PSI - Issue 37

Karina Buka-Vaivade et al. / Procedia Structural Integrity 37 (2022) 563–569 Karina Buka-Vaivade et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 4. (a) load-displacement curves for TCC specimens; (b) TCC classic after collapse.

The values of maximal shear stresses in TCC specimen with different amount of non-glued areas in timber concrete connection obtained by 3D numerical models are shown on Fig.5. The first part of the study shows that poor-quality areas with the same length equal to the 10% of the specimen total length, according to the Fig. 3 (a) schemes, provides very similar level of the shear stresses regardless of the total amount of defective areas (Fig. 5(a)). The larger difference is 1.8% of the maximum mean shear stresses in the considered 4 cases. In the case with scheme 25% (according to Fig. 3(a)), non- glued areas with a length exceeding 10% of the total specimen length are formed, which results in a 10.7% increase in the value of the maximum shear stresses, compared to cases where the length of non-glued areas is within 10% of the total specimen length. Defects up to 10% of the total length of the specimen do not affect the energy absorption of the specimen. According to the second part of the study the maximum shear stresses increase trend by the increase of the area of the separate non-glued area has been identified (Fig. 5(b)). Moreover, large separate areas with defects in adhesive connection can significantly affect the energy absorption of the TCC subjected to the flexure. On the Fig. 6 are shown numerically obtained load-displacement curves for specimens with defect area of 30%, 40% and 50% of the total surface area of the connection, where 23.8%, 72.0% and 136.8% larger displacements are formed in comparison with 100% quality connection. Displacement values at a load level of 30 kN for two types of TCC specimens obtained experimentally confirms numerically obtained results. As can be seen on Fig. 6, the displacement value of TCC produced by classic dry method is close to the displacement value obtained for model with a 40% area without adhesion between the concrete and timber layers, which is confirmed by the collapse view of the specimen (Fig. 4 (b)).

Fig. 5. The values of maximal shear stresses in TCC specimen with different % of non-glued areas in connection (a) defect areas consist of many identical areas equal to 10% of all connection surface area; (b) defect area consist of one non-glued area.