Load-bearing Walls Research Articles

Physical and Mechanical Properties of Mortar Mixed with Paper Mill Waste

The industrial and construction sectors are experiencing continuous growth each year. Concrete, which is used as the main material in construction, is composed of cement, aggregate and water. Research on mortar and aggregate is carried out to create concrete according to the required specifications of certain buildings. However, 8% of global carbon dioxide emissions come from the cement manufacturing process which is one of the main materials in mortar. In the industrial sector, the paper industry is one of the top producers of waste, approximately 48 tonnes for every 100 tonnes of pulp produced. The main wastes of this industry include slaker grits, dregs, lime mud and fly ash which only end up in landfill. To address this problem, this research investigates the modification of mortar mix materials by utilising paper mill waste. Specifically, fly ash and grits are used as substitute for cement and fine aggregate, respectively. Results indicate that the density value of concrete decreased with the increase of fly ash mixture, and the compressive strength value of mortar with varying additions of 0%, 10%, 20%, 30%, 40% and 50% fly ash reached 7.42, 6.68, 6.18, 4.97, 3.93 and 2.97 MPa. The decrease in density and compressive strength with increasing fly ash content can be attributed to the lower adhesive power of waste compared to cement owing to its lower lime oxide content. The value of compressive strength samples 1, 2 and 3 belong to the N type, which can be used as load-bearing walls, while samples 4, 5 and 6 fall into the O type, which can be used as non-load-bearing and decorative walls in accordance with SNI 03-6882-2014 standards.

The Influence of Building Materials and Electrical Parameter Variability on Electromagnetic Wave Propagation

The article presents an analysis of the influence of building materials on the propagation of an electromagnetic wave and the values of the electric field intensity. The topics of the analysis were two types of walls (partition and load bearing) built of different building materials. Different variants of walls were considered due to the building material used: concrete, aerated concrete, solid brick, clinker bricks, and three types of hollow bricks. The requirements for structures in terms of wall thickness were taken into account. The article, using concrete as an example, also describes the influence of changes in the electrical parameters of the building material on wave propagation and the values of the field. The results concerning the influence of complex materials, such as hollow bricks, on the non-uniform distribution of the electric field were also included. Due to the different percentage share of ceramic mass in hollow bricks, the article discusses its influence on the values of the field, taking into account the variability of conductivity. The analysis was performed using the Finite Difference Time Domain (FDTD) method. The results were compared with the analytical solution. The analysis, among others, showed that with the increase in the ceramic mass in bricks, the electric field values are higher but result in an uneven distribution of the field. Using the example of hollow bricks used to build load-bearing walls, it was observed that a small modification of the hollows practically does not affect the field intensity (the difference is approx. 2%). When planning the installation of wireless networks, the best solution is walls made of ceramics with a large number of hollows, where the ceramic mass constitutes only approx. 30%. A multivariate analysis allows for a better understanding of field phenomena inside single-family homes.

Fire Resilience of Load-Bearing Wall Made of Hollow Timber Elements

During a fire load, a charred layer forms on the timber elements, which is a natural protection against fire, so that a certain level of fire resistance could be achieved by using elements with a larger cross-section. However, this modus of fire protection is not always suitable. One of the most commonly used fire protection systems are fire protection boards. In this work, a large-scale fire test was carried out on a protected load-bearing wall made of hollow elements under the effect of sustained mechanical loads and fire exposure. Different stages of charring were observed. The test was aborted at the 91st minute due to a decrease in the load-bearing capacity and integrity criteria. The allowable average temperature rise on the non-exposed side of the specimen (140 K) was not exceeded until the 91st minute of the test, and the allowable maximum temperature rise on the non-exposed side of the specimen (180 K) was not exceeded until the 90th minute of the test. The loss of specimen integrity occurred at the 90th minute of the test. For surfaces protected by fire-resistant panels, it should be considered that the onset of charring is delayed until a certain time. According to EN 1995-1-2, charring can start before the fire protection is removed, but at a lower charring rate than the rates up to the time of failure of the fire protection. The expression proposed in EN 1995-1-2 shows relatively accurate results for certain systems and thicknesses of fire protection linings. However, it does not consider the presence of more than one lining layer or the full range of lining thicknesses themselves. For the wall described in this paper, the predicted failure time of the fire boards would therefore be 41.5 min, which is not consistent with the results of the experiment (51 min). The results of the calculation model according to EN 1995-1-2 did not fully agree with the results of the fire test on the protected load-bearing wall.

Advanced FE nonlinear numerical modeling to predict historical masonry vaults failure: Assessment of risk collapse for a long span cloister vault heavily loaded at the crown by means of a general-purpose numerical protocol

A simple and rapid approach aimed at the failure prediction of historical masonry vaults exhibiting stability issues under gravity loads is presented and applied to a paradigmatic case study in Italy. The benchmark structure under examination is a cloister vault with a considerable span, over which a slender load-bearing wall was built over the keystone. The urgency of a stability assessment to prevent failure is evident. The geometrical characteristics and some material information are obtained through in situ surveys. To assess its stability, determine the risk of collapse and propose a sound strengthening on the already cracked structure, a general numerical protocol that comprises five different 2D finite element models is proposed, each with different assumptions. In all models, blocks are discretized using 4-noded elastic elements in plane-strain, and mortar joints are modeled employing (i) orthotropic shell elements coupled with (ii) fragile cutoff bars. Model 1 considers only the arch without spandrels, unlike Model 2, which comprises them. The backfill is included in Models 3 and 4 using a system of equivalent forces mimicking both soil self-weight and the horizontal passive pressure, whilst Model 5 −used for validation purposes- employs elastic perfectly plastic elements that obey a Mohr-Coulomb failure criterion. Model 3 and Model 4 differ only in the dimension of the buttresses, which are thickened in Model 4 to improve the stability of the vault. Additionally, in Model 3 the effect of a possible retrofitting intervention is studied, having an insight into the role played by Carbon Fiber Reinforced Polymer (CFRP) strips positioned at the intrados and modeled with elastic perfectly ductile cutoff bars connected to surface nodes, thus ensuring a perfect bond between substrate and reinforcement. After a thorough analysis of the results, which focuses on both global force–displacement curves and failure mechanisms triggered, a safety assessment of the cloister vault is provided.

A Geophysical Investigation in Which 3D Electrical Resistivity Tomography and Ground-Penetrating Radar Are Used to Determine Singularities in the Foundations of the Protected Historic Tower of Murcia Cathedral (Spain)

This study presents a procedure in which 3D electrical resistivity tomography (ERT) and ground-penetrating radar (GPR) were used to determine singularities in the foundations of protected historic towers, where space is limited due to their characteristics and location in highly populated areas. This study was carried out on the Tower of the Cathedral “Santa Iglesia Catedral de Santa María” in Murcia, Spain. The novel distribution of a continuous nonlinear profile along the outer and inner perimeters of the Tower allowed us to obtain a 3D ERT model of the subsoil, even under its load-bearing walls. This nonlinear configuration of the electrodes allowed us to reach adequate investigation depths in buildings with limited interior and exterior space for data collection without disturbing the historic structure. The ERT results were compared with GPR measurements and with information from archaeological excavations conducted in 1999 and 2009. The geometry and distribution of the cavities in the entire foundation slab of the Tower were determined, verifying the proposed procedure. This methodology allows the acquisition of a detailed understanding of the singularities of the foundations of protected historic towers in urban areas with limited space, reducing time and costs and avoiding the use of destructive techniques, with the aim of implementing a more efficient and effective strategy for the protection of other tower foundations.

Influence of rubber aggregates from the recycled tires on the physico-mechanical and durability properties of compressed earth blocks

To meet sustainable development goals, global policies are strongly oriented toward valorizing alternative resources such as local materials and waste from different sectors of activity. This study aims to evaluate the influence of adding rubber aggregates from used/recycled tires (GPU) on the physico-mechanical and durability properties of compressed earth bricks (CEB). The CEB were made with an earthen matrix containing 8% cement, and 0 to 2% mass of GPU. The CEB were cured under ambient conditions (30±5°C) for 28 days. The results showed a real improvement in physical and mechanical performance and durability indicators of CEB with increasing GPU content. The apparent density changed slightly from 1697 kg/m3 to 1733 kg/m3. Total water absorption decreased from 21% to 19% with a slight decrease in water-accessible porosity from 35.7% to 33.1%. The capillary absorption coefficient at 10 minutes also decreased from 14 g/cm2.min1/2 to 10 g/cm2.min1/2 The increase of 29% was noted on the compressive strength in the dry state ranging from 3.5 to 4.5 MPa and of 60% on the compressive strength in the wet state ranging from 1.1 MPa to 1.7 MPa. This resulted in the improvement of the structural efficiency coefficient by 27% ranging from 2080 to 2651 Pa.m3/kg. Abrasion resistance coefficient increased more than 50% ranging from 10.8 to 16.9 cm2/g. By comparing the results to the normative references, the CEB containing GPU can be classified as CEB usable in load-bearing walls in a dry environment and resistant to abrasion.

Mechanics-based machine learning for failure classification of load-bearing walls

This paper presents novel methodologies that combine analytical mechanics with artificial intelligence to classify the failure mode of reinforced concrete walls under lateral loading. The adequacy of existing approaches is examined, including design equations and established machine learning algorithms, against experimental datasets consisting of 330 specimens. Findings indicate that the machine learning algorithms outperform the empirical design equations in terms of failure mode classification; however, the former lacks physical interpretability. To address this limitation, a new concept is proposed by integrating analytical and computational platforms for identifying attributes that dominate the failure characteristics of the walls. Non-dimensional features are derived and substituted into the machine learning algorithms. The aspect ratio of the walls and the amount of vertical rebars in boundary elements are found to be salient factors when categorizing failure modes, followed by the amount of horizontal rebars in the web. Through the application of decision boundaries stemming from the mechanics-based machine learning protocol, design recommendations are suggested to effectively classify the failure mode of load-bearing walls.

Experimental insights into the seismic behaviour of flanged URM walls

Considerable attention has been given to understanding and modelling the seismic response of unreinforced masonry piers with rectangular cross-sections. However, the seismic performance of load-bearing masonry walls with flanges, commonly found in actual building configurations, remains less explored. This study investigates the behaviour of flanged walls through cyclic quasi-static tests on four full-scale C-shaped specimens comprising two primary seismic-resistant walls (webs) interconnected by a single flange. The construction of the specimens varied: two were built using standard solid calcium-silicate bricks with general-purpose mortar, while the other two utilised large-sized calcium-silicate blocks with tongue-and-groove interlocks and a thin layer of cement-based adhesive mortar. All specimens were subjected to cyclic horizontal loading parallel to the webs under consistent overburden load and double-fixed boundary conditions. The primary variable in testing the two walls of each type was the number of cyclic loading repetitions. This paper initially describes the key characteristics of the wall specimens, including geometry, construction details, and mechanical properties. Subsequently, it details the instrumentation plan and test protocol, and summarises the major observations from the tests, illustrating damage evolution and hysteretic force-displacement response. The results highlight the effect of the flange on initial stiffness and lateral force resistance, as well as the influence of block type and loading repetitions on failure mode, displacement capacity, and energy dissipation. Additionally, the study demonstrates the impact of floor slab uplift due to in-plane rocking of the webs on the top boundary conditions and the out-of-plane stability of the flange.

Structural Performance of Bamboo Sandwich Panel (BSP) With Openings as Load Bearing Wall

Structural Performance of Bamboo Sandwich Panel (BSP) With Openings as Load Bearing Wall

ADHESIVE ABILITY OF GYPSUM-CONTAINING PLASTER COMPOSITIONS

The traditional material for the construction of buildings in the Northern Black Sea region is a cheap local stone ‒ limestone-shell rock. Most of the buildings in the central part of the city of Odesa, which are of historical and architectural value, are constructed of this material. With proper care and maintenance, these structures can perform their functions for hundreds of years, but as a result of shell rock moisture due to negligent operation and a number of other reasons, the supporting structures are damaged, followed by the collapse of the building. In many cases, the direct cause of the destruction of load-bearing walls is the damage or absence of the outer plaster layer. Repairing walls with cement compounds exacerbates the problem. The article discusses some aspects of the possible use of gypsum-based composite materials for repairing damaged walls of limestone-shell rock buildings. The requirements for the repair composition are formulated. The expediency of using gypsum as a binder for the repair plaster mixture for exterior repairs is substantiated. An ash-gypsum-cement composition was used to increase the water resistance of the plaster. Sufficient water resistance and vapor permeability of the proposed composition were confirmed. This paper presents the results of studying the adhesive strength of the contact of the developed composition with the surface of various materials. Methods and measuring equipment developed at the ODABA were used. The adhesion strength of the proposed mixture with the surface of shell rock is close to the standard strength. The use of the adhesive additive Ceresit CC 81 increases the adhesive strength of the joint of the proposed composition with shell rock by 1.5 ‒ 2 times. The optimal amount of the adhesive additive to be introduced will be determined by the results of a multifactorial experiment to study the effect of a complex of chemical additives of different functional purposes on the properties of the proposed repair composition.

Effects of burnt sawdust ashes from timber species on the strength properties of laterite-interlocking blocks

The most basic problem facing man is shelter, apart from food. This problem is acute in Ghana and other developing countries due mainly to the high growth rate of the population, inflation, unemployment and poor economic resources. Today in Ghana both middle and low income earners can hardly afford their own houses. From one point of view one can see that some of the materials used in building are of good quality and can last. The study aimed to partially replace ordinary Portland cement (oPc) with burnt sawdust ash (BSDA) from different timber species (Wawa, Mansonia, Teak, Odum, Ceiba, Essah and Mahogany) in making interlocking laterite blocks by replacing 0–30 wt %. Mix proportion was 1:8 (cement + BSDA: laterite) with a 0.60 water-to-cement ratio. 528 specimens of size 185 mm × 220 mm × 120 mm were produced and cured at normal temperature and humidity under shady and sunny conditions for 7, 14, 21 and 28 days. Compressive and tensile strengths were subsequently evaluated. However, an initial strength increase was observed with curing time for specific wood species (Wawa, Mansonia, Teak, Odum, Essah, Ceiba, and Mahogany). Notably,Wawa, Mansonia and Odum ash exhibited superior strength performance at 10–20% replacement levels, potentially satisfying relevant standards for load-bearing wall construction. This research suggests that up to 10% replacement with Wawa, Mansonia or Odum BSDA presents a promising eco-friendly approach for partially substituting oPc in LIB production.

Production-oriented approach for optimal mass-customisation of floor panel layouts in cross-laminated timber (CLT) buildings

PurposeThis study aims to develop a production-oriented approach for optimal mass-customisation of floor panel layouts in cross-laminated timber (CLT) buildings. The study enables meeting building clients’ unique floor plan requirements at an optimal cost and simultaneously enhances manufacturers’ profit by minimising material and manufacturing process waste.Design/methodology/approachThe present research uses a hybrid approach consisting of field data collection, mathematical modelling, development of a Genetic Algorithm (GA) and scenario analysis. Field data includes engineered timber production information, design data and building code requirements. The study adopts the Flexible Demand Assignment (FDA) technique to formulate a mathematical model for optimising the design of mass timber buildings and employs GA to identify optimal production solutions. Scenario analysis is performed to validate model outputs.FindingsThe proposed model successfully determines the load-bearing wall placement and building spans and specifications of floor panels that result in optimal production efficiency and the desired architectural layout. The results indicate that buildings made of a single category of thickness of panels but customised in various lengths to suit building layout are the most profitable scenario for CLT manufacturers and are a cost-effective option for clients.Originality/valueThe originality of the present study lies in its mathematical and model-driven approach towards implementing mass customisation in multi-storey buildings. The proposed model has been developed and validated based on a comprehensive set of real-world data and constraints.

Choosing the Best Sustainable Prefabricated Building Systems Using the Analytical Network Process (ANP) Technique

Attention should be paid to prefabricated construction, as the consumption of raw materials in traditional construction is large and affects the country's resources and economy. Sustainable prefabricated building systems in Iraq suffer from a clear weakness in management due to the use of old methods and a lack of focus on important management criteria. This research addresses this issue by modeling the analytical network process (ANP) technique to select the best types of systems. By reviewing the general literature, 80 indicators were identified within the 12 relevant categories. These indicators formed the basis of a closed questionnaire distributed to 90 experienced respondents. Three prefabricated building systems were identified based on the structural composition (load-bearing wall system, frame system, and box system). The expert questionnaire was analyzed using the ANP technique and the Sustainability Index (SI) for each system was found using the Excel program and it was found that the best sustainable prefabricated building system is the box system. This research helps to improve the management of prefabricated building projects and increase speed, quality, pollution, and reduce the cost of housing in Iraq, which suffers from high costs

Experimental and Numerical Characterization of the In-Plane Shear Behavior of a Load-Bearing Hollow Clay Brick Masonry System with High Thermal Performance

Modern masonry systems are generally built with hollow clay bricks with high thermal insulating properties, fulfilling the latest sustainability and environmental criteria for constructions. Despite the growing use of sustainable masonries in seismic-prone countries, there is a notable lack of experimental and numerical data on their structural behavior under lateral in-plane loads. The present study investigates the in-plane shear behavior of load-bearing masonry walls with thin bed joints and thermal insulating hollow clay blocks. Shear-compression tests were performed on three specimens to obtain information about their shear strength, displacement capacity and failure modes. The experimental characterization was supplemented by three shear tests on triplets, along with flexural and compression tests on the mortar for the thin joints. Furthermore, two Finite Element (FE) models were built to simulate the shear-compression tests, considering different constitutive laws and brick-to-brick contact types. The numerical simulations were able to describe both the shear failure modes and the shear strength values. The results showed that the experimental shear strength was 53% higher than the one obtained through Eurocode 6. The maximum shear load was found to be up to 75% greater compared to similar masonry specimens from the literature. These findings contribute to a better understanding of the potential structural applications of sustainable hollow clay block masonry in earthquake-prone areas.

Damage assessment method of clay brick masonry load-bearing walls under intense explosions with long duration

The vulnerability of clay brick masonry load-bearing (CBML) walls under low-intensity explosions has been extensively investigated. In recent years, large-scale explosions have raised wide concerns about the destructive effect of intense explosions. Intense explosions induced by large TNT equivalent explosives usually cause severe damage to building structures within several kilometers. Although the damage of building structures under intense explosions and normal low-intensity explosions might be different, the differences have yet received any attention in previous studies. Therefore, this study numerically investigates the dynamic performance of CBML walls under intense explosions with long duration (IELD). Firstly, the numerical model is validated by reproducing experimental records. Then the verified model is utilized to investigate the dynamic response and dynamic modes of CBML walls under IELD. Based on the identified failure mechanism, the effects of several parameters such as axial compression ratio, compressive strengths of masonry materials and wall geometry on the damage degrees of CBML walls are analyzed in detail. The damage index based on the residual axial loading capacity of CBML wall is proposed for damage evaluation. The damage assessment method is established for CBML walls under IELD, which can help to evaluate the damage level of clay brick masonry structures under far-field intense explosive scenarios.

Making the Hypar Up pavilion: (in)efficiencies of upcycling surplus timber products

This paper illustrates the design and fabrication processes of the Hypar Up pavilion, which served as a proof-of-concept to demonstrate the viability of a design-to-fabrication workflow for complex yet modular architectural geometries that utilise small and planar timber offcuts geometries discretised as Planar Quadrilateral (PQ) meshes. By integrating computational design and optimisation with efficient manufacturing processes, this research highlights the technical challenges of repurposing materials with unknown characteristics, notably detailing solutions, and evaluates the efficiency of design-to-manufacturing workflows with surplus timber products, using a quantitative cost analysis of the fabrication and assembly phases. While exploring the potential of repurposing scrap wood into hypar-shaped modular construction components, this work expands on existing research on segmented shells and investigates methods and means to move beyond the use of shell structures as monolithic and static artefacts. The pavilion is intended as a 1:1 modular prototype that can be resized to accommodate different dimensions of the timber panel offcuts and potential applications to be tested in future applications, such as load-bearing walls and facade retrofitting.

The Impact of Wall Structure with Photovoltaic Function on Prefabricated Buildings

The wall structure is the main load-bearing component of the prefabricated building, which plays an important role in the stability and aesthetics of the building. With the deepening of the application of new energy in the construction field, the application of photovoltaic wall with photovoltaic function is becoming more and more extensive. However, there is still controversy about whether the photovoltaic function can meet the requirements of the building. On this basis, this paper discusses the wall structure with photovoltaic function in depth, and analyzes its energy consumption, heat preservation, ventilation and cost indicators. The results show that the wall structure of photovoltaic function can improve the aesthetics of prefabricated buildings, meet customer demand rate of more than 75%, save energy consumption by 25%~30%, increase indoor temperature by 1~3 degrees, and ventilate at 1.2 levels. It can be inferred that the load-bearing wall of photovoltaic function is suitable for prefabricated buildings and has the potential and role of vigorous development.

Performance of structural insulation panels under eccentric axial and racking loads with varying opening ratios

Structural insulation panels, which are actively applied in the housing market in North America and Europe by utilizing wood, an eco-friendly material, as the main material, are composed of OSB (Oriented Strand Board), EPS (Expanded Polystyrene), and SPF (Spruce-Pine-Fir), which is used as a connection between the panels. Structural insulated panels are used as a load-bearing wall to resist external forces without installing separate columns. The production of structural insulation panels consists of applying adhesive to both sides of EPS, which acts as an insulation material, and pressing wood boards (OSB), which exert strength as a structural material. The OSB on the outside resists compressive and tensile forces, while the EPS on the inside resists shear forces. The joints and openings of the structural insulation panels are reinforced with SPF (Spruce-Pine-Fir) structural wood. When structural insulated panels are used as an exterior wall structure, the installation of openings is essential. Based on the opening size that is popularly used in wooden structures, the performance evaluation of structural insulation panels under eccentric axial load and repeated lateral load due to the reduction of the cross-sectional area by installing the opening was carried out, and the behavior analysis through variable analysis and comparison analysis with the design equation was carried out.

The Jajarkot Earthquake: Revealed the Vulnerability of Load Bearing Structures in Western Nepal

The Jajarkot Earthquake, which occurred on 3rd November, 2023 of magnitude 5.7 (Mw) exposed Nepal’s longstanding vulnerability to seismic activity. This paper presents damage assessments derived from both on-site field observations and secondary resources to evaluate the damages sustained by load bearing masonry structures. In the region, 95% of the building structures are based on masonry construction. The damage status of structures in Jajarkot and Rukum East highlighted that about 50% of the building structures were partially and complete damage. The evaluation encompassed various aspects, including the types, mechanisms, and underlying causes of the damage incurred by structures. The observed damage was categorized using an established catalogue originally developed for the identification of failure mechanisms and vulnerability assessment. The common types of damage encompassed features like cracks in the load bearing external walls and corners, diagonal cracks originating from door and window corners, vertical out-of-plane displacement of external walls, collapse of external walls, and partial collapse of load bearing internal walls, fracturing of window and door lintels and complete collapse of structure. Some special forms of damage which was of new nature and distinct from those observed in prior seismic events such as the Gorkha earthquake included ruptures in the outer surfaces of loadbearing external walls, partial roof structure collapses, out-of-plane fragmentation or disintegration as well as rupture. The causes underlying this general damage were attributed to irregular bonding systems, weak mortar, stone block formation, size of stone blocks, absence of tie beams, weakly connected corners, insufficient connections of wall-roof and wall-floor systems, and differing internal wall systems. The mechanisms of damage varied based on the number and specifics of these causative factors, as well as certain structural attributes.

Identification of Structural and Non-Structural Defects of Load-Bearing Wall Systems in Low Rise Buildings

Identification of Structural and Non-Structural Defects of Load-Bearing Wall Systems in Low Rise Buildings