| 1. |
- Svensson Tengberg, Charlotte, 1971
(författare)
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A design-build contractor risk assessment framework for new technical solutions in the construction industry
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Design–build contractors are often challenged to introduce new technical solutions into construction projects. However, they might not have methods and resources required to avoid serial failure, which is defined as multiple cases of failure when a technical solution fails to sustain the performance requirements. Here, the focus is on serial failures arising from the design or production that could have been predicted through calculations or assessment during the design phase. This work aims to reduce the occurrence of serial failures related to new technical solutions by suggesting a systematic approach for risk assessment with a focus on moisture safety, seen from a design–build contractor perspective. Earlier studies on methods and tools for evaluation and risk assessment of technical solutions were used to define a framework for the risk assessment approach. Current practices of implementing new technical solutions and the need for improvement were explored via semi-structured interviews. Two case studies of recent new technical solutions were used in the subsequent evaluation: cross-laminated timber in the construction phase and joint sealing tape in precast concrete sandwich facades. Besides the technical findings of risk evaluations based on the framework used in each case study, the proposed risk assessment framework is shown to provide a structured evaluation method that can be applied as a pre-qualification for new technical solutions before their implementation in construction projects. The company-level perspective, tollgates to structure the process, expert involvement in workshops and structured documentation and communication of assessment and results are the framework’s key elements. The framework facilitates the implementation of new technical solutions and helps the design–build contractor to prevent or reduce the occurrence of serial failures when introducing new technical solutions.
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| 2. |
- Henriksen, Rie, et al.
(författare)
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Effect of contact incubation on stress, behavior and body composition in the precocial Red jungle fowl
- 2021
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Ingår i: Hormones and Behavior. - : Academic Press. - 0018-506X .- 1095-6867. ; 128
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Tidskriftsartikel (refereegranskat)abstract
- Birds use contact incubation to warm their eggs above ambient temperature required for embryonic development. In contrast, birds in the industry as well as many birds in breeding programs and scientific studies are incubated in conventional incubators that warm eggs via circulating warm air. This means that contact incubated eggs have different thermal properties than eggs incubated in a conventional incubator. In light of previous studies showing that small differences in incubation temperature can affect chicks post-hatching phenotype, we investigated the consequences of incubating Red jungle fowl eggs at the same temperature (37 degrees C) either via contact incubation or warm air incubation. We found that contact incubated chicks had a more robust body composition, were more explorative and had a higher temperature preference early in life, as well as a sex dependent difference in plasma Corticosterone levels pre-hatch (measured in down-feathers) and post-hatch (measured in plasma) compared to chicks incubated in a conventional warm air incubator. While previous studies have demonstrated that embryonic development and post-hatch phenotype is sensitive to small variations in temperature, our study demonstrates for the first time that the way heat is distributed to the egg has a similar magnitude of effect on post-hatch phenotype and highlights the sensitivity of the incubation period in shaping birds post-hatch phenotype.
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| 3. |
- Svensson Tengberg, Charlotte, 1971, et al.
(författare)
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Impact on a CLT structure concerning moisture and mould growth using weather protection
- 2021
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 2069:1
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Konferensbidrag (refereegranskat)abstract
- Timber buildings, including cross laminated timber (CLT), are gaining market shares globally, mainly due to anticipated environmental benefits, but a new technical solution also raises new questions. Durability is critical to obtain real sustainable constructions built for the future. There are field studies concerning hygrothermal conditions of timber structures, however, there is a lack of documented experiences combining hygrothermal conditions, mould growth potential and weather protection during construction using CLT. The use of full weather protection is being debated in the building industry as well as in the research community, due to lack of knowledge of the combined effects. How does weather protection during the construction affect hygrothermal conditions and risk of mould growth in a CLT structure? A case study using a weather protected six-storey CLT building was performed. The hygrothermal conditions - indoors and outdoors - were monitored during construction and samples from CLT were analysed with respect to mould. The results were analysed together with simulations of mould growth using actual hygrothermal conditions. Theoretical conclusions show the weather protection gives significantly improved conditions resulting in lower potential of mould growth compared to outdoor conditions. The results also show lessons to be learned concerning planning of the construction site.
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| 4. |
- Svensson Tengberg, Charlotte, 1971, et al.
(författare)
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Risk assessment framework to avoid serial failure for new technical solutions applied to the construction of a clt structure resilient to climate
- 2021
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Ingår i: Buildings. - : MDPI AG. - 2075-5309. ; 11:6
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Tidskriftsartikel (refereegranskat)abstract
- Design-build contractors are challenged with the task of minimizing failure risks when introducing new technical solutions or adapting technical solutions to new conditions, e.g., climate change. They seem to have a disproportional trust in suppliers and their reference cases and might not have adequate resources or methodologies for sufficient evaluation. This creates the potential for serial failures to spread in the construction industry. To mitigate this, it was suggested that a predefined risk assessment framework should be introduced with the aim of providing a prequalification and requirements for the use of the technical solution. The objectives of this paper are to develop a comprehensive risk assessment framework and to explore the framework’s potential to adequately support the design-build contractor’s decisions. The framework uses qualitative assessment, relying on expert workshops and quantitative assessments, with a focus on simulation and probabilities. Tollgates are used to communicate risk assessments to the contractor. The framework is applied to a real-life case study of construction with a CLT-structure for a Swedish design-build contractor, where exposure to precipitation during construction is a key issue. In conclusion, the chosen framework was successful in a design-build contractor context, structuring the process and identifying difficulties in achieving the functional requirements concerning moisture. Three success factors were: documentation and communication, expert involvement, and the use of tollgates. Recommendations to the design-build contractor on construction of CLT structure are to keep construction period short and to use full weather protection on site.
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| 5. |
- Svensson Tengberg, Charlotte, 1971, et al.
(författare)
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Risk assessment of joint sealing tape in joints between precast concrete sandwich panels resilient to climate change
- 2021
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Ingår i: Buildings. - : MDPI AG. - 2075-5309. ; 11:8
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Tidskriftsartikel (refereegranskat)abstract
- Lately, a new technical solution, pre-compressed joint sealing tapes in precast concrete sandwich panel facades, has been introduced in Sweden. Although the consequences of performance failure can go far beyond the component, affecting the building, the introduction has gained little attention in terms of risk assessment in the literature and in industry. Instead, reference cases are used as verification without formal evaluation, potentially leading to serial failure. The aim of this paper was to provide guidance on how a design–build contractor should handle this new technical solution. A risk assessment framework using a design–build contractor’s perspective was applied to the case. The framework addresses new technical solutions or adaption to new conditions (e.g., climate change) with the aim of preventing serial failures. Moisture conditions within the joints were simulated using present and future climates, and probabilities of failure were assessed using the Monte Carlo method. The results of the study included identified risks of failure associated with the solution and factors influencing the probability of failure. A main issue was the exposure of the facade to driving rain but also run-off areas and imperfections in the application of the joint sealing tape. Future climate changes affect performance negatively. In conclusion, the new technical solution might be possible to use if draining potential is ensured in all detailed designs and a set of recommendations, including full-scale testing, is provided for the design–build contractor.
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| 6. |
- Sauveroche, Mathilde, et al.
(författare)
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Hair cortisol in horses (Equus caballus) in relation to management regimes, personality and breed
- 2020
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Ingår i: Journal of Veterinary Behavior. - : Elsevier. - 1558-7878. ; 37
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Tidskriftsartikel (refereegranskat)abstract
- Hair cortisol is a promising biomarker to measure long-term stress since cortisol is incorporated into the hair shaft as it grows. However, few studies have previously assessed hair cortisol concentrations (HCC) in horses. In this study, HCC was evaluated in both mane hair from the neck and body hair from the withers in 153 horses of different breeds, from seven different stables with three different management regimes (Free-roaming horses, Riding school horses, Trotter horses). In addition, 4 hours of behavioral observations were performed at each stable, and for 43 of the horses, a personality survey was completed. Mane and withers HCC correlated moderately, but significantly (rs=0.48, p<0.001). Differences between the stables were found for both mane and withers hair (both p<0.01) and the stable with lowest HCC also showed highest occurrences of positive social and resting behaviors (both p<0.01). There were no significant differences in HCC between the management regimes even though Free-roaming horses showed less negative social behavior compared to Riding school horses (p=0.041) and Trotter horses (p=0.055). The personality traits Dominance, Anxiousness, and Excitability revealed weak to moderate correlations with mane HCC (rs=-0.34, p=0.027; rs=-0.46, p=0.002; rs=-0.31, p=0.043 respectively) which might suggest that personality could also be related to long-term stress levels in horses.
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| 7. |
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| 8. |
- Svensson Tengberg, Charlotte, 1971, et al.
(författare)
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Implementing a framework for qualitative assessment of new technical solutions: A case study on CLT
- 2020
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Ingår i: Current Topics and Trends on Durability of Building Materials and Components - Proceedings of the 15th International Conference on Durability of Building Materials and Components, DBMC 2020. - : CIMNE. ; , s. 247 -254
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Konferensbidrag (refereegranskat)abstract
- New technical solutions are introduced at a fast pace in the Swedish construction industry, mainly driven by issues concerning costs and productivity. These new technical solutions can comprise new materials, new goods, new designs but also new processes. The record of accomplishment when introducing new technical solutions in the industry is not unproblematic and serial failures of different new technical solution have occurred. In an earlier interview study exploring introduction of new technical solutions in the Swedish construction industry, a common lack of thorough methods for evaluation of new solutions was identified. To address this issue, a case study was performed, exploring a method of evaluation with respect to building physics while implementing a cross laminated timber frame in a multifamily building. The case study uses a framework of assessment with focus on building physics. This paper presents the findings from the case study focusing on how evaluation of a new technical solution with respect to building physics is performed, together with an evaluation of the method, using the experiences of the participants in the case study.
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| 9. |
- Svensson Tengberg, Charlotte, 1971, et al.
(författare)
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Relying on reference cases when evaluating new technical solutions? Evaluation of technical documentation in a case study
- 2020
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Ingår i: E3S Web of Conferences. - : EDP Sciences. - 2555-0403 .- 2267-1242. ; 172
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Konferensbidrag (refereegranskat)abstract
- Serial failures have occurred when introducing new technical solutions in the Swedish construction industry. In an earlier interview study exploring introduction of new technical solutions, documentation and reference cases provided by the supplier are given as the main sources for evaluation. This paper aims at addressing the questions: 1. What kind of documentation concerning building physics are provided by suppliers? 2. How well does the suppliers' documentation meet the need for verification? In order to address these questions, the case of hygrothermal performance of cross laminated timber structures in multifamily dwellings was chosen. An inquiry of data was sent out to four suppliers at the Swedish market, asking for documentation and reference cases provided. Based on the documentation given, an assessment was made of to which extend the documentation can support verification of appliance to the relevant requirements of the Swedish building regulations. The case study shows reference cases are scarce and existing documentation is not comprehensive, thus indicating the building industry might have a disproportional high confidence in reference cases. The results will be used to suggest requirements for reference cases to be used for verification.
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| 10. |
- Sundman, Ann-Sofie, et al.
(författare)
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Long-term stress levels are synchronized in dogs and their owners
- 2019
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- This study reveals, for the first time, an interspecific synchronization in long-term stress levels. Previously, acute stress, has been shown to be highly contagious both among humans and between individuals of other species. Here, long-term stress synchronization in dogs and their owners was investigated. We studied 58 dog-human dyads and analyzed their hair cortisol concentrations (HCC) at two separate occasions, reflecting levels during previous summer and winter months. The personality traits of both dogs and their owners were determined through owner-completed Dog Personality Questionnaire (DPQ) and human Big Five Inventory (BFI) surveys. In addition, the dogs activity levels were continuously monitored with a remote cloud-based activity collar for one week. Shetland sheepdogs (N = 33) and border collies (N = 25), balanced for sex, participated, and both pet dogs and actively competing dogs (agility and obedience) were included to represent different lifestyles. The results showed significant interspecies correlations in long-term stress where human HCC from both summer and winter samplings correlated strongly with dog HCC (summer: N = 57, chi(2) = 23.697, P amp;lt; 0.001, beta = 0.235; winter: N = 55, chi(2) = 13.796, P amp;lt; 0.001, beta = 0.027). Interestingly, the dogs activity levels did not affect HCC, nor did the amount of training sessions per week, showing that the HCC levels were not related to general physical activity. Additionally, there was a seasonal effect in HCC. However, although dogs personalities had little effects on their HCC, the human personality traits neuroticism, conscientiousness, and openness significantly affected dog HCC. Hence, we suggest that dogs, to a great extent, mirror the stress level of their owners.
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