The present paper is aimed at the analysis of under ballast mats (UBM) which are used in ballasted track structures as vibration isolators and to protect the ballast layer against fast degradation. The mats were tested in the laboratory and afterwards a novel 4-DoF mechanical model of the track structure with UBM was developed. The novelty of this study consists in the comparison of two testing procedures: a procedure based on the popular German standard DIN 45673-5 and a new European standard EN 17282, released in October 2020. Major discrepancies were demonstrated in the determined values of the static and dynamic characteristics using both approaches—especially in reference to the mats with higher stiffness.
The article presents and describes the methodology of conservation of masonry structures that are architectural monuments discovered as part of the work carried out during archaeological excavations. The authors' experiences presented in the article result from many years of cooperation between the Faculty of Civil Engineering at Warsaw University of Technology, the National Museum in Warsaw and the Antiquity of Southeastern Europe Research Center at the University of Warsaw. Examples of preserved masonry structures come from excavations located in the Black Sea area - from the archaeological site in Tyritake in Kerch on the Crimean Peninsula and Tanais near Rostov-on-Don in Russia. Works on masonry structures located in the area of archaeological excavations are characterized by a unique specificity covering both formal issues, resulting from international standards and agreements regulating the conservation of historic buildings, as well as technical and environmental issues. The basic technical issues include ensuring the safety of further excavation works, protection of masonry structures against the destructive effects of atmospheric conditions and preparing the structure for possible exhibition in archaeological parks organized on the site of excavations. Environmental issues relate to local, social and economic conditions. The article presents the procedures that should be used in the conservation of these types of structures and presents the specific technological and material solutions used in the presented objects.
Every conservation works related to an ancient masonry structures should be preceded by an appropriate diagnostic. This should be understood as geometrical survey and various tests, which results with a proper analysis of the structure, identification of materials, technologies and techniques used during construction. The effective tool which could be used in this field is 3-D laser scanning. The digital image obtained as a result of scanning could be a proper base for a preservation programme, as well as help for creation of a precise digital models for a structural analysis. The examples of 3-D laser scanning application presented in the article are diagnostic works carried by the Division of Fundamentals of Building, Warsaw University of Technology, with the cooperation of Warsaw University, at the archaeological sites in Alexandria, Egypt and in Tanais, Rostov, Russia. Based on this works some most important advantages of laser scanning in identification, diagnostics and preservation of ancient architectural monuments was stated.
The article presents and describes the conservation of masonry structures at archaeological site in Tanais near Rostov-on-Don in Russia. The authors' experiences presented in the article result from many years of cooperation between the Faculty of Civil Engineering at the Warsaw University of Technology and the Centre for Research on the Antiquity of Southeastern Europe at the University of Warsaw. Works on masonry structures located in the area of archaeological excavations are characterized by a unique specificity covering both formal issues, resulting from international standards and agreements regulating the conservation of historic buildings, as well as technical and environmental issues. The basic technical issues include ensuring the safety of further excavation works, protection of masonry structures against the destructive effects of atmospheric condition and preparing the structure for possible presentation in archaeological parks organized on the site of trenches. Environmental issues relate to local, social and economic conditions. The article presents the procedures that should be used in the maintenance of antique irregular masonry and presents the specific technological and material solutions used in the example objects.
The article presents a constitutive model for Shape Memory Alloys (SMA) along with result of dynamic simulations of SMA model. The applications of devices incorporating SMA in civil engineering focus mostly on mitigation of the seismic hazard effects in new-build and historical buildings or improvement of fatigue resilience. The unique properties of SMA, such as shape memory effect and superelasticity give promising results for such applications. The presented model includes additional phenomenon of SMA – internal loops. The paper shows the method of formulation of physical relations of SMA based on special rheological structure, which includes modified Kepes’s model. This rheological element, introduced as dual-phase plasticity body, is given in the context of martensite phase transformation. One of the advantages of such an approach is a possibility of formulation of constitutive relationships as a set of explicit differential equations. The application of the model is demonstrated on example of dynamic simulations of three dimensional finite element subjected to dynamic excitation.
Biskupin is one of the most recognizable archaeological site in Pola1nd and Central Europe. The origins of the excavations dates back to year 1934 and had lasted almost continuously until 1974. In the framework of the grant from the Ministry of Culture and National Heritage interdisciplinary team of scientists from Archaeological Museum in Biskupin and Warsaw University of Technology performed multi-dimensional analysis of the settlement. Based on the integrated vector documentation, resulting from the photographic documentation, numerical models of structural systems of main types of buildings and defensive rampart were prepared. The aim of the analysis was a verification of the earlier findings of archaeological and architectural researches. The analysis allowed to verify both the arrangement of individual parts of structure of buildings, their work and the interconnection, as well as the possible dimensions of the individual components.