Search Results (36)

The failure behaviour of historic unreinforced masonry (URM) structures is strongly influenced by the properties of bricks and mortar. Over time, degradation processes compromise these materials, with significant effect on structural response and safety. Nevertheless, deterioration effects on the nonlinear behaviour of masonry have been only marginally investigated. This study investigates the mechanical behaviour and failure mechanisms of historic brick masonry with weak and irregular mortar joints, representative of Mediterranean traditional constructions. An extensive experimental programme was conducted on mortars, historic clay bricks, prisms, wallets, and triplet specimens, complemented by in-situ flat jack tests. Results confirm the critical role of mortar quality and joint irregularities in reducing compressive and shear strength and in influencing deformation capacity of historic masonry. The experimental findings served as a basis for the calibration of a Finite Element Model (FEM), subsequently employed to gain deeper insight into the governing failure mechanisms in a real study case. A critical discussion of compression and shear failure criteria is presented, focusing on historic masonry. Experimental and analytical comparisons show major discrepancies in classical criteria, especially with degraded mortars. The study shows that in historic masonry with weak joints, failure is often governed by compression rather than shear. Full article

This article presents the study of an architectural-constructive type located in Valencia: ribless brick vaults built with the “catalan” technique (one single brick plement approximately 5 cm thick). This is a very specific variant of the star-shaped vault, from the late 15th and early 16th centuries, of which we will examine a representative example: the vault that covers the entrance to the Mas Palace in Valencia. The methodology used is dual in nature: on the one hand, a historical study has been carried out to contextualize the typology, and on the other, a metric analysis of the Mas Palace vault has been carried out using laser scanning technology as a prominent tool. These two parts have finally been put into relationship, determining the formal correspondences that define the type, as well as the particularities of the built work. The main finding of the research is the consideration of this star-shaped vaults, not as a set of particular cases, but as a well-defined typology, which was widespread and successful in its context. We have also determined that its formal characteristics are not only due to aesthetic but also functional (stability and fire resistance) issues. This research, therefore, has allowed us to ponder the importance of a constructive solution that usually goes unnoticed and whose originality does not lie in the techniques used but in their original combination. Full article

Automation of the structural health monitoring process involves the use of successful methods for detecting defects and determining their critical characteristics. An efficient means of crack detection in composite materials is the ultrasonic method, but its application to determine critical crack parameters, such as depth in construction practice, is difficult or leads to large errors. This article focuses on machine learning methods usage to detect cracks in composite materials like brickwork. Ceramic bricks with various mechanical properties and with pre-grown cracks from 2 to 60 mm are considered. To understand the processes occurring during the ultrasonic pulse transmission, modeling was performed in the ANSYS environment. The brick is considered a porous medium weakened by a crack. Numerical modeling allows for the identification of the main features of the signal response and the determination of the amplitude-time range for different porosity and crack depth values. Using machine learning methods made it possible to solve two related problems. The first, binary classification, i.e., the presence or absence of a crack, is solved with 100% accuracy. The second is determining the crack depth. A neural network was built using an ensemble of decision trees. The accuracy of crack depth prediction is R² = 0.983, and the error in predicted values is within 8%. Full article

Texture regularity, for example, the repeating pattern of a carpet, brickwork, or tree bark, is a ubiquitous feature of the visual world. The perception of regularity has generally been studied using multi-element textures whose regularity is manipulated by the addition of random jitter to the elements’ nominal positions. Here, we investigate the selectivity of regularity perception for the luminance contrast polarities of the elements. Our psychophysical tool was simultaneous regularity contrast, or SRC, the phenomenon in which the perceived regularity of a central test texture is shifted away from that of the surrounding regularity. Stimuli were composed of arrays of dark and/or white Gaussian elements. Surround and center test textures consisted of either the same (“congruent”) or opposite (“incongruent”) polarities. In addition, we tested a “mixed” condition consisting of a random mixture of polarities in both the surround and test. The perceived regularity of the test was measured using a match stimulus with the same polarity dimension as the test. The regularity of the match stimulus was adjusted on each trial using a forced-choice staircase procedure and the point-of-subjective equality between the match and test regularities was estimated from the resulting psychometric functions. SRC was observed in both congruent and incongruent conditions, but with the mixed condition, the perceived regularity of the test was shifted toward rather than away from the surround regularity, an example of assimilation, not contrast. The analysis revealed no significant difference in the magnitude of SRC between the congruent and incongruent conditions, suggesting that SRC could be mediated solely by polarity agnostic mechanisms, although there are other possible explanations for the “null” result. However, trend analysis using a non-linear (sigmoidal-shaped) function indicated a significant difference between the congruent and incongruent conditions, which, together with the mixed polarity results, suggests the presence of at least some polarity selective mechanisms. Previous reports have suggested that regularity perception is encoded by the “peakedness” in the distribution of spatial-frequency-tuned linear filter responses. We modelled SRC quantitatively by incorporating peakedness with spatial-frequency-selective surround inhibition and found that the model gave a good account of the SRC data. Possible reasons for the assimilation effect—with the mixed polarity condition are discussed. Full article

Ultrasonic crack detection is one of the effective non-destructive methods of structural health monitoring (SHM) of buildings and structures. Despite its widespread use, crack detection in porous and heterogeneous composite building materials is an insufficiently studied issue and in practice leads to significant errors of more than 40%. The purpose of this article is to study the processes occurring in ceramic bricks weakened by cracks under ultrasonic exposure and to develop a method for determining the crack depth based on the characteristics of the obtained ultrasonic response. At the first stage, the interaction of the ultrasonic signal with the crack and the features of the pulse propagation process in ceramic bricks were considered using numerical modeling with the ANSYS environment. The FEM model allowed us to identify the characteristic aspects of wave propagation in bricks and compare the solution with the experimental one for the reference sample. Further experimental studies were carried out on ceramic bricks, as the most common elements of buildings and structures. A total of 110 bricks with different properties were selected. The cracks were natural or artificially created and were of varying depth and width. The experimental data showed that the greatest influence on the formation of the signal was exerted by the time parameters of the response: the time when the signal reaches a value of 12 units, the time of reaching the first maximum, the time of reaching the first minimum, and the properties of the material. Based on the regression analysis, a model was obtained that relates the crack depth to the signal parameters and the properties of the material. The error in the predicted values according to this model was approximately 8%, which was significantly more accurate than the existing approach. Full article

Uplifted occurrences of fine-grained glaciogene marine sediments are found throughout the northern hemisphere. These sediments could be used to produce local construction materials, to rely less on imported construction materials from southern regions. In this study, a representative occurrence from Ilulissat, West Greenland, was investigated as a potential resource for local brick production. The study comprised three parts: (1) raw material characterization based on grain size distribution, major element chemistry, including total carbon, sulfur, and chloride concentrations, mineralogy, morphology, and Atterberg limits; (2) the production of test bricks at a Danish brickwork; and (3) testing of the bricks based on total shrinkage, water absorption, hygroscopic adsorption, open porosity, bulk density, compression strength, and mineralogy. The bricks produced proved to have excellent compression strength, low open porosity, and low water absorption. The shrinkage could be reduced by adding 10% chamotte to the marine sediment. Based on the investigated properties, this indicates that this type of clay is highly suitable as a resource for bricks. Full article

The twist-bend nematic liquid crystal phase is a three-dimensional fluid in which achiral bent molecules spontaneously form an orientationally ordered, macroscopically chiral, heliconical winding of a ten nanometer-scale pitch in the absence of positional ordering. Here, the structure of the twist-bend phase of the bent dimer CB7CB and its mixtures with 5CB is characterized, revealing a hidden invariance of the self-assembly of the twist-bend structure of CB7CB, such that over a wide range of concentrations and temperatures, the helix pitch and cone angle change as if the ground state for a pitch of the TB helix is an inextensible heliconical ribbon along the contour formed by following the local molecular long axis (the director). Remarkably, the distance along the length for a single turn of this helix is given by 2πR_mol, where R_mol is the radius of bend curvature of a single all-trans CB7CB molecule. This relationship emerges from frustrated steric packing due to the bent molecular shape: space in the fluid that is hard to fill attracts the most flexible molecular subcomponents, a theme of nanosegregation that generates self-assembled, oligomer-like correlations of interlocking bent molecules in the form of a brickwork-like tiling of pairs of molecular strands into duplex double-helical chains. At higher temperatures in the twist-bend phase, the cone angle is small, the director contour is nearly along the helix axis z, and the duplex chains are sequences of biaxial elements formed by overlapping half-molecule pairs, with an approximately 45° rotation of the biaxis between each such element along the chain. Full article

Whilst upcoming innovations on digital technology and renewable energy can have a significant impact on the reduction of operational carbon emissions in the construction industry, readily available fast-growing building materials like bamboo are already proving reductions in the embodied carbon of dwellings above 60% when compared to traditional brickwork in Colombia. This paper presents a like-by-like comparison of the environmental impact of a conventional clay brick house (CBH) and a bamboo house for social housing in Colombia, which was built using adapted vernacular technologies. The bamboo house uses bamboo species Guadua angustifolia Kunth as the main structural support for the light cement bamboo frame (LCBF) system, a.k.a. ‘cemented bahareque’, whilst the CBH combines clay bricks and steel for the load-bearing walls. Traditionally built Guadua angustifolia Kunth bahareque (GaKB) houses are a key part of the vernacular architecture in the ‘coffee cultural landscape of Colombia’ (CCLC) recognised by UNESCO. A life cycle assessment (LCA) was performed to calculate the carbon footprint of the houses following four phases: (1) definition of objective and scope; (2) inventory analysis; (3) impact assessment; and (4) interpretation of results. The results show that the carbon footprint of the GaKB house accounts for about 40% of the CBH, i.e., the GaKB generates a carbon footprint of 107.17 CO₂-eq/m² whilst the CBH results in a carbon footprint of 298.44 kg CO₂-eq/m². Furthermore, from a carbon balance calculation, the carbon footprint of the GaKB house is further reduced to about 36% of the CSB house. LCA results for the built GaKB house demonstrate that vernacular housing projects that preserve cultural heritage can also be resilient and climate-neutral. This paper sets a precedent for the establishment of targeted government policies and industry practices that preserve the cultural heritage and vernacular technologies in the CCLC region and in other emergent economies worldwide whilst promoting future-proof and net-zero carbon construction. Full article

This study explores the critical determinants impacting labor productivity in brickwork operations within the construction industry—a matter of academic and practical significance, particularly in the era of increasing human–robot collaboration. Through an extensive literature review on construction labor productivity, this study identifies factors affecting brickwork productivity. Data were collected from active construction sites during brick wall construction through on-site measurements and participatory observation, and the relative importance of these factors is determined using Principal Component Analysis (PCA)-factor analysis. The validity of the analysis is established through the Kaiser–Meyer–Olkin (KMO) test and Bartlett’s test of sphericity, with a KMO value of 0.544 and significance at the 0.05 significance level. The analysis reveals four principal components explaining 75.96% of the total variance. Notably, this study identifies the Euclidean distances for the top factors: weather (0.980), number of helpers (0.965), mason competency (0.934), and number of masons (0.772). Additionally, correlation coefficients were observed: wall area had the highest correlation (0.998), followed by wall length (0.853) and height (0.776). Interestingly, high correlations did not necessarily translate to high factor importance. These identified factors can serve as a foundation for predictive modeling algorithms for estimating production rates and as a guideline for optimizing labor in construction planning and scheduling, particularly in the context of human–robot collaboration. Full article

Buildings with load-bearing structures made of hollow clay blocks with horizontal holes and cement-based mortar are quite common in Italy, yet the current design standards do not consider specific modeling issues to be addressed by practicing engineers. In the absence of peculiar specifications, the prescriptions given for ordinary masonry walls are thus commonly adopted. However, experimental tests proved that walls built with hollow brick masonry performed quite differently from ordinary masonry walls. Considering the in-plane flexural behavior under horizontal loads, unlike ordinary masonry walls that exhibit some ductility, this construction typology performs quite poorly, showing very little deformation capacity and ductility. In recent experimental campaigns, a brittle collapse mechanism was observed due to the toe crush, which entailed the inability of the wall to further withstand the vertical loads. In this paper, the effects of incorrect modeling choices on the characterization of the in-plane behavior of this construction typology and the consequences related to overestimating ductility are discussed; the effects of the reduced ductility on the reliability of the assessment of an existing building as well as on the conceptual design of possible structural retrofit measures are investigated. From the critical discussion, the need emerged to accurately model the in-plane flexural behavior and to update the code provisions to explicitly consider masonry walls with hollow clay bricks with horizontal holes. Full article

This research aims to promote a new cost-saving method for rebuilding old masonry brickwork façade by installing a suspended brickwork system. This research introduces a case study for rebuilding masonry façade by applying MCDM (multiple-criteria decision making) and BIM (building information modeling) methodologies with the evaluation of three types of brickwork façade installation alternatives prepared for production. The first type is the installation of suspended brickwork and mounting of brickwork lintels; the second type is the installation of suspended brickwork and pre-prefabricated stainless-steel components, which have been manufactured offsite, completed with adhesively bonded brick slips; and the third type is the installation of prefabricated suspended brickwork masonry panels. The main aim of the research is to promote a cost-saving production method by comparing these three alternative types of brickwork production using the BIM application in accordance with the multiple-criteria assessments. A multiple-criteria system was developed, and an expert survey was employed to estimate the relative weights of the criteria; afterwards, the alternatives were assessed using the WASPAS (Weighted Aggregated Sum Product Assessment) method. A BIM brickwork façade model was developed based on survey data, analyzed design solutions, and adaptation for the production of suspended brickwork elements. The final results and details regarding the best BIM applications in the multiple-criteria assessment of suspended brickwork façade are presented in the conclusions. Full article

Bamboo weaving is an intangible cultural heritage in China. Exploring people’s aesthetic preferences for bamboo weaving patterns to better serve the design of bamboo architectural decoration can help promote the upgrading of traditional crafts. This study explored the differences between genders in the oculomotor indicators in different bamboo weaving patterns through an eye-movement experimental study combined with a subjective questionnaire to explore whether different genders have aesthetic preferences for people’s pictures of bamboo weaving patterns. The results showed that both males and females preferred less visually striking and softer corrugated patterns, with males paying more attention to the more ‘angular’ hexagonal and triangular patterns, while females were more interested in the more regular and uniform brickwork and diagonal patterns. Full article

The Golești Manor ensemble consists of architectural monuments dating back to the 17th, 18th, and 19th centuries, with ephemeral architecture roots from Phanariot times but also some pre- Brancovan influences. The Turkish steam bath is placed in the northeast of the enclosure, and it is thought to have been built by Stroe Leurdeanu. Although there are still original fragments of the old plaster that have been preserved, the Turkish bath has undergone several restorations through time, some of them poorly documented. Hyperspectral imaging (HSI) combined with LIBS were used in order to analyze the bricks and the mortars, evaluate their preservation state, map the original elements, and document and classify the interventions previously made. Based on the supervised classifications, several areas of interest were selected for LIBS elemental analysis, and multivariate data analysis was conducted in order to discriminate similar composition materials and to map the interventions and the original. By analyzing the variability of the spectral profiles, different algorithms were applied to the SWIR hyperspectral images in order to classify the main elements of the brickwork. Full article

Remote measurement of historic buildings and structures using the technology of terrestrial laser scanning (TLS) is becoming a more and more popular approach for conducting inventory activities, documentation and conservation works. In this paper, TLS was harnessed for analysis of historic brickwork structures from the 19th century. During the research programme, chosen brickwork heritage buildings were scanned. Based on the collected geometric data of the point cloud, it was possible to create an exact model of the scanned objects. The obtained radiometric information of the point cloud allowed us to identify changes in the surface of walls, such as cavities, cracks and previous repairs. Moisture was also identified in some cases. The conducted tests enabled the identification of brickwork in need of urgent repair. It was possible to assess the general technical state of the tested structures. The possibilities and limitations of the TLS diagnostic methodology of analysing the quality of historic brickwork and its future possible applications were indicated. Full article

Domes, vaults and arches are structural components of high vulnerability, due to the horizontal component of the thrust they impose to the supporting vertical elements (piers or walls), accentuated by the asymmetry of loading due to seismic actions. In order to explore the possibilities of reducing this vulnerability, a cross vault made of brickwork and supported by two stone masonry walls was tested on the earthquake simulator. A series of seismic tests was performed to the specimen at its as-built state, as well as after strengthening using techniques adequate for monuments, namely, grouting of piers, arrangement of struts/ties at the base of the cross vault and vertical prestressing of the masonry piers. The tests have confirmed the vulnerability of the original specimen, as well as the improvement of its behavior after strengthening, in terms of sustained maximum base acceleration, deformations and observed damage. Full article