Movement of brick panel cladding

Movements of masonry brick panels, determined from dimensional changes measured at the joints, have been measured in three directions: horizontal and vertical in the plane of the wall and perpendicular to it. They were analysed as a function of temperature change and as a function of time. The analyses supported the hypothesis that thermal movement in the horizontal direction is altered by moisture content variations in the porous panels. Movements caused by moisture attenuated, and in some cases overrode, thermal movements. In the vertical direction the panels made one large movement in winter corresponding to the yearly temperature change and oscillated in other seasons. Movements perpendicular to the panel indicated curling of the edges.     

Salt diffusion in brick structures

Salts causes surface damages and efflorescence for masonry walls. This has increased the interest to understand the salt transfer phenomena taking place in porous matrix. There is still however a lack of published transport data in the literature. Especially the diffusion coefficients of salts in different brick structures are lacking. In this work a method for measuring the rate of diffusion of salt in ceramic material is presented and applied to the measurement of diffusivity of NaCl in three different brick materials. Fick's first law of diffusion was applied to calculate the diffusion coefficients in a pseudo stationary state by means of linear regression analysis. The result for the diffusivity of 0.05 molar NaCl in water in new Finnish red brick was (0.499 ± 0.004 ) * 10^–5 cm²/s in the temperature of 25 ± 0.05°C. The corresponding values for the old light brick and old dark brick was (0.453 ± 0.008) * 10^–5 cm²/s and (0.337 ± 0.009) * 10^–5 cm²/s respectively. The diffusion coefficients are given as an effective diffusion coefficients calculated with the porosity value measured to each of the specimen. The concept of salt diffusion and diffusion mechanism inside the porous matrix are also discussed.     

Studies on brick masonry under compression

In China, brick masonry is extensively used in the construction of multi-storey dwellings, as well as in single-storey industrial plants and warehouses. Therefore, studies in this field are numerous. This paper presents only the experimental studies and proposed calculations for unreinforced and reinforced brick masonry under compression.     

An 8-node brick finite element

An 8-node brick element based on the assumed stress hybrid formulation is described. With three additional stress fields, the element stiffness matrix now has the required rank of 18, and the ‘bending’ response is exact with rectangular elements. Surprisingly, the 2 × 2 × 2 Gauss rule suffices for all numerical integrations, to satisfy the constant stress patch test.     

Studying of salt diffusion behaviour in brick

In this paper, an analysis of the diffusion behaviour of salts in fully saturated brick is presented. This paper extends the previous work to including more salt types and measurement data. Dependence of diffusion coefficient on temperature and other factors is discussed. Starting from the mathematical model which has been verified before, the obtained results are 2-fold: first the diffusion coefficients for different types of salts are given which are evaluated from measurements; moreover, dependence of temperature and ambient salt concentration on diffusion coefficient is presented.     

In-plane behavior of perforated brick masonry walls

This paper reports the results of experimental and theoretical research conducted on perforated brick masonry walls under in-plane loading. The walls?? structural behavior depends strongly on their specific features, e.g. geometry, mechanical properties of the masonry material, brick arrangement and loading conditions. The experimental program was designed to study the incidence of brick arrangement in the spandrels and piers, and of the acting vertical load on the failure mode and load-bearing capacity of the walls. Six specimens of brick masonry wall with a central opening were submitted to a constant vertical load and a monotonic horizontal force that was gradually increased until the kinematic mechanism condition was reached. The object of the theoretical research was to develop a simplified analytical model for describing the kinematic mechanism of the walls. The results of the experiments indicate that brick arrangement strongly influences the failure mode and load-bearing capacity of the walls. Proper a priori assessment of the failure mode of walls becomes fundamental to an accurate evaluation of their load-bearing capacity using the proposed model.     

Causes of damage to industrial brick masonry chimneys

From the early 19th to the middle of the 20th century, brick chimneys formed part of the industrial landscape. As technology advanced, factories were abandoned and became absorbed by the cities growing around them but masonry brick chimneys found a new role as part of the historical heritage. A large number of these structures are now protected buildings, which means they have to be maintained in a good state of conservation. Architects and engineers who have to assess the condition or retrofit these structures therefore need to be familiar with the different types of damage that can affect brickwork chimneys, and having access to a classification of the different types of damage they are prone to would be very useful to them. This paper classifies and describes the most common defects found in these structures, compiled after a close inspection of 538 Spanish industrial chimneys. The types of damage were classified according to: a) changes in the materials used in their construction, b) damage caused by repeated actions, c) damage due to extraordinary events, and d) damage caused by living organisms.     

Added value and employment effects of brick industry

In Germany manufacturing and distribution of bricks care for direct employment of about 10,000 persons. Procurement of preliminary work and the utilisation of the payed salaries, social security contributions, taxes, and profits secure more than further 25,000 jobs. It can be assumed that a substitution of masonry by other building materials is not possible in the near term, since the masonry has increased its market share in the past few years even slightly. Thereby the masonry participates in the added value based on the shell construction of buildings in the amount of 32.4 billion Euro, and in the employment of 480,000 working people. The expansion of these buildings leads to further added value in the amount of 39 billion Euro and further employment of 691,000 employees. In the year 2016 in total, the construction of buildings with masonry has led to an overall economic added value amounting to more than 70 billion Euro and to an employment of about 1.17 million persons. Masonry products form the basis of this added value and employment, without which the construction of the buildings would not be possible.     

An improved EAS brick element for finite deformation

A new enhanced assumed strain brick element for finite deformations in finite elasticity and plasticity is presented. The element is based on an expansion of shape function derivatives using Taylor series and an extended set of orthogonality conditions that have to be satisfied for an hourglassing free EAS formulation. Such approach has not been applied so far in the context of large deformation three-dimensional problems. It leads to a surprisingly well-behaved locking and hourglassing free element formulation. Major advantage of the new element is its shear locking free performance in the limit of very thin elements, thus it is applicable to shell type problems. Crucial for the derivation of the residual and consistent tangent matrix of the element is the automation of the implementation by automatic code generation.     

Shear capacity of brick masonry with partially supported slab

In order to investigate the influence of a partially supported slab on the in‐plane shear resistance of masonry walls, six shear tests on full scale walls were performed at the Chair of Structural Concrete of the University of Kassel in cooperation with ”Arbeitsgemeinschaft Mauerziegel“. The walls were made of large chamber clay masonry units and the depths of the partially supported slabs were different. The large chamber units are typically used for thermally insulated exterior walls, with the slabs only being partially supported. The influence of this constellation is not taken into account in shear capacity assessment according to the current version of Eurocode 6 for Germany. This article describes the test results and provides a comparison with Eurocode 6. In addition, the results of older shear tests on masonry walls made of vertically perforated units with eccentric load application were used.     

Fracture mechanics in the characterisation of brick masonry structures

The analysis of the mechanical behaviour of masonry structures is based on the assumption that this material does not withstand tension. In this field many researchers are studying how to refine analytical and experimental procedures to obtain a more accurate correspondence between the real behaviour and the simulated one. However, this hypothesis cannot explain the masonry strength with respect to dynamic and seismic load conditions, which cause tensile stresses and dilating strains in masonry structures. The aim of this work is to give a complete set of experimental results in order to determine the mechanical properties of brick masonry. In particular, an extensive experimental programme was carried out to characterise the mechanical and structural behaviour of masonry composite in compression, along both the material directions, and in tension, along the horizontal mortar joint direction. Tensile properties in particular were estimated by means of four-point bending (FPB) tests owing to the lack of a standard tensile test and because bending tests are considered to be reliable indirect tensile ones and easy to carry out. The experimental results obtained using this testing procedure highlighted the behaviour of a bimodular material when subjected to tensile stresses, and these were then analysed by means of fracture mechanics theory to estimate the masonry toughness and stress intensity factor as further material characteristics.     

Elastoplastic analysis using the 14-node brick element family

Typical brick-based finite elements in current use are the 8-and 20-node members of the serendipity group. For displacement analyses of solids the 8-node element can be quite stiff in certain deformation modes, while the 20-node element can be quite expensive to use, involving as it does 60 degrees of freedom and a fairly high order of quadrature to avoid spurious eigenmodes of the element stiffness. In this paper a family of intermediate 14-node elements is investigated. Derivation of their properties can be considerably assisted by computer algebra. Performance is evaluated for elastic and elastoplastic problems.     

A geometrical non-linear brick element based on the EAS-method

This paper presents the development of a 3-D brick element with enhanced assumed strains for a geometrically non-linear theory. Some linear and non-linear examples show that this element can be used successfully in the whole range of solid structures. Thin 2-D- and 3-D-beam and shell structures are calculated with few 3-D elements and the results are the same as for shell or beam elements. © 1997 John Wiley & Sons, Ltd.     

Last brick finalized for the IEC BIS standards complex

正The last of the five IEC 62820 standards for building intercom systems(BIS)was officially released by IEC in February,marking the final completion of five international standards for BIS developed under the leading effort of China.The standard proposal was formulated by the Chinese national alarm and electronic security standardization technical committee(SAC/TC 100)and submitted in March 2012 by SAC to IEC technical committee for alarm and electronic     

高速无菌牛奶砖包机上下位机通讯设计

为了解决高速无菌牛奶砖包机在设计中出现的通讯问题,并考虑对操作员操作及对砖包机维护的需要,使用工控机作为上位机,采用GE90系列PLC作为下位机,上位机对PLC内部底层通讯协议SNP进行封装,使用多寄存器寻址方式,实现了在一个采样周期内完成对一台下位机的多类型寄存器的数据采集,阐述了实现高速数据采集实现原理,并结合寄存器修改方式,实现了上位机对下位机PLC输入端口的“虚拟输入”,在此基础上,编写了上位机对下位机的监视及控制程序,并建立了基于网络的远程故障诊断及维护系统。     

A hybrid brick element with rotational degrees of freedom

An 8-node brick element using Allman's displacement interpolation is proposed. The optimal number of 36 stress modes is identified. The six equal-rotation strainless modes which are intrinsic to Allman's interpolation are stabilized by using a penalty method. The penalty also enforces the equality of the nodal rotation and the continuum-defined rotation. To enhance computational efficiency, 39 stress modes are initially assumed, three constraints on the stress field are then imposed. The flexibility matrix is simplified, such that only four symmetric 3 × 3 matrices are required to be inverted. Numerical test results are presented, showing good accuracy.     

Amelioration of crushed brick - lime composites using nano-additives

Crushed brick is widely known as a pozzolanic additive for composite building materials. However, crushed brick - lime composites usually show high porosity, low compressive strength and slow reaction kinetics. In this paper, we present multidisciplinary research on the amelioration of crushed brick - lime composites, using nanosilica (SiO₂) and nanotitania (TiO₂) as additives at 3% w/w of binder. The results suggest that despite the dominant effect of the crushed brick, nanosilica significantly improves the early-age properties of the composites, while nanotitania potentially increases their resistance against salt crystallization. Supplementary FTIR, DTA/TG and SEM analyses confirm the better hydration and carbonation evolution of lime composites with crushed brick and nano-additives.