Search Results (68)

A wave of energy efficiency-focused activity has spread across Europe in recent years, with ambitious goals for improving the energy performance of existing buildings through various directives. Among these existing buildings, there are older structures with heritage-protected facades. Some of the protected facades consist of timber plank frame walls, which were common in Norway in the 19th and early 20th centuries. Internal insulation is an option for increasing the energy efficiency of such walls while preserving their protected facades. However, this approach alters the moisture performance of the wall and introduces a potential risk for mould growth, which must be assessed. To better understand the performance of these walls, the $s_d$ values of traditional types of building paper have been tested, as timber plank frame walls comprise vertical planks covered in building paper. In addition, the risk of mould growth in timber plank frame walls has been evaluated using the one-dimensional simulation tool WUFI^® Pro by modelling the wall with internal retrofitting and varying input parameters. The types of building paper used have a wide range of vapour resistance values (diffusion-equivalent air layer thicknesses, $s_d$ values), which range from 0.008 m to 5.293 m. Adding 50 mm of interior insulation generally resulted in a low risk of mould growth, except in cases involving the use of a moisture-adaptive vapour barrier (MAVB). The MAVB did not result in an acceptable mould growth risk in any of the tested scenarios. Full article

As energy-efficient buildings become central to climate change mitigation, the opportunity for interior and interstitial moisture accumulation and mould growth can increase. This study investigated the potential simulation-based mould growth risks associated with the current generation of insulated low-rise timber framed external wall systems within southeastern Australia. More than 8000 hygrothermal and bio-hygrothermal simulations were completed to evaluate seasonal moisture patterns and calculate mould growth potential for nine typical external wall systems. Results reveal that the combination of increased thermal insulation and air-tightness measures between the 2010 and 2022 specified building envelope energy efficiency regulations further increased predicted Mould Index values, particularly in cool-temperate climates. This was in part due to insufficient moisture management requirements, like an air space between the cladding and the weather resistive layer and/or the low-water vapour permeability of exterior weather resistive pliable membranes. By contrast, warmer temperate climates and drier cool-temperate climates exhibit consistently lower calculated Mould Index values. Despite the 2022 requirement for a greater water vapour-permeance of exterior pliable membranes, the external walls systems explored in this research had a higher calculated Mould Index than the 2010 regulatory compliant external wall systems. Lower air change rates significantly increased calculated interstitial mould growth risk, while the use of interior vapour control membranes proved effective in its mitigation for most external wall systems. The addition of ventilated cavity in combination with either or both an interior vapour control membrane and a highly vapour-permeable exterior pliable membranes further reduced risk. The findings underscore the need for tailored, climate-responsive design interventions to minimise surface and interstitial mould growth risk and building durability, whilst achieving high performance external wall systems. Full article

With the aim of reducing the environmental impact of buildings, the appropriate selection of building materials is essential, as a building is a complex system composed of various materials. With this background, a multi-criteria decision-making approach has recently gained traction. This study demonstrated the effect of building material selection on both environmental and economic parameters of a building in the context of Japan. A comparative analysis of five structural frame options was conducted utilizing a reference building model to assess the implication of material choices. The findings indicated that wooden frame options are advantageous in environmental aspects compared to non-wooden frames, provided that sustainable forestry practices and appropriate recycling scenarios are implemented. Conversely, it was found that a Cross Laminated Timber (CLT) frame is the most expensive option. This suggests that a hybrid approach, which combines various frame materials, could yield a more effective solution in terms of both environmental and economic sustainability. In addition, it was highlighted that building envelopes, such as foundation, exterior wall, and roof, should be prioritized to enhance the sustainability of a building from a material perspective. Furthermore, gypsum board, commonly used for sheathing building elements, should be selected with careful consideration of its environmental impact. Full article

This study analyses the many different parameters of the in-plane flexibility problem regarding the lateral behaviour of light timber-framed (LTF) wall elements with different types of sheathing material (FPB, OSB, or even reinforced concrete), as well as the thickness of the timber frame elements (internal or external wall elements). The analysis simultaneously considers bending, shear, and timber-to-framing connection flexibility, while assuming stiff-supported wall elements as prescribed by Eurocode 5. Particular emphasis is placed on the sliding deformation between sheathing boards and the timber frame, which can significantly reduce the overall stiffness of LTF wall elements. The influence of fastener spacing (s) on sliding deformation and overall stiffness is comprehensively analysed, as well as the different bending and shear behaviours of the various sheathing materials. The results show that reducing the fastener spacing can significantly improve the stiffness of OSB wall elements, while it is less critical for FPB elements used in mid-rise timber buildings. A comparison of external and internal wall elements revealed a minimal difference in racking stiffness (3.3%) for OSB and FPB specimens, highlighting their comparable performance. The inclusion of RC sheathing on one side of the LTF elements showed significant potential to improve torsional behaviour and in-plane racking stiffness, making it a viable solution for strengthening prefabricated multi-storey timber buildings. These findings provide valuable guidance for optimizing the design of LTF walls, ensuring improved structural performance and extended application possibilities in modern timber construction. Full article

The construction sector generates more than one-third of global waste. Although there is a consensus on the need to reduce it, empirical research evaluating current systems to develop circular solutions remains limited. Using a full-scale model, this article evaluates the disassemblability of the corner joint between two prefabricated lightweight timber-framed walls, a system widely adopted in residential construction in North America. The analysis deconstructed the disassembly actions, identified their level of difficulty, and classified the recovered materials into three categories: reusable, recyclable, and waste. The results reveal that the lack of design criteria for disassembly significantly limits the system’s circularity, as it prioritizes assembly speed and energy performance. The predominant use of nails as fasteners complicates the separation of layers, damages materials, and restricts their reuse. This highlights the urgent need to redesign construction solutions that enable efficient disassembly, promote component recovery, and extend their time in circulation. This study establishes a foundation for the evolution of lightweight timber-framed panel design toward systems more aligned with circularity principles. Full article

The behaviour of horizontal floor diaphragms plays a crucial role in ensuring the overall response of a building during earthquakes, as the stiffness of these diaphragms determines whether the structure will act as an integrated system. If the diaphragms do not exhibit sufficient stiffness, differences in the redistribution of forces on wall elements arise, increasing the risk of significant deformations and even local damage, which is commonly observed in earthquake-affected areas. Additionally, flexible diaphragms heighten the risk of torsional effects. Due to these factors, more attention should be given to the response of buildings with flexible diaphragms. Eurocode standard specifies general requirements under which diaphragms should be considered rigid within their plane, depending on the maximum diaphragm moment. However, specific guidelines regarding the geometric and material properties of elements that significantly impact seismic behaviour are not included in the existing European standards. This served as a basis for conducting a numerical study analysing the in-plane behaviour of floor elements made from different materials. This study, limited to a simple box-shaped structure with masonry walls, symmetrical in both orthogonal directions, evaluated and thoroughly analysed the deformations for different types of diaphragms, including prefabricated wooden frame-panel floors, CLT panels, and reinforced concrete slabs. Special emphasis was placed on wooden structural elements due to the increased demand for timber construction, as the behaviour of these elements needs to be properly studied, especially in seismic regions. The study results were obtained through FEM analysis using the SCIA Engineer software, version 22. The modelling of elements was carried out considering the orthotropy of brick wall and wooden ceiling elements, as well as simulating the appropriate shear stiffness of the connecting means. Full article

Masonry structures, particularly those used in developing countries and in historic buildings, typically consist of unreinforced masonry (URM) walls connected by timber or reinforced concrete elements. This study proposes enhancements to the existing two-dimensional (2D) deformable frame model (DFM) to enhance its ability in simulating masonry walls with a specific focus on accurately predicting the transient dynamic response of three-dimensional (3D) masonry structures while maintaining a minimal number of degrees of freedom (DOF). For the modeling of URM walls, the DFM framework employs elastic beams and diagonal struts with nonlinear constitutive behavior. Structural elements, such as reinforced concrete or timber reinforcements, are represented using conventional beam finite elements. This paper first reviewed the current DFM configuration, which primarily addresses the in-plane (IP) behavior of URM structures. It then introduced modifications tailored for 3D structural analysis. The reliability of the enhanced model was validated through two approaches. First, a modal analysis compared the results from the updated DFM with those from a reference 3D model based on cubic finite elements. Second, a shaking table experiment conducted on a half-scale masonry house was simulated. The findings demonstrate that, despite its limited number of DOF, the updated DFM effectively captures the main natural vibration modes. Furthermore, it shows the model’s ability to predict the nonlinear transient dynamic response of 3D masonry structures with accuracy and limited computational time. Full article

On 18 December 2023, a 6.2-magnitude earthquake struck Jishishan, affecting multiple counties and cities in Gansu and Qinghai Provinces. The seismic intensity of the meizoseismal area was VIII, resulting in extensive structural damage and building collapses. A damage assessment was conducted of the epicenter and surrounding high-intensity zones. To understand the typical structures and characteristics of the buildings that were damaged in these high-intensity zones, this study summarizes the characteristics of the damage to typical rural houses, compares the damage of the rural houses across different sites, and analyzes the causes behind these variations. The findings of the study indicate the following: (1) Timber and some brick–timber structures, due to their age, insufficient material strength, and lack of adequate connections between parts of the building, primarily experienced severe damage or total collapse, characterized by through-wall cracks, partial collapses, or complete collapses. (2) Brick–concrete structures predominantly suffered moderate to severe damage due to factors such as improper layout, uneven façades, and inadequate or incomplete seismic measures. The observed damage included significant wall cracks and extensive damage to two-story buildings. (3) Frame structures, mainly used for public facilities like schools, hospitals, and health centers, exhibited strong integrity and excellent seismic performance, resulting in minimal to no damage, with damage largely confined to non-load-bearing components. (4) The amplification effects of seismic waves in thick loess basin areas, slope sites, and the hanging wall effect of faults exacerbated structural damage to rural houses located in certain villages within the high-intensity areas. The results of this study can serve as a reference for post-disaster reconstruction and seismic retrofitting of buildings and contribute positively to enhancing the disaster resilience of rural housing. Full article

Timber–concrete composite (TCC) systems join the positive aspects of engineered wood products (good seismftaic behaviour, low thermal conductivity, environmental sustainability, good behaviour under fire if appropriately designed) with those of concrete (high thermal inertia, durability, excellent fire resistance). TCC facades are typically composed of an internal insulated timber-frame wall and an external concrete slab, separated by a ventilated air cavity. However, there is very limited knowledge concerning the performance of TCC facades, especially concerning their thermal behaviour. The present paper deals with the development and optimization of a 2D Computational Fluid Dynamic (CFD) model for the analysis of TCC ventilated façades’ thermal behaviour. The model is calibrated and validated against experimental data collected during the annual monitoring of a real TCC ventilated envelope in the north of Italy. Also, a new solver algorithm is developed to significantly speed up the simulation (i.e., 45 times faster simulation at an error below 3.5 °C compared to a typical CFD solver). The final model can be used for the time-efficient analysis (simulation time of approximately 23 min for a full day in real-time) and the optimization of the thermal performance of TCC ventilated facades, as well as other ventilated facades with external massive cladding. Our simulation strategy partially avoids the expensive and time-consuming construction of mock-ups, or the use of comparably slow (conventional) CFD solvers that are less suitable for optimization studies. Full article

The light weight and moderate stiffness of multistorey timber buildings make them susceptible to increased lateral displacements and accelerations under service-level wind loading. Therefore, the fulfilment of serviceability requirements is a major challenge. In this study, linear elastic finite element analysis was used to perform a parametric study of moment-resisting timber frames combined with cross laminated timber walls. In the parametric study, various mechanical and geometrical parameters were varied within practical ranges. The results of the parametric study were used to derive simplified analytical expressions and to train artificial neural networks which can be used to estimate fundamental frequency, mode shape, top floor displacement, maximum inter-storey drift, and wind-induced acceleration. The analytical expressions and the artificial neural networks can be used for the preliminary assessment of serviceability performance of moment-resisting timber frames with and without cross laminated timber walls, under service-level wind loading. Full article

High-rise timber structures signify a rising trend, thanks to their significant environmental and economic advantages that occur over their complete lifespan. Enhancing spatial effectiveness in these structures is a critical design consideration for project feasibility. Currently, there has been no comprehensive study on the space efficiency of such towers. This article analyzed 79 cases all over the world to deepen the knowledge of design features shaping spatial efficiency. The critical findings are as follows: (1) the most common architectural preferences include residential function, a centrally located service core, and prismatic arrangements; (2) the preferred structural material is composite, while a shear walled frame system is the favored structural system; (3) the average spatial efficiency and percentage of core area to GFA were recorded at 84% and 10%, ranging from the lowest values of 70% and 4% to the highest values of 95% and 21%, respectively; and (4) no significant differences were detected in the effect of core design approaches on spatial effectiveness if appropriately planned, with similar inferences drawn concerning form and the structural material used. This article will assist in developing design directions for different interested parties, including architectural designers taking part in the advancement of high-rise timber towers. Full article

Rehabilitating water-damaged structures in buildings results in increased material extraction and energy use, and, consequently, a higher carbon footprint of the housing industry. Despite its prevalence, quantifying the carbon footprint caused by water damage or flooding has not gained much attention. Thus, this study investigated the quantitative carbon footprint associated with rehabilitating flooding in a detached house caused by torrential rain. Three different construction methods of the house were looked at; a timber frame construction, a masonry variant made by concrete blocks of Lightweight Expanded Clay Aggregate (LECA), and an alternative with exterior walls composed of concrete-moulded Expanded Polystyrene (EPS) foam boards. A life-cycle assessment according to NS 3720 was used to investigate the carbon footprint (CO_2eq.) of typical flooding in a detached building. Rehabilitating the flooding in a house with concrete-moulded boards resulted in a lower carbon footprint (2.45 × 10³ CO_2eq.) than rehabilitating the same flooding in a house with LECA masonry (7.56 × 10³ CO_2eq.) and timber frames (2.49 × 10³ CO_2eq.). However, the timber-frame house had the lowest total carbon footprint (2.95 × 10⁴ CO_2eq.) owing to their original low footprint. This study found that flooding significantly contributed to the carbon footprint of buildings and, therefore, the topic should be given attention when choosing a construction method and moisture safety strategy. Full article

High-rise office structures constructed using timber material (with a minimum of eight stories) signify a burgeoning and favorable sector, mainly owing to their ability to offer substantial environmental and economic advantages across their lifespan. However, it is crucial to recognize that the current corpus of scholarly literature lacks a thorough investigation into vital aspects concerning the architectural and structural planning of these sustainable structures. In an effort to fill this gap and augment the understanding of advancing international tendencies, this paper delved into data originating from 27 high-rise offices on a worldwide scale. The primary findings were: (i) Central core arrangements were the most popular, accounting for 67%, followed by peripheral types at 22%. (ii) Prismatic designs were the most frequently used at 85%, with free forms making up 11%. (iii) Material combinations involving timber and concrete were widely prevalent, making up 70% of composite constructions, which were 74% of the sample group, with pure timber constructions at 26%. (iv) Structural systems predominantly utilized shear walled frame systems, comprising 85% of the total. This article serves as a valuable resource for architectural designers, offering guidance on planning and executing future sustainable developments in the domain of high-rise timber office. Full article

To improve the out-of-plane collaborative performance of timber frames and walls, a metal connector is proposed and designed. A finite element model of the wall is established, and the composite block damage criteria and surface contact behavior are validated. Additionally, one group without metal connectors and three groups with different numbers of metal connectors placed at various positions in traditional residential wall models are established. Using static loading simulation, the influence of different numbers of metal connectors on the out-of-plane damage patterns, deformation characteristics, and shear force distribution is analyzed. The study reveals that top metal connectors significantly reduce the out-of-plane displacement of the top wall by up to 84.6%. Metal connectors have a significant impact on the deformation capacity of brick walls, with a maximum enhancement of 65.3%. The metal connectors in the middle and lower parts transfer the wall loads to the columns, increasing the horizontal shear at the column head by approximately 7%. The connectors in the middle and lower parts effectively improve the collaborative performance of brick walls and wooden frames. Full article

The current goal of the European Commission, which aims to reduce CO₂ by 90% compared to values estimated in 1980, and the ever-increasing sensitivity to environmental sustainability, fully involve the construction sector, which, according to the OECD (Organization for Economic Co-Operation and Development) is responsible for over one-third of the world’s energy requirement. In this frame, numerous researchers and companies are focusing on ecologically sustainable building materials, to be used in new and existing buildings, that are able to simultaneously fulfill the constructive function and improve the energy behavior of the building envelope. The goal of the present paper is the analysis of the energy performance of some innovative locally produced natural building materials (timber, sheep wool, rammed earth, lime-based plaster, natural fibers) used in multilayer vertical closures, compared to that of more common building materials (bricks, concrete, synthetic insulation). First, the physical-mechanical characterization of the local natural materials was carried out, then the model of a building was implemented, whose energetic performance was simulated by varying the type of stratigraphy of the walls, including the use of both innovative and common materials. The building chosen for the simulation consists of one of the BESTEST ANSI/ASHRAE reported in the 140-2017 standard using the climatic data of the Mediterranean area. The results of the simulation have been presented and discussed. Full article