Up to now, structural sealant glazing façades have been extensively applied. They are at the cutting edge of technology and meet the highest standards. The objective of several research projects was to develop stiffening glass fronts, which replace expensive frameworks or wind bracings behind the large glass windows. Thus, potential applications...
In a former paper by the authors , the elastic behavior of Cross Laminated Timber (CLT) and timber panels having periodic gaps between lateral lamellae has been analyzed. A thick plate homogenization scheme based on Finite Elements computations has been applied. The predicted behavior was in agreement with experimental results. In this paper, simplified closed-form solutions are derived in order to avoid FE modeling. Both cases of narrow gaps of CLT panels and wide gaps of innovative lightweight panels are investigated. CLT and timber panels with gaps are modeled as a space frame of beams connected with wooden blocks. The contribution of both beams and blocks to the panel’s mechanical response is taken into account, leading to closed-form expressions for predicting the panel’s stiffnesses and maximum longitudinal and rolling shear stresses. The derived closed-form solutions are in agreement with the reference FE results and they can be used for practical design purposes.
In this chapter I describe a multidisciplinary research project into cross-laminated timber (CLT) panels which aims to transform the Australian construction and development industry and involves a range of key partners. This project will introduce CLT panels as a way to build with a lightweight prefabricated low-carbon construction system that is advantageous for urban infill and residential buildings. The challenge, research questions, and the advantages of this system are explained herein.
As the state of Oregon begins to introduce a new cap and trade program to reduce the effects of its greenhouse gas emissions, the state has opted not to incorporate its largest greenhouse gas emitter; the timber industry. The decline of the timber industry after the 1980’s had lasting effects on disadvantaged communities, and state politicians have battled the cap and trade bill in fear of further deterioration of the timber industry. In this paper I aim to take an in depth look at the potential that CLT has in Oregon, how it can be promoted by the government, and what the environmental effects of it are. I found that, with the rise of mass timber construction and promotion of green building, the state has the opportunity to use revenues from its cap and trade program to economically incentivize CLT construction that can provide relief to economically stressed rural logging communities, all whole bolstering its efforts to better the environmental impact of an ever expanding construction industry.
We conducted a systematic literature search and meta-analysis of studies with side-by-side life cycle analysis comparisons of mid-rise buildings using mass timber and conventional, concrete and steel, building materials. Based on 18 comparisons across four continents, we found that substituting conventional building materials for mass timber reduces construction phase emissions by 69%, an average reduction of 216 kgCO2e/m2 of floor area. Studies included in our analysis were unanimous in showing emissions reductions when building with mass timber compared to conventional materials. Scaling-up low-carbon construction, assuming mass timber is substituted for conventional building materials in half of expected new urban construction, could provide as much as 9% of global emissions reduction needed to meet 2030 targets for keeping global warming below 1.5 °C. Realizing the climate mitigation potential of mass timber building could be accelerated by policy and private investment. Policy actions such as changing building codes, including mass timber in carbon offset crediting programs and setting building-sector-specific emissions reduction goals will remove barriers to and incentivize the adoption of mass timber. Private capital, as debt or equity investment, is poised to play a crucial role in financing mass timber building.
More and more people live in cities. The building industry is responsible for 33% of waste production and is set to increase further to 50% in 2025. The energy efficiency is continuously increased, but the waste production at the end of life of a building is largely ignored. This design proposes a solution in the form of a zero-waste high-rise design. It uses only recyclable or renewable materials. Mass-timber is chosen as the main material as it is not only renewable and easily reusable, it is also a storage of CO2. The design reuses the foundation of existing buildings, and with the lightweight properties of mass-timber, increases the density on the location by building taller. The design is four times taller as the current buildings. To allow for sustainable densification, the design offers public and collective qualities. The building has been designed is such a way to be easily refitted during its life cycle or to be completely disassembled at the end of life.
Nowadays, it is possible to build zero-energy houses or even positive energy buildings. Nevertheless, many incoherencies exists if we attach importance to the embodied energy of its constructions. The present paper lays on the logic of structural insulated panel which is used in many low-energy and passive houses and go further in order to reduce the global greenhouse gases emissions. For this purpose, cross-laminated timber is used instead of oriented strand board and the insulation used is made of wood wool. The structure, the technology and the thermal aspects are discussed as well as the fire resistance in order to show if its new product is economically and technically interesting. Results show that the embodied energy can be drastically reduced compared to the structural insulated panels. A wood consumption reduction of thirty percent can also be obtained compared to the classical cross-laminated timber construction.
Project contact is Vikram Yadama at Washington State University
The broader impact/commercial potential of this PFI project is in development of a commercially-viable process for manufacturing high-performing, durable mass strand timber panels for building construction from low-value and underutilized small-diameter softwood trees, such as from hazardous fuel thinning operations for improved forest health. The broader impacts are: (1) advancement of discovery and understanding while promoting teaching, training, and learning by including students and faculty in the research; (2) enhancement of infrastructure for research and education by establishing collaborations between interdisciplinary, yet complementary academic and industry stakeholders; (3) broadening of research dissemination to enhance understanding by involving industry and academia in the research, publishing project results in diverse media sources, and presenting research results in several formats that will benefit a wide range of forest products industry stakeholders; and (4) improved economic competitiveness of the U.S. forest products industry. In addition, if this proof-of-concept research leads to commercial applications, the benefits to society are: (1) new products with reduced environmental impacts, improved durability, and longer service-life; (2) technology that increases the U.S. forest products industry's competitiveness through creation of new jobs and increased opportunities for potential exports; and (3) increased use of wood, an environmentally-friendly, renewable, sustainable, and carbon-sequestering material.
The proposed project addresses challenges facing cross-laminated timber (CLT) panels in mass timber construction. Construction currently requires extreme care to protect CLT panels from moisture while ensuring long-term durability. Although builders take measures to reduce moisture exposure, it is inevitable that the CLT panels will take on water during their service-life. This project addresses these problems by utilizing thermal modification to produce chemical-free, mass timber panels with increased resistance to moisture and decay and improved dimensional stability. The goals are to: (1) evaluate process-performance relationships for thermal modification of small-diameter wood strands, and (2) demonstrate the feasibility of manufacturing high-performance cross-laminated strand-veneer lumber (CLSVL) mass timber panels. The objectives are to: (1) demonstrate the feasibility of utilizing thermally modified laminated strand veneer lumber for production of high-performance CLSVL panels, and (2) determine the potential environmental impacts of the new CLSVL panels. The technical results include validation of a repeatable process for thermally modifying small-diameter pine strands, validation of a method for manufacturing CLSVL panels, verification of physical and mechanical performance of the CLSVL panels, and establishment of commercially-viable process-performance relationships to enable commercial production of the CLSVL mass timber panels.