining wall is conducted by finite element analysis, and its mechanical behavior and influencing methods are studied in accordance with relevant theories. The results showed that the properties of back fill, reinforced spacing, reinforced stiffness, reinforced length, and panel stiffness all affect the mechanical behavior of retaining walls. According to the example calculations of different wall heights, the distribution of panel horizontal displacement and maximum tensile stress are analyzed. The gravel with good gradation has better durability and can reduce the amount of reinforcing steel; with the decrease of the reinforcement spacing, the deformation of the wall panel will become smaller, and the reinforcement effect will be improved; the length of reinforcement is not the longer the better, and the deformation of wall panel can be minimized at the suitable length; the larger the elastic modulus of the wall panel, the smaller the deformation of the wall panel will be.

Non-Linear Time History Analysis of an Elevated Water Tank

2021 ◽  
Vol 9 (VI) ◽  
pp. 4327-4334
Author(s):  
Mr. Rohit Kiran Chaudhari
Keyword(s):  
Reinforced Concrete ◽  
Seismic Analysis ◽  
Linear Time ◽  
Time History ◽  
Seismic Energy ◽  
Soil Condition ◽  
Mode Shapes ◽  
Water Tank ◽  
Elevated Water ◽  
Water Tanks

It was discovered that reinforced concrete elevated water tanks with frame staging outperformed reinforced concrete elevated water tanks with shaft staging in terms of seismic resistance. These can be due to the frame staging's seismic energy absorption capability. As a result, the primary goal of this research is to better understand the seismic behavior and performance characteristics of elevated water tanks with frame staging. Furthermore, when compared to other shapes, circular tanks have the smallest surface area for a given tank size. As a result, the amount of material needed for a circular water tank is less than for other shapes. As a result, a circular water tank was chosen, and seismic analysis of elevated RC circular water tanks was carried out according to IITK-GSDMA guidelines, with the behavior of the water tank analysed for various parameters such as zone factor, soil condition, and different staging heights. SAP 2000 was used to determine the structure's modal characteristics (mode shapes and modal participation mass ratio).

Tire Vibrations

1977 ◽  
Vol 5 (4) ◽  
pp. 202-225 ◽  
Author(s):  
G. R. Potts ◽  
C. A. Bell ◽  
L. T. Charek ◽  
T. K. Roy
Keyword(s):  
Natural Frequencies ◽  
Standing Waves ◽  
Resonant Mode ◽  
Mode Shapes ◽  
Resonant Vibrations ◽  
Resonant Frequencies ◽  
Radial Tire ◽  
Analysis Techniques ◽  
Thin Ring ◽  
Good Agreement

Abstract Natural frequencies and vibrating motions are determined in terms of the material and geometric properties of a radial tire modeled as a thin ring on an elastic foundation. Experimental checks of resonant frequencies show good agreement. Forced vibration solutions obtained are shown to consist of a superposition of resonant vibrations, each rotating around the tire at a rate depending on the mode number and the tire rotational speed. Theoretical rolling speeds that are upper bounds at which standing waves occur are determined and checked experimentally. Digital Fourier transform, transfer function, and modal analysis techniques used to determine the resonant mode shapes of a radial tire reveal that antiresonances are the primary transmitters of vibration to the tire axle.

Effect of Bass Bar Tension on Modal Parameters of a Violin's Top Plate

2015 ◽  
Vol 39 (1) ◽  
pp. 145-149 ◽  
Author(s):  
Ewa B. Skrodzka ◽  
Bogumił B.J. Linde ◽  
Antoni Krupa
Keyword(s):  
Modal Analysis ◽  
Experimental Modal Analysis ◽  
Mode Shapes ◽  
Modal Parameters ◽  
Normal Value ◽  
Modal Damping

Abstract Experimental modal analysis of a violin with three different tensions of a bass bar has been performed. The bass bar tension is the only intentionally introduced modification of the instrument. The aim of the study was to find differences and similarities between top plate modal parameters determined by a bass bar perfectly fitting the shape of the top plate, the bass bar with a tension usually applied by luthiers (normal), and the tension higher than the normal value. In the modal analysis four signature modes are taken into account. Bass bar tension does not change the sequence of mode shapes. Changes in modal damping are insignificant. An increase in bass bar tension causes an increase in modal frequencies A0 and B(1+) and does not change the frequencies of modes CBR and B(1-).

Study and Evaluation of Stored Drinking Water Characteristics Using Three Types of Roof Water Tanks in Kirkuk Governorate, Iraq

2019 ◽  
Vol 7 (1) ◽  
pp. 11-16
Author(s):  
Abdulkhaleq K Mahmood ◽  
Ali A Kamal ◽  
Ako R Hama
Keyword(s):  
Drinking Water ◽  
Storage Time ◽  
Total Dissolved Solids ◽  
Water Tank ◽  
Dissolved Solids ◽  
Water Characteristics ◽  
Three Samples ◽  
Water Metal ◽  
Water Tanks ◽  
Better Than

The scarcity of safe drinking water is one of the problems faced by the majority of cities in the world. Kirkuk city is one of these cities, which suffer from a shortage of drinking water. People have adopted the use of different rooftop tanks to overcome this problem. This research focuses on studying the effect of storage time on the five main characteristics of drinking water, which include, acid index (pH), electrical conductivity (EC), total suspended solids (TSS), total dissolved solids (TDS), and turbidity (Tr). Three types of tanks were used predominantly (galvanized metal, plastic, and aluminum tanks). By analyzing the results, the characteristics of three samples of municipal source water obtained. Three samples were taken from each tank at different periods (4, 8, and 12 days). The results showed that the storage time affected the characteristics of drinking water. These characteristics differed from one tank to another. Metal tanks showed an increase in total dissolved solids, due to the evaporation process, even as plastic and aluminum tanks showed an increase in pH. The properties of all storage water tanks changed with times, but overall, the results were within the Iraqi limitation for drinking water. It was not easy to only depend on the results of this study to believe that any one type of water tank was better than the other, as the values of most of the variables studied had varied from one type to other. However, many studies have indicated a number of health risks, and most significantly with regard to plastic tanks, which are said to contain dangerous organic compounds that can be transferred to water. Metal tanks can cause zinc leakage, caused by a number of environmental factors at high levels. Aluminum tanks also can have an effect on the water in tanks.

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