The Polish Institute of Advanced Studies (PIASt) began functioning within the structure of the Polish Academy of Sciences on 2 January 2017. We caught up with its director, Prof. Przemysław Urbańczyk, to discuss the Institute’s objectives.
In the paper I show why we should consider Stoicism as the historical source of St. Thomas’s distinction between ‘conscience’ and ‘synderesis’. I claim that the Stoic terms syntērēsis and syneidēsis became, through the ages, the Thomistic synderesis and conscientia. The Stoic syntērēsis meant ‘self-preservation’, and in all animals this ‘first instinct’ refers to the body. The man is the only creature, which, because of its ‘rational nature’, preserves not necessarily its body but rather its soul, i.e. a system of values. Such preservation of someone’s axiological integrity equals ‘salvation’, and thus assimilates Stoicism to Christianity. In the Stoic system, human values follow ‘the nature’ (or ‘the human nature’ in particular), and in Thomism, they follow ‘synderesis’, or the natural inclination toward the good. In both cases we find a natural instinct that transforms itself into a rational structure of conscience. I also argue that, thanks to the moral phenomena of ‘adaptation’ (oikeiōsis) and ‘advancement’ (teleiōsis), the Stoic ethics is not completely egocentric, but incorporates also social duties.
This paper deals with a Continuous Stiffness Degradation (CSD) version of advanced analysis of braced steel framing. It is based on the gradual stiffness degradation concept of frame and truss members. A novelty of the approach presented herein is related to the introduction of the bracing member response in the whole range of its behaviour in tension and compression, including the post-limit range. The validation of the proposed advanced analysis is performed for braced framework with rolled angle section braces. The validation of the brace force-deformation model has been presented in the author’s earlier publication. The basis for the presented CSD advanced analysis is briefly summarized and its difference with regard to the Refined Plastic Hinge (RPH) version of advanced analysis is emphasized. Experimental investigations dealing with tests on portal braced sub-frame specimens are referred to briefly. Results of the experimental investigations are presented in the form of a frame global response and they are used for the validation of the developed computational model.
Cracks in concrete are inevitable but fortunately cracking enables the structures to get rid of its bending moment peaks. The reduction is due to the redistribution of the load induced moments and cut of the temperatureimposed moments. However, cracking becomes completely harmless if the crack widths are controlled properly by reinforcement. In this regard a method for crack width prediction is presented in this paper which thanks its reliability is widely accepted in the standards EN 13084, CICIND and DIN 1056.
Influenced by the dynamic pressure of the front abutment pressure and the lateral abutment pressure, large deformation of surrounding rock occurs advancing working face in the entry heading adjacent to the active longwall mining face. Based on the cause analysis of entry large deformation, a new technology was put forward to solve the problem, and the designing method of drilling hole parameters for directional hydraulic fracturing was formed. Holes are drilled in the entry or in the high drainage entry to a certain rock layer over the adjacent working face, hydraulic cutting or slotting at the bottom of a borehole were also applied in advance to guide the hydraulic fractures extend in expected direction, through which the hard roof above the coal pillar can be cut off directionally. As a result, the stress concentration around the entry was transferred, and the entry was located in a destressing area. The field test at Majialiang coal mine indicates that the propagation length of cracks in single borehole is more than 15 m. After hydraulic fracturing, the large deformation range of the entry is reduced by 45 m, the average floor heave is reduced by 70%, and the average convergence of the entry’s two sides is reduced by 65%. Directional hydraulic fracturing has a better performance to control the large deformation of the dynamic pressure of the entry heading adjacent to the advancing coal face. Besides, it can improve the performance of the safety production.
This paper is entirely devoted to practical aspects of direct design and assessment of safety and serviceability of steel planar framework using advanced analysis. The development of advanced analysis has been driven by a desire for a more accurate representation of the behaviour of planar framework by considering the beam and spring numerical modelling technique together with plasticity and geometrically nonlinear effects as well as structural imperfections accounted for. The validated 2D version of CSD advanced analysis developed by the author is used in this paper for its practical application towards the resistance and serviceability assessment of existing simple construction framework. This steel braced frame was a subject of technical expertise. The same structure geometry but with different joint detailing is then considered to show how the effect of joint properties may affect the braced frame performance. Results of investigations are presented in the form of frame global response at both the ultimate limit state and the serviceability limit state, and also in the form of member local responses. Conclusions with regard to general design and assessment practice are drawn.