Behavior Of Masonry Research Articles

Experimental investigation of the compressive and shear behaviours of grouted and hollow masonry constructed with PVA fibre-reinforced mortar and grout

Polyvinyl alcohol (PVA) fibres are ultra-high-performance fibres that can be used to reinforce cementitious composites. This study experimentally investigated the compression and shear behaviours of grouted and hollow masonry constructed with fibre-reinforced mortar (FRM) used for the joints and/or PVA fibre-reinforced grout (FRG). In this regard, the effect of increasing the fibre content of 6 mm PVA fibres in the FRM on the behaviour of masonry was investigated. Moreover, the effect of changing the fibre length (8 mm and 13 mm PVA fibres) and the fibre content of 13 mm PVA fibres in the FRG on the behaviour of masonry was investigated. This was accomplished by constructing and testing 31 masonry prisms and 29 masonry assemblages. The behaviour of PVA-reinforced masonry was evaluated based on compressive strength, shear strength, modulus of elasticity, modulus of rigidity, compressive strain at peak compressive stress, shear strain at peak shear stress, compression ductility index and compression toughness. In addition, the compression and shear stress-strain curves, failure modes and crack propagation of PVA-reinforced masonry were compared with unreinforced masonry. It was concluded that using PVA fibres in the grout minimized the masonry face shell spalling, and most of the post-peak deterioration appeared in the form of masonry cracks and less face shell spalling compared with unreinforced masonry. In addition, using PVA-FRM only or PVA-FRM with PVA-FRG could increase the compressive strength of grouted masonry. In contrast, using PVA-FRM did not change the compressive strength of hollow masonry. Furthermore, all grouted assemblages with PVA-FRM and PVA-FRG (except for assemblages with 13 mm PVA-FRG with a fibre content of 0.10% by weight of grout) have similar average shear strength compared with unreinforced assemblages. Finally, As the fibre content of 6 mm PVA fibres in the FRM of hollow assemblages increased, the shear strength and the modulus of rigidity decreased. This study highlights the improvements and drawbacks of using PVA Fibres in mortar and grout on the compressive and shear performances of hollow and grouted masonry.

Thermal Analysis of Concrete Blocks and Stack-Bond Prisms under Different Boundary Conditions

Fire is a significant threat to human lives and the integrity of buildings. To better understand the complex behavior of masonry exposed to high temperatures, thermal analyses were carried out to evaluate the temperature distribution in concrete blocks and stack-bond prisms exposed to high temperature levels. The effects of distinct specimen boundary conditions (restrict or easy access to air circulation inside the voids of the block and prisms) on the thermal response of the masonry materials were investigated. Thersys 2.0 software was used to implement three-dimensional thermal analysis of distinct finite element models. Four-node tetrahedral elements and full integration were used in all models. The modeling approach was validated by experimental data obtained from thermocouples embedded into masonry components. The results indicated that the boundary conditions significantly affected the time required for homogenization of temperature in blocks and prisms. Easy access to air circulation inside the voids of the prisms provided a faster temperature homogenization. In this scenario, the prism reached temperature ranges of (300 ± 0.5% × 300) °C and (600 ± 0.5% × 600) °C after exposure times of 2 h and 2 h 10 min, respectively. When access to air circulation within the voids of the prisms was limited, the same temperature ranges were achieved after exposure times of 5 h 20 min and 6 h, respectively.

Numerical Modeling of Two Adjacent Interacting URM Structures

Masonry structures in addition to their long heritage are still widely used in civil engineering practice. It should be emphasized that a lot of research has already been done on the seismic behavior of masonry structures. However, due to the nature of such a problem, its complexity and seriousness, the development of numerical models and their connection with experimental tests are always important. This is particularly significant considering their vulnerability to the action of horizontal forces generated during seismic excitations. In recent decades, many researchers have tried to capture the behavior of unreinforced masonry (URM) structures or reinforced concrete (RC) frames with masonry infills exposed to earthquakes, using different approaches. This paper tackles numerical modeling based on the finite element method (FEM) for the estimation of the dynamic response of two adjacent interacting URM units, subjected to shaking table motions. Geometrical and material properties of the specimen are provided by the Horizon 2020 project SERA-AIMS (The Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe – Seismic Testing of Adjacent Interacting Masonry Structures). The analyses of dynamic performance were executed in SAP2000 software. Obtained results on the numerical model provide useful guidelines for modeling the nonlinear seismic behavior of masonry buildings.

Future readiness of lime-based building materials: From heritage to innovation

Construction materials that last more than 500 years, will last 500 years or more if applied today. Learning from the past and particularly from cultural heritage as a knowledge depository and inspiring solution database, has driven us not only to develop preservation strategies but also to develop innovative sustainable and lasting construction materials. In depth research of lime mortar-based constructions integrating todays scientific insights and tools, helps understanding processes of carbonation and their influence on behaviour of masonry. Questioning the paradigm that “modern” building materials developed in the beginning of the 20th century, developed insights on the value of traditional knowledge.

Shrinkage and creep behaviour of thin layered mortared masonry

Shrinkage and creep behaviour of thin layered mortared masonry

A proposal for the numerical modelling of monotonic and cyclic behaviour of masonry infilled reinforced concrete frames

A proposal for the numerical modelling of monotonic and cyclic behaviour of masonry infilled reinforced concrete frames

Analytical Modeling of Eco-Friendly Concrete Blocks from Construction and Demolition Waste using ANSYS

This research underscores the feasibility of repurposing C&D waste, particularly old concrete, for both new construction endeavors and revamping existing projects. This approach offers a dual advantage: preserving precious landfill space while curbing the extraction of raw materials for fresh construction initiatives. Focusing on the utilization of demolished waste as partial replacements for coarse aggregates sourced from C&D Waste Traders in Sirjala, Bengaluru, 10 mm sized recycled aggregates are employed.
 Recognizing the porous nature of crushed aggregates owing to residual slurry, a meticulous treatment process is adopted. This includes two-stage treatment involving abrasion to eliminate residual loose slurry, followed by immersion in a fly ash solution with a concentration ratio of 1:6. Subsequently, these treated aggregates, after the curing process, are amalgamated with a robust geopolymer precursor in a mix ratio of 1:3:6 to fabricate 400X200X150 mm blocks.
 To gauge the masonry behavior of these innovative concrete blocks, a battery of tests conforming to ASTM codes is meticulously conducted. These evaluations serve as a robust assessment of the structural integrity, durability, and performance characteristics of the blocks, providing critical insights into their potential for widespread adoption in construction practices. This comprehensive analysis contributes to the growing body of knowledge on sustainable construction materials and practices, advocating for a paradigm shift towards eco-friendly construction methodologies amidst the burgeoning challenges of waste management and resource scarcity.

Influence of coconut fiber on mortar properties in masonry walls

The scarcity of stone materials, such as sand, has led to the exploration of alternative, sustainable options for mortars, including coconut fiber. This material, with minimal intervention in various areas of Peru, has proven to be an excellent choice in mortar preparation due to its characteristics of strength and durability. The study aimed to assess the influence of coconut fiber in mortar applications on the mechanical properties of clay brick masonry. Mixes were created with ratios of 1:3, 1:4, and 1:5, incorporating coconut fiber pre-treated at percentages of 0.5%, 1%, 1.5%, and 2% relative to the weight of cement and a length of 3 cm, respectively. Tests, including fluidity, compressive strength, and flexural strength, were conducted on mortar specimens. The behavior of clay brick masonry was evaluated through flexural strength, axial compression in prisms, and diagonal compression in walls. The most favorable result was observed in the 1:3 mix with the addition of 0.5% fiber, demonstrating a remarkable 22.6% increase in flexural strength compared to standard mortar. Subsequently, in masonry tests, the addition of 0.5% coconut fiber in 1:3 ratio mortars showed increases of 3.9%, 65.9%, and 3.3% in compressive strength, flexural strength, and diagonal compression in walls, respectively, compared to the standard samples. In conclusion, the addition of coconut fiber contributes significantly to the enhancement of mortar properties.

Seismic behavior of masonry-infilled reinforced concrete frames strengthened using ultra-high performance concrete diagonal strips

An extensive experimental program was undertaken which aimed at investigating the lateral cyclic behavior of non-ductile masonry infilled RC frames strengthened with Ultra-High Performance Concrete precast plates. In response, a series of four ½ scale single-storey, one-bay masonry infilled RC frames were meticulously designed and constructed. Among these, one frame was tested as-build with masonry infill, another was strengthened with 300 mm wide CFRP diagonal sheets, while the remaining two were strengthened with 355 mm wide UHPC diagonal plates. CFRP and UHPC strengthening was applied to one side of the masonry infill and the main test variable was the thickness of the UHPC plates. Based on experimental results, it was found that UHPC-strengthened specimens exhibited approximately twice the peak lateral strength that of the as-built specimen and 1.3 times that of the FRP strengthened specimen. Stiffness analysis indicated that UHPC-strengthened frames possessed an initial stiffness approximately 71% higher than the as-built frames, contributing significantly to their enhanced seismic performance. Nevertheless, it is important to note that UHPC-strengthened specimens also experienced stiffness degradation, although at a slower rate when compared to the as-build and CFRP-strengthened specimens. Moreover, UHPC-strengthened frames dissipated roughly three times more energy than the as-built frame and twice as much as the FRP-strengthened frame. While doubling the UHPC plate thickness from 10 mm to 20 mm led to a significant increase in masonry tensile strength, it also introduced structural asymmetry between the strengthened and unstrengthened sides of the wall. This asymmetry resulted in masonry panel buckling, ultimately leading to the failure of both UHPC-strengthened specimens at the same peak lateral load. In summary, this investigation underscores the promising role of UHPC retrofitting as a highly effective and occupant-friendly strategy for enhancing the seismic performance of masonry infilled RC frames. These findings carry significant implications for enhancing structural safety and resilience in earthquake-prone areas. Furthermore, this study provides a solid basis for further research and practical implementations in the realm of seismic retrofitting, contributing to the advancement of safer and more resilient infrastructure globally.

A single-surface multi-failure strength domain for masonry

In this paper, we propose a simple approach to derive a single-surface multi-failure strength domain for the in-plane behaviour of masonry. The approach, that lays the basis for homogeneous continuum model developments relies on micro-mechanical analyses employing a block-based model for masonry in which blocks, modelled as finite strength continuum bodies, interact through zero-thickness interfaces. In order to derive the strength domain, firstly three failure mechanism typologies are identified, namely crushing failure, joint failure and mixed joint-block failure. Then, the limit surface for each mechanism is obtained relying on limit equilibrium considerations, also introducing a novel rational treatment of the mixed mechanism. Accordingly, a multi-surface strength domain is built by intersecting all the limit surfaces. Finally, such multi-surface strength domain is reduced to a single-surface one exploiting the RealSoftMax function, which allows to preserve the multi-failure nature of the approach, i.e. the explicit distinction between all the failure mechanisms. Following the proposed procedure, the resulting strength domain inherits the material parameters characterizing the block-based model. A finite element block-based model and available experimental data are employed to validate the proposed strength domain. The good agreement obtained with reference results confirms the soundness of the approach.

On the mechanical behaviour of masonry infilled RC frames, with and without openings, subjected to simultaneous in-plane (IP) and out-of-plane (OoP) loading

On the mechanical behaviour of masonry infilled RC frames, with and without openings, subjected to simultaneous in-plane (IP) and out-of-plane (OoP) loading

In-plane seismic behaviour of urm and confined masonry built from vertically perforated blocks and polyurethane glue

Masonry construction using vertically perforated clay blocks with large holes and polyurethane glue is a modern technology designed primarily for low thermal losses. This study aims to evaluate the in-plane seismic behaviour of masonry constructed using unreinforced masonry (URM) and confined masonry construction technology. The experimental methods consist of triplet tests on joints and cyclic shear compression tests on eight full-scale walls, six of which are URM and two of which are confined masonry. Tests on URM walls are performed at three different levels of compressive stress to analyse the effect of compressive stress on the seismic response. The effects of compressive stress on shear resistance and drift capacity are quantified and compared with results from a database. The performance of the tested walls is comparable to what is expected from modern URM walls. Two confined masonry walls were of the same dimensions as the URM walls and are evaluated at the highest compressive stress level used in tests of URM walls. The results indicate that confined masonry should be the preferred technology for seismic regions because of its higher strength, displacement capacity, ductility, and energy dissipation.

Complete stress-strain analysis of masonry prisms under compressive loading-unloading cycles through digital image correlation

This paper presents the findings of an experimental study focused on the behaviour of masonry structures subjected to uniaxial loading-unloading compression. The study's primary objective is to examine the impact of joint mortar on the failure mode and the development of permanent strains using the digital image correlation technique (DIC). Masonry prisms were constructed using two types of fired bricks and five different mortars, each with varying cement and lime contents. The prisms were instrumented with a linear variable differential transformer (LVDT) for displacement measurements and prepared for image processing using DIC. The prisms were then subjected to compression testing until failure to capture their complete behaviour. The experimental results obtained through DIC and LVDT measurements showed good agreement. The DIC technique proved its effectiveness in providing comprehensive strain evaluations of the brick prisms, enabling a detailed stress-strain analysis at a full-scale level. Furthermore, the study revealed that prisms with lower cement content exhibited a more ductile behaviour in the post-peak region, with strain localisation observed at the joint mortar interface.To validate DIC's reliability in characterising masonry's cyclic behaviour, the results obtained from analytical modelling were compared with those derived from DIC. This comparison aimed to confirm the accuracy and consistency of DIC measurements. Overall, this study contributes to our understanding of masonry behaviour under compression and highlights the capabilities of DIC in capturing strain patterns and providing valuable insights into the influence of joint mortar on the structural response of masonry elements.

Evaluation of the Impact of Bricks of Various Characteristics on Internally Insulated Masonry Walls in Cold Climate

Energy consumption in historic building stock is high compared to current energy efficiency standards. The heritage value of the façade and the limited space on the external surface in densely populated urban streets limit the application of external insulation. Internal insulation can be applied instead. However, it is considered to be a riskier technology due to moisture-related damage. In addition to mold growth and wood rot, frost damage should be considered in cold climates. This study aims to assess the impact of a vapor-open capillary-active calcium silicate internal insulation system with and without adhesive glue on the hygrothermal behavior of masonry from various historic bricks in cold climates by performing numerical simulations in the software Delphin. Test results of hygrothermal properties of 40 historic brick samples were used in numerical experiments to assess the impact of a brick type, the quality of the application of calcium silicate (with or without adhesive), and the impact of cold climate on the hygrothermal behavior. Results show that temperature behavior is similar to all wall types whereas a large difference is observed in moisture behavior. The application of adhesive glue tends to reduce moisture spikes caused by rain events when compared to the same samples without adhesive. Findings only partly correspond to other studies on factors affecting moisture behavior.

Explicit Method in the Seismic Assessment of Unreinforced Masonry Buildings through Plane Stress Elements

The complex nonlinear behaviour of unreinforced masonry (URM), along with the interaction between structural elements, still represents a challenge for the seismic assessment of existing URM buildings. A large variety of mathematical tools have been developed in the last decades to address the issue. The numerical work herein presented attempts to provide some insights into the use of FEM models to obtain reliable results from nonlinear dynamic analyses conducted with explicit methods. Through plane stress elements, two in-plane mechanisms were studied to identify optimal parameters for unreinforced masonry elements subjected to dynamic actions. The results were then compared with outcomes generated by an implicit solver. Subsequently, these parameters were used in nonlinear dynamic analyses on a building section for the seismic assessment in both unreinforced and reinforced conditions. The element type, hourglass control, damping, and bulk viscosity influence the dynamic response, mainly when the nonlinearities become larger. The hourglass control techniques employ a scaling factor to suppress the occurrence of spurious modes. Values ranging from 0.01 to 0.03 have shown effective results. When the stiffness-damping parameter for Rayleigh damping is of a similar order of magnitude or lower than the time increment without damping, the time increment remained in feasible ranges for performing analysis. Additionally, the bulk viscosity can stabilise the response without causing substantial alterations to the time increment if the values are under 1.00.

Meso-scale numerical simulation of the mechanical behaviour of brick masonry in earth mortar

The paper discusses the mechanical behaviour of masonry composed of fired solid bricks and earth mortar. Such masonry is a typical construction technique in South and Southeast Asia. As its mechanical behaviour is complex due to high anisotropy attributed to noticeable difference in stiffness and strength between bricks and earth mortar, it is still considered challenging to comprehend the mechanical behaviour of such masonry. Taking into account this background, the present research addresses the formulation of the mechanical behaviour of brick masonry in earth mortar. Numerical analysis was performed to reproduce uniaxial compression and diagonal compression tests, referring to empirical evidences on interface behaviour between bricks and earth mortar. Meso-scale analysis was performed, applying a multi-surface failure criterion composed of cracking, shearing and crushing to unit-joint interfaces. The analysis showed very similar stress-strain relations and failure patterns to the tests. The simulation of the uniaxial compression test presented that the distributions of compressive stress shifted along with the progress of cracks. In the reproduction of the diagonal compression test, vertical stress was irregularly distributed after diagonal stepwise cracks appeared. Two comparative studies were conducted to examine the shear performance of brick masonry in earth mortar. First, sensitivity analysis indicated the noticeable influences of compressive strength, friction angle and facture energy of unit-joint interfaces. Second, macro-scale analysis was conducted, using a homogeneous material model. The observed diagonal crack patterns were similar to the test. The paper contributes to the understanding of the mechanical behaviour of brick masonry in earth mortar.

Structural Analysis of Steel Truss and Masonry Bridge Interaction: A Case of Ali Fuat Pasha Bridge in Sakarya, Türkiye

Restoration of historical structures using new materials and techniques is widespread worldwide. In these applications, relatively new materials such as steel, concrete, reinforced concrete (RC), or composite are generally preferred. However, it is often ignored whether old materials and new materials work in compatibility. In this respect, Ali Fuat Pasha Bridge (or Bayezid II Bridge), which was built by Bayezid II in 1495 over the Sakarya River in Geyve-Sakarya, was examined. The bridge is 196.50 meters long and consists of 15 arches with different spans and three arches of the bridge were destroyed as a result of the earthquake. Then, the bridge has been restored by constructing a steel truss system in place of the destroyed arches. Within the scope of this study, the structural performance of the bridge, which is currently serving vehicle and pedestrian traffic, is examined by using finite element analyses (FEAs). Moreover, this research examines the combined behavior of steel and masonry materials and investigates the structural behavior of steel truss and masonry bridge interaction. According to the results of the analyses, there are significant behavioral differences between the masonry structure and the steel structure. The main cause for this disparity is thought to be the varying levels of stiffness and ductility in steel and masonry sections.

Evolution of EC 6—Influence on masonry constructions made from AAC

AbstractWithin the scope of developing a new generation of Eurocodes also the European masonry standards are subjected to an evolution. Thereby new drafts for all four parts of EN 1996 have been elaborated and the final versions are available. Aim of the evolution was to implement the application experiences of the actual version, improving the ease of use and reducing the number of National determined parameters. The most severe changes of the new versions of the standards are the modifications of the calculation methods in EN 1996 parts 1‐1 and 3. Especially for masonry walls with a compressive strength and for constructions with partly supported ceilings the new simplified calculation methods showed a significant difference in the maximum capacities. Basing on this finding the conditions and rules for the design of AAC masonry according to EN 1996‐3 were adapted and thus improved for the final draft. This was a result of a big number of comparing calculations which took into account the special properties and behaviour of AAC masonry especially the ratio between compressive strength and modulus of elasticity. Regarding fire resistance of masonry walls several new test results have been implemented in EN 1996‐1‐2 for revising the tabulated values. The new tables also provide clearer allocations in terms of minimum thicknesses of walls for fulfilling the conditions regarding the different periods of fire resistance.

Experimental and numerical insights on the in-plane behaviour of unreinforced and TRM/SRG retrofitted brick masonry walls by diagonal compression and shear-compression testing

The experimental determination of the parameters that characterise the in-plane shear behaviour of masonry structures is still a challenging task. Different authors have identified the key role of tensile strength in the definition of the in-plane shear behaviour of masonry, but unfortunately its direct experimental characterisation is not always feasible, and masonry’s tensile strength needs to be obtained from complex testing methodologies. As a result, tensile strength needs to be assessed from testing setups such as diagonal compression testing and shear compression testing when the failure mode of masonry is featured by tensile diagonal cracking. However, different formulations are available in the scientific literature regarding the interpretation of the experimental results derived from such tests. This work provides new insights on the interpretation of in-plane shear experimental behaviour of double-leaf historical clay brick masonry walls with low strength mortar joints, both unreinforced and retrofitted with textile reinforced mortar and steel reinforced grout. The research evaluates results derived from both testing methodologies, and investigates the potential correlation between them to fully characterise the in-plane shear behaviour of masonry walls. Finally, a numerical model is used to simulate each testing configuration and study the stress state at the centre of the walls to determine the tensile strength and its correlation with the shear strength and the maximum load attained.

Compressive stress–strain behaviour of masonry prisms made of low elastic modulus burnt clay bricks

Masonry, being a quasi-brittle material, displays mechanical properties and manifests non-linear behaviour, which is influenced by the specific attributes of its constituent units and mortar. The compressive stress–strain behaviour of masonry is a vital factor in the realistic analysis of masonry structures when subjected to ground deformations arising from construction activities such as excavation, underground tunnel construction, utility installations, and for evaluating their seismic vulnerability. In India, the commonly used masonry unit is burnt clay bricks, which are highly localized due to changes in the constituent material and manufacturing process. This leads to variations in the strength and stiffness of brick units from region to region. An experimental investigation was conducted using twenty-four brick specimens, seventy-two mortar cube specimens and forty-eight four-unit single-wythe masonry prism specimens, subjected to displacement-controlled uniaxial compressive load. The specimen displacements of brick units and masonry prisms were obtained using Digital Image Correlation analysis. The stiffness of the brick units was significantly lower than those reported in studies conducted in India or elsewhere. Statistical analysis has been performed, and relations between the respective compressive strength and elastic modulus of brick units, mortar and masonry prism specimens have been obtained. An equation has been proposed to estimate masonry prisms’ elastic modulus from its components. An analytical model has been proposed for predicting the compressive stress–strain curve of masonry prisms, incorporating the elastic modulus of masonry prisms, which can be predicted using the expression proposed in this study. This is a fundamental improvement over the expressions available in the literature.