The aim of this paper is to investigate the influence of eccentric load and the presence of an opening near the column on the punching shear strength of reinforced concrete (RC) flat slab without shear reinforcement using analytical investigation and numerical simulations. A model based on the finite element method is proposed and its validation is confirmed in this study, by comparing the results with the existing experimental studies available in published literature. Twenty slabs supported directly on columns were analyzed, along with variation of load and opening position in the slab. The punching shear strength for all slabs was calculated according to Eurocode 2 (EC2) and numerically. It was found that the obtained punching shear strength was significantly underestimated by EC2. In addition, this research has shown that the opening position in relation to the direction of the bending moment caused by the eccentric load significantly affects the punching shear strength, while EC2 neglects this position.

Quality assessment of stiffness and load-carrying capacity of composite connections is of great importance when it comes to designing timber–concrete composite structures. The new European regulation intended explicitly for timber–concrete structures has made a significant contribution to this field, considering that until today there was no adequate design standard. Due to the proposed general expressions for determining the stiffness and load-carrying capacity of composite connections made with dowel-type fasteners, which are incapable of describing most of the commonly applied fasteners, engineering, and scientific practice remained deprived of a quality assessment of the essential mechanical properties of the connection. In order to overcome this problem, this paper proposes a numerical model of the connection suitable for determining the whole load–slip curve, allowing it to estimate the stiffness and load-carrying capacity of the connection. The model was developed by considering the non-linear behavior of timber and fasteners, which is determined through simple experimental tests. For the numerical model validation, experimental tests were carried out at the level of the applied materials and on the models of the composite connection. Through numerical simulations, analysis of obtained results, and comparison with experimental values, it can be confirmed that it is possible to simulate the pronounced non-linear behavior of the timber–concrete connection using the proposed model. The estimated values of stiffness and load-carrying capacity are in agreement with the conducted experimental testing. At the same time, the deviations are much less than the ones obtained from recommendations given by the new regulation. Additionally, apart from evaluating the value and the simulation of the complete curve, it is possible to determine local effects, such as the crushing depth in timber and concrete, the fastener’s rotation, and the participation of forces in the final capacity of the connection.

This work analyses cross laminated timber (CLT), contemporary building material produced of dried wooden elements - laminates. Laminates in CLT panels are equally wide and timber fibers are rectangularly plated within layers. Paper shows basic physical - mechanical characteristics of CLT panels and analytic models that are most commonly used in designing of CLT floor and wall construction elements. Advantages and disadvantages of this new construction system are stated according to contemporary requirements in designing environmentally and ecologically acceptable constructions.

U radu su ispitane vibracije peteroslojnih međukatnih križno lameliranih drvenih panela visine 14 cm izazvane ljudskim djelovanjem. Analizirana su tri međukatna panela identičnih visina, ali s različitim kombinacijama debljine lamela u križnim slojevima variranjem njihovih raspona. Navedeni su bitni kriteriji što ih pri projektiranju treba zadovoljiti međukatna konstrukcija da bi se osiguralo njezino prihvatljivo ponašanje u uvjetima dinamičkog opterećenja. Izračun efektivne krutosti na savijanje panela obavljen je Gamma metodom, K-metodom i Kreuzingerovom analogijom. Analitički je određena osnovna frekvencija vibriranja svakog panela, kao i maksimalni progib zbog jedinične statičke sile, a dobiveni su rezultati uspoređeni s vrijednostima dobivenim modalnom i statičkom analizom u programskom paketu Ansys. Svi su dobiveni podatci uspoređeni s važećim kriterijima i selektirani su paneli koji ispunjavaju kriterije sa stajališta graničnog stanja uporabivosti. Rezultati su pokazali da su analizirani međukatni paneli raspona do 4,5 m prihvatljivi sa stajališta adekvatnoga dinamičkog ponašanja pri ljudskom djelovanju. Rezultati su također pokazali da su kombinirani kriterij i kriterij maksimalnoga dopuštenog progiba zbog jedinične statičke sile znatno stroži od kriterija minimalne vrijednosti osnovne frekvencije vibriranja.

Purpose: The purpose of this paper is to contribute to the solution of the buckling and resonance stability problems in inelastic beams and wooden plane trusses, taking into account geometric and material defects.Design/methodology/approach: Two sources of non-linearity are analyzed, namely the geometrical non-linearity due to geometrical imperfections and material non-linearity due to material defects. The load-bearing capacity is obtained by the rheological-dynamical analogy (RDA). The RDA inelastic theory is used in conjunction with the damage mechanics to analyze the softening behavior with the scalar damage variable for stiffness reduction. Based on the assumed damages in the wooden truss, the corresponding external masses are calculated in order to obtain the corresponding fundamental frequencies, which are compared with the measured ones.Findings: RDA theory uses rheology and dynamics to determine the structures' response, those results in the post-buckling branch can then be compared by fracture mechanics. The RDA method uses the measured P and S wave velocities, as well as fundamental frequencies to find material properties at the limit point. The verification examples confirmed that the RDA theory is more suitable than other non-linear theories, as those proved to be overly complex in terms of their application to the real structures with geometrical and material defects.Originality/value: The paper presents a novel method of solving the buckling and resonance stability problems in inelastic beams and wooden plane trusses with initial defects. The method is efficient as it provides explanations highlighting that an inelastic beam made of ductile material can break in any stage from brittle to extremely ductile, depending on the value of initial imperfections. The characterization of the internal friction and structural damping via the damping ratio is original and effective.