When constructing a building, to reduce environmental impact, it is significant to consider, at the design stage, what materials will be used and their transport distances. Although use of local wood ...has increased, one building requires countless materials usually procured from a more global market. Buildings are currently designed and constructed without sufficient knowledge concerning quantities and production areas of the materials used. We studied a small wooden building and determined composition (volume for individual material categories) and identified history (production area and transport distance) and traceability of materials, to show a building as a composition of different materials.
Hurricanes are one of the major causes of damage and loss to residential wooden buildings in the United States. The study of hurricane-imposed risks to residential wooden buildings is, therefore, a ...fundamental step to mitigate these damages and losses. Within this context, a probabilistic methodology is provided for the fragility analysis of residential wooden buildings. Two damage mechanisms are considered in this methodology, excessive dynamic wind pressure and impact from windborne debris. Unlike existing frameworks, the methodology defines the geometric configuration as well as the required extension of the neighboring buildings to estimate the damage from both mechanisms. A case study illustrates the methodology on residential communities composed of archetype gable-roof buildings. Ten construction cases are defined to cover a range of resistances of building components for both considered damage mechanisms. Three floor-area ratios (FAR) are also considered. The resulting fragility curves highlight: (1) the effect of the FAR on enhancing the performance of residential buildings due to the effect of shielding; and (2) the significance of windborne debris in increasing the estimated hurricane risk. The estimated fragility curves can be used to directly model residential buildings in community resilience frameworks.
•A methodology for the risk and fragility analysis of wooden buildings is presented.•Damage from windborne debris is considered in the developed methodology.•Fragility curves for archetype gable-roof buildings are presented.•The significance of windborne debris and floor-area ratio are highlighted.•The estimated fragility curves can be used in community resilience frameworks.
Multi-story wooden buildings are hailed as a favorable means toward reducing the embodied energy of the construction sector. However, the sector’s path-dependent nature hinders acceptance of using ...wood in multi-story construction. As a result, research predominantly focuses on examining the perceptions of construction professionals to identify means of breaking the path dependency. We propose using citizens’ perceptions about the use of wood to inform professional decision makers. Our research thus aims to answer two questions: What are citizens’ perceptions about using wood as a construction material, and are there country-based cultural differences between these perceptions? To elicit this spectrum of citizen views, an online survey was deployed in Austria, Denmark, Finland, Germany, Norway, Sweden, and the United Kingdom. Qualitative content analysis was used to analyze 6633 open-ended responses to the survey. Respondents held multi-faceted opinions about the physical properties, environmental, social, and economic aspects of using wood as a construction material. Citizens from Finland, Norway, and Sweden expressed discernably different perspectives about the acceptability of using wood than did citizens from Austria, Denmark, Germany, and the United Kingdom. Overall, respondents from all countries expressed high approval for the use of wood in construction.
Hurricanes can have adverse effects on residential communities and pose a significant risk to their economic prosperity. The ingress of water into a building due to wind-driven rain (WDR) and inland ...flooding can cause significant damage leading to downtime or temporary loss of housing. Existing frameworks focus on estimating the amount of water ingress due to WDR and inland flooding separately. This paper provides a comprehensive framework that considers both WDR and inland flooding when estimating the amount of water ingress into residential buildings due to hurricane rainfall. The framework estimates the water ingress due to WDR by combining the WDR intensity with the perforated area of the building envelopes. The intensity of the WDR is quantified using an Eulerian Multi-phase Model. The buildings’ envelope is considered susceptible to damage from the impact of windborne debris and excessive dynamic wind pressure. The framework to characterize and quantify inland flooding uses a coupled hydrologic-hydrodynamic model to estimate the inundation depth at each building. A case study consisting of a residential community in Houston, TX, which is subject to Hurricane Harvey illustrates the ability of the framework to capture the influence of WDR and inland flooding when quantifying water ingress.
•A framework is presented for building water ingress estimation due to hurricane rainfall.•Both wind driven rain and inland flooding are considered simultaneously.•Wind driven rain is modeled through an Eulerian multiphase model.•Inland flooding is estimated using a coupled hydrologic-hydrodynamic model.•The importance of both WDR and inland flooding when estimating losses is shown.
Modeling and estimating the damage to the built environment caused by hurricane winds is an essential requirement to enhance community resilience. Consideration of damage to a building’s envelope ...caused by windborne debris impact is necessary. To model this damage for a certain subdivision of houses, debris generated in neighboring subdivisions, defined as exogenous debris, must be taken into account. Existing physics-based damage estimation models do not consider the effect exogenous windborne debris has on the estimated damage due to hurricane winds. This paper provides a methodology to identify the extent of the neighboring subdivisions that needs to be considered during damage simulation to accurately account for exogenous windborne debris. The presented methodology is based on first identifying the extent of the neighboring subdivisions through a simulation-based strategy which follows an iterative scheme. For each size increment, the iterative scheme estimates the number of exogenous windborne debris using a physics-based damage estimation model. The single building solution is then generalized to a subdivision of any arbitrary shape. The proposed methodology is applied to analyze a hypothetical residential community in Miami, FL. Analysis results show the effect on the required extent of the neighboring subdivisions of the hurricane maximum wind speed, the floor-area ratio and the resistance of the building envelope components. The analysis concludes with a regression model that can be used to estimate the size of the neighboring subdivisions to be used in damage estimation models.
•A methodology to model exogenous windborne debris during hurricanes is presented.•The proposed methodology solves for a subdivision of any arbitrary boundary.•The methodology accounts for factors related to the neighboring subdivisions.•The methodology accounts for factors related to the hurricane hazard.•A regression model is presented to account for exogenous windborne debris.
This research set out to investigate emotions and physiological responses elicited by neighbour sounds in wooden residential buildings. A laboratory experiment was performed in an audiometric booth ...with individual (i.e. footsteps, speech, or music) and combined sounds (i.e. footsteps in combination with music or speech) from neighbours. Participants performed a self-assessment of their levels of arousal and valence using the Self-Assessment Manikin (SAM). The participant's physiological responses were also monitored throughout the experiment in terms of facial electromyography (fEMG in the corrugator supercilii (CS) and zygomaticus major (ZM) muscle groups), heart rate (HR) and electrodermal activity (EDA). The results showed that arousal and valence ratings of individual and combined sounds were organised along the defensive motivation circuit. The impact of sound pressure level (SPL) on affective ratings were significant except for individual music clip and footsteps sound combined with music. Listening to neighbour sounds evoked significant activities in physiological responses. Compared with the baseline only with ambient noise, neighbour sounds evoking affective responses led to an increase in fEMG CS activity and to a decrease in fEMG ZM activity, HR and EDA. The differences in fEMG ZM activities between individual and combined sounds were significant and the SPL had little effect on physiological responses. Arousal ratings were significantly correlated with fEMG CS activity, while valence ratings were strongly associated with EDA. The affective ratings were influenced by self-rated noise sensitivity, but this was not the case for physiological responses.
•Arousal and valence ratings were organised along the defensive motivation circuit.•Listening to neighbour sounds evoked significant activities in physiological responses.•Arousal and valence ratings were significantly correlated with some of the physiological responses.•Affective ratings were influenced by sound pressure level and noise sensitivity.
Owing to the serious natural ageing phenomenon of ancient wooden buildings, to better explore the effect of drying and wet ageing degree on the exothermic behaviour of wood combustion, firstly, wood ...treated with different degrees of dry and wet ageings was obtained by artificially accelerating the dry and wet ageing method. The pore characteristics, along with the capacity of the heat transport of wood treated and wood combustion heat flow with different dry and wet ageing degrees, were analysed by scanning electron microscopy, thermophysical property, and thermal analysis test. Finally, according to Friedman’s differential equivalent conversion method, the reaction process of the distribution of apparent activation energy of wood in various exothermic stages was computed and appraised, revealing the mechanism of the effect of the wood treated with dry and wet ageings on thermal reaction process. In the accelerated exothermic stage, the initial dry and wet ageing process (10 to 30 times) led to the opposite change in the trend of the apparent activation energy of wood and the fresh wood as a whole. The effect of the dry and wet ageings on the energy demand of the oxidation reaction at the end of prompt exothermic stage could decrease with the deepening of the ageing degree.
Fire safety engineering in timber buildings Östman, Birgit; Brandon, Daniel; Frantzich, Håkan
Fire safety journal,
07/2017, Letnik:
91, Številka:
Special Issue
Journal Article
Recenzirano
Odprti dostop
The combustibility of timber is one of the main reasons that many building regulations strictly limit the use of timber as a building material. Fire safety is an important contribution to feeling ...safe, and an important criterion for the choice of building materials. Historically, the combustibility aspect of wood has been a disadvantage for using timber as a construction material. The main precondition for an increased use of timber in buildings is providing adequate fire safety. This paper reviews the opportunities and challenges to reach this goal by implementing Fire Safety Engineering and Performance Based Design principles.
•Ultimate bearing capacity of bonding steel-plate joints for timber structures.•Creep trends and coefficients of bonding steel-plate joints with different stress levels.•Creep coefficients ...predictions of joints in the duration of service life.•Long-term slip stiffness and the ratio of stiffness reduction for bonding steel-plate joints.
The long-term performance of bonding steel-plate joints in controlled environmental conditions in this work. The bonding steel-plate joint consists of a steel plate with a vulcanized rubber layer and six wood screws. The vulcanized rubber layer is intended to improve the ductility of bonding steel-plate joints. Six pull-pull specimens were tested in order to determine the short-term load bearing capacity of bonding steel-plate joints, and the dimension of the shear plane of each bond line was 80 mm × 80 mm. A total of 12 specimens were employed in long-term tests. Two stress levels, including the 30% and 60% of ultimate bearing capacity, were adopted. All specimens were monitored over 800 days except that one series of specimens with 0.6 stress level which failed during the long-term tests. At the end of 858-day loading, the average slip at the connection for the specimens with 30% and 60% stress level were 0.623 mm and 0.939 mm, respectively. The creep coefficients were calculated according to the measured experimental data. The Burger’s model, two term and six term Kelvin’s model were adopted to fit the curves of creep coefficients, and then predict the creep slip of joints in the duration of service. The long-term slip stiffness and the ratio of stiffness loss are calculated according to experimental curves, and are predicted on the basis of the prediction results of creep coefficients through by six term Kelvin’s model.
•Multi-Fickian simulation of the hygro-thermal behaviour of timber bridge members.•Comparisons of numerical results with measurements from sensor-based monitoring.•Analysis of moisture levels and ...moisture gradients in painted wooden elements.
This work presents a numerical model to analyse the hygro-thermal behaviour of wooden bridge members. A multi-Fickian hygro-thermal model, previously implemented by some of the authors, is extended by including the dependency of wood sorption on temperature above and below zero degrees Celsius to predict moisture, temperature and relative humidity in wood under Northern European climates. The performance of the model in the presence of protective paints is particularly investigated. The finite element analysis based on the proposed model simulates the hygro-thermal behaviour of a glue-laminated beam of Älsvbacka Bridge located in Skellefteå (North of Sweden). The beam, coated by paints and claddings, was monitored by using wireless sensors in a previous research. Comparisons with the available measurements reveal that the numerical model is able to predict the moisture content in locations sheltered from rain and sun with moisture levels below the fibre saturation point. A study of the influence of different protective paints shows that the maximum and minimum moisture content at various depths along horizontal paths of the beam cross section, as well as the moisture gradients in different seasonal periods, are strongly affected by the type of paint. The proposed numerical approach is a promising tool to facilitate sensor-based monitoring techniques and to optimize the choice of protective paints for improved performance of timber bridges and other wooden structures under variable climates.
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