Brick Structures Research Articles

Reinforcement of brick structures with carbon fiber

Based on the analysis of approaches to reinforcing the brick masonry structures, the advantages of carbon fiber as a reinforcing component are presented. Methods for calculating brick structures reinforced with carbon fiber under central and eccentric compression are proposed. These methods allow determining the longitudinal force taking into account the calculated compressive resistance of the masonry, the masonry working conditions and the influence of long-term load, as well as the coefficient of the masonry surface reinforcement at the reinforced wall. The schemes of strengthening the wall with vertical canvases and at the same time vertical and horizontal carbon fiber canvases are considered. Depending on the direction of the eccentricity of the load application, methods for calculating the strength of reinforced masonry under the action of a moment in the masonry plane and from the wall are developed. The ultimate deformations of carbon fiber are estimated taking into account possible options for the destruction of masonry reinforcing elements.

Overcoming Barriers to Health Care Access in Rural Latino Communities: An Innovative Model in the Eastern Coachella Valley

Latino farmworkers lack access to basic needs, including health care services. These farmworkers face barriers common to rural areas (eg, limited health services and public transportation), as well as language barriers, an unfamiliar medical system, no health insurance, and income-based financial challenges exacerbated by a lack of workers' rights. This study involved focus group discussions to elicit community health priorities and barriers to health care service use among Latinos in rural farm working communities, as well as participants' ideal model for health care services delivery. Free mobile clinics were subsequently implemented at locations and times the community identified as ideal, and pre- and postinterviews of patients' experiences utilizing clinic services, and perceptions of access barriers, were conducted. Results from focus group discussions (n = 82) and one-on-one interviews (n = 15) to evaluate mobile clinic health care services use confirmed documented barriers to health care for this population, shed light on structural and cultural barriers to service access, and suggested innovative models for service delivery to Spanish-speaking Latino farmworkers in rural communities. These models should (1) provide care within farm working communities, (2) offer services at times outside of business hours, and (3) encourage provider immersion in patient communities to better understand their health care needs. Traditional models of care that expect patients to access health care services at brick and mortar structures are impractical for Latino farmworkers in rural communities. Innovative models bringing health care services to community spaces can reduce access barriers and emergency department utilization and improve health outcomes for this structurally vulnerable population.

Effects of Different Roller Profiles on the Microstructure and Peel Strength of the Ultrasonic Welding Joints of Nonwoven Fabrics

Nonwoven fabrics are widely used in the textile manufacturing industry due to their advanced characteristics, such as their soft, water-repellent, recycle, ecological, and resilient functions. Nowadays, one of the innovated technologies applied to bond nonwoven fabrics is the ultrasonic welding method, due to the advantages afforded by its clean, fast, and reliable approach. In this work, isotactic polypropylene (PP) nonwoven fabrics were bonded by a continuous ultrasonic welding process. In order to consider the influence of the roller on the formation of welding joints and their mechanical properties, different roller profiles were designed, fabricated, and tested. Eight types of roller profiles corresponding to No. 1–No. 8 in the experiments were divided into four groups. After bonding, the microstructure in a typical case (i.e., No. 1) was captured by scanning electron microscopy (SEM) to examine the formation of the welding joints. Additionally, the load and the peel strength of the welding joints of all eight roller profiles were analyzed. The results showed that no welding defects, such as cracks or blowholes, were visible in the melted zone. The load depended on the area ratio(s) of the welding area (S0) to the cycling area (S1). Furthermore, it was found out that the peel strength of the welding joints with brick structures were higher than the peel strength in the case of solid line structures.

Numerical simulation of stress behavior of dowel–brick structures in TMSR

As essential elements of the graphite reflector in thorium-based molten salt reactor, dowel–brick structures are used to withstand complex working loads in the reactor core and their failure may lead to serious damage of the graphite reactor core. It is crucial to investigate the stress behavior of dowel–brick structures for safe operation of the graphite reactor. In this study, three groups of finite element analyses and a strain test were carried out to investigate how the geometric parameters of the dowels affect the stress behavior of the dowel–brick structure. The numerical results indicate that the stress behavior of a dowel–brick structure is significantly affected by the diameter, length, and aspect ratio of the dowels. The maximum stress in the lower and upper bricks decreases with an increase in the dowel length. The location of maximum stress on both lower and upper bricks shifts from the root of the socket to the edge of that socket beside the contact region, as the length of the dowel increases. The shift of the maximum stress location occurs earlier for the upper bricks than for the lower bricks. The results of strain tests show good agreement with those of numerical analyses.

Tortuosity in the Brick and Mortar Model Based on Chemical Conduction

Diffusion is a reoccurring phenomena in many fields and is affected by the geometry in which it takes place. Here we investigate the effects of geometry on diffusion in a Brick and Mortar model system. The tortuous effects are evaluated based on generalized Fick’s law, i.e. diffusion driven by differences in chemical potential. The presented formalism gives a general (semi-) exact analytic expression for the tortuosity using impermeable bricks, which is successfully validated against standard techniques and finite element method results. The approach allows for anisotropic properties of the mortar, which we show can be significant and is not captured with known analytic techniques. Based on the introduced concept of chemical conductivity we also find generalized Fick’s law consistent with Ohm’s and Fourier’s law in terms of their constituent parts, which further makes the main results for Brick and Mortar structures directly applicable to diffusion of either charge, heat, or mass.

Finite element based micro modelling of masonry walls subjected to fire exposure: Framework validation and structural implications

This paper presents a 2-D finite element (FE) based micro modelling framework for thermo-mechanical response history analysis of solid brick masonry structures subjected to fire. The 2-D FE framework considers geometric and material nonlinearities, and transient states of strain in conjunction with the temperature-dependent material properties. Material nonlinearity within the 2-D FE model is considered by the temperature-dependent total strain rotating crack model. The FE framework is validated against the thermo-mechanical response of a half-scale masonry wall subjected to one-sided fire exposure, and it is observed that the predictions of the FE framework are reasonably accurate. Utilizing the validated FE framework, thermo-mechanical response history characterization is performed on a full-scale masonry wall subjected to one-sided fire exposure. Critical physical phenomena which include thermal bowing, heat diffusion, unit-mortar thermo-mechanical interaction, cracking and stress profiles within the masonry structures are studied intricately. Furthermore, thermo-mechanics within representative volumes enclosing unit as well as mortar and their correlation with the global thermo-mechanical response is studied. Such 2-D micro-scale thermo-mechanical computations on masonry walls followed by a detailed discussion on their thermo-mechanics are one of the novel features of the present study. It is observed that thermal bowing resulted from a complex interaction between thermal dilation and cracking and crushing in the mortar and unit within the masonry structure.

Damage assessment of the in-service brick masonry structure using acoustic emission technique

Most of the current researches on masonry damage assessment are qualitative rather than quantitative analysis. In this work, two acoustic emission (AE) rate process mathematical models were used to analyze the AE data during the in situ uniaxial compression test. The results showed that there was a linear correlation between AE cumulative events and the damage parameter, and the mathematical model proposed by S. T. Dai was suitable for analyzing the microcrack evolution of brick masonry material. Furthermore, the comparison of the fourth-order polynomial function and the Dai model with respect to the proportional coefficient k further demonstrated the applicability of the Dai model in damage assessment of in-service brick masonry structures.

Masonry renewal technology

For the construction of residential facilities, even today, they often use a frame-monolithic scheme with floor filling with enclosing structures made of artificial materials - brick, foam concrete, etc. For objects built 25-30 years ago, today there is a whole complex of common problems associated with the destruction front (front) layer of masonry. For this, domestic and foreign developments in the field of inspection and reinforcement of bearing and self-supporting brick structures are analyzed. Among the main criteria for destruction, factors of natural and anthropogenic origin are determined. Climatic conditions - ambient temperature, humidity - significantly affect the choice of basic material, and the current requirements for energy efficiency of building structures significantly affect design decisions for the use of various heaters. At the same time, all architectural and constructive solutions built on modern energy-saving technologies in compliance with current regulations are ineffective in poor quality work. And the desire of the developer to reduce the cost of square meters of housing due to savings on high-quality materials and their required volumes leads over time to emergency situations. In the case of brickwork, most often there are interfloor destruction and loss of elements of the outer surface due to the incorrect (insufficient) number of bonds between the planes. The traditional methods of performing work with reinforcing and restoring masonry are analyzed.The article discusses options for reinforcing multilayer brickwork, which can be applied locally. Formwork fastening elements can be used as reinforcing elements and anchor systems for further reinforcement or finishing. The basic recovery scheme is based on the concept of minimizing costs with a high level of technological processes

Application of fiber optic light guides with quartz core and cladding and plastic coating as indicators of the emergence of cracks in brickwork

Fiber optic light guides can be used as indicators (witness devices) of the emergence of cracks in masonry composed of construction-grade ceramic bricks. In this study, we experimentally investigated the relationship between the type and size of the fiber optic light guide and the size of the crack opening that caused fiber breakage by physically modeling a crack opening on a special stand. Two sizes of multimode fiber optic light guides with quartz core and cladding and poly(methyl methacrylate) (acrylic) coating were studied in detail. The results are useful for the practical implementation of the proposed method in automatic optoelectronic crack detection systems for brick buildings and structures.

Problems of Creation and Usage of 3D Model of Structures and Theirs Possible Solution

This article describes problems that occur when creating three-dimensional (3D) building models. The first problem is geometric accuracy; the next is the quality of visualization of the resulting model. The main cause of this situation is that current Computer-Aided Design (CAD) software does not have sufficient means to precision mapping the measured data of a given object in field. Therefore the process of 3D model creation is mainly a relatively high proportion of manual work when connecting individual points, approximating curves and surfaces, or laying textures on surfaces. In some cases, it is necessary to generalize the model in the CAD system, which degrades the accuracy and quality of field data. The article analyzes these problems and then recommends several variants for their solution. There are described two basic methods: using topological codes in the list of coordinates points and creating new special CAD features while using Python scripts. These problems are demonstrated on examples of 3D models in practice. These are mainly historical buildings in different locations and different designs (brick or wooden structures). These are four sacral buildings in the Czech Republic (CR): the church of saints Johns of Brno-Bystrc, the Church of St. Paraskiva in Blansko, further the Strejc’s Church in Židlochovice, and Church of St. Peter in Alcantara in Karviná city. All of the buildings were geodetically surveyed by terrestrial method while using total station. The 3D model was created in both cases in the program AUTOCAD v. 18 and MicroStation.

Uncertainty in Bond Strength of Unreinforced Fly-Ash Brick Masonry

AbstractLateral loads such as wind and inertial forces from earthquakes are resisted by the bond strength of brick masonry structures. The consideration of uncertainty in both load and resistance c...

Out-of-plane response of ECC-strengthened masonry walls

ABSTRACTThis paper focuses on the flexural behavior of masonry walls strengthened with precast engineered cementitious composite (ECC) sheet. The walls were subjected to out-of-plane static loading and analyzed using ABAQUS. For the validation of numerical results, four masonry walls of size 762 × 480 × 230 mm were cast using burnt clay bricks and cement mortar. Out of four, two masonry walls were strengthened with precast ECC sheet using epoxy as adhesive, and the remaining two acted as control specimens. The validation of numerical results with the experimental results shows that the model can effectively capture the nonlinear behavior of masonry and ECC to predict the strength and failure mechanism. The influence of mesh size on the numerical results is also reported. Further, a parametric study has been carried out to observe the effect of several parameters such as percentage of ECC reinforcement ratio, span/depth (L/d) ratio and width/thickness (b/h) ratio of the strengthened masonry walls. This study reveals that the precast ECC sheet increases the load-carrying capacity and ductility of brick masonry walls and hence demonstrates its performance as a strengthening element for brick masonry structures.

Enlarged brick blocks as an alternative to masonry

Brick structures are one of the most common and useful construction materials. However, brick laying consists of the most labor-intensive processes with the largest part of manual works. The main purpose of the research is to find an alternative technology for the brick structures construction that have geometric and physical parameters of brickwork, the processes of which are less labor-intensive and more mechanized. Using factory-made enlarged brick blocks was suggested in the article as an alternative. A brick block is a factory - made element of a brick wall structure that is installed in the design position by crane equipment. By reducing the part of manual labor in installing the brick block, the total duration of construction is reduced while maintaining the final result – a brick wall. The research method was a comparative analysis of the resulting indicators of construction of structures made of individual bricks and installation of enlarged brick blocks. As a model for comparative analysis, a brick wall of specified parameters was proposed, on the basis of which calculations were made. The results show diagrams of labor and material resources spent on the construction of the wall for the two technologies under consideration. Based on the results obtained, we can conclude that it is possible to use enlarged brick blocks of high factory readiness as an alternative to masonry.

Analytical study on seismic performance of bed joint reinforced solid brick masonry walls

It is notable that brick work structures endure a lot of harm during seismic tremors, prompting huge loss of lives. Practically 75% of the disaster, credited to seismic tremor in a century ago, is because of breakdown of workmanship structures [1]. A greater part of the apartments in India are Unreinforced Masonry (URM) structures that are powerless and helpless much under moderate quakes and due to high wind forces out-of-plane action is acting on the wall which makes a severe damage at high wind loads and it is well known that Reinforced masonry construction has got a significant number of advantages than the masonry without reinforcement, whose application is very less in Indian construction practices and still there are no specified codes prescribed and in most constructions there been used shear walls instead of reinforced masonry walls even at the moderate earthquakes [2]. On the other hand, a great need to focus on understanding masonry buildings that are subjected to both axial loaded and seismic loads [3]. The main objective of this paper is to study the methods available in the literature to obtain the seismic vulnerability of un-reinforced masonry walls using linear static analysis [4]. To achieve this, analysis (Staad.Pro software) have been carried out as a part of this research. Two walls with same dimensions with an unreinforced and bed type reinforced masonry were analysed under uniaxial loading. A constant axial compressive load was maintained for each specimen during the analysis [5]. Idealized Load vs Deflection plots are used to describe the wall deflections and maximum stresses evolved by using STAAD.Pro. The final outcome of this performance analysis declares the efficiency of Reinforced masonry walls over the masonry walls without reinforcement under both axial and seismic loads (Load vs Maximum shear stress).

Engineered cementitious composite and its applications

Engineered Cementitious Composite (ECC) is a cement based composite material containing discontinuous short polymeric fibers performing strain hardening behavior and high ductility based upon its micromechanics. Micro-mechanics mean that a micro-mechanical model is developed for the mechanical interaction between fibers, matrix, and interface which relates these constituent properties to composite response. ECC has high ductile properties after the first crack and due to this property, it is also known as Ductile Fibers Reinforced Composite (DFRCC). ECC exhibits strain-hardening performance with multiple micro-cracking during the inelastic deformation unlike the conventional fibers reinforced composite. This study investigates the properties of ECC and differentiate its behavior with High Performance Fibers Reinforced Cementitious Composites (HPFRCC) and other Fibers Reinforced Concrete (FRC). Moreover, this study provides an insight on application of ECC in the structural engineering so far around the world. Furthermore, an experimental study has been performed to determine the efficiency of precast ECC sheets for strengthening of masonry walls. The precast ECC sheets are pasted to masonry walls by use of epoxy as adhesive. The out-of-plane response of the unstrengthened and strengthened masonry walls are determined. The present study shows that the application of precast ECC sheet increases the load bearing capacity and ductility of the masonry walls and hence demonstrates its performance as strengthening element for brick masonry structures.

A detailed micro-model for brick masonry structures based on a diffuse cohesive-frictional interface fracture approach

In the past decades, the mechanical behavior of brick masonry material has been largely investigated using different modeling strategies, ranging from purely microscopic to purely macroscopic ones. The so-called simplified micro-modeling approaches, in which the behavior of mortar joints and brick/mortar interfaces is lumped in discontinuous elements, are commonly judged as very effective for accurately representing the interaction between the masonry constituents with an acceptable computational burden. However, they completely disregard the competition between brick/mortar decohesion and mortar cracking, whose role is not negligible, especially in presence of sufficiently thick joints and/or high-strength mortars. In this work, a detailed micro-modeling approach is proposed for the nonlinear analysis of brickworks subjected to in-plane loads. Such an approach allows failure to occur at the brick/mortar interface level and/or inside the mortar layer, while keeping the discrete nature of fracture phenomena. For this purpose, a novel diffuse cohesive-frictional interface approach for joints is presented, able to simulate multiple micro-crack onset and propagation along a-priori unknown paths. Suitable comparisons with a simplified micro-model are provided to validate the proposed approach. Moreover, a good agreement with the experimental outcomes is found, thereby assessing the reliability of the present fracture-based detailed micro-model in the numerical prediction of masonry strength under complex loading conditions.

The destruction of buildings walls brickwork on an unevenly deformed base

The article is dedicated to the analysis of the results of experimental testing of brick structures resistance. The experimental testing aimed at revealing a qualitative pattern of deformation and the character of losing the bearing capacity of a system “brick beam-wall – deformed base” and obtaining quantitative data about the strained and deformed state of the system undergoing short-term force and deformation at all stages of loading. Revealing the structure and phases of deformation and destruction of brickwork subjected to the increasing loading and the construction of dependences “loading – deformation” corresponding to the process of brickwork deformation and destruction was also an important task. It has been proved that the mechanism of the destruction of brick structures walls fragments, supported by uneven deformed base, occurs according to the scheme of shear, cut and breaking to pieces, as well as destruction of brick material and mortar with clear determination of deformation stages and brickwork destruction. The results of analysis of the experiments allowed to determine the influence of the amount of loading acting on cracks formation and brickwork functioning as a whole.

Pushover analysis of soft brick unreinforced masonry walls using analytical and numerical approaches

The seismic behaviour of low strength unreinforced masonry (URM) structures comprising soft bricks is still not clearly understood. This challenge can be addressed by numerically modelling soft brick URM wall panels using the simplified micro modelling technique. Alternatively, an analytical approach can be adopted to derive the load-deformation curves for soft brick URM walls. This paper presents results from pushover analysis on URM walls and compares the results obtained from the analytical and numerical techniques. The pushover curves and failure modes obtained from the finite element analyses are in good agreement with the results obtained using the analytical approach. It is concluded that the analytical and numerical techniques account for the various possible damage mechanisms associated with soft brick masonry and can be adopted for large scale analyses of soft brick URM structures.

Mechanical properties of high strength eco-concrete containing crushed waste clay brick aggregates as replacement for sand

Utilization of clay brick wastes for production of high strength eco-concrete enables the combat of raw resources depletion due to excessive mining as well as mitigating environmental pollution caused by demolition of old brick structures in an effort to achieve environmental sustainability in line with the sustainable development goals (SDGs). This study investigates the beneficial usage of crushed clay brick as partial replacement for natural sand in producing high strength eco-friendly concrete. The replacement percentages of the crushed clay brick in respect to sand are 0, 10, 20, 30, 40 and 50% by weight using a mix proportion ratio of 1:1:2 at a constant water-cement ratio of 0.25, aiming at the 28 days compressive strength of about 40 MPa. The chemical characterization of the crushed clay brick and cement was conducted via X-ray fluorescence (XRF). The mechanical properties tests were performed on about 80 specimens using 100 x 100 x 100 mm for cubes, 100 x 100 x 500 mm for beams and 100 x 200 mm diameter for cylinders after 7, 14 and 28 days of curing in water. Results showed that concrete containing crushed clay brick as partial replacement for sand compare favourably well with the control. Consequently, it is suggested that generated clay brick wastes can be crushed and used as replacement for natural sand for the production of eco-friendly high strength concrete.

Sustainable Brick Masonry Bond Design and Analysis: An Application of a Decision-Making Technique

This research intends to explore the sustainable masonry bond formation and interface behaviour of brick masonry bonds with different cement mortar ratios. To test the sustainable behaviour of different brick bonds, different tests were applied to evaluate the performance of the developed five brick masonry structures with the help of four mortar ratios. Following that pattern, the methodologies of a prism triplet test, a bond wrench test, a shear bond test and strength tests for brick masonry were applied. The prism triplet test explained the bonding behaviour of mortar by producing a maximum strength (0.21 MPa) with a 1:3 mix ratio, and the minimum strength (0.095 MPa) with a 1:8 mix ratio. The bond wrench test showed a bond strength of maximum 0.0685 MPa with a mortar ratio of 1:3 and a minimum of 0.035 MPa with a mortar ratio of 1:8. The strength tests for masonry structures expressed that compressive strength (0.786 MPa) and flexural strength (0.352 MPa) were found to be at maximum level with a mortar ratio (1:3) with an English bond formation. For predictions of compressive and flexural strength, artificial neural networks (ANNs) were deployed, and successful predictions of these values along with the relationships between different properties of the material, mortar combinations and bond combinations are presented to complete the exploration of the relationship. This pattern can be helpful for the selection of sustainable brick masonry formations for housing development.