Elastic design of steel-timber composite beams

• Published in: Wood material science and engineering 2022-07, Vol.17 (4), p.243-252
• Main Authors: Aspila, Aku, Heinisuo, Markku, Mela, Kristo, Malaska, Mikko, Pajunen, Sami
• Format: Article
• Language: English
• Subjects: CLT; composite beam; Composite beams; Dynamic tests; Elasticity; Equivalence; Full scale tests; Homogenization; layered beam theory; Slabs; STC; Steel; Steel beams; Stiffness; Structural analysis; Timber; Wood laminates
• ISSN: 1748-0272; 1748-0280
• DOI: 10.1080/17480272.2022.2093128

In this paper, the well-known elastic theory of layered beams (ETLB) is employed for the structural analysis of steel-timber composite (STC) floors, where the cross-laminated timber (CLT) slabs are located on top of a steel beam and assuming the linear elastic behaviour of the STC structure. In the analysis, the CLT slab is homogenized, i.e. the lamellas are replaced by a uniform fictitious material such that the resulting slab has equivalent selected structural properties to the original. Two homogenization methods are presented and compared for selected cases. The first method (EI-equivalent) is based on the bending stiffness of the CLT cross-section, where the shear factor is obtained by the Gamma method. The second method (EA-equivalent) enforces equal axial stiffness for the homogenized slab. The two methods are compared against full-scale test results available in the literature, including static four-point bending tests, and dynamic test cases. The goal is to explore the usability of the ETLB for STC structures and examines which of the two homogenization methods provides more accurate results. Based on the evaluation of the experiments, it can be concluded that the ETLB yields an accurate analytical approach for STC structures, and both methods provide accurate results.