| 1. |
- Olsson, Anders, 1973-, et al.
(författare)
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Relationships between stiffness of material, lamellas and CLT elements with respect to out of plane bending and rolling shear
- 2023
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Ingår i: European Journal of Wood and Wood Products. - : Springer Nature. - 0018-3768 .- 1436-736X. ; 81, s. 871-886
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Tidskriftsartikel (refereegranskat)abstract
- The use of cross laminated timber (CLT) for construction has increased greatly in recent years and the large volumes ofwood used for CLT means that it is important to optimize the use of the material. This requires relevant grading of lamellasand knowledge of relationships between lamella and CLT properties. In the present study, the relationship between dynamicaxial modulus of elasticity (MoE) of lamellas and the quasi-static out of plane bending stiffness of CLT is investigated. Bymeans of four-point bending test, it is shown that the effective quasi-static MoE of lamellas in CLT is only 2–6% lower thanthe average axial dynamic MoE of the individual lamellas. With this knowledge, producers of CLT can easily predict andcontrol the important out of plane bending stiffness of the produced CLT. Moreover, it is shown that effective rolling shearstiffness of layers in CLT can be accurately determined by means of digital image correlation performed in connection tofour-point bending of CLT, even for long test spans. For layers of lamellas of Scots pine of size 40 × 190 mm2the averageapparent or effective rolling shear modulus was determined to be 159 MPa. The average rolling shear modulus of the samematerial was determined to be 56 MPa.
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| 2. |
- Pantak, Marek, et al.
(författare)
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Dynamic characteristics and dynamic response of timber footbridges to dynamic human activities
- 2023
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Ingår i: World Conference on Timber Engineering (WCTE 2023), 19-22 June, Oslo. - : World Conference on Timber Engineering 2023 (WCTE 2023). - 9781713873297 ; , s. 1930-1935
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Konferensbidrag (refereegranskat)abstract
- The dynamic action of footbridge users in different forms of activity (especially during walking andrunning) may cause an excessive vibration of the footbridge deck and may disturb the comfort of use of the structure. Thedynamic susceptibility of the footbridges varies depending on the construction material used to build the footbridge andthe typical construction solutions (construction details) resulting from the construction material used. The paper presentsthe basic dynamic characteristics of timber footbridges of various structural solutions, collected during dynamic field testsof these structures. The obtained results indicate relatively high dynamic resistance of timber footbridges to the dynamicloads generated by users under normal conditions of use. In addition, the results show that in the case of timberfootbridges, it is possible to consider changing the requirements of international standards defining the range of naturalfrequencies sensitive to the dynamic impact of users. In the case of timber footbridges, characterized by a relatively highself-weight (compared to steel footbridges), high stiffness and high damping, it is possible to consider changing therequirements for performing forced vibration analyses only for structures with fundamental vertical vibration frequency fv <= 3.0 Hz instead of the currently defined fv <= 5.0 Hz.
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