Masonry Walls Research Articles

Experimental and Numerical Simulation of Effects of High Temperature on RC Frame Infilled with Sandwich Panel

This study investigated the structural behavior of reinforced concrete (RC) frames infilled with masonry walls and polyurethane (PU) sandwich wall panels at elevated temperatures. This study aims to assess the influence of temperature on the stiffness and load-carrying capacity of infilled frames, optimize the thickness of the sandwich wall panel, and compare the performance of masonry and sandwich infill systems. Analytical investigations were conducted using finite element analysis software (ABAQUS) to simulate the behavior of the frames at elevated temperatures and consider various configurations of skin thickness for PU sandwich panels. Experimental tests were performed to validate the analytical results. The frames were subjected to transient temperature conditions and uniform unit loads to evaluate their response. Experimental tests were conducted on RC frames infilled with masonry and sandwich-wall panels at elevated temperatures. The frames were subjected to static loading, and their deformations and failure modes were observed. The analytical study revealed that an increase in the skin thickness of the sandwich panel improved its temperature resistance, stress-withstanding ability, and displacement. A skin thickness of 0.45 mm was determined to be the optimal choice considering stress levels and economic factors. The infilled frame with the sandwich wall panel exhibited a 19.22% higher initial stiffness than the masonry wall panel in the experimental tests. The ultimate load-carrying capacity decreased by 17.86% in the infilled sandwich wall panel frame compared to the masonry infill system. The study provides valuable insights into the behavior of RC frames infilled with masonry walls and sandwich wall panels under elevated temperatures. The optimized thickness of the PU sandwich panel was determined by balancing the thermal resistance and the structural performance. The infilled frames with sandwich wall panels exhibited enhanced stiffness but slightly reduced ultimate load-carrying capacity compared with the masonry infill. These findings contribute to the understanding of thermal effects on building structures and can aid in the design and construction of more resilient and efficient buildings in the future. Doi: 10.28991/CEJ-2024-010-01-018 Full Text: PDF

Masonry walls from reclaimed concrete demolition waste

The construction sector is the largest consumer of non-renewable resources and the most significant contributor to CO2 emissions. Reusing entire components or reclaiming their constituent parts, instead of recycling structural elements at the material level, is preserving the embodied energy of the structural elements. This contributes to energy conservation and addresses the mounting issue of construction waste in landfills. In order to develop a new avenue for reusing concrete, this study uses concrete demolition waste to construct masonry wallets, employing a construction technique reminiscent of traditional stone masonry with mortar. Importantly, this methodology is not confined to buildings initially designed for reuse, making it applicable to any reinforced concrete structure earmarked for demolition. Mechanical tests were conducted on the masonry wallets, including simple and diagonal compression tests. The results indicate that the strengths achieved are comparable to those of clay hollow brick masonry, opening up diverse applications, especially in the construction of residential buildings. Numerical analysis started with digital twinning of small-scale masonry wallets as a first step to future micro-modelling, FEM simulation, and calibration to best conform with the experimental test results. Through a comprehensive analysis encompassing embodied carbon footprint, mechanical properties, and economic considerations at the load-bearing wall level, this study highlights this reuse approach’s key advantages and drawbacks, providing insights into its feasibility within the framework of modern construction practices.

Preliminary Ranges of Critical Vertical Settlements of Italian Masonry Building Stock for SHM Applications

Structural health monitoring plays a crucial role in ensuring the safety and reliability of masonry structures, by providing continuous and real-time monitoring of their structural behavior and identifying any potential issues or anomalies before they become critical. The measurement of vertical displacements (by means of mechanical gauges, optical instruments or even satellite-based interferometry) in masonry structures due to settlements provide useful information for the assessment of the vulnerability of existing masonry buildings. This paper aims to define a preliminary range of critical vertical displacements that activate in-plane local damages in masonry walls in terms of flexural and shear failure, for monitorability. In particular, flexural, diagonal shear and sliding local mechanisms are analyzed in this paper. Large scale analyses have been performed assuming simplified models where materials, loads and geometrical information of masonry structures are based on main Italian databases. Building models are generated by means of Monte Carlo analyses in order to simulate the behavior of Italian masonry buildings. The analysis results allow to provide preliminary fragility curves based on maximum likelihood estimation method.

Towards a better understanding of 3D heat flow in masonry walls

Towards a better understanding of 3D heat flow in masonry walls

The Safe Insulation from the Inside as a Solution to the Energy and Climate Crisis

Abstract During the time when the European Union is facing an energy crisis, it is essential to understand ways to overcome it more easily. As one of the consuming sectors, buildings play a crucial role in improving energy efficiency. Therefore, one of the ways to fight with energy crisis and high energy consumption in buildings is insulation from the inside. This study assesses the hygrothermal performance of masonry walls with 9 interior insulation systems (mineral wool with vapor barrier, XPS, PIR, cork, expanded cork, aerogel blanket, wood fibre plates, perlite board) exposed to different external conditions in the climate chambers. Masonry walls were tested in a steady cycle with cold box temperature 18 °C and 40 % RH), a dynamic cycle that follows daily fluctuations, a dynamic cycle with rain. Also, an identical simulation of the hygrothermal process was carried out in the DELPHIN software to compare results of both testing methods. The temperature between the thermal insulation layer and the brick wall in all thermal insulation systems is approximately 7-8 hours behind the temperature of the outdoor climatic chamber. A dynamic cycle with rain simulation has a significant impact on the hygrothermal behaviour of thermal insulation systems. The study provides valuable data on hygrothermal processes in different wall insulation systems from the inside.

Seismic retrofitting of an existing hospital with external steel brace

Earthquakes may cause serious damage to buildings and result in heavy losses to society, therefore, it is necessary to enhance the seismic capacity of existing buildings via structural retrofitting. The traditional retrofitting approaches are based on the component-level, but their improvement effect for the overall structure is not obvious. Until now, the seismic retrofitting technology can be generally divided into three types. The first is strength-improving type, the second is ductility-improving type, and the third is seismic dissipation/isolation type. Commonly a combination of these three types is used in retrofitting solutions. Most of them are focused on member based or component-level improvements of strength and/or ductility applied to poorly reinforced concrete walls or columns and masonry walls. Meanwhile, the weak element of the existing structure can be strengthened by external sub-structures as steel frames to make the overall structural capacity or stiffness more uniform. In addition, because the construction is an external operation, it can achieve non-disturbing retrofitting without affecting the normal use of the inner structure, which is of great practical significance and social benefits for lifeline projects such as schools and hospitals that cannot be interrupted. In the present case study, the efficiency of a seismic retrofitting with external steel frame of the university hospital Zurich (USZ) will be discussed. The original 3-story reinforced concrete building with a rectangular floor plan of 44m x 24m was built in 1966. Subsequently, in 1970, the building was extended by 4 floors with a composite steel structure. On the roof floor there is a helipad for emergencies. The stiffening steel structure was connected to the building with post-installed anchors. The first results of a response spectrum analysis showed major deficiencies in terms of horizontal and torsional stiffness, so that a strengthening measure became necessary. The results were verified by means of a push-over analysis, which showed that the measure applied was very effective. Finally, the structural design and the connection details to the existing concrete structure are shown.

Development and application of the truss method on masonry walls to determine the in-plane behavior: A parametric study

Development and application of the truss method on masonry walls to determine the in-plane behavior: A parametric study

Numerical model for the cyclic behaviour of a rubble stone masonry wall with opening and reinforcement

Numerical model for the cyclic behaviour of a rubble stone masonry wall with opening and reinforcement

Assessment of reinforced overlay for masonry retrofitting: Lime vs cementitious plaster

Reinforced overlay is a very common retrofitting technique adopted in existing masonry buildings to improve their performance under seismic action, both in-plane and out-of-plane. The most traditional and widespread approach considers the use of cementitious mortar as plaster with steel meshes as reinforcement. However, cementitious materials may raise compatibility problems with the base material and sustainability issues, thus the use of lime mortar should be preferred. This paper presents the results of an experimental program aimed at assessing the contribution of the reinforced plaster strengthening system in increasing the load carrying capacity of masonry walls, comparing the performance of cementitious and lime mortar plaster. Cyclic diagonal compression tests were performed under displacement control. Unreinforced specimens were also tested as reference for the improvement evaluation. The results showed an improved performance with respect to the unreinforced ones for both the materials (cementitious and lime mortar), in terms of both strength and deformation capacity. The peak load seemed to be not significantly affected by the type of plaster, while higher displacement at the ultimate load was observed in case of lime mortar. Finally, an analytical method formulated to predict the strength of walls retrofitted with cementitious reinforced plaster was applied to check its validity also in case of lime-based plaster.

Numerical model for the cyclic behaviour of a rubble stone masonry wall with opening and reinforcement

Numerical model for the cyclic behaviour of a rubble stone masonry wall with opening and reinforcement

Failure Mechanism of Confined Masonry Wall under Pushover Load

The confined masonry wall has various performances and failure mechanisms under earthquake excitation. This excitation, which is applied to the specimen in laboratory tests, can be simplified by conducting pushover loading. This research aims to exhibit the capacity and failure mechanism of confined masonry walls due to pushover loading that was applied on the top of the specimen. The pushover load was applied to the full-scale specimen with the size of 3 m x 3 m. The specimen failed due to bed-joint sliding failure with the maximum pushover load of 34.716 kN. The crack was observed on the contact between the bottom reinforced concrete tie-beam and the brick masonry wall. Thus, the vertical bars that connect the beam and the wall are essential to apply to the tie-beam to hold the shear force on the area.

Horizontal stiffness of masonry walls infilled frame

Walls used to fill a frame structure may serve non-load bearing (visual, acoustic or fire separation) or load bearing and stiffening functions which provide geometrical stability of a structure. They are shear walls without any vertical load from higher floors. This paper proposes an algorithm for determining stiffness of a singular frame area, taking into account standards CSA S304.1-04, FEMA 306 and FEMA 274. An attempt was made to cover all valid standards (EN 1996-1-1:2010 and prEN 1996-1-1:2017) applied for designs.

Flanges' Impact on Persian Historical Masonry Walls: Modeling Safety Factors

Flanges' Impact on Persian Historical Masonry Walls: Modeling Safety Factors

Hydrothermal performance of wooden beam on solid masonry with capillary-active internal insulation

With the increasing requirements for the energy performance of buildings, there is a demand for internal insulation systems in buildings where it is not possible to apply an external insulation system for legislative reasons. Currently, there has been an upsurge in the development of diffusion-open insulation materials whose properties can compensate for the risks of damage to solid masonry walls insulated with traditional diffusion-closed internal insulation systems. The properties of diffusion-open systems are already well known. This paper focuses on the simulation of the thermal moisture behaviour of a detail of a timber beam embedment in a wall with capillary active thermal insulation in cold climatic conditions of Central Europe.

Structural behaviour of unbonded post-tensioned masonry walls with threaded rods in clay block

Structural behaviour of unbonded post-tensioned masonry walls with threaded rods in clay block

Verifying the shear load capacity of vertically reinforced masonry walls by the VRd–NEd interaction diagram

This paper describes principles of verifying load capacity of reinforced masonry walls subjected to horizontal and vertical loading in accordance with EN 1996-1-1:2010 and the draft version of Eurocode 6 (prEN 1996-1-1:2017), These standards specify three methods for positioning reinforcement: the V method only for vertical reinforcement, the VH method that includes both vertical and horizontal reinforcement, and the H method only for horizontal reinforcement. Each of them can be subdivided into cases a, b, and c which differ in the course of standard stresses at the wall edges. This paper focuses on the V method which refers to reinforcement that is positioned vertically. It also presents equations required to determine load-carrying capacity of cross-section against vertical load NEd with neglected vertical reinforcement. Examples of VRd – NEd interaction diagrams are included.

Influence of tensile strength on the load bearing capacity of tall reinforced masonry walls

Influence of tensile strength on the load bearing capacity of tall reinforced masonry walls

The role of in situ dynamic tests on model updating of existing R.C. infilled structures

Infill masonry walls are one of the most common non-structural elements worldwide adopted to create external and internal partition walls in reinforced concrete (RC) frame structures. Both in the design of new RC frame buildings and in the assessment of the existing ones, it is common practice to neglect the presence of infill walls that are only considered as added masses and loads. However, as revealed by earthquakes, the performance of this type of building can be significantly affected by the presence of infill walls according to their type and distribution in the plane and along the height. In last decades, often vibration-based tests have been adopted to investigate in-situ the influence of the non-structural elements on the dynamic behavior of buildings. This paper discusses the usefulness of the dynamic characterization of buildings based on the use of ambient vibration tests at different phases of rehabilitation works to highlight the role of internal and external infill walls. The case study is an existing RC framed building designed for gravity loads and containing unreinforced masonry infill walls. Three ambient vibration tests, i.e., on the as built structure, after the demolishment of the internal partition walls and after the partial demolishment of the external infill walls, have been carried out. The 3D finite element model of the building has been successfully updated based on the global modes identified by the in situ tests, pointing out the important role of the non-structural components for this type of building. The experimental tests have also allowed the monitoring of the evolution of the building modal properties during the main phases of rehabilitation works.

Procenjivanje ponašanja strukture zidova od cigli od reciklirane plastike pod monotonim i cikličnim opterećenjem

Introduction/purpose: This study evaluates the structural performance of masonry walls made from recycled plastic bricks under monotonic and cyclic loading. The purpose was to investigate the feasibility of using recycled plastic bricks as an alternative for masonry construction, focusing on their structural viability and potential environmental benefits. Methods: A simplified micro-modeling approach in Abaqus was employed to simulate the behavior of these walls. The plastic bricks were represented with solid elements, while the mortar joints were modeled through cohesive interactions. The numerical model underwent validation through a mesh sensitivity analysis and was subjected to vertical compression followed by horizontal loading. Results: The findings indicated a reduction in strength compared to traditional masonry materials. However, the study successfully captured the structural response and damage evolution of masonry walls under the specified loading conditions. Despite the reduced strength, the structural viability of recycled plastic bricks was strongly affirmed, and the behavior observed under load conditions was particularly informative. Conclusions:The investigation underscored the potential of plastic composite bricks in contributing to sustainable building practices. The outcomes validated the feasibility of incorporating plastic bricks into construction, highlighting their environmental benefits and sustainable implications. This study advanced the field of sustainable construction materials by demonstrating the practical application and benefits of using recycled plastic bricks.

Structural safety of existing masonry-tunnel-linings: a methodology derived from existing buildings approaches

Masonry linings were the primary solution for tunnels before the introduction of reinforced concrete. As a result, many tunnels with masonry linings have been in operation for over a century and may exhibit damage due to ageing and prolonged water infiltration. Currently, there are no specific regulations for the static verification of masonry tunnels. These tunnels share characteristics and problems with historic masonry structures such as bridges and building facades. Therefore, the scientific literature and normative references developed for masonry heritage structures were here considered. This work focuses on estimating the masonry strength of tunnel linings. To demonstrate the proposed methodology and the addressed problems, the ‘Giovi’ tunnel on the historic Genoa-Valle del Po motorway in Genoa, Italy was selected as an exemplary case. The masonry’s resistance is measured in situ using flat-jacks and estimated using methodologies proposed for both new and existing buildings. The comparison of these methodologies highlights the unique characteristics of tunnel linings, including thick mortar bed-joints and massive curved masonry walls, with only one free face.