The investigation of load carrying capacity of elastic-plastic strain hardening bisteel i-section beams

In the present study, CPT is modelled by static elastic-plastic small strain finite element method (FEM) analysis of axi-symmetric problem. Undrained soil properties and Tresca yield criterion is used for determining cone resistance of clay. Sand is modelled by using drained soil properties and Mohr-Coulomb yield criterion. Cone penetration problem is formulated as a collapse load problem. Associated and non-associated flow rules were used for modelling. A number of numerical experiments were performed to determine rational size of discrete region. Received dimensions of region were used for further research. Cone factor Nc for clay was obtained and the comparison of Nc values with other theoretical solutions is presented. A conclusion may be made that the limit of the validity of geometrically linear systems has been reached. The evaluation of the effect of cone penetration requires the analysis of large strains to be made. First Published Online: 30 Jul 201

Magistrantūra Vilniaus Gedimino technikos universitete 2016–2017 m.

Leidinyje „Magistrantūra Vilniaus Gedimino technikos universitete 2016–2017 m.“ pristatomos antrosios pakopos studijos, stojimo galimybės bei studijų tęstinumas VGTU. Čia glaustai aprašyta ne tik studijų sistema VGTU, bet ir pagrindinės stojimo sąlygos, konkurso organizavimas. Studijų programos, specializacijos pateiktos pagal studijų sritis, tad ieškantieji informacijos apie konkrečias studijas taip pat galės susipažinti su konkrečios studijų srities ir krypties alternatyviomis studijų programomis. Autoriai dėkoja Vilniaus Gedimino technikos universiteto bendruomenės nariams, prisidėjusiems prie leidinio rengimo

Investigation of traffic‐induced vibration in Vilnius Arch‐Cathedral Belfry

The influence of city traffic‐induced vibration on Vilnius Arch‐Cathedral Belfry is investigated. Two sources of dynamic excitation are studied. Conventional city traffic is considered to be a natural source of excitation while excitation imposed artificially by moving a heavily loaded truck is considered to be the source of increased risk excitation. The influence of induced vibrations is recorded by accelerometers located in various positions of the Belfry's structures and shown by accelerograms. Dynamic effects are evaluated by considering acceleration magnitudes and response spectra. A comparative analysis of both effects is presented and conclusions and recommendations are provided. First published online: 27 Oct 201

University management solutions during the COVID-19 pandemic: a case study of Lithuania

Purpose – The article is aimed at analyzing university management decisions during the COVID-19 pandemic thus emphasizing the impact of the decisions made on the effective management of the situation. Research methodology – To achieve the established goal, research methodology involved the qualitative research strategy applying the semi-structured interview method and scientific literature analysis. The article is of a theoretical and empirical nature. The empirical part presents its individual research on implementing strategies in the field of adapting appropriate areas of the University as an important part of the study implementation process. The study involved 15 experts – 12 men and 4 women. The research results are the basis for developing practical guidelines for higher education institutions. Findings – Research findings have disclosed that successful management decisions fall into eight categories: management actions, the collaboration between the different levels of authorities and the academic community, the development and maintenance of a technical base, timely and continuous academic support for teaching staff, multipurpose support for students, control over the studying process, security assurance, solutions at the level of study programs. The article demonstrates a holistic approach to making the required decisions. Research limitations – Research limitations impose conducting a study in a specific culture and the organizational context of Lithuania. Practical implications – Practical implications suggest that the conducted research helps the leaders of various levels at educational establishments make the most useful necessary decisions for the institution in an emergency. Originality/Value – The uniqueness of the conducted research lies in the first attempt to show management solutions worked out by the universities in Lithuania during the COVID-19 pandemic

Low-resolution spherical harmonics models in application to quasi-quadric particle shapes

In this paper a numerical analysis was performed developing low-resolution spherical harmonics (LRSH) models in order to describe particle shapes. The potential of LRSH, limited by the expansion degree L ≤ 3, to describe quasi-regular particle shapes was explored. The term “quasi” is used hereafter to indicate the monomeric, almost regular shaped, particle described by a single continuous function. This approach reflects the shape of a major part of soil minerals. It was shown, that even the simplest case of the suggested low-resolution harmonics technique with L = 1 showed sufficient accuracy. The main drawback of the suggested approach was that the low-resolution harmonics yield particle shapes with nearly sharp angles, there-fore, enhanced analysis of local surface curvatures becomes necessary. An application using quasi-ellipsoidal particles is enclosed

The investigation of stiffness of hybrid bisteel I-section beams

The stiffness analysis of the simple supported hybrid bisteel I-section beam subjected by uniformly distributed load is considered in this paper. The hybrid bisteel I-section beam presents a composition of high-strength steel inclusions for the flanges in the region of maximum stresses and of low-strength steel for remaining volume of the beam. The explicit analytical model for evaluation of stiffness of the beams mentioned is presented. The geometrical linear approach and elastic plastic material model have been assumed. The application of high-strength steel inclusion in case perfectly elastic state of the hybrid bisteel I-section beam, increase the deflection insignificantly (up to 10%). While strain hardening effect reduces the deflection by about 4 times compared to the perfect plasticity. The verification of the theoretical analysis has been performed by the FEM. After simple transformations, the proposed model can be easily applied to the evaluation of stiffness of otherwise loaded and supported hybrid bisteel I-section beams. First published online 16 June 202

Elastic-plastic analysis of bisteel i-section beams/Bimetalių dvitėjų sijų būvio analizė, įvertinant plastinių deformacijų įtaką

The elastic-plastic analysis of simple bisteel I-section beam subjected to uniform distributed load (Fig 1) is considered in this paper. The bisteel beam presents a composition of high-strength steel inclusions for the flanges in the region of maximum stresses and of low-strength steel for remaining volume of the beam. The aim of the paper is development of the explicit analytical model for description of plastic regions with respect to different steel properties as well as to dimensions of high-strength inclusions. The geometrical linear approach and perfectly plastic material model have been assumed. The variation of the strength ratio of the both steels and the variation of the length of inclusion leads to different distributions of plastic regions in the web and the flanges (Fig 2). By fixing the depth of plastic penetration different explicit expressions (1–10) of the limit bending moment and plastic boundaries (11–18) presented in Fig 3 have been derived. After integration over elastic and plastic regions explicit expressions (19–21) of middle-span deflection have been derived. Influence of different dimensions and material properties are investigated and presented graphically on Figs 5–8. The proposed analytical model has been also tested numerically by the finite element method. The ANSYS code and tetrahedral elements have been used for these purpose (Figs 9–11). A good agreement between the proposed analytical model and numerical experiments has been obtained if the relative length of the high-strength inclusion does not exceed 60% (l inc /l ≤ 0.6) (Fig 12). Outside the range of this limit the influence of shear stresses is growing and analytical model has to be corrected by additional terms. First Published Online: 30 Jul 201

Žmonių sauga Lietuvos statybose/Occupational safety on construction sites of Lithuania

Social instability, violation of human rights to work have made the conditions of safe and harmless work worse. 19 mortal, 42 serious and 796 slight accidents occurred on construction sites during 1995 in Lithuania. The main reasons of occupational accidents are violation of work discipline and lack of organization. 24 708 days are lost because of occupational injuries, or in other words 96 builders did not work for the whole year, and 528.9 thousand litas was paid out according to the lists of disablement. The bad state in occupational safety is unprofitable. Besides, old norms and regulations are still valid at the present time, and hundreds of them are approved as far back as 1980. The drawing up of new regulations is just taking place in Lithuania. The compensation system being in force for employees, who work under harmful and hazardous conditions and social security system for those, who had suffered injuries and occupational diseases, do not stimulate employers to create healthy and safe working conditions. The factor of rest can be observed on construction sites. The heads of construction sites entrust the workers themselves to organize the work without the projects of work execution. Instructions on occupational safety and fire protection are just formal. Many of employees work without the employment contracts. Employers start to understand already that it's better to have labour protection service instead of paying fines for violation of labour protection regulations. The intellect and exacting every-day control of labour protection service specialist brings much more benefit for the prevention of occupational accidents than seldom visits of State Labour Inspection inspector to the enterprise or construction sites. The state of occupational safety depends on psychological factors, too. These factors can be grouped into three groups: • natural of the human—natural inborn dispositions (the nervous system, memory, attention, the speed of reaction, intellect); • psychological peculiarities of personality (the features of human professional activities, leadership, erudition); • professional knowledge formed during learning, studying and training. The human psychology determines how the person interprets and copes with the things going on around him and related to him. Two different persons will act differently in the same situation. When a person reacts sensitively to weak and insignificant signals, he will pay attention to preparative and preventive work, think about potential danger and will take care to avoid accident. And vice versa, people who are not sensitive for such signals takes too little care to insure against accidents. It is reasonable to test psychologically an employee before signing an employment contract with him under market circumstances. It will be one of the conditions fulfilled for professional selection, which will decrease expenses for further training and professional activity of an employee. Fatal and serious disasters on construction sites decreased twice in 1995 as compared to 1994. And the total number of accidents decreased by 12 cases only (Table 1). Dynamics of mortal, heavy and slight accidents in 1991–95 is depicted in Fig. 1. The usage of alcohol is closely related to psycho-emotional stress. It has an influence on the accidents, too. 8 employees were killed while being drunk in 1995. It is 42.11% of total number of killed employees. The most dangerous occupations on construction sites are those of auxiliary workers, bricklayers, carpenters, welders and concreters. Majority of accidents happen to the persons who work for less than one year (fatal accidents—8, heavy accidents—16, slight accidents—163, or 44.44%, 41.08%, 32.21%, respectively). First Published Online: 26 Jul 201