scholarly journals Research on Damage Characteristics of Brick Masonry under Explosion Load

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Jifeng Wei ◽  
Zhixin Du ◽  
Yonghui Zheng ◽  
Oundavong Ounhueane
Keyword(s):  
Power Function ◽  
Explosive Charge ◽  
Masonry Wall ◽  
Pressure Vessels ◽  
Brick Masonry ◽  
Ejection Velocity ◽  
Load Bearing ◽  
Damage Characteristics ◽  
Explosion Load ◽  
The Relationship

As the main structural component of partition wall or load-bearing wall, brick masonry has been widely used in construction engineering. However, brick and mortar are all brittle materials prone to crack. Nowadays, fireworks, gas stoves, high-pressure vessels, and other military explosives may explode to damage nearby structures. Many explosion casualties had shown that the load-bearing capacity of brick masonry decreased dramatically and cracks or fragments appeared. Previous studies mainly focused on noncontact explosion in which shock wave is the main damage element. In fact, the response and damage effect of brick masonry wall under contact explosion are more complex, which attracts more attention now. In order to explore the damage characteristics of brick masonry under explosion load, a series of simulations and verification experiments are conducted. RHT and MO granular material models are introduced to describe the behaviour of brick and masonry, respectively, in simulation. The combination effect of front compressive wave and back tensile wave are main factors influencing the breakage of masonry wall. The experimental results are well in accordance with the simulation results. The front cross section dimension of crater is closely related to the radius of spherical explosive charge. A power function predictive model is developed to express the relationship between the radius of hole and the radius of explosive. Furthermore, with increasing the quantity of explosive charge, the number and ejection velocity of fragments are all increased. The relationship between maximum ejection velocity and the quantity of explosive also can be expressed as a power function model.

scholarly journals A method for determining the relationship between increasing insulation and potential freeze thaw damage in brick masonry walls.

2021 ◽  
Author(s):  
Braden Johnson
Keyword(s):  
Residential Building ◽  
Masonry Wall ◽  
Brick Masonry ◽  
Masonry Walls ◽  
World War ◽  
Viable Option ◽  
World War 2 ◽  
Freeze Thaw ◽  
Moisture Performance ◽  
The Relationship

When considering insulation retrofits, property limit distances and setbacks make interior insulation of residential homes the only viable option. When pursuing an interior insulation retrofit the potential for brick masonry freeze thaw damage needs to be considered. Studying the impacts of an interior insulation retrofit Pre-World War 2 residential building in Toronto, Ontario, a comparison of the retrofitted building using WUFI against 8 other insulation types was completed to determine if the change of insulation affects the potential for freeze thaw damage. Based on the results of the WUFI analysis the answer would be yes. The insulation type and R value does have an impact brick masonry freeze thaw resistance. However this relationship is general and not linear. The method provided shows that if critical saturation (SCRIT) is known predictive modeling on the impacts of interior insulation on the moisture performance of the brick masonry wall can be used.

scholarly journals A method for determining the relationship between increasing insulation and potential freeze thaw damage in brick masonry walls.

2021 ◽  
Author(s):  
Braden Johnson
Keyword(s):  
Residential Building ◽  
Masonry Wall ◽  
Brick Masonry ◽  
Masonry Walls ◽  
World War ◽  
Viable Option ◽  
World War 2 ◽  
Freeze Thaw ◽  
Moisture Performance ◽  
The Relationship

When considering insulation retrofits, property limit distances and setbacks make interior insulation of residential homes the only viable option. When pursuing an interior insulation retrofit the potential for brick masonry freeze thaw damage needs to be considered. Studying the impacts of an interior insulation retrofit Pre-World War 2 residential building in Toronto, Ontario, a comparison of the retrofitted building using WUFI against 8 other insulation types was completed to determine if the change of insulation affects the potential for freeze thaw damage. Based on the results of the WUFI analysis the answer would be yes. The insulation type and R value does have an impact brick masonry freeze thaw resistance. However this relationship is general and not linear. The method provided shows that if critical saturation (SCRIT) is known predictive modeling on the impacts of interior insulation on the moisture performance of the brick masonry wall can be used.

scholarly journals On the Notion of Reproducibility and Its Full Implementation to Natural Exponential Families

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1568
Author(s):  
Shaul K. Bar-Lev
Keyword(s):  
Power Function ◽  
Exponential Family ◽  
Probability Distributions ◽  
Infinite Divisibility ◽  
Variance Function ◽  
Exponential Families ◽  
Natural Exponential Family ◽  
Natural Exponential Families ◽  
Convolution Properties ◽  
The Relationship

Let F=Fθ:θ∈Θ⊂R be a family of probability distributions indexed by a parameter θ and let X1,⋯,Xn be i.i.d. r.v.’s with L(X1)=Fθ∈F. Then, F is said to be reproducible if for all θ∈Θ and n∈N, there exists a sequence (αn)n≥1 and a mapping gn:Θ→Θ,θ⟼gn(θ) such that L(αn∑i=1nXi)=Fgn(θ)∈F. In this paper, we prove that a natural exponential family F is reproducible iff it possesses a variance function which is a power function of its mean. Such a result generalizes that of Bar-Lev and Enis (1986, The Annals of Statistics) who proved a similar but partial statement under the assumption that F is steep as and under rather restricted constraints on the forms of αn and gn(θ). We show that such restrictions are not required. In addition, we examine various aspects of reproducibility, both theoretically and practically, and discuss the relationship between reproducibility, convolution and infinite divisibility. We suggest new avenues for characterizing other classes of families of distributions with respect to their reproducibility and convolution properties .

Explosive Removal of Concrete From Reinforced Walls

2007 ◽  
Author(s):  
Denis D. Rickman ◽  
John Q. Ehrgott ◽  
Stephen A. Akers ◽  
Jon E. Windham ◽  
Dennis W. Moore
Keyword(s):  
Explosive Charge ◽  
Research Effort ◽  
Us Army ◽  
Steel Reinforced Concrete ◽  
The Past ◽  
The Us ◽  
Development Center ◽  
The Relationship ◽  
Improved Methods ◽  
Combat Environment

During the past several years, the US Army has focused considerable attention toward developing improved methods for breaching walls in the urban combat environment. A major thrust area is centered on finding improved methods to breach the toughest wall type that Army units are likely to face: a double (steel) reinforced concrete (RC) wall. One impediment to this effort is that the relationship between the contact explosive charge configuration and the quantity of concrete removed has not been thoroughly understood. The U.S. Army Engineer Research and Development Center has conducted a research effort to better define the effectiveness of various explosive charge configurations in breaching RC walls. This paper presents a discussion of results from this research.

Influence of Sulphate on the Moisture Movement of Calcium Silicate Brick Masonry Wall

2010 ◽  
Vol 133-134 ◽  
pp. 201-204
Author(s):  
Ibrahim Mohamad H. Wan ◽  
B.H. Abu Bakar ◽  
M.A. Megat Johari ◽  
P.J. Ramadhansyah
Keyword(s):  
Relative Humidity ◽  
Calcium Silicate ◽  
Masonry Wall ◽  
Sodium Sulphate ◽  
Brick Masonry ◽  
Masonry Walls ◽  
Moisture Movement ◽  
Moisture Expansion ◽  
Curing Period ◽  
Wet Condition

This paper presents the behaviour of moisture movement of calcium silicate brick masonry walls exposed to sodium sulphate environment. The walls were exposed to three sodium sulphate conditions with sulphate concentrations of5%, 10% and 15%. For comparison, some walls were also exposed to dry and wet condition which acts as a control conditions. All specimens were prepared and cured under polythene sheet for 14 days in a controlled environmental room and maintained at relative humidity and temperature of 80 ± 5% and 25 ± 2°C, respectively. After the curing period, the specimens were exposed to sodium sulphate as well as drying and water exposures, during which moisture movement was measured and monitored for a period of up to 7 months. As a result, the moisture expansion was observed and recorded for all masonry wall specimens after exposed to the sulphate condition.

scholarly journals CARACTERIZAÇÃO HIDRÁULICA DO MICROASPERSOR DAN SPRINKLERS GRUPO MODULAR

Irriga ◽  
2001 ◽  
Vol 6 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Marcio Antonio Vilas Boas ◽  
Eurides Kuster Macedo Júnior ◽  
Silvio Cesar Sampaio ◽  
Melânia Inês Valiati
Keyword(s):  
Production Process ◽  
Power Function ◽  
Characteristic Equation ◽  
State University ◽  
The West ◽  
Potential Equation ◽  
Group 2 ◽  
The Relationship

CARACTERIZAÇÃO HIDRÁULICA DO MICROASPERSOR DAN SPRINKLERS GRUPO MODULAR                                     Márcio Antônio Vilas BoasEurides Kuster Macedo JuniorSilvio César SampaioMelânia Inês ValiatiUNIOESTE - Universidade Estadual do Oeste do ParanáCEP: 85814-110 - Cascavel – PR - Brasil - Cx. Postal   711Fone: (045) 225 -2100  (R-249) - Fax : (045) [email protected]  1 RESUMO  Este  trabalho  teve  como  objetivo  avaliar as características hidráulicas  do  microaspersor DAN SPRINKLERS do grupo modular de fabricação da DAN SPRINKLERS - ISRAEL, de uso recente no Oeste do Paraná. Os ensaios foram realizados no Laboratório de Hidráulica do Departamento de Engenharia da Universidade Estadual do Oeste do Paraná – UNIOESTE. Na  avaliação dos microaspersores  estudou-se, a variação decorrente do processo de fabricação e a determinação da equação característica da relação vazão–pressão. Os microaspersores do Grupo modular com diâmetros de bocais 0,94; 1,16;1,41;1,92 e 2,34 mm,  foram submetidos às pressões de 100, 150, 200, 250, 300 e 350 kPa. As equações características determinadas indicaram que o microaspersor testado não é auto-compensante , tolerante a sensibilidade de variações de pressões e que a equação potencial se ajusta bem aos dados. Os coeficientes de variação de fabricação obtidos foram menores que 5%, classificando-se, de acordo com a Norma ISO, como de categoria A. UNITERMOS: Microaspersão, coeficiente de variação, modelo potencial.  VILAS BÔAS, M. A., MACEDO JUNIOR, E. K. HYDRAULIC CHARACTERIZATION OF MICROSPRINKLER DAN SPRINKLER - MODULATE GROUP   2 ABSTRACT This work had as objective to evaluate the characteristics hydraulic of the microsprinklers of the group to modulate of production of DAN SPRINKLERS - ISRAEL, of recent use in the West of Paraná. The tests was accomplished in the Laboratory of Hydraulics of the Department of Engineering of the State University of the West of Paraná - UNIOESTE. In the evaluation of the microasprinklers it was studied such characteristics as, the variation due to the production process and the determination of the characteristic equation of the relationship vazão-pressure. The microsprinklers of the Group to modulate with diameters of nozzle 0,94; 1,16;1,41;1,92 and 2,34 mm, the pressures were submitted 100, 150, 200, 250, 300 and 350 kPa. The certain characteristic equations showed that the tested microsprinklers is not solemnity-compensante and that the potential equation was fit well to the data. The obtained coefficients of production variation were everybody below 5% being able to not this way to classify them in agreement with for ISO  category as A. KEYWORDS: Microsprinkler, coefficient variation, power function.

Experimental study on seismic performance of fire-exposed perforated brick masonry wall

2018 ◽  
Vol 180 ◽  
pp. 77-91 ◽  
Author(s):  
Jin Zhang ◽  
Hao Ma ◽  
Cheng Li ◽  
Qingfeng Xu ◽  
Weibin Li
Keyword(s):  
Experimental Study ◽  
Seismic Performance ◽  
Masonry Wall ◽  
Brick Masonry

scholarly journals Flashover Performance and Process of Suspension Insulator Strings Artificially Covered with Snow

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2916 ◽  
Author(s):  
Yuyao Hu ◽  
Sihua Guo ◽  
Richang Xian ◽  
Xingbo Han ◽  
Zhongyi Yang ◽  
...  
Keyword(s):  
Power Function ◽  
Electrical Performance ◽  
Salt Deposit ◽  
Influencing Mechanism ◽  
Suspension Insulator ◽  
Deposit Density ◽  
Ac Arc ◽  
Dc Arc ◽  
The Relationship ◽  
Snow Thickness

Snow accumulates on the surface of insulator string, causing a decrease in its electrical performance, seriously threatening the reliable operation of the power grid. Most previous studies have focused on iced insulators; however, there is a lack of research on snow-covered insulators. In this paper, to reveal the influencing mechanism that snow has on the electrical characteristics of insulator string, based on an artificial snowing test in a chamber, the effects of equivalent salt deposit density, applied voltage type, and snow thickness on the flashover performance of snow-covered insulators are analyzed, and the flashover process is investigated. The results show that the relationship between the arc flashover gradient and the equivalent salt deposit density is a power function with a negative exponent, which is similar to that of polluted and ice-covered insulator strings. For the insulator strings with the same snow accretion, the direct current (DC) arc flashover gradient is lower than the alternating current (AC) arc flashover gradient. The relationship between arc flashover gradient and snow thickness is also a power function. The formation of a dry band during the flashover of snow-covered insulator string is similar to the flashover of the polluted insulator, and the arc propagation along the surface of the snow-covered insulator is similar to the flashover of the iced insulator.

scholarly journals Load Bearing Capacity Calculation of the System “Reinforced Concrete Beam – Deformable Base” under Torsion with Bending

2019 ◽  
Vol 97 ◽  
pp. 04059 ◽  
Author(s):  
Alexey Dem’yanov ◽  
Vladymir Kolchunov ◽  
Igor Iakovenko ◽  
Anastasiya Kozarez
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cross Sections ◽  
Concrete Beam ◽  
Equations Of State ◽  
Reinforced Concrete Beam ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Deformable Base ◽  
The Relationship

It is presented the formulation and solution of the load bearing capacity of statically indeterminable systems “reinforced concrete beam – deformable base” by spatial cross-sections under force and deformation effects. The solution of problem is currently practically absent in general form. It has been established the relationship between stresses and strains of compressed concrete and tensile reinforcement in the form of diagrams. The properties of the base model connections are described based on a variable rigidity coefficient. It is constructed a system of n equations in the form of the initial parameters method with using the modules of the force (strain) action vector. The equations of state are the dependences that establish the relationship between displacements which are acting on the beam with load. Constants of integration are determined by recurrent formulas. It makes possible to obtain the method of initial parameters in the expanded form and, consequently, the method of displacements for calculating statically indefinable systems. The values of the effort obtained could be used to determine the curvature and rigidity of the sections in this way. It is necessary not to set the vector modulusP, the deformation is set in any section (the module is considered as an unknown) during the problem is solving. This allows us to obtain an unambiguous solution even in the case when the dependence M–χ has a downward section, i.e one value of moment can correspond to two values of curvature.

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