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(a) Manufacturing phases of prefabricated timber frame housing elements at the production site. (b) Storage of prefabricated timber frame walls ready for the transportation phase.  

(a) Manufacturing phases of prefabricated timber frame housing elements at the production site. (b) Storage of prefabricated timber frame walls ready for the transportation phase.  

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Article
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Cross-Laminated Timber is one of the most widely used engineered wood products, thanks to its numerous advantages, among which construction speed is the most appreciated, both by clients and by designers. However, construction scheduling compression refers exclusively to CLT structures, while the rest of the construction process still requires a lo...

Contexts in source publication

Context 1
... fact, wood is characterized by certain (Received 15 March 2015;revised 19 July 2015;accepted 20 July 2015) intrinsic features, such as low weight and simple manufacturing, which make it suitable for the realization of prefabricated components for the construction industry (Smith 2014). Moreover, computer-aided design and production applied to new timber technologies allow even higher quality standards to be reached and enhance possibilities for product customization, according to the specific needs of individual buildings (see Figure 1 (a) and (b)) ( Staib et al. 2008, see Research Report 2009). ...
Context 2
... this context, façade elements such as balconies, eaves and so on have not been considered. The first step has been the construction details design as far as the traditional way to build CLT construction is concerned, that is, to say, Option A (see Figure 10(a) and (b)). Layers needed to complete the technical solution from the inside have not been taken into account in time and cost analysis, as they do not have any relevance within the scope of this work. ...
Context 3
... CLT panels h Repetition of e, f, g phases n −1 times, where n is the building storey number The first one aims to mimic window functioning, so interrupting the movement of fluids from indoor to outdoor and vice versa. This is why this has been defined as a "geometrical method", as it uses shaped wooden elements in order to prevent air/ water exchange between the indoor and outdoor environments, as shown in Figure 11(a)-(c). This method has been used for the evaluation of benefits in the case of both B-SP and B-LP. ...
Context 4
... address this issue, an implemented version of the previously proposed solution has been studied. The ambition is to introduce an innovative technical system, imitating the functioning of unitized glass façades (Rigone 2014), which guarantees air and water tightness through the use of gaskets (see Figure 12(a)-(c)). This allows, at the same time, full compatibility of opaque elements with an all height glass modular element, providing designer with a higher freedom level as far as façade texture design is concerned. ...
Context 5
... system compatibility with different kinds of structures; Figure 11. (a) "Geometrical method". ...
Context 6
... from the cost analysis confirmed that prefab- ricating façade elements off-site allows for a signifi- cant reduction in costs (see Figure 13(a) and (b)). It is noteworthy that this is also true without consid- ering the expenses derived from scaffolds. ...
Context 7
... durations in Table XIII, related to the first floor, have simply been multiplied by the number of storeys of the case study building. Figure 14 (a) and (b), which show the percentage duration divided according to the installation of various components, clearly highlights that the impact in terms of time related to façade installation (CLT panels) is significantly more in the case of small panels than in the case of large panels. ...
Context 8
... both prefabricated solutions perform more strongly compared to non-prefabricated ones (see Figure 15), time saving guaranteed from Option B -SP, within the defined boundary conditions, is not large enough to justify this choice compared to the traditional construction way. ...

Citations

... These panels usually have high stiffness and strength and are widely adopted as structural walls and floors [3,4]. Other advantageous characteristics of CLT include high strength-to-weight ratio and dimensional stability [5,6], great environmental benefits [7], improved fire protection [8], and rapid construction time [9]. Owing to these advantages, CLT has been increasingly used for multi-story residential, commercial and public buildings globally. ...
Article
Connection is the most important part in cross-laminated timber (CLT) buildings as it guarantees necessary strength, stiffness, ductility, and integrality for the whole CLT structure. This paper proposes an innovative energy-dissipating hold-down connection for CLT structures, which combines the advantages of the soft-steel bracket and high-damping rubber for providing great energy-dissipating capacity and high ductility. A series of tests were performed under quasi-static monotonic and reversed cyclic loading to investigate the failure mechanisms and mechanical properties of the novel hold-down connection. Test results demonstrate that the connections can continue to work as a whole even after the occurrence of preliminary failures of steel ribs rupture and weld fracture. Final failure modes, including debonding between the rubber and steel plates, rupture of the front steel plate and breakage of screws, caused the invalidation of the connection. Meanwhile, load–displacement curves of the connections usually exhibit a bi-linear form, and the connection’s yielding is caused by the yielding of steel ribs. All the tested specimens exhibited stable energy-dissipating capacity in the working stage and were all classified as highly ductile. Furthermore, efforts were made to develop a simplified analytical model for estimating the basic mechanical properties of the novel hold-down connections. Comparison with test results shows that the analytical model can provide reasonable estimations of the initial stiffness, post-yield stiffness, yield force and failure force. The test results and analyses presented herein provide useful technical bases for supporting future studies and practical applications of the novel hold-down connection for CLT buildings.
... For example, when using CLT, buildings can be completed faster, allowing owners to generate revenue sooner and improve return on investment (Jones et al. 2016). The literature clearly supports that construction times are faster with CLT-sometimes by several months (Gasparri et al. 2015;Jones et al. 2016). For instance, construction sites using CLT have noted savings in labor expenses due to efficiencies gained in the construction process (Jones et al. 2016). ...
... For instance, construction sites using CLT have noted savings in labor expenses due to efficiencies gained in the construction process (Jones et al. 2016). Due to the prefabricated nature of the CLT panels, an estimated 75% fewer workers are needed for a CLT construction project (Gasparri et al. 2015). Waugh Thistleton Architects (2017) reported that 80% fewer on-site deliveries were made using CLT versus traditional construction materials which improves efficiency and lowers costs. ...
Article
Full-text available
Cross Laminated Timber (CLT) is an engineered wood product for the construction industry offering multiple structural, environmental and supply chain benefits. CLT can be used for an entire building, as both the lateral and vertical load resisting system, or for select elements such as the roof, floors or walls. CLT products were developed in the early 1990’s and have been widely adopted throughout Europe, and more recently, in Canada. However, use of CLT products is still relatively rare in the US. We present the results of a nationwide phone survey in the US conducted with architects and structural engineers to gauge their awareness, rate of adoption and assimilation of CLT products. Although adoption of CLT amongst architects and structural engineers is still at a nascent level within the construction sector, awareness is high, with 100% of our sample respondents cognizant of CLT. Architects and structural engineers perceive relative advantages of using CLT as well as compatibility with traditional construction. However, the adoption process is impeded by issues associated with complexity, trialability and observability. Key barriers to adoption of CLT as perceived by these two stakeholders are lack of experience from construction stakeholders, lack of training and tools for construction management stakeholders, lack of client requests and CLT inventory.
... Wood construction also supports the Finnish government's bioeconomic strategy for a carbon-neutral society by 2035 and addresses European climate policy [19]. In particular, engineered wood products (EWPs) such as cross-laminated timber (CLT) are being used in increasingly demanding applications [20] to meet the sustainable construction challenge [21][22][23]. The many advantages of CLT include low carbon and high thermal insulation, excellent in-plane and out-of-plane strength, high strength-to-weight ratio, and large-scale and high-rise buildings to be built [24,25]. ...
Chapter
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Increasing the construction of wooden apartment buildings has its place as part of preventing climate change. This chapter aims to explore the possibilities of expanding the construction of wooden apartment buildings on plots owned by the City of Helsinki in the Mellunkylä area by developing a series-produced wooden apartment building concept suitable for complementary construction—The Noppa concept. The sustainability of this approach is considered from the perspective of materials, construction methods, adaptability of the designed spaces, and housing design flexibility. In this study, the Noppa wooden apartment building concept with cross-laminated timber (CLT) elements has been developed varying in its facilities and architectural design features through architectural modeling programs to be used for complementary construction. The research findings are based on a theoretical approach that has not yet been practically tested but is proposed considering existing construction practices that need further investigation. It is believed that this chapter will contribute to the spread of wooden apartments to achieve a low-carbon economy as one of the key tools in tackling climate change problems. Particularly, proposed architectural design solutions will contribute to decarbonization of buildings as well as zero energy building (nZEB) approach.
... During the construction of mass timber buildings, use of appropriate storage systems with minimum exposure to ground or flood water and wrapping of panels if wet events are predicted are some of the recommendations in the available literature. Additionally use of temporary roofing on sections that can be prone to long term moisture exposure have been recommended in construction management of mass timber buildings [15,80,81]. ...
Article
This paper summarises the existing literature on water ingress and egress concerns in mass timber products. The main emphasis of this review paper is to identify and present the existing gap in knowledge regarding mass timber products’ water absorption and desorption characteristics in comparison with the information available for solid wood. The paper also focuses on highlighting the need for further studies on climate effects on mass timber products, particularly in relation to hotter and more humid environments. The paper concludes that existing knowledge in this field mainly concentrates on wood species from North America and Europe under temperate conditions, while major climate differences in Australia and other similar climatic regions, could have dissimilar effects on the in-service performance of mass timber products. This review includes details of testing experiments and techniques used to model and monitor water gain in mass timber products and identifies an existing gap in unified methods for testing and sampling. The review also outlines a plan for defining water ingress and egress characteristics of mass timber products in the Australian climate. This review is a part of a larger project focusing on water ingress and egress issues in mass timber buildings in tropical and sub-tropical climates of Australia as part of the National Centre for Timber Durability and Design Life (NCTDDL) research program.
... As mentioned in previous sections, the use of prefabricated wood elements is also a very interesting strategy for mass timber buildings. Since it is possible to build with higher quality and more precision by including products, such as CLT and glulam or other custom-made products, this could lead to process innovations, such as lean manufacturing [153,154]. Using prefabricated wood elements results in (1) a reduction in on-site installation time and the overall schedule, (2) a reduction in on-site deliveries, (3) a reduction in on-site waste and related disposal costs, (4) the ability to use other compatible products and simultaneously perform off-site work under controlled conditions, (5) a reduction in the number of change orders issued and requests for information or improvements, and (6) a reduction in the scheduling phase and on-site labor costs for follow-up trades [155]. ...
Article
Full-text available
The main goal of this study was to review current studies on the state of the art of wood constructions with a particular focus on energy efficiency, which could serve as a valuable source of information for both industry and scholars. This review begins with an overview of the role of materials in wood buildings to improve energy performance, covering structural and insulation materials that have already been successfully used in the market for general applications over the years. Subsequently, studies of different wood building systems (i.e., wood-frame, post-and-beam, mass timber and hybrid constructions) and energy efficiency are discussed. This is followed by a brief introduction to strategies to increase the energy efficiency of constructions. Finally, remarks and future research opportunities for wood buildings are highlighted. Some general recommendations for developing more energy-efficient wood buildings are identified in the literature and discussed. There is a lack of emerging construction concepts for wood-frame and post-and-beam buildings and a lack of design codes and specifications for mass timber and hybrid buildings. From the perspective of the potential environmental benefits of these systems as a whole, and their effects on energy efficiency and embodied energy in constructions, there are barriers that need to be considered in the future.
... Wood in building applications is gaining importance (Gasparri et al. 2015). Consumers are choosing wood predominantly due to environmental awareness and positive health impacts (Strobel et al. 2017, Lähtinen et al. 2019, Malá et al. 2019. ...
Article
Wood is one of the most important building materials. During the service life of wood and derived materials, various degradation factors affect performance. To assess how weathering influenced the material resistance and moisture dynamics of wood, 11 different materials were exposed to natural weathering for 9, 18 and 27 months or artificial accelerated weathering. Afterwards, the moisture performance of wood was determined in line with the Meyer-Veltrup procedure. Weathered samples were also exposed to the brown-rot fungus Gloeophyllum trabeum for 16 weeks. Respective materials were classified into durability classes according to EN 350, and relative resistance dose (D rd rel) was calculated. Weathering resulted in leaching of biologically active extractives, changed surface morphology and increased permeability. All these changes were reflected in decreased relative resistance dose for all tested materials. The largest deceases were determined for thermally modified wood, Scots pine, European larch and sweet chestnut heartwood. ARTICLE HISTORY
... Wood in building applications is gaining importance (Gasparri et al. 2015). Consumers are choosing wood predominantly due to environmental awareness and positive health impacts (Strobel et al. 2017, Lähtinen et al. 2019, Malá et al. 2019. ...
Article
Full-text available
Wood is one of the most important building materials. During the service life of wood and derived materials, various degradation factors affect performance. To assess how weathering influenced the material resistance and moisture dynamics of wood, 11 different materials were exposed to natural weathering for 9, 18 and 27 months or artificial accelerated weathering. Afterwards, the moisture performance of wood was determined in line with the Meyer-Veltrup procedure. Weathered samples were also exposed to the brown-rot fungus Gloeophyllum trabeum for 16 weeks. Respective materials were classified into durability classes according to EN 350, and relative resistance dose (Drd rel) was calculated. Weathering resulted in leaching of biologically active extractives, changed surface morphology and increased permeability. All these changes were reflected in decreased relative resistance dose for all tested materials. The largest deceases were determined for thermally modified wood, Scots pine, European larch and sweet chestnut heartwood.
... Researchers outlined best-practice production methods, including finger-jointing, adhesive application, and hydraulic or vacuum pressing, with emphasis on quality control procedures for guaranteed product speciation (Brandner 2013). Moreover, increases in the level of prefabrication of CLT panels by the inclusion of façade elements in the factory manufacturing process have been shown to result in construction program acceleration (Gasparri et al. 2015). ...
Article
One emerging trend in sustainable medium-density construction is the use of mass timber products such as cross laminated timber (CLT), which is a novel approach that involves numerous connectors. Researchers have not previously investigated the potential health impacts of different connectors. This paper proposes a framework to correlate the specification of CLT connectors to the potential risk of exposure to hand arm vibration syndrome (HAVS). We also propose an innovative adaptation of the Location-Based Management System flow line by adding a health risk dimension. The usefulness of the proposed framework is tested using a cutting-edge case study building, the tallest timber building in Scotland. The contribution of this research is a novel appreciation of the impact on installers’ Health & Safety based on the specified type of CLT connectors. With the methodology outlined in this paper, a HAVS variable can be added to design analysis to increase social sustainability in the built environment alongside other sustainability pillars. The findings are relevant to structural engineers, architects, key industry stakeholders, and researchers in the built environment.
... However, calculating the NVP shows a wooden building has only 0.2% NPV than its RC counterpart. Thanks to prefabricated modules and less capital construction works [19][20][21], CLT construction took only 13 months, cf. 15-month RC erection works. ...
Article
Full-text available
Sustainable development as a concept of construction arose some 20 years ago. Nowadays, this is a global trend in conventional construction. This paper analyzes the sustainable development indicators, mainly the economy of wooden housing. The proposed method for calculating the economic sustainability indicators is based on calculating the full life cycle of a house with a breakdown into such stages as design, construction, operation, and disposal. The paper compares wooden housing against conventional reinforced-concrete residential buildings in terms of this economic indicator. Stakeholder analysis assesses the sustainability factors (environmental, economic, and social); the assessment can be used to draw sustainable development policies, strategic goals and objectives pertaining to wooden housing.
... The use of timber in buildings may also be beneficial to boost productivity, which is one of the major challenges the construction industry is currently facing [3,4]. Buildings made using timber components are highly suited to off-site fabrication, because timber is lighter than many other building materials, large 2D prefabricated elements or 3D modular systems can be conveniently transported and handled on-site and, thereby, contribute to reductions in construction time, as well as improving site safety, and quality more generally [5,6]. ...
... The presentation of the research which follows has focussed on the development of fully prefabricated timber-based envelopes enabling a simple, fast and scaffold-free installation. The use of such a system within the new generation of tall timber together provides many advantages: higher on-site safety and risk reduction for all stakeholders; process and product quality enhancement; construction time and cost optimisation [6,11]; and immediate protection of timber structures from on-site prolonged exposure to unfavourable weather. ...
Article
Tall timber building is today both possible and desirable due to the advantages that timber construction offers the industry in terms of productivity gains and sustainable development. Prefabrication certainly represents a unique opportunity for timber technologies to lead the construction sector's shift towards a more industrialised approach, and new solutions need to be put in place for future generations of tall timber buildings. This paper examines the design of newly-conceived timber-based envelope systems for multi-storey buildings, which are fully preassembled off-site to maximise construction efficiency and safety. The prefabricated external wall assemblies are provided with all functional layers (including windows and cladding) to enable site installation from the constructed floor without scaffolds or any action from the outside of the building. An aluminium/gasket frame system is integrated within the external walls to guarantee air and water tightness at panel interfaces and guide the installation of the “mega-panels” on-site. The technical solution is presented in the form of 2D technical drawings and a three-dimensional model, developed for the application in a load bearing CLT-based envelope configuration. A full-scale (though small-size) mock-up was assembled to account for fabrication and installation issues, as well as to demonstrate the versatility of the solution for the use-case of a non-load bearing curtain wall configuration. The research innovation is found in the systematic and novel design approach to the development of industrialised timber-base envelopes, rather that in the specific instance of the design outcome presented and analysed here. This is a particularly important innovation because, as the key mitigating barrier for buildings, envelope design is context-related and has to be conducted on a case by case basis. This article presents the most substantial design outcome of the first author's doctoral research and is now being further developed as part of an industry embedded research project investigating industrialised construction and tall timber buildings.