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. 6. Load-displacement curves for TCC specimens with good-quality connection equal to the 50%, 60%, 70% and 100% of all connection surface. 4. Conclusions Defects in adhesive connection between timber and concrete layer may be the cause of the drastically different behavior of TCC. The use of classical production method for rigid connection is dangerous because it is difficult to predict the quality of the obtained connection. So, it is not safe to predict the behavior of such TCC by models with the full composite action. The rigid connection produced by proposed method, by gluing of granite chips, allows visual control of the glued connection quality before fresh concrete placing, provides naturally developing of the bond between concrete matrix and granite chips as aggregates of concrete and provides full composite action between timber and concrete layers. Moreover, granite chips can provide local strengthening of concrete. It can be concluded that the increase of shear stresses is influenced not so much by a total amount of non-glued areas, but by the size of the individual defective areas. Large non-glued areas significantly reduce the energy absorption of elements subjected to the flexure, which was also observed experimentally in three-point bending test of the TCC specimen produced by classical dry method. Non-glued areas in timber to concrete connection results in higher shear stresses, which means that the shear strength limit is reached faster in the connection and, consequently, the load-bearing capacity of the composite is lower compared to TCC with a high-quality glued connection. The proposed connection production method, which is based on the use of granite chips, provides a high-quality connection between timber and concrete layers, with insignificant ration between possible defect and total connection surface area, which is equal to the area of one granite chips edge. Acknowledgements This research was supported by Riga Technical University's Doctoral Grant program and Latvian Council of Science funded project “Method of correlation of coaxial a ccelerations in 6-D space for quality assessment of structural joints (COACCEL)” (Nr. lzp -2020/1-0240). References Buka- Vaivade, K., Serdjuks, D., Goremikins, V., Vilguts, A., Pakrastiņš, L. , 2017. Experimental Verification of Design Procedure for Elements from Cross-Laminated Timber. Procedia Engineering 172, 1212-1219. Buka-Vaivade, K., Serdjuks, D., Podkoritovs, A., Pakrastins, L., Mironovs, V., 2021. Rigid connection with granite chips in the timber-concrete composite. Environment. Technology. Resources: Proceedings of the 13th International Scientific and Practical Conference, Latvia, Rezekne, 17-18 June 2021. 36-39. Destro, R., Boscato, B., Mazzali, U., Russo, S., Peron, F., Romagnoni, P., 2015. Structural and thermal behaviour of a timber-concrete prefabricated composite wall system. Energy Procedia 78, 2730 – 2735.