Wall Typologies Research Articles

Novel Sustainable Masonry from Ancient Construction Techniques by Reusing Waste Modern Tiles

The recycling and reuse of wastes, especially Construction Waste (CW), is a fundamental way for sustainability. The act of reusing is not a modern practice; as early as in Ancient Rome and even more during the Middle Ages, materials were already being taken from existing buildings in order to reuse them in different ways. Starting from these general considerations and taking inspiration from specific construction techniques found in some Roman and Romanesque masonries made by unbroken tiles and tile fragments, two novel sustainable masonry constructive techniques are proposed here. They are composed of modern U-shaped tiles and their fragments so as to use CW. Monotonic and cyclic compression tests were performed so as to determine their main mechanical characteristics, such as compressive strength, Young’s modulus, and failure mode, and a first attempt at establishing their possible use in the construction sector is sought. A comparison with the literature values from other constructive techniques with similar values was also performed. It results that both the wall typologies showed satisfactory mechanical properties (i.e., compressive strengths are in the range of 1.28 ÷ 2.27 MPa), provided that their use is restricted for constructions of moderate dimensions.

Investigation of the Influence of Design Parameters on the Strength of Steel–Concrete Composite Shear Walls by Finite Element Simulations

In this paper, the influence of design parameters on the strength of steel–concrete composite shear walls is investigated by means of finite element (FE) simulations. The shear wall typology studied in this paper consists of multiple composite plate shear wall-concrete encased on one or both sides of the plates. The FE models include contact technology to capture debonding between concrete and steel, tensile cracking in concrete, and large deflection theory involving local instabilities. Some design parameters considered in this work are the height-to-width ratio of the steel plates and their thickness, number of steel plates, the cross-section of the columns, and the height-to-width ratio of the shear wall. Furthermore, a sensitivity analysis of the normalised shear strength per unit cost of structure for these design parameters is also studied. Our numerical predictions are validated successfully with experimental data reported in the literature, revealing the predictive capabilities of the model. The present results provide further insight into the structural behavior of steel–concrete composite shear walls and pave the way for the future development of more efficient and innovative steel–concrete composite systems.

In-plane flexural behavior of hollow brick masonry walls with horizontal holes

Recent seismic events proved that buildings built with hollow brick masonry walls performed quite poorly when subjected to horizontal actions. To provide insights, an experimental study was conducted to evaluate the flexural behavior of existing slender masonry walls built with clay hollow bricks with horizontal holes and cement-based mortar. Two full-scale specimens were designed and built to exhibit an in-plane rocking behavior when subjected to cyclic horizontal loads such as those induced by an earthquake; the pivotal aim of the experimental test is to assess the actual ductility of such a mechanism for this specific wall typology. The test results show that, unlike other masonry wall typologies exhibiting ductility in the case of in-plane flexural mechanism, this construction typology performs quite poorly under horizontal loads also in the case of rocking, with very little deformation capacity, which reduces by increasing the compressive strength of the mortar. A sudden failure was observed for quite reduced drifts in the experimental tests; failure was associated with the brittle crushing of the pier toe, in which compressive stresses were concentrated. The brittle collapse mechanism also entails the inability of the wall to further sustain the vertical loads, once the ultimate in-plane flexural capacity is reached. A numerical study was carried out; the finite element model was validated against the experimental results. The comparative assessment showed that the finite element model accurately predicts the structural behavior, lateral strength, and failure mechanism of the specimens. Parametric analyses on the validated finite element model (FEM) were carried out to further investigate the structural behavior of different wall layouts or mechanical properties. Finally, a simplified bilinear behavior-curve is proposed to model the flexural response of slender walls, which can be specifically implemented when addressing an equivalent frame approach in the seismic vulnerability assessment of existing buildings built with the analyzed construction typology.

The First 3D-Printed Building in Spain: A Study on Its Acoustic, Thermal and Environmental Performance

The first 3D-printed building in Spain is the object of this study, and it is presented and physically described herein from different points of view. This study combines on-site measurements, simulations, and a life cycle assessment to assess some relevant parameters concerning the acoustic, thermal and environmental performance of the 3D-printed house. The main objectives are to analyze whether the house complies with the acoustic and thermal regulations and to assess whether it can act as a sustainable alternative to conventional masonry construction, especially when time plays an important role. The build surface (3D prototype) of the house is approximately 23 m2. The internal space includes a living room (12.35 m2), a bedroom (7.36 m2) and a bathroom (3.16 m2). The total surface of the house is 22.87 m2 and it has a volume of 64.03 m3. The acoustic insulation was measured according to the ISO 9869-1:2014 standard. In terms of the acoustic insulation, the sound reduction index was tested following the guidelines of the ISO 140-5:1999 standard. Additionally, the study includes a comparative life cycle assessment comparing the 3D-printed façade with two conventional wall typologies. The 3D-printed house displays an excellent thermal performance, with a measured thermal transmittance of 0.24 Wm−2K−1, suitable for all Spanish climate zones. Regarding the acoustic insulation, the measured global sound reduction indexes of the façades range from 36 to 45 dB, which is adequate for areas with noise levels of up to 75 dB. The environmental results indicate that 3D-printed façade manufacturing emits 30% more CO2e than a façade constructed using concrete blocks and 2% less than a masonry block wall. Overall, this study shows that, in addition to its multiple advantages in terms of the construction time, the studied 3D-printed house has similar acoustic, thermal and environmental traits to the most common construction typologies. However, it cannot be considered a sustainable construction method due to its high amount of cement.

Numerical investigation into the performance of cold-formed steel framed shear walls with openings under in-plane lateral loads

Recently, there has been a resurgence in the adoption of lightweight cold-formed steel (CFS) profiles as structural elements in low- to mid-rise modular construction. Typically, openings for doors and windows are ever-present in the front and rear elevations where shear walls find their optimal position to ensure lateral stability in CFS modular structures. These architectural design features translate into reduced areas for lateral load resistance throughout the structure. This paper discusses the performance of CFS framed shear walls with openings under lateral loads through experimental tests and numerical simulations. Overall, three shear wall typologies were designed for force transfer around opening (FTAO) and tested under monotonic lateral loads (nine tests in total). An advanced finite element analysis (FEA) modelling protocol was elaborated to simulate the lateral behaviour of the tested walls as well as to interpret the physical tests. Evaluation of the numerical and experimental test results validated the FEA modelling protocol that demonstrated to be reliable in predicting the strength and stiffness as well as failure modes of CFS framed shear walls with openings subjected to lateral loads. The effects of sheathing-to-CFS screw spacing, the size and number of openings as well as the geometry of sheathing panels on the lateral behaviour of CFS framed shear walls were scrutinized. Subsequently, load-path mappings from the developed modelling protocol enabled the analysis of the flow of the in-plane lateral loads from the sheathing-to-CFS screw level into the wall system level where insight into a more efficient lateral design of CFS framed shear walls with openings have been highlighted. The obtained results shed light on the conservative nature of the AISI S400-15 design provisions for Type II shear walls and that of the perforated design methods available in the literature.

The role of the openings in the out-of-plane behaviour of masonry infill walls

This research work aims to present an experimental study concerning the effect of the openings in the out-of-plane (OOP) behaviour of masonry infills in RC buildings. The experimental campaign comprises the OOP testing of three full-scale infill walls made up of horizontal hollow clay bricks, two of them with a central window and the remaining one with a central door. One of the specimens with a central opening was first subjected to a previous in-plane test and, after that, the damaged wall was subjected to an OOP test. All the tests consisted of applying a loading–unloading-reloading history of imposed displacements in the OOP direction through a uniformly distributed load. An innovative setup was used and adapted for each wall typology. The results are presented in terms of OOP force–displacement responses, damage evolution, relative stiffness and energy dissipation capacity. Finally, the test results are compared to each other to assess the effect of: i) the area of the opening; and ii) the previous damage. It was found that the openings reduced the maximum strength of 30% for undamaged panels, and it occurred for lower displacement demands. The increase of the opening area did not affect the peak load; however, it reduced their energy dissipation capacity significantly. The energy dissipation capacity reduced from 42% to 70%.

Mould Growth Models and Risk Assessment for Emerging Timber Envelopes in Australia: A Comparative Study

Timber envelopes provide multiple benefits in reducing both operational and embodied energy environmental impacts in construction. However, when poorly designed, they may incur in high risk of mould growth, affecting both building performance and occupant’s wellbeing. This research investigates the risk of mould growth associated with emerging timber envelopes in Australia, particularly looking at mass-timber and timber-framed wall typologies. The study compares the use of two mould growth assessment models: the VTT and the IBP biohygrothermal. Results provide relevant insights on both current design approaches and performance assessment methodologies. Whilst the study is based on Australian practice, conclusions have international relevance and applicability.

Updating mechanical properties of two-leaf stone masonry walls through experimental data and Bayesian inference

The work presents the study carried out to build a database of mechanical properties related to the most recurring two-leaf stone masonry wall typologies. The main objectives of this study are: (1) to perform a systematic review of experimental studies (2) to apply a data fusion technique, based on a Bayesian framework, to update the selected mechanical parameter using the information stored in the final database.The results obtained are compared to the ranges proposed in current standard and guidelines. Therefore, the outcomes presented in this work can provide a valuable support in practice-oriented engineering activities addressing the assessment of existing buildings.

A Comparative Study of the Thermal Performance of Plastic Bottle Wall against Traditional Composite Brick Wall Typologies

According to the container recycling institute, nearly a million plastic beverage bottles are sold every minute around the world. Plastic bottles are considered as an urban junk, however, it has shape characteristics which make them usable in construction in lieu of conventional bricks. This research promotes the use of recycled plastic bottles as eco-bricks by substituting it with the typical construction bricks. It evaluates the thermal performance of sand filled plastic bottle-walls in a comparative analysis with traditional composite brick walls. The thermal performance of the plastic bottle walls was evaluated through COMSOL® Multi-physics and the results are noted.

Development of Retrofitting Solutions: Remedial Wall Ties for Masonry Enclosure Brick Walls

The external envelope walls of a significant percentage of the residential building stock in Southern European countries is commonly constituted by infill masonry walls. However, thousands of square meters of this masonry wall typology presents severe issues of cracking and instability, related to the incorrect and deficient support conditions of the outer brick panel of the double-leaf wall solution. In this work, an experimental campaign divided in two phases has been performed to evaluate the effectiveness of two different remedial wall ties retrofitting techniques (Solution A and Solution B) used for double leaf horizontally hollowed clay brick masonry façades. The first phase of the experimental campaign was performed on 120 isolated specimens of horizontally hollowed clay bricks, resorting to post- and pre-NP EN 771-1 brick exemplars (that is, new and pre-existent aged bricks, respectively), as well as on 4 square wallettes, with a side length of 1.20 m, considered as representative of a real scale scenario, for evaluating the two remedial wall ties retrofitting techniques. The second phase of the experimental campaign was performed to fully characterize the different failure types as well as the slipping phenomena observed in the first phase of the experimental campaign, focusing solely on the retrofitting technique Solution B and comprises 24 tests performed on isolated specimens, resourcing to new and pre-existent aged bricks as well. The results obtained by the use of these techniques revealed an average anchorage strength value ranging from 0.25 to 2.5 kN for each tested tie-bar. Solution B reveals an increase of double of the anchorage strength value in comparison to Solution A. In this sense, the global results revealed a suitable applicability of both retrofit studied solutions.

Assessing the challenges affecting the investigative methods to combat online child exploitation material offenses

Abstract Technology has dramatically simplified the process of engaging in a variety of crimes, particularly the distribution of child exploitation materials, or CEM. The ability to share photos and video across the globe through high speed Internet connections and mobile devices has made it easy to access CEM. At the same time, technology has complicated the investigation of these crimes by increasing the scope of spaces to police that is operated by public and private entities. This review outlines the challenges inherent in the investigation of CEM in the context of Wall's typology of policing online spaces, recognizing formal and informal sources of social control. The methods used by law enforcement to affect CEM are discussed, highlighting current limitations inherent in online investigations; namely the sheer scope of the problem and the nexus between rapid technological advances and commensurate legal responses, among others. The review highlights the need for engagement from industrial and non-governmental organizations in addition to law enforcement in order to facilitate the investigation of CEM offenses; strategies to improve the state of policing CEM need to include integrating public and private sphere responses to these offenses.

In-Situ Determination of Buildings’ Thermo- Physical Characteristics: Method Development, Experimentation, and Computation

In-Situ Determination of Buildings’ Thermo- Physical Characteristics: Method Development, Experimentation, and Computation

Quality Control of the Thermal Properties of Superstructures in Accommodation Spaces in Naval Constructions

The application of passive design strategies in ships, such as the use of superstructures with high thermal insulation, allows the energy demand of heating, ventilation, and air conditioning systems to be reduced. There is a knowledge gap in the scientific literature on the possibilities to thermally characterize superstructures. Knowing such possibilities would make a methodology available for the quality control of naval constructions and for the inspection of the appropriate state of insulations in existing ships. For this purpose, a total of three different typologies of ship superstructures were monitored, and the data obtained were analyzed by using various existing approaches for the thermal characterization of façades: the heat flow meter method and temperature measurement methods. The results showed that the heat flow meter method constitutes a valid methodology to obtain representative results. In addition, guaranteeing a thermal gradient dependent of the wall typology and placing probes in zones not influenced by thermal bridges ensure that representative results are achieved.

Towards the implementation of periodic thermal transmittance in Spanish building energy regulation

The recent development of the calculation methodology for dynamic thermal properties of buildings has opened new possibilities for reducing their energy demand; however, building codes still rely on the traditional static approach. This research aims at filling in this gap by exploring how periodic thermal properties can be implemented in the Spanish regulatory framework. For this purpose, 2,413 wall typologies were analysed in the two extreme climate zones as per the Spanish regulation pertaining to energy efficiency. Results show that the static U-value itself is not sufficient to optimize the energy demand of buildings, as for a single value of U variations of 4,000 kWh in the energy demand are expected. Regarding periodic variables, decrement factor and time shift were the most effective to minimize the energy demand, along with flexible limitations for the periodic thermal transmittance and the time shift. In warm climates, the former can be disregarded if the latter is greater than 15 h. The findings from this study disscuss the applicability of the static thermal transmittance and propose a methodology to select and limit periodic variables for the two most extreme climates in Spain.

Adaptations of the flat jack test for its application in cob walls

The single and double flat jack tests have been successfully applied for the first time in cob walls. This technique has been used for over 40 years in the field of cultural heritage conservation to investigate the levels of stress in different masonry and earthen wall typologies and to determine their mechanical properties [1]. Two standards [2–7] have been developed for the application of the technique in masonry walls and this paper presents the adaptation of those methods for its application in cob walls.•The control points have been pinned to the material instead of glued to the surface which has facilitated its installation and speed the process.•A timber frame has been fabricated, to which the cutting device has been supported and strapped, to facilitate the cutting of the slot thus obtaining a better-quality cut and a safety increase for the ring saw operator.•The connection of the hydraulics system has been slightly modified by connecting the pressure transducer next to the flat jack's inlet, instead of just after the pump, thus avoiding the recording of pressure peaks while manually pumping the oil.

In-Situ Determination of Buildings’ Thermo- Physical Characteristics

In-Situ Determination of Buildings’ Thermo- Physical Characteristics

Automation and optimization of in-situ assessment of wall thermal transmittance using a Random Forest algorithm

Reducing energy consumption and greenhouse gases emissions is among the main challenges of building sector. It is therefore crucial to know the characteristics of envelopes. There are experimental methods to determine thermal transmittance, but limitations are presented. By using techniques of artificial intelligence, this article solves the limitations of current methods by predicting correctly the thermal transmittance value of ISO 6946 and the building period of a wall with monitored data. The methodology used is extrapolated to any country: 163 real monitorings and 140 different typologies of walls have been combined to generate the dataset (22,820 items). The results show the optimal operation of the Random Forest algorithm because both the thermal transmittance of ISO 6946 and the building period are determined by using the most common methods: the heat flow meter method and the thermometric method. This study makes progress towards more automatized processes to characterize thermal transmittance.

Laboratory and In-Situ Measurements for Thermal and Acoustic Performance of Straw Bales

This paper investigates the performance of timber-framed walls insulated with straw bales, and compares them with similar walls containing expanded polystyrene (EPS) instead of straw bales. First, thermal conductivity, initial water content, and density of the straw bales were experimentally measured in a laboratory set-up, and the dependence of the thermal conductivity of the dry material on temperature was described. Then, the two insulation solutions were compared by looking at their steady and periodic thermal transmittance, decrement factor, phase shift, internal areal heat capacity and surface mass. Finally, the acoustic performance of both wall typologies was analyzed by means of in situ measurements in two-story buildings built in Southern Italy. The weighted apparent sound reduction index for the partition wall between two houses and the weighted standardized level difference for the façades were assessed based on ISO Standard 16283. The results indicate that the dry straw bales have an average thermal conductivity of k = 0.0573 W/(m·K), and their density is around 80 kg/m3. In addition, straw bale walls have good steady thermal performance, but they still lack sufficient thermal inertia, as witnessed by the low phase shift and the high periodic thermal transmittance. Finally, according to the on-site measurements, the results underline that the acoustic performance of the straw bale walls is far better than the walls adopting traditional EPS insulation. Overall, the straw bales investigated are a promising natural and sustainable solution for thermal and sound insulation of buildings.

Performance comparison between building insulating materials made of straw bales and EPS for timber walls

This paper studies the thermal and acoustic performance of straw bale walls used in timber-frame semi-detached houses recently built in Sicily (Southern Italy), and compares them to similar walls where expanded polystyrene (EPS) is adopted in place of the straw bales. In-situ measurements were carried out to analyse the acoustic performance of both wall typologies. The weighted Apparent Sound Reduction Index for the partition wall between two houses, as well as the weighted Standardized Level Difference for the façades were assessed based on the ISO Standards 16283. Moreover, the two insulating solutions were compared in relation to their steady and dynamic thermal performance. The results underline that the acoustic performance of the straw bale walls is far better than the walls adopting traditional EPS insulation. However, slight improvements are suggested to further increase the sound insulation properties of straw bales. On the other hand, EPS is a more effective thermal insulation even if straw bale walls comply with Italian standards. Finally, the dynamic performance of straw bales should be improved by increasing their density. Overall, the proposed straw bales used can be conveniently used in low-energy and n-ZEB buildings in warm and mild countries.

Mechanical and Typological Characterization of Traditional Stone Masonry Walls in Old Urban Centres: A Case Study in Viseu, Portugal

Essential for any intervention in existing buildings, a thorough knowledge of both structural and material characteristics is even more important in the case of traditional stone masonry buildings, due both to the variability of this technology’s properties and the degradation buildings might have sustained. In Portugal, a number of in situ and laboratory experimental campaigns has allowed us in recent years to expand the knowledge on the mechanical properties of stone masonry walls. Nevertheless, the existence of different wall typologies built with the same material necessitates that this characterization takes into account the various regional constructive cultures. This paper presents the results obtained through an in-situ characterization campaign carried out in the old urban center of Viseu, for which there is no information available in the literature. Granite stone masonry walls of two different buildings were analyzed and characterized considering their geometrical and material features, contributing to the identification of stone masonry typologies present in the city’s old urban center. Flat-jack testing yielded resistance and deformability parameters to be used both in safety evaluation and intervention design. The properties obtained can be said to be consistent with those deriving from other experimental campaigns, conducted in granite walls of different typologies, throughout the country. Simultaneously, relevant conclusions about the use of flat-jacks to characterize this type of stone masonry were drawn.