Papers by Keyword: Brick Masonry

Abstract: This study is about a church built at the end of the 19th century, made of burnt brick and lime mortar with sand, inadequately renovated. The objective of the study is to signal about the damages suffered by the old buildings due to the use of inadequate materials in repair. The present building was less than 20 years ago renovated by replacing the old lime-sand plaster with cement mortar, a fact that led to the accumulation of moisture in masonry, resulting the damage of the finishes and affecting the safe health conditions. The article presents temperature, humidity and dew point measurements, a calculation of the comfort index, and a software modelling, as well as the correct solutions.

Abstract: Masonry made with soft clay brick is commonly used in gravity load bearing of construction in India. The masonry piers and walls typically fail by vertical splitting. The purpose of this study is to improve the strength of masonry columns under compression using wrapping for additional confinement. The compressive load carrying performance and capacity of masonry columns wrapped with fiber reinforced composites in organic and inorganic matrixes are compared. For the purpose of overall improvements in cost and durability, glass and basalt fiber reinforcement is used. 30-40% improvement in the compressive performance of masonry prisms was achieved for both Organic and Inorganic matrixes. However, the specimens with inorganic matrixes were found to exhibit higher ductility compared to organic matrixes. Glass fibers were found to be more effective in wrapping masonry specimens compared to Basalt fiber specimens owing to its higher fiber count per unit length. Analytical models for predicting the compressive capacity of masonry columns with wrapping are verified against the experimental results.

Abstract: An experimental investigation of compressive failure in masonry made of soft clay bricks is presented. The research attempts to address the concern of strong/stiff mortars available in the market today in combination with poor quality burnt clay bricks available in India. Masonry assemblages are tested to evaluate the influence of the relative strength of mortar on the observed damage evolution and compressive failure. Damage evolution associated with the formation and propagation of vertical splitting cracks during the compressive load response of masonry assemblages in the stack bonded arrangement are studied using a full-field optical technique based on digital image correlation. The stress state in the composite material produces tension in the mortar and confined compression in brick. Using image correlation clear evidence of the crack forming in the mortar and propagating into the brick is established. Failure is produced by vertical splitting and the number of cracks depend upon the tensile strength of the mortar relative to the brick and the number of head joints. Head joints act as stress risers, leading to high tensile stress.

Abstract: In this study, confined masonry specimens with regular arranged openings are tested in order to study the influence of different enhancements of the columns on seismic failure modes. In particular, five brick masonry walls and three half-scale two-storey masonry structures are tested under quasi-static loads. The experimental results show that increasing column ratio improves the seismic behavior of the wall specimens to some extent, but an excessive reinforcement ratio of the columns decreases the ductility. The global failure mode of the two-storey masonry structures is modified by inserting iron wires in the mortar bed joints, improving the structural collapse resistant capacity effectively.

Abstract: The paper is part of a research that aims at investigating the relationship between fire and post-fire (i.e. residual) mechanical behaviour of masonry walls, paying attention to the possible exploitation of numerical tools for simplified approaches. The goal is to establish relationships between exposure severity under ISO834 conditions and decay in mechanical properties after exposure; the parameter of wall thickness is especially investigated, by choosing four different values (i.e. 12, 25, 38 and 51 cm). This is performed by means of FEM analysis with DIANA 9.4.4 software, simulating a standard ISO 834 fire resistance test followed by a mechanical compressive failure test on each investigated type of wall. The FE analyses’ outcomes allow to draw exponential expressions of the decay in compressive strength as a function of the exposure severity.

Abstract: Digital image correlation (DIC) is a recently developed optical technique allowing high-definition maps of displacements and deformations of the element under view. Various fields of application are already known where thermal and mechanic distorsions of the object have been explored by comparing false-colour images recorded in different deformation states. The method is becoming more common in civil engineering where first applications were limited to metal structural elements and composite material reinforcements [1-3]. The main advantages of this optical technique lie in contact-free, full-field measurements. In order to enhance the displacement spatial resolution, one of the recognised requirements of the method – in fact, so far, unavoidable – is the preparation of the investigated surface by applying a thin, white mat coating followed by a distribution of speckles (black dots) of appropriate sizes. This preliminary procedure constitutes a disadvantage of DIC due to the necessary preparation time and to inappropriateness of the requirement in case of testing high-value objects such as cultural heritage [4]. In this work, an innovative experience of DIC is presented for a case of mechanical test monitoring of brick masonry, in the lab (specimen dimensions: 0.50x0.5x0.12 m³). In addition, no coating of the surface of interest has taken place. The attempt is to validate the applicability and reliability of the method for this composite material when the masonry materials’ texture is exploited as the reference pattern to monitor geometry variations of the specimen under increased load levels. A further challenge of the experiment was due to the visible degradation state of the masonry specimen, which prior to the destructive compression load test had undergone accelerated ageing through cycles of salt crystallization and consequent discolouring and partial skin loss. The aims were to obtain from DIC high-definition full-field information able to reliably replace traditional measurement instruments such LVDTs, extensometers or TML gauges, determining instead 3D in-plane and out-of-plane displacements, tensions and strains at different load levels up to specimen collapse. The outcome of the experiment provided a better understanding of the masonry behaviour under axial load and of the local and global distribution of the above mentioned characteristic mechanical parameters together proving the reliability of the DIC technique under the specific monitoring constraints.

Abstract: The innovative technique here illustrated is the result of historical evolution of ancient systems of hooping and is conditioned by design criteria that take into account the structural life in the respect of existing elements. It consists in the application of small diameter cords able to provide overlapping hoops at every course over the entire height of the column. Three series of uniaxial compression tests, with a total of 22 specimens, were conducted on model brick masonry columns with these variables: cross-section geometry, amount and scheme of confining reinforcement. Laboratory outcomes have shown how the investigated confining systems are able to provide significant gains in terms of compressive strength. Test results have been finally used to assess the reliability of the existing design equations suggested by Italian National Research Council for design of FRP strengthening of masonry columns.

Abstract: To research the brick masonry wall between windows under the low cyclic load test. Combining with ABAQUS finite element software simulated the wall between windows. Analyze the destruction process, ductility and seismic performance of the wall between windows. Explore the beneficial influence on the wall between windows which under the pressure. The results of study show that the brick masonry wall between windows occurred flexural failure.With the increase of pressure, the ductility of Brick masonry wall between windows will be decreased. But the yield load, maximum bearing capacity and limit bearing capacity is improved obviously. When compared 0.3MPa,the maximum bearing capacity under 0.4MPa, 0.5MPa, 0.6MPa increased by 8.3% , 16.4% and 23.9%. The seismic performance was improved. It had good engineering significance in practice.

Abstract: Brick masonry cracks only variety, shapes, and the phenomenon is more common, it may affect the beauty of buildings, resulting in infiltration Water Leakage, or reduce the bearing capacity, stiffness, stability and integrity, durability of building structure, but also can lead to an overall collapse of serious quality accidents. Therefore, the correct analysis of the reasons of cracks, puts forward the prevention measures is very necessary.

Abstract: The wall between windows is the smallest,the most weakest anti-seisnic unit^[. Under the action of a strong earthquake,the longitudinal window that parallel to the main direction,often produced Xshaped cracks due to lack of shear bearing capacity .But under the earthquake,masonry structure had goodsecsmic performance,large ductility,light damage and showed reversible,easy to repair^[ and so on. Given the advantages of bending failure of the above, Professor Zhang Wenfang has proposed a new earthquake mitigation technologies in the literature [. This model avoids the whole cross-section brittle shear slip, and has good ductility after yielding. Therefore, this paper combines the free shear failure of masonry structures seismic test specimen design. And it can simulate the window wall W-1 with 10mm isolated seam,the wall W-2 between windows and the ordinary wall W-3.Compared their damage morphology and mechanical characteristics in the vertical load and horizontal loads, some useful can be got and become the basis for teoretical analysis and engineer design of masonry structures for the future.