To simulate the effect of variable strains on steel grades S275 and S355, an experimental displacement control test of plate specimens was performed. Specimens were tested under monotonic and cyclic loading according to the standard loading protocol of SAC 2000. During experimental testing, strain values were measured with an extensometer at the tapered part of the specimen. Strains obtained by the experimental tests are disproportional to the applied displacements at the ends of the specimens. This phenomenon occurs due to the imperfections of the specimen, hardening of the material, and the buckling behaviour that appears in real structures due to the high deformation experienced during earthquakes. Due to the relative simplicity and wide applicability of the Chaboche hardening model of steel, the calibration of hardening parameters based on experimental test results was conducted. For the first time, calibration of steel hardening parameters was performed following the Chaboche procedure to define the cyclic behaviour with variable strain ranges. The accuracy of the hardening model with variable strain ranges, which were simulated using ABAQUS software, was verified using the experimental results.

Existing models for the evaluation of mechanical properties of corroded reinforcement, defined as a function of the mean cross-sectional loss or mass loss of the reinforcement, are not suitable in the case of chloride-induced corrosion, which causes irregular corrosion attack with pronounced localized damage—pits, whose geometry and spacing have a major influence on the mechanical properties of the reinforcement. Models that consider the irregularity of damage due to chloride corrosion are efficient, but as with models based on cross-sectional or mass loss, it is necessary to extract corroded rebars from the reinforced-concrete structure, which is a destructive procedure that can only be performed to a limited extent on an in-service building. To fill the above gaps, a new method based on the non-destructive measurement of corrosion parameters is proposed. The corrosion depth determined from the monitoring correlates directly with the remaining mechanical properties of the reinforcement; therefore, it is not necessary to determine the remaining cross-sectional area and geometry of the pits. The proposed models are based on experimental research on reinforced-concrete beam specimens subjected simultaneously to sustained loading and accelerated chloride corrosion in an environmental chamber in order to induce corrosion similar to that on real structures. Doi: 10.28991/CEJ-2024-010-11-02 Full Text: PDF

A new structural damage estimation procedure using grey relation coefficient and curvature of displacement influence line in beams using sparse measurement is proposed in this paper. The method is based on static structural response which can be obtained using single sensor. determination of damage location as well as determination of corresponding damage severity can be easily calculated with simple arithmetic operations, which is the main advantage of the proposed method. Conducted numerical simulation for different damage scenarios and various measurement sparseness and experimental validation confirm the effectiveness of proposed damage severity estimation procedure.

In the current European Code EN 1992-1-1 a truss model with variable inclination angle of concrete compressive struts with a quite wide range of inclination angle, from 21,8° to 45°, is intended for use for shear design of reinforced...

In this study, a hysteresis envelope mathematical model for the double extended end-plate bolted beam-to-column joint is proposed. The aim of a proposed joint model is to provide a more realistic behaviour of steel frames under seismic loading by using nonlinear static pushover analysis. The hysteresis envelope model defines the ratios between the monotonic properties of the joints and the properties of the joints during cyclic deformation. The proposed models are based on the hysteresis curves of the joints obtained by numerical simulations. The numerical model takes into account the geometric nonlinearity of the connecting elements, preloading of bolts, contacts between plates and bolts, and nonlinear properties of steel. Nonlinear static pushover analyses of steel frames are performed where the behaviour of the joints is described using the proposed hysteresis envelope models. The results are compared with the nonlinear static pushover analyses of steel frames with a trilinear monotonic joint model. Based on the results, the values of maximum peak ground acceleration for moment-resisting frames with the monotonic model of joints and hysteresis envelope model are estimated.