Timber Building Construction Research Articles

Review of floor impact sound insulation performance measurement evaluation methods and timber floor specifications in Japan

Since the 1970s, heavy-weight floor impact noise has been a concern in Japan, prompting the development of unique measurement and evaluation methods standardized by JIS (Japanese Industrial Standards). JIS A 1418-1 specifies the measurement method for light-weight floor impact sound insulation performance, while JIS A 1418-2 defines the measurement method for heavy-weight floor impact sound insulation performance. Two types of standard impact sources, namely car-tire impact source and rubber ball impact source, are specified for measuring the heavy-weight floor impact sound insulation performance. JIS A 1419-2 defines the evaluation method for floor impact sound insulation performance. These methods differ from the international ISO standards, making performance comparison challenging. This paper provides an overview of these Japanese methods. Furthermore, since the enforcement of "the Act on Promotion of Use of Wood in Buildings to Contribute to the Realization of a Decarbonized Society," construction of timber buildings has been promoted in Japan with the aim of encouraging wood usage and contributing to the SDGs (Sustainable Development Goals). However, the floor impact sound insulation performance of timber floors tends to be low, with various specifications for timber floor cross-sections differing among private companies. This paper introduces these specifications and also compares driving-point impedances.

Experimental Study on the Bending and Shear Behaviors of Chinese Paulownia Wood at Elevated Temperatures.

Chinese Paulownia wood has been extensively used in the construction of timber buildings and lightweight sandwich structures. However, the bending and shear behaviors at elevated temperatures were not well understood. A total of 162 specimens were tested to investigate the bending, tangential shear, and radial shear performances of Chinese Paulownia wood under temperatures from 20 to 220 °C. It was found that the bending specimens exhibited ductile failure due to the progressive damage after reaching the peak load, while the tangential and radial shear specimens exhibited brittle shear failure along the shear plane. The elevated temperatures had limited effects on the failure modes. Under the same temperature, the retention rate of the modulus of elasticity is significantly higher than that of the modulus of rupture. Moreover, the bending strength, tangential shear strength, and radial shear strength generally and nonlinearly decreased with the increasing temperature. The EN 1995-1-2 design curve for the shear strength of wood at elevated temperatures is conservative for both the tangential and radial shear specimens. However, the design curve may not be adopted to estimate the tangential shear strength at temperatures higher than 220 °C.

Elements of the Fourth Industrial Revolution in the Production of Wood Buildings

We are on the threshold of a technological revolution that fundamentally changes the way we live, work and communicate with each other. To some extent, scale and complexity, this transformation will be as fundamental to humanity as no other technological change in the past. We do not know how it will evolve, but one thing is clear: the response to it must be integrated and comprehensive, involving all stakeholders on a global basis, from the public to the private sector, to the academic community and to civil society. In the context of sustainable and efficient construction, traditional material bases such as wood are becoming increasingly prevalent and implemented in modern design processes and design solutions. The great potential of this building material is achieved due to developments in production as well as the actual construction of timber buildings. Possible ways of production and construction of wooden buildings are diverse. Especially through prefabricated and solid wood products, which are also cross-glued laminated timber products, modern timber construction represents an interesting and sustainable construction technology. The aim of this paper is to define the basic aspects of industrial building industry in the context of new trends and to introduce the possibilities of implementation of elements of industry 4.0 in the field of wood-based construction.

Hygrothermal characterization and modeling of cross-laminated timber in the building envelope

Cross-laminated timber (CLT) is a type of mass timber panel used in floor, wall, and roof assemblies. An important consideration in design and construction of timber buildings is moisture durability. This study characterized the hygrothermal performance of CLT panels with laboratory measurements at multiple scales, field measurements, and modeling. The CLT panels consisted of five layers, four with spruce-pine-fir lumber and one with Douglas-fir lumber. Laboratory characterization involved measurements on small specimens that included material from only one or two layers and large specimens that included all five layers of the CLT panel. Water absorption was measured with panel specimens partially immersed in water, and a new method was developed where panels were exposed to ponded water on the top surface. This configuration gave a higher rate of water uptake than the partial immersion test. The rate of drying was much slower when the wetted surface was covered with an impermeable membrane. Measured hygrothermal properties were implemented in a one-dimensional transient hygrothermal model. Simulation of water uptake indicated that vapor diffusion had a significant contribution in parallel with liquid transport. A simple approximation for liquid transport coefficients, with identical coefficients for suction and redistribution, was adequate for simulating panel-scale wetting and drying. Finally, hygrothermal simulation of a CLT roof assembly that had been monitored in a companion field study showed agreement in most cases within the sensor uncertainty. Although the hygrothermal properties are particular to the wood species and CLT panels investigated here, the modeling approach is broadly applicable.

Design of envelopes for timber buildings in terms of sustainable development in the low-energy construction

The paper focuses on theoretical analysis of physical determinants affecting construction of envelopes for wood-based structures in the intentions of sustainable development under the current and expected legislation in Slovakia after 2020. It deals with the optimization of model building envelopes in terms of heat loss according to the requirements of the Europe 2020 Strategy and consequently calculates the values of the fire resistance considering Eurocode 5. It assesses the application and fire safety of analysed envelopes in construction of buildings with a combustible construction system, i.e. wood-based buildings intended for housing and accommodation, in accordance with the Slovak legislation. The paper also concentrates on the optimisation of built-in thermo-insulating and facing materials of wooden load-bearing members in the model building envelopes in terms of the environmental burden throughout their life cycle and the impact on the resulting fire resistance. It assesses the possibilities of using building components made from recycled materials in the construction of timber buildings as a full-valued replacement of standard building materials from non-renewable sources.

Failures of the Listed Wooden Buildings in Istanbul

Istanbul, which has been the capital city of different empires throughout history, houses numerous listed architectural and cultural historical buildings. There are diverse applications of timber structures all through Anatolia. As capital city of Ottoman period, construction of timber had high and low periods in Istanbul. As masonry houses have suffered numerous intense and destructive earthquakes, wooden buildings gained importance to be safe especially among rich people. As several fires wiped out thousands of houses and the districts, masonry buildings were made obligatory by law in the form of building regulations. Later however, due to many damages caused by repeated earthquakes, construction of timber buildings was once again allowed under the law. Between the 15th and the 18th centuries, the Turkish dwellings of timber framed construction with brick filling were developed. After the 18th century, the quality of work was decreased; the wall frames constructed without any filling sheathed with timber planks or lathed plaster became popular. Today, although these timber dwellings are listed, they are in very poor condition due to lack of maintenance and wrong interventions. In order to make risk assessment of these structures, more than 20 houses were inspected in Historical Peninsula of Istanbul. This paper will discuss risks sources, assessment of damage level and evaluation of the present condition of these buildings.