scholarly journals The Effects of Plaster Thicknesses on Cyclic Behavior of Infill Walls with Different Materials

2020 ◽  
Author(s):  
Mehmet Emin Arslan ◽  
Elif Ağcakoca ◽  
Merve Şentürk
Keyword(s):  
Energy Dissipation ◽  
Cyclic Behavior ◽  
Dissipated Energy ◽  
Cyclic Loads ◽  
Reinforced Concrete Structure ◽  
Backbone Curve ◽  
Infill Walls ◽  
Load Carrying ◽  
Materials Used ◽  
Set Up

Reinforced concrete structure systems are usually designed as frame or shear wall-frame systems. It is possible to reduce the deformation and displacement in the system by increasing the structural stiffness. Besides, large displacements on the floors caused by horizontal load are damped by the cracks in these walls. The present paper aims to examine the effects of materials used in the wall construction as well as thickness of the plaster on the behavior of infill walls under cyclic loads. In order to investigate the above mentioned effects, three Infill walls that were produced from three different materials namely, horizontal hollow bricks, pumice blocks and aerated concrete blocks were tested in three setups (without plaster, with 1 cm plaster and 2.5 cm plaster on it). In order to determine pure wall contribution, the infill walls were placed in a steel frame test set-up which was hinged from all four corners and were then exposed to cyclic loads taking into account the displacement controlled loading protocol proposed in FEMA 461. Right after applying the plaster to the infill walls, load carrying and energy dissipation capacities of the walls were examined comparatively. Load-displacement, backbone curve and cumulative dissipated energy curves of each infill walls are generated using the data collected from the experiments and the infill walls behaviors are graphically explained. Test results showed that existence and thickness of plaster significantly affected cyclic behavior of the test walls by increasing energy dissipation capacities and load carrying capacities.

scholarly journals Effects of mortar compressive strength on out of plane response of unreinforced masonry walls

2021 ◽  
Vol 20 (2) ◽  
pp. 371-381
Author(s):  
Atabak Pourmohammad Sorkhab ◽  
◽  
Mesut Küçük ◽  
Ali Sari ◽  
◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Unreinforced Masonry ◽  
Infill Wall ◽  
Infill Walls ◽  
Clay Bricks ◽  
Mortar Strength ◽  
Load Carrying ◽  
Out Of Plane ◽  
Structural Behaviors ◽  
Major Crack

In this study, the out-of-plane response of infill walls that are widely used in Turkey and the surrounding regions were experimentally investigated. Several out-of-plane wall tests were performed in the laboratory, with the walls specimens produced with lateral hollow clay bricks (LHCB) and different mortar qualities. The walls were tested in their out-of-plane (OOP) direction under static load conditions and evaluated based on the load-bearing and energy dissipation capacities, crack propagations, mortar strengths, and initial stiffnesses. These walls are experimentally investigated to understand the effects of the mortar strength on the infill wall structural behaviors and to assess the effectiveness of the out-of-plane strength formulations. It was found that when the mortar strength is low, the first major crack occurs at the mortar, however, because of the arch mechanism efficiency in this situation the OOP load-carrying and energy dissipation capacities of unreinforced walls can be significantly increased. When the first major crack in the wall occurs in the brick itself, the arc mechanism is provided with delicate sections in the brick, which leads to strength decreasing in the walls. In this case, excessive deviations occur in the out-of-plane strength formulations estimates. This study shows that the arc mechanism, the damage start region and progress can change significantly unreinforced masonry (URM) infill walls behaviors.

Damage and Crack Analysis for Reinforced Concrete Energy Dissipation Braced Frame (EDBF) under Low Cyclic Loads

2006 ◽  
Vol 324-325 ◽  
pp. 611-614
Author(s):  
Mei Ling Xiao ◽  
Liao Yuan Ye ◽  
Sheng Miao ◽  
Ben Yu Liu
Keyword(s):  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Ground Motion ◽  
Damage Variable ◽  
Dissipated Energy ◽  
Earthquake Ground Motion ◽  
Displacement Curve ◽  
Cyclic Loads ◽  
Braced Frame ◽  
Factor C

Application of Miner criterion, cumulate damage variable was estimated based on pseudo-static experiment study for reinforced concrete energy dissipation braced frame (EDBF) under low cyclic loads, accordingly, the constitutive relations about damage was established; the linear hook law turned into non-linear stress-strain relations; the dissipated-energy factor c β was determined based on following factors: the cumulate damage variable, hysteretic energy determined by load-displacement curve, maximum deformation and yield force of EDBF; it supplied a quantitative basis of dissipated-energy for EDBF; There were two reasons in energy dissipation for EDBF: one was energy dissipation equipment acting, the other was concrete damaged and cracked or low cycle fatigue failure in this structure, and the latter part of energy was associated with amounts of cracks and crack size; then the forced mechanism of EDBF was analyzed, and the reason caused cracks and crack type of EDBF columns, beam and braces were explained based on forced mechanism: the columns, beam and braces of EDBF were compressed or tensed under low cyclic loads, so most of cracks of columns, beam and braces belonged to mode I cracksThis study supplied a method for estimating energy of EDBF under earthquake ground motion, and the results showed: columns in EDBF are easily damaged under earthquake ground motion, so the structural elements must be designed strong column, weak beam and weak brace.

Viscoelastic Material Calibration Procedure for Rolling Resistance Calculation

2019 ◽  
Vol 47 (3) ◽  
pp. 232-256
Author(s):  
Gabriel N. Curtosi ◽  
Pablo N. Zitelli ◽  
Jorge Kuster
Keyword(s):  
Energy Dissipation ◽  
Rolling Resistance ◽  
Good Method ◽  
Calibration Procedure ◽  
Dissipated Energy ◽  
Rubber Compounds ◽  
Different Temperatures ◽  
Material Sample ◽  
Materials Used ◽  
Material Calibration

ABSTRACT As tire engineers, the authors are interested in predicting rolling resistance using tools such as numerical simulation and tests. When a car is driven along, its tires are subjected to repeated deformation, leading to energy dissipation as heat. Each point of a loaded tire is deformed as it completes a revolution. Most energy dissipation comes from the cyclic loading of the tire, which causes the rolling resistance in addition to the friction force in the contact patch between the tire and road. Rolling resistance mainly depends on the viscoelastic energy dissipation of the rubber materials used to manufacture the tires. To obtain an accurate amount of dissipated energy, a good understanding of the material mathematical model and its behavior is mandatory. For this reason, a calibration procedure was developed. To obtain a good method for calculating rolling resistance, it is necessary to calibrate all rubber compounds of the tire at different temperatures and strain frequencies. Thus, to validate the calibration procedure, simulations were performed to evaluate the error between the tests and models at material sample and tire levels. For implementation of the calibration procedure in the finite element models of rolling tires, a procedure is briefly described that takes into account the change in properties caused by the temperature during the simulations. Linear viscoelasticity is used to model the properties of the materials and is found to be a suitable approach to tackle energy dissipation due to hysteresis for rolling resistance calculation.

scholarly journals New Metallic Damper with Multiphase Behavior for Seismic Protection of Structures

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 183
Author(s):  
Amadeo Benavent-Climent ◽  
David Escolano-Margarit ◽  
Julio Arcos-Espada ◽  
Hermes Ponce-Parra
Keyword(s):  
Energy Dissipation ◽  
Large Deformations ◽  
Cyclic Behavior ◽  
Displacement Curve ◽  
Hysteretic Model ◽  
Reinforced Concrete Structure ◽  
Shake Table Tests ◽  
Energy Dissipation Capacity ◽  
Multiphase Behavior ◽  
Metallic Damper

This paper proposes a new metallic damper based on the plastic deformation of mild steel. It is intended to function as an energy dissipation device in structures subjected to severe or extreme earthquakes. The damper possesses a gap mechanism that prevents high-cycle fatigue damage under wind loads. Furthermore, subjected to large deformations, the damper presents a reserve of strength and energy dissipation capacity that can be mobilized in the event of extreme ground motions. An extensive experimental investigation was conducted, including static cyclic tests of the damper isolated from the structure, and dynamic shake-table tests of the dampers installed in a reinforced concrete structure. Four phases are distinguished in the response. Based on the results of the tests, a hysteretic model for predicting the force-displacement curve of the damper under arbitrary cyclic loadings is presented. The model accurately captures the increment of stiffness and strength under very large deformations. The ultimate energy dissipation capacity of the damper is found to differ depending on the phase in which it fails, and new equations are proposed for its prediction. It is concluded that the damper has a stable hysteretic response, and that the cyclic behavior, the ultimate energy dissipation capacity and failure are highly predictable with a relatively simple numerical model.

Growth and yield of okra (Abelmoschus esculentus (L.) Moench) grown in the marginal upland area of Sta. Rita, Samar as influenced by different planting densities and mulching materials

2017 ◽  
pp. 44-54
Author(s):  
Zenaida Gonzaga ◽  
Warren Obeda ◽  
Ana Linda Gorme ◽  
Jessie Rom ◽  
Oscar Abrantes ◽  
...  
Keyword(s):  
Bare Soil ◽  
Abelmoschus Esculentus ◽  
Growth And Yield ◽  
Planting Density ◽  
Rice Hull ◽  
Plastic Mulch ◽  
Lady’S Finger ◽  
Materials Used ◽  
Set Up ◽  
A Minor

Okra or Lady’s finger, botanically known as Abelmoschus esculentus (L.) Moench, is a tropical and sub-tropical indigenous vegetable crop commonly grown for its fibrous, slimy, and nutritious fruits and consumed by all classes of population. It has also several medicinal and economic values. Despite its many uses and potential value, its importance is under estimated, under-utilized, and considered a minor crop and little attention was paid to its improvement. The study was conducted to evaluate the effects of different planting densities and mulching materials on the growth and yield of okra grown in slightly sloping area in the marginal uplands in Sta. Rita, Samar, Philippines. A split-plot experiment was set up with planting density as main plot and the different mulching materials as the sub-plot which were: unmulched or bare soil, rice straw, rice hull, hagonoy and plastic mulch. Planting density did not significantly affect the growth and yield of okra. Regardless ofthe mulching materials used, mulched plants were taller and yielded higher compared to unmulched plants. Moreover, the use of plastic mulch resulted to the highest total fruit yield. The results indicate the potential of mulching in increasing yield and thus profitability of okra production under marginal upland conditions.

Rolling Resistance Calculation Procedure Using the Finite Element Method

2019 ◽  
Vol 48 (3) ◽  
pp. 224-248
Author(s):  
Pablo N. Zitelli ◽  
Gabriel N. Curtosi ◽  
Jorge Kuster
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Rolling Resistance ◽  
Element Model ◽  
The Finite Element Method ◽  
Temperature Changes ◽  
Rubber Compounds ◽  
Different Temperatures ◽  
Materials Used ◽  
Account Temperature

ABSTRACT Tire engineers are interested in predicting rolling resistance using tools such as numerical simulation and tests. When a car is driven along, its tires are subjected to repeated deformation, leading to energy dissipation as heat. Each point of a loaded tire is deformed as the tire completes a revolution. Most energy dissipation comes from the cyclic loading of the tire, which causes the rolling resistance in addition to the friction force in the contact patch between the tire and road. Rolling resistance mainly depends on the dissipation of viscoelastic energy of the rubber materials used to manufacture the tires. To obtain a good rolling resistance, the calculation method of the tire finite element model must take into account temperature changes. It is mandatory to calibrate all of the rubber compounds of the tire at different temperatures and strain frequencies. Linear viscoelasticity is used to model the materials properties and is found to be a suitable approach to tackle energy dissipation due to hysteresis for rolling resistance calculation.

scholarly journals Effects of Infills in the Seismic Performance of an RC Factory Building in Pakistan

Buildings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 276
Author(s):  
Nisar Ali Khan ◽  
Giorgio Monti ◽  
Camillo Nuti ◽  
Marco Vailati
Keyword(s):  
Numerical Model ◽  
Construction Materials ◽  
Building Codes ◽  
Construction Technique ◽  
Infill Walls ◽  
Mortar Strength ◽  
Materials Used ◽  
Seismic Response Of Buildings

Infilled reinforced concrete (IRC) frames are a very common construction typology, not only in developing countries such as Pakistan but also in southern Europe and Western countries, due to their ease of construction and less technical skills required for the construction. Their performance during past earthquakes has been in some cases satisfactory and in other cases inadequate. Significant effort has been made among researchers to improve such performance, but few have highlighted the influence of construction materials used in the infill walls. In some building codes, infills are still considered as non-structural elements, both in the design of new buildings and, sometimes, in the assessment of existing buildings. This is mainly due to some difficulties in modeling their mechanical behavior and also the large variety of typologies, which are difficult to categorize. Some building codes, for example, Eurocode, already address the influence of infill walls in design, but there is still a lack of homogeneity among different codes. For example, the Pakistan building code (PBC) does not address infills, despite being a common construction technique in the country. Past earthquake survey records show that construction materials and infill types significantly affect the seismic response of buildings, thus highlighting the importance of investigating such parameters. This is the object of this work, where a numerical model for infill walls is introduced, which aims at predicting their failure mode, as a function of some essential parameters, such as the friction coefficient between mortar and brick surface and mortar strength, usually disregarded in previous models. A comprehensive case study is presented of a three-story IRC frame located in the city of Mirpur, Pakistan, hit by an earthquake of magnitude 5.9 on 24 September 2019. The results obtained from the numerical model show good agreement with the damage patterns observed in situ, thus highlighting the importance of correctly modeling the infill walls when seismically designing or assessing Pakistani buildings that make use of this technology.

scholarly journals Reconstruction of the 3D pressure field and energy dissipation of a Taylor droplet from a $$\upmu$$PIV measurement

2021 ◽  
Vol 62 (4) ◽  
Author(s):  
Ulrich Mießner ◽  
Thorben Helmers ◽  
Ralph Lindken ◽  
Jerry Westerweel
Keyword(s):  
Energy Dissipation ◽  
Pressure Gradient ◽  
Pressure Field ◽  
Estimation Method ◽  
Dissipated Energy ◽  
Spatial Integration ◽  
Mean Flow ◽  
Bypass Flow ◽  
Taylor Flow ◽  
Piv Measurement

Abstract In this study, we reconstruct the 3D pressure field and derive the 3D contributions of the energy dissipation from a 3D3C velocity field measurement of Taylor droplets moving in a horizontal microchannel ($$\rm Ca_c=0.0050$$ Ca c = 0.0050 , $$\rm Re_c=0.0519$$ Re c = 0.0519 , $$\rm Bo=0.0043$$ Bo = 0.0043 , $$\lambda =\tfrac{\eta _{d}}{\eta _{c}}=2.625$$ λ = η d η c = 2.625 ). We divide the pressure field in a wall-proximate part and a core-flow to describe the phenomenology. At the wall, the pressure decreases expectedly in downstream direction. In contrast, we find a reversed pressure gradient in the core of the flow that drives the bypass flow of continuous phase through the corners (gutters) and causes the Taylor droplet’s relative velocity between the faster droplet flow and the slower mean flow. Based on the pressure field, we quantify the driving pressure gradient of the bypass flow and verify a simple estimation method: the geometry of the gutter entrances delivers a Laplace pressure difference. As a direct measure for the viscous dissipation, we calculate the 3D distribution of work done on the flow elements, that is necessary to maintain the stationarity of the Taylor flow. The spatial integration of this distribution provides the overall dissipated energy and allows to identify and quantify different contributions from the individual fluid phases, from the wall-proximate layer and from the flow redirection due to presence of the droplet interface. For the first time, we provide deep insight into the 3D pressure field and the distribution of the energy dissipation in the Taylor flow based on experimentally acquired 3D3C velocity data. We provide the 3D pressure field of and the 3D distribution of work as supplementary material to enable a benchmark for CFD and numerical simulations. Graphical abstract

Experimental study on seismic performance of suspended ceiling components

2021 ◽  
Author(s):  
Yong Wang ◽  
Huanjun Jiang ◽  
Chen Wu ◽  
Zihui Xu ◽  
Zhiyuan Qin
Keyword(s):  
Experimental Study ◽  
Energy Dissipation ◽  
Seismic Performance ◽  
Seismic Vulnerability ◽  
Axial Loading ◽  
Deformation Capacity ◽  
Severe Damage ◽  
Strong Earthquakes ◽  
Static Tests ◽  
Load Carrying

<p>Suspended ceiling systems (SCSs) experienced severe damage during strong earthquakes that occurred in recent years. The capacity of the ceiling component is a crucial factor affecting the seismic performance of SCS. Therefore, a series of static tests on suspended ceiling components under monotonic and cyclic loadings were carried out to investigate the seismic performance of the ceiling components. The ceiling components include main tee splices, cross tee latches and peripheral attachments. All specimens were tested under axial loading. Additionally, the static tests of cross tee latches subjected to shear and bending loadings were performed due to their seismic vulnerability. The failure pattern, load-carrying ability, deformation capacity and energy dissipation of the ceiling components are presented in detail in this study.</p>

scholarly journals Cyclic behavior of GFRP strengthened infilled RC frames with low and normal strength concrete

2019 ◽  
Vol 26 (1) ◽  
pp. 30-42 ◽  
Author(s):  
Mehmet Emin Arslan ◽  
Ahmet Durmuş ◽  
Metin Hüsem
Keyword(s):  
Lateral Loading ◽  
Cyclic Behavior ◽  
Test Results ◽  
Normal Strength Concrete ◽  
Strength Concrete ◽  
Rc Frames ◽  
Load Carrying ◽  
Concrete Blocks ◽  
Normal Strength ◽  
Infilled Rc Frames

AbstractThis paper presents the experimental behavior of plane, non-strengthened and glass fiber reinforced polymer (GFRP) strengthened infilled reinforced concrete (RC) frames with low strength concrete (LSC) and normal strength concrete (NSC) under lateral reversed cyclic loading. For this purpose, eight full-scale, one-bay, one-storey plane and infilled (brick and aerated concrete blocks which are commonly used in RC construction) RC frames with LSC and NSC were produced and in-plane lateral loading tests were carried out. Test results indicate that infill walls considerably change the behavior of frames by increasing rigidity and load carrying capacity. By contrast, GFRP fabric used for strengthening of infilled RC frames improves ductility, load carrying and energy dissipation capacity of infilled frames with LSC and NSC as well. After all the test results were evaluated together, a GFRP strengthened brick infilled frame demonstrated the best performance under cyclic lateral loading.

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