The load–deformation behavior of connections in timber structures, as well as their influence on the deformation behavior and the internal load distribution within the structural system, are analyzed in this contribution by means of numerical simulations of traditional carpenter-type connections in a timber frame structure, and different modeling strategies are compared.

Timber-concrete composite (TCC) floor systems have gained interest as a sustainable alternative to concrete floors, particularly in applications requiring longer spans than typical timber floor systems. By connecting timber elements to concrete slabs with shear connectors, TCC systems increase the structural stiffness and improve vibrational characteristics while maintaining a reduced carbon footprint. This study investigates the dynamic performance of a 6 m span glued-laminated timber-concrete composite (GLTCC) floor by means of forced vibration testing and finite element (FE) simulations. Experimental results revealed a first natural frequency of 13.25 Hz, surpassing the 8 Hz requirement specified in Eurocode 5, and a damping ratio of 3.34% for the first mode – close to recommended values for TCC floors with a floating screed. The FE model closely predicts the experimentally measured frequencies and mode shapes, demonstrating the validity of the numerical approach. Parametric studies further highlight the importance of support conditions and connection properties. Continuous supports such as walls or sufficiently stiff beams help maintain higher frequencies, while column supports reduce the frequency in certain modes. Enhanced connection stiffness, as achieved by notches, raises the overall dynamic response, whereas less stiff alternatives, such as screws, lead to reduced composite action and lower frequencies. Overall, these findings confirm the effectiveness of GLTCC floor systems for medium-span applications and highlight the need for careful consideration of support conditions and connection details to ensure optimal vibrational performance.

Currently growing interest in use of timber-concrete composite (TCC) floor systems indicates thatthey can be an effective alternative to traditional concrete floors and an efficient solution for rehabilitatingexisting timber floors. This study aims to experimentally verify a novel sustainable timbersteel-concrete composite floor system implemented in a real building. The system's performance wasassessed under static and dynamic loads, with a particular focus on the impact of longitudinal joints,before and after they were grouted. Static tests used IBC water tanks to apply a 3 kN/m² load, anddeflections were measured with LVDTs and a levelling instrument. Dynamic tests involved measuringeigenfrequencies under self-weight and additional loads, and impact loads. The experimentsdemonstrate the effectiveness of grouting joints in enhancing the structural performance of the compositefloor system, reducing deflection, and improving dynamic response.

Structural floor systems made of Timber-Concrete Composites (TCC) slabs are becoming more and more popular in office and residential buildings as well as in systems used for the renovation of old ceilings. Timber elements can be constructed as beams or solid slabs (massive CLT). Regardless of the main structural layout, individual components require using interlayer connections, which provide composite action in cross-sections. The most used connection types for TCC are mechanical fasteners, grooved or notched connections, and bonded shear joints. Bonded connections with rigid thin-layer adhesives provide high load capacity, but they are characterized by brittle failure due to their low ductility and introduced stress concentrations. An innovative flexible adhesive joint that ensures the transfer of high loads and high deformations simultaneously is presented in the paper. This connecting structural element, named PolyUrethane Flexible Joint (PUFJ) was examined experimentally in double shear lap tests of connections formed between two external CLT slabs of dimension 120 × 350 × 400 mm3 and a central concrete slab of dimension 100 × 250 × 400 mm3. Shear connections between the composite elements were made of a two-component polyurethane PS type adhesive layer of thickness 3 mm. The tested specimens were prepared in two variants of the application: wet application in the form of liquid adhesive and dry application in the form of prefabricated polyurethane layer glued to the elements by thin polyurethane adhesive. The effect of the adhesive application method on the stiffness and capacity of the TCC joint was investigated. In the paper, the analysis of the experimental tests’ results is presented.