Application of Support Vector Regression to the Prediction of the Long-Term Impacts of Climate Change on the Moisture Performance of Wood Frame and Massive Timber Walls

The objective of this study was to explore the potential of a machine learning algorithm, the Support Vector Machine Regression (SVR), to forecast long-term hygrothermal responses and the moisture performance of light wood frame and massive timber walls. Hygrothermal simulations were performed using a 31-year long series of climate data in three cities across Canada. Then, the first 5 years of the series were used in each case to train the model, which was then used to forecast the hygrothermal responses (temperature and relative humidity) and moisture performance indicator (mold growth index) for the remaining years of the series. The location of interest was the exterior layer of the OSB and cross-laminated timber in the case of the wood frame wall and massive timber wall, respectively. A sliding window approach was used to incorporate the dependence of the hygrothermal response on the past climatic conditions, which allowed SVR to capture time, implicitly. The variable selection was performed using the Least Absolute Shrinkage and Selection Operator, which revealed wind-driven rain, relative humidity, temperature, and direct radiation as the most contributing climate variables. The results show that SVR can be effectively used to forecast hygrothermal responses and moisture performance on a long climate data series for most of the cases studied. In some cases, discrepancies were observed due to the lack of capturing the full range of variability of climate variables during the first 5 years.

Measurements of thermal Transmittance of an External massive timber wall in-situ and in the Laboratory

The thermal transmittance of an exterior massive timber wall was measured in situ in Appenzell, Switzerland according to the standard ISO 9869-1. The measurements were performed with two different measurement sets in parallel. The measurements started in February and stopped at end of April. The measuring data were analyzed using mean values of the thermal transmittance coefficient and of the thermal resistance following the procedure of ISO 9869-1. In order to clarify if the in-situ measurement results show significant deviations from the measurement results of the thermal transmittance obtained in the laboratory, the thermal transmittance of the identical wall construction was measured in the laboratory of Bern University of Applied Sciences in Biel according to the standard EN ISO 8990 for steady state boundary conditions in a guarded and calibrated hot box. The test results will be presented and the measurement setup will be described. The calculation value of the thermal transmittance coefficient of the massive timber wall according to EN ISO 6946 is U = 0.53 W/(m2K). The test results of the thermal transmittance coefficient, U-value of the wall, measured in the hot box, agreed well within a confidence level of 95 % with the calculated value. The in-situ measurement results of the thermal transmittance coefficient of the two measurement sets differ significantly in the order of 8 % referred to the calculated U-value of the wall as the basic amount. Furthermore, both in situ test results of the U-value of the wall show significant deviations from the calculated U-value up to 27 %.

Storm damage at Craig Phadrig hillfort, Inverness

In January 2015 severe winter storms caused substantial damage to Craig Phadrig fort (Scheduled Monument 2892) after two wind-blown trees exposed a section of the inner rampart. Prior to consolidation and reinstatement, Scheduled Monument Consent was granted for an archaeological evaluation of the damaged area. This revealed three principal phases of construction, the earliest a massive timber-laced wall burnt in the 4th–3rd century bc. The upper elements of this ruined structure were incorporated into two secondary phases of refortification comprising construction of a palisade along its crest followed several centuries later by reprofiling of the rampart upper bank. The chronology of the second and third phases is more equivocal, with a single 5th–6th century ad radiocarbon date providing a terminus post quem for the erection of the palisade, while the other features indicate activity in the 11th–13th centuries.

More Is Less – The Integral Mass Timber Bridge

<p>Today, few new bridges are made of timber. Since the industrialization, timber bridges have increasingly lost ground to steel and later concrete bridges. In addition, timber bridges developed a reputation of high maintenance and low durability from many crossings built between the 1970s and 1990s.</p><p>Interest in timber bridges has recently grown due to new motivations in design, including an increased focus on sustainability. Efforts in research and engineering to reexamine timber bridges have led to the development of the “Integral mass-timber bridge”. The bridges will be a first: timber integral bridges without any movement joints or bearings between the superstructure and the concrete abutments.</p><p>These structures were developed taking into account the efficient use of natural resources as well as the carbon-emissions during the entire life span of the bridge: from the design and manufacturing to maintenance and operation. The body of the bridge is made of block-laminated timber beams and articulates the guiding principle of mass timber: the sequestration of carbon within the massive timber construction.</p><p>Currently, the first three of these bridges are being constructed in Germany, with completion in May 2019. The concept has been awarded with the German Timber Construction Award 2017.</p>

Collaboration Enables Innovative Timber Structure Adoption in Construction

Timber structures in construction have become more popular in recent years. Nevertheless, besides the complexity of designing, contracting and building these structures, a barrier to their market growth is the complexity of their supply chain relationships encompassing architects, engineers, builders and suppliers. The objective of this study is therefore to identify and characterize the supply chain relationships shared by these stakeholders within a massive timber construction project. Twenty-seven semi-structured interviews with architects, structural engineers, builders and timber element suppliers from nine countries, participant observations and secondary data were used to study the various relationship levels involved in timber construction projects. Triangulation and qualitative data analysis were also conducted. Three levels of relationships were then identified: “Contractual,” “Massive timber construction project” and “Massive timber construction industry development.” Results showed that timber structures involve value-added stakeholder relationships rather than linear relationships. These relationships appeared closer and more frequent and involved knowledge and information sharing. Furthermore, prefabricated systems allow for smoother relationships by limiting the number of stakeholders while promoting innovative thinking.

Wood Constructions for Sustainable Building Renovation

This paper discusses the potentials of different wood constructions for the renovation and extension of existing buildings for sustainable urban renewal. The renovation and extension of existing buildings with wood constructions can contribute significantly to sustainable urban redevelopment. The renovation of building envelopes, such as façades and roofs, with highly insulated wooden components, can reduce the transmission heat losses and related heating energy demand of existing buildings significantly. The extension of existing buildings contributes to the redensification of urban areas and can create synergies with the improvement of existing buildings’ performances. The manifold advantages of specific wooden constructions can be related to different aspects, such as construction type and material properties, building execution, design, logistic and sustainability. The results of this research discuss the architectural design and planning relevant properties of specific timber construction types, such as wood frame, cross-laminated timber (CLT), massive timber, and hybrid timber-concrete, considering the properties of different soft (such as spruce) and hard (such as beech) construction timber species. Timber constructions are compared with conventional massive constructions out of concrete and steel. The results confirm the significant advantages of timber constructions regarding all aspects.