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The heterogeneous FEM models of brick walls are analyzed in order to estimate possibility to predict proper failure mechanisms for different biaxial stress modes. The micro-modeling of masonry structures with the application of cohesive elements to describe the mortar joint zone is applied. For the boundary value problems modeling different brick patterns the typical biaxial tests are simulated. In one case (the most typical pattern) the comparison of numerical test solutions with laboratory experiment results on masonry panels in biaxial stress states made by Page is done. The qualitative comparison between numerical and real-life experiments shows the possibilities of application of Abaqus FEA build-in constitutive material models in evaluating the behavior of masonry under biaxial stresses. Such models properly verified can be treated as virtual experimental tests for determination of parameters for macroscopic continuum elasto-plastic models.

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The paper presents solutions for thermo-elasticity problems with an unsteady heat flow for various layered systems typical for Polish traffic categories KR4 and KR7. The tasks were solved assuming a plain strain case for material parameters, which in most cases were determined in a laboratory tests, under thermal type of loading, which simulates an extremely unfavorable weather condition. For the selected structural variants, the resulting stress state was analyzed in relation to the determined tensile stress limits for individual mixture materials. In half analyzed cases, exceeding the material tensile strength in second layer (L2) was observed only as a result of the decreasing temperature.

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This article presents a method of approximate finding of forces and strains resulting from the so-called membrane effect in the reinforcement of the transmission layer of embankments located on a soft soil improved by columns (rigid inclusions). The model task needed to determine the characteristic values in geosynthetic reinforcement supported on rigid columns was formulated. The reinforcement is treated as an isotropic membrane, in which the strains are determined using the formula for the length of the curve, i.e. it deviates from the assumptions of the small strain theory. Spatial problems are reduced to equivalent one-dimensional static tasks for analysis using the isotropic membrane theory. The closed form solution of this task exists only in the case of uniform load. For other types of loads, it is necessary to approximate the formula for the length of the curve occurring in the expression defining the strains in the membrane, e.g. using the Taylor series, and then solving the strongly non-linear equation in which the membrane tension force is unknown. The article presents the analysis of the effect of the length curve approximation with usage of the Taylor series on the accuracy of the results obtained. The presented analysis is very important from the point of view of standard engineering calculations needed to design the reinforcement of the transmission layer in the case of embankments located on soft soil reinforced with rigid inclusions.

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No abstract is provided for this article.

This paper presents the results of resilient moduli tests carried out on selected hydraulically bound mixtures (HBM). Both static and dynamic loading procedures were used. In total, thirteen hydraulically bound mixtures designed for construction of road base and subgrade improvement were tested. The mixtures were composed of crushed granite, dolomite or recycled concrete mixed with a hydraulic road binder, cement and two types of fly ash. The specimens were subjected to cyclic loading with 0.248 s and 50 s load times. Moreover, the specimens were subjected to compressive and tensile strength tests. The tests showed that the load duration had no significant effect on the obtained resilient modulus. This resulted from good linear correlation between the values obtained with the two load times, namely 0.248 s and 50 s. Non-linear relationships were established between the values of compressive and tensile strength and the resilient modulus. Some differences were noted in the shape of curves drawn for the respective granular materials and binders. This indicates that some physical ingredients may have an impact on the above-mentioned relationships.

The application of the hyperelasticity constitutive relationships for modelling of elastomeric bridge bearings is presented. Elastomers which are used for bridge bearings are nearly incompressible materials. Consequently, two models of hyperelasticity for rubber-like materials, i.e. neo-Hookean and Yeoh models are considered. The neo-Hookean model is the simplest possible model of hyperelasticity but unfortunately it has a number of disadvantages (i.e. at certain deformation modes it gives physically unreasonable predictions). The Yeoh model for nonlinear elastic materials is superior to neo-Hookean model and leads to rational description of the behavior of the elastomers for significant elongations and is implemented in many commercial programs using finite element method (FEM). In this work, ABAQUS program is utilized for modelling of chosen bridge bearings. The parameters of two constitutive models are determined based on experimental results and are used in numerical calculations for selected examples of bridge bearings. Concluding remarks are drawn and directions of future research are outlined.

This article is a continuation of work on the use of plastic waste (such as PP, PS, LDPE, HDPE, and their mixtures) processed in the proprietary pyrolysis process as asphalt additives. The article carried out detailed tests of the mixes of selected additives with pen-graded bitumen 50/70, taking into account, among others, the influence of impurities and the ratio of PE to PP in the additives as well as short- (RTFOT) and long-term (RTFOT + PAV) ageing. An extensive research program was carried out, including functional and rheological tests in a wide range of temperatures. First, tests of stability and adhesion to various types of aggregates were carried out, demonstrating the usefulness of the proposed additives. Then, the elastic recovery and the impact of technological ageing on penetration, Fraass breaking temperature, and plasticity range were assessed. The same binder mixes were subjected to rheological tests in a wide range of technological and operational temperatures, assessing, among others, viscosity, the norm of the complex shear modulus, elastic recovery and compliance in the MSCR test, and stiffness in the bending beam rheometer. This entire class of tests was carried out for clean samples and those containing impurities, indicating their impact on individual material parameters.

H-section beam-columns under compression and bending moment about their stronger principal axis are generally sensitive to flexural-torsional buckling when insufficiently restrained against lateral-torsional deformations. Depending upon the section inertia properties about principal axes and the proportion between the compressive axial force and the maximum bending moment, the influence of large displacements on the buckling resistance may be more or less important, or even negligible. In this paper, the effect of prebuckling and postbuckling displacements on the buckling state of H-section beam-columns is evaluated, finite element simulations are performed and their results are discussed with regard to the Eurocode's General Method postulated for engineering practice.

Laterally and torsionally unrestrained steel I-section beams are susceptible to torsional deformations between supports; therefore, according to Part 1-1 of Eurocode 3, they need to be designed to resist lateral-torsional buckling. Eurocode’s steelwork design criteria require safety checking based on two stability interaction formulae utilizing the so-called equivalent uniform moment factors and the cross-section resistance formula that, in the case of moment gradient, refer to the beam end section. Uncoupling the beam stability resistance criterion and the cross-section resistance criterion may result in a nonuniform safety assessment of I-section beams. Finite element simulations of the beam resistance for different moment gradient ratios are performed. Verification of the buckling resistance is conducted by varying the following parameters: the slenderness ratio, the location of maximum end moments about both axes and the section depth-to-width ratio (i.e., considering rolled I- and H-sections). The variation in the accuracy of the current Eurocode resistance evaluation method is identified, and an approach for a better equalization of the safety predictions is suggested by considering different values of the most important factors influencing the stability performance of steel I-section beams.

Cylindrical bolted steel tanks with H/D~1 can be made from very thin steel courses the thickness of which is determined by tension. The important issue is to stiffen the whole shell with intermediate stiffeners to prevent from stability loss in situations when the tank is empty and exposed to a strong wind. The FEM package Abaqus with nonlinear Riks algorithm was used for analysis. A parametric study programmed in python, internal Abaqus language was conducted to establish the influence of number and position of intermediate stiffeners on buckling resistance of the tank. After calculating nearly one thousands tasks, results were gathered with python script and compared with classic design recommendations proposed in Eurocode 3, DIN 18 800 Part 4 and AWWA D103-09. Simplified analytical approaches present in current standards are rather conservative and one may want to look for more sophisticated methods of analysis of tank shells presented in this paper for more economical design of such structures. From the comparison of the results obtained with different numerical strategies such as linear buckling analysis (LBA), geometrically nonlinear analysis of perfect (GNA) and imperfect (GNIA) structure a necessity of taking into account imperfections in GNA arises. Otherwise a capacity of the shell structure may be overestimated even over the value obtained from LBA.