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- Atashipour, Rasoul, 1983, et al.
(författare)
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On buckling of layered composite heavy columns—Effect of interlayer bonding imperfection
- 2023
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Ingår i: International Journal of Solids and Structures. - : Elsevier BV. - 0020-7683 .- 1879-2146. ; 260-261
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Tidskriftsartikel (refereegranskat)abstract
- Buckling loads of partial composite columns under distributed axial loads is investigated in this paper for the first time. The interlayer interaction corresponding to the level of interfacial bonding imperfection in the layered heavy composite columns is formulated in the model by a shear slip/stiffness modulus. Governing differential equations and boundary equations are derived and represented in a general dimensionless form. A semi-analytical solution is applied to the governing buckling equations of the presented model using power-series technique to extract critical loads of partial composite columns. Five different classical end types are considered namely clamped–clamped (C-C), clamped-pinned (C-P), clamped-sliding (C-S), clamped-free (C-F) and pinned–pinned (P-P). Also, for two extreme cases of non-composite/zero-interaction and full-composite/perfectly-bonded layered columns, exact closed-form characteristic buckling equations are introduced. A convergence study is conducted to ensure stability of the applied power-series solution. It is demonstrated that the obtained buckling loads for partial composite columns with different end conditions approach those obtained from the exact closed-from solution for the full-composite extreme case when the interfacial shear modulus approaches infinity. Effect of imperfect bonding between the column layers and slip on critical buckling loads is investigated. It is shown that a more realistic model based on the partial composite interaction hypothesis predicts critical loads that are less than those based on idealized composite columns with perfect interfacial bonding.
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- Girhammar, Ulf Arne, 1948-, et al.
(författare)
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Stabilisering och bjälklag kritiska för höghus i trä
- 2011
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Ingår i: Husbyggaren. - Stockholm : Svenska Byggingenjörers Riksförbund. - 0018-7968. ; 53:1, s. 16-21
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- INDUSTRI- OCH KONTORSBYGGANDE Stabilisering och bjälklagsutformning är kritiska moment vid byggandet av flervåningshus i trä. Bjälklagen måste bland annat klara stora spännvidder. Nu finns en nyutvecklad plastisk metod som ska säkra horisontalstabilisering.
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- Girhammar, Ulf Arne, 1948-
(författare)
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Wood in Buildings : Technical and business development of wooden buildings, especially multi-storey timber buildings
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Wood plays an important role in the construction industry to meet the challenges of the climate, finite natural resources and energy consumption. It plays a significant role in environmental and climate effects on society as well as the well-being of its individual citizens.Multi-storey wooden buildings in the Nordic region have proven to be the main business opportunity in the new bioeconomy. However, it is emphasized that the technical challenges must first be overcome and access on design tools come to the same level as the equivalent for concrete and steel.The future potential for increased construction of multi-storey wooden buildings has also recently been studied. It emphasizes that based on demographics (strong population growth and strong urbanization), climate (climate impact reduction) and employment (keeping employment at a high level with a “reasonable” distribution of jobs between urban and rural areas), industrial timber construction can contribute as follows until 2025: (1) Build capacity for industrial timber construction to be able to deliver 50 % of the multi-storey houses in wood on the Swedish market; (2) Create 8 000 new jobs in prefabrication companies and help relocate 6 000 jobs from big cities to the countryside.Business development focuses on identifying opportunities and developing resources for new, expanded or changed business operations. For the construction industry, this means to create business models for the building process, including design, manufacturing and construction, and involve consultants, contractors and small and large suppliers.Business models are linked to current technical activities. When business models and technologies interact, this connection needs to be a starting point. We need to link industrial construction with companies’ business models. Business models for industrialized construction of multi-storey wooden houses that are in focus can provide a better understanding of its potential for competitiveness and profitability. Industrialized construction is also a driving force in shaping new or changing business models.The work comprises of three main activity areas: (1) the technical part, (2) the business part, and (3) the application part.Technical part: This part includes developing different types of design tools that the industry needs to produce and build multi-storey buildings in wood. Mainly within the areas (1) architecture and building design; (2) structural engineering – building systems, horizontal stabilization and sway, robustness, components and connections.Business part: This part includes developing business models for wood building projects, especially for multi-storey wooden buildings. Especially for the industrialized manufacturing and construction processes, integration of SME’s into big wood construction projects, and interaction between the different market players.Developing business models for industrialized multi-storey wooden buildings would include adapting a general business model to the industrialized building setting and choose the major business model elements, identify frequently used business models and model elements, and establish a good fit between the business model its model elements. The business model elements include prefabrication mode, role in the building process, end-user segments, offering, and resources for design and onsite construction.Application part – demo and pilot projects: This part includes following up on real wood building objects under and after construction, to identify weaknesses and challenges for learning and further study. And studying the industrialization of the wood construction process from manufacturing to erecting and the digitization with respect to planning and design.Critical issues to evaluate are:(1) Horizontal stability, robustness and building sway;(2) Business models and business elements; planning, management and interaction between participating partners (consultants, wood companies, entrepreneurs) and between main supplier (“locomotives”) and subcontractors (SME’s); and(3) Industrialisation and digitization of the different processes.
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