Masonry Assemblages Research Articles

Mechanical behavior of masonry assemblages manufactured with recycled-aggregate mortars

Abstract Mortars containing recycled aggregate, instead of quartz sand, were characterized to find an alternative application for the fine recycled-aggregate fraction coming from building debris processing. Tests on bond strength of mortar to masonry units were carried out, as well as tests on compressive and shear strengths of masonry assemblages. The results obtained were related to the mechanical properties of mortars and brick. On the basis of the characterization results and performance evaluations, recycled-aggregate mortar appears to be superior to ordinary mortars in terms of mortar–brick bond strength and shear strength of masonry assemblages. This improved performance is of particular interest for the masonry structures in zones of seismic activity. In addition, the use of fine recycled aggregate is in accordance with the sustainable development concept, where recycling of building rubble plays a key role in ending the building life cycle.

Semismooth Newton method for frictional contact between pseudo-rigid bodies

Recently developed semismooth Newton approach is adopted in the context of the frictional contact between three-dimensional pseudo-rigid bodies. The Signorini–Coulomb problem is formulated according to the formalism of the Contact Dynamics method. Hybrid linearisation, penalty scaling and line search techniques are combined as the global convergence enhancements of the Newton algorithm. Quasi-static simulations of dry masonry assemblies exemplify performance of the presented framework.

Evaluation of ASTM Methods to Determine Splitting Tensile Strength in Concrete, Masonry, and Autoclaved Aerated Concrete

Abstract Tensile strength of concrete or masonry is a fundamental material characteristic used to predict crack formation. ASTM C 496 and C 1006 are specifically designed to determine the splitting tensile strength of concrete cylinders and masonry units, respectively. Finite element studies for the above tests were completed with the maximum tensile strength compared to the theoretical value in the corresponding ASTM equations. The objectives of this paper are as follows: (1) evaluate current ASTM test methods to determine splitting tensile strength using finite element analysis; (2) evaluate the splitting tensile strength of masonry assemblages through modifying an existing ASTM test; (3) evaluate the application of ASTM test methods to determine the splitting tensile strength of autoclaved aerated concrete; and (4) evaluate a proposed ASTM test to evaluate the splitting tensile strength of thin-bed mortar used in AAC construction. A case study of the splitting tensile strength of autoclaved aerated concrete is used to propose a single test method for this new material.

Multilaminate Macromodel for Concrete Masonry: Formulation and Verification

A macromodel was developed to predict the in-plane behavior of concrete masonry. In this multilaminate model, the masonry assemblage is replaced by an equivalent material which consists of a homogenous medium intersected by two sets of planes of weakness along the head and bed joints. Additionally, two sets of reinforcement, normal and parallel to bed joints are used when modeling reinforced masonry. The macrobehavior of the equivalent material is determined by smearing the influence of these planes of weakness and reinforcement sets (when present) to determine the global behavior of the model. Different failure surfaces are defined for each masonry component. Based on the order in which different components reach their failure surface, redistribution of stresses occurs and different possible modes of failure are predicted. The proposed model’s prediction of the response of unreinforced and reinforced masonry is verified by comparison with the experimental results of masonry panels subjected to different ...

Design of anchor bolts in masonry

AbstractA review of the methods used to design anchors for masonry in Canada, Australia, New Zealand, Europe and the United States was conducted. It was determined that with the exception of the American standard (MSJC), most provisions for connections for masonry require anchors to be designed using some form of performance based criteria.The MSJC uses design equations to predict anchor behavior and an evaluation of these equations using recent published test results suggests that the nominal tension anchor bolt capacity equations appear to give relatively good results at smaller anchor diameters. However, unaccounted for tension splitting/flexural modes appear to be present in larger anchor diameters.The investigations also suggest that the shear load provisions in the MSJC appear to be adequate when predicting the capacity of smaller diameter bolts, but they can be very unconservative for shear load capacities for bolts above 19 mm in diameter. The masonry break out equation does not appear to accurately predict the splitting/prying masonry failures observed with these large diameter anchors. In addition, it appears that splitting failures may occur in smaller masonry assemblies and further work must be conducted to determine if this is a testing protocol artifact or a failure mode that can be realistically expected in the field such as the proposed shear bearing model.Finally, results of combined shear and tension load tests, appear to suggest that the interaction equation for anchors used in grouted cavities in masonry assemblies is a power function, with a value between 1.4 and 1.67.

In Situ Shear and Compression Tests in Ancient Stone Masonry Walls of Tuscany, Italy

Abstract The present paper reports methods and results of an extensive experimental project performed to assess the mechanical characteristics of ancient stone masonry walls of Tuscany (Italy). Some relevant considerations concerning the determination of common design shear strength parameters via experimental test results are also presented. Results from 22 in situ tests performed on nine large-scale stone masonry panels are reported. Test panels were selected as part of shear walls in six different old masonry buildings in the northern part of Tuscany so as to represent a reliable sample of the most common masonry types in this region. In situ tests were carried out according to experimental schemes for vertical compression, shear compression, and diagonal compression. After the first test, several panels were repaired and reinforced by means of cement mortar injections (full cement grouting) or reinforced concrete (RC) jackets, and then tested again to determine the effectiveness of the intervention. Particular attention was then devoted to evaluate the referential shear strength τk of these masonry assemblages in the original state. To this purpose, a fitting process for experimental data was used, adopting two different schemes for interpretation of the shear strength of masonry (the Coulomb and the Tumsek-Cacovic equations). The results from this work have shown that the Turnsek-Cacovic equation gives a better fit to experimental data than the Coulomb equation, especially for medium- and poor-quality masonry walls. Finally, conclusions are presented noting the difference between shear strength values calculated from fitting the data from test results and the values suggested by European and Italian standards.

対角線加力試験法による鉄筋コンクリート組積造耐力壁の斜張力剪断性状に関する実験的研究

This paper deals with shear behaviors of reinforced masonry load bearing walls, where bond beam types of comparatively strong masonry units and mortar and concrete grouts are combined with each other under the various construction conditions. Two simple equations are clarified to be effective for predicting shear strength and rigidity before producing masonry units and assemblages.

Finite Element Analysis of Infilled Frames

Design of infilled frames to resist lateral loads on buildings in terms of their failure modes, failure loads, and initial stiffnesses using procedures proposed by previous authors is verified. This verification is made by comparing the results of the analytical procedures of the previous authors with those of a new finite element model for infilled frames, which are verified using experimental results. To model the interface between the frame and the infill and the mortar joints surrounding the blocks of masonry, a nonassociated interface models is formulated using the available test data on masonry joints. The failure criteria for masonry include the von Mises criterion for the plane stress condition for uncracked masonry (assembly) and a smeared crack model. Additionally, the finite element model provided more insights into the failure mechanisms of the infilled frames.

Creep analysis of clay masonry assemblages

When loads are applied to a masonry structure, viscoelastic behaviour is exhibited where the response can be divided into two distinct parts: an instantaneous elastic part and a time-dependent one. With the change in masonry construction during the last century from thick, low-stressed walls to thinner, more highly stressed ones, the latter portion of the response is becoming more important in the design of masonry structures. The main objective of this paper is to examine suitable methods of creep prediction for clay masonry. The results of a large, continuing experimental programme begun in 1988 were used to evaluate the minimum and maximum values of specific creep and creep ratio. The test setup and the effect of moisture content on the creep behaviour of masonry are also described briefly.

Creep analysis of clay masonry assemblages

Creep analysis of clay masonry assemblages

空洞部の大きい高強度メーソンリーユニットの組積状態における圧縮強度

Compressive strength of masonry assemblages with hollow and bond beam high strength masonry units, which was indispensable for actualizing more than medium rise reinforced masonry buildings, was experimentally examined from the viewpoints of approximating the strength, that is to say the characterized strength for masonry structural design, and predicting the fracture patterns in case of concrete and clay masonry units.

Behaviour of concrete block masonry prisms under axial compression

A nonlinear three-dimensional finite element model was developed to study the complex behavior of ungrouted and grouted concrete block masonry prisms under axial compression. The model detects crack initiation and traces crack propagation in the masonry assemblage. Variable strengths for blocks, mortar, and grout were used to study the effect of the mechanical properties of prism constituents, and their combinations, on the prism strength and modulus of elasticity. The effect of the number of courses was also investigated. The results of the finite element analysis were used to develop simplified relationships to predict prism strength and modulus of elasticity. Good agreement was observed between the available experimental data and the predicted prism strengths. Key words: compressive strength, concrete blocks, failure modes, finite element, masonry, modulus of elasticity, prisms.

Masonry structures: behavior and design

The world of ancient masonry the world of modern masonry building design masonry materials behaviour of masonry assemblages reinforced beams and lintels flexural walls loadbearing walls under axial load and out-of-plane bending columns and pilasters shear walls infill walls and partitions masonry veneer and cavity walls connectors application of building science for environmental loads construction considerations and details design of loadbearing single storey masonry buildings.

Interface Model Applied to Fracture of Masonry Structures

The failure of unreinforced masonry structures subjected to lateral loads is dominated, to a large extent, by the fracture of mortar joints as well as the cracking and crushing of masonry units. This can be simulated by means of a finite element approach in which the mortar joints are modeled with interface elements and the masonry units are modeled with smeared crack elements. To this end, a dilatant interface constitutive model capable of simulating the initiation and propagation of interface fracture under combined normal and shear stresses in both tension‐shear and compression‐shear regions, and capable of simulating the experimentally observed dilatancy was developed in this study. The performance of the interface model in representing the behavior of masonry mortar joints is evaluated with the available experimental results. Furthermore, the failure of unreinforced concrete masonry panels is analyzed with the aforementioned approach. It is concluded that the numerical model is capable of predicting the response of a masonry assemblage based on the response of its basic constituents.

Finite Element Analysis of Concrete Masonry Prisms

Using the physical and geometric properties of mortar and concrete brick (or block) elements, and attempt is made to predict the behavior and ultimate strength of brick or concrete block masonry prisms or assemblage. The loading curve for a given strength mortar is obtained from experimentally measured stress-strain data. Failure envelopes were established for the mortar following Mohr's theory of failure line, and for the block from the results of numerical analysis of solid masonry prisms. The proposed failure envelopes for predicting ultimate strength of masonry prisms showed good agreement with available experimental data.

Out‐of‐Plane Bending of Concrete Block Walls

The test results for 21 full‐scale concrete block walls subjected to uniformly distributed loading normal to the surfaces of the walls are reported. The variables included in this experimental study include three wall lengths of 6.0 m (19 ft, 8 in.), 5.2 m (17 ft, 1 in.), and 3.6 m (11 ft, 10 in.) with a constant 2.8 m (9 ft, 2 in.) wall height. In addition, tests were performed with simple support conditions on all four boundaries, on the bottom and two sides, on only the two sides, and on only the top and bottom of the wall. Also, one series of tests was done with precompression loading in the vertical direction. Three repetitions for each combination of parameters were performed to provide a better statistical sample. The test results were compared with both elastic‐plate and yield‐line analyses. In these analyses, the bending strengths used were taken from tests of masonry assemblages constructed to allow testing of individual joints under bending normal to the bed joint and parallel to the bed joint....

Numerical evaluation of shear strength of structural masonry assemblages

Structural assemblages include brick and block masonry. Their complex behaviour is simulated with a numerical model that is presented in this paper. A computer program coded in Fortran allows material and geometric properties of the assemblage as input data, and incremental vector loads may be generated automatically. For any stress vector applied to the assemblage, there is a corresponding strain response. The stress loading may continue progressively until failure occurs in the assemblage. This algorithm is used to model the behaviour of an assemblage under shear stresses with test data, and the results show that the single plane of weakness theory is applicable to structural assemblages. Further, the shear strength of an assemblage could be predicted by subjecting it to typical shear-compression-tensile stress regimes.

Plane stress analysis for anisotropic no tension materials with hardening in compression

Mechanical behaviour of structural materials such as metamorphic or sedimentary rocks and block masonry assemblies is strongly influenced by intrinsic anisotropy. Directional effects of cleavage, bedding or mortar joints are quite dominant, as are those due to inelastic strains. Accounting for this feature and the low tensile strength an incremental elastic-plastic model with zero strength in tension and work-hardening in biaxial compression is proposed. This model is formulated on the basis of a linearized failure condition achieved either theoretically or experimentally and enjoys a simple hardening rule. Merits and limitations are discussed in view of numerical analysis.