Monika Mackiewicz
@pb.edu.pl
Politechnika Bialostocka
Scopus Publications
Scopus Publications
Joanna A. Pawłowicz, Piotr Knyziak, Janusz R. Krentowski, Monika Mackiewicz, Aldona Skotnicka-Siepsiak, and Carles Serrat
Elsevier BV
M. Mackiewicz, K. Zimiński, J.A. Pawłowicz, and P. Knyziak
Elsevier BV
Monika Mackiewicz, Janusz Ryszard Krentowski, Kamil Zimiński, and Aldona Skotnicka-Siepsiak
MDPI AG
The evaluation of the technical condition of historic buildings that have operated for several hundred years is a complicated issue. Even buildings that are in very poor condition must be checked and assessed in terms of their further repair, strengthening, or compliance with conditions that allow the facility to be safely operated. Most 18th-century buildings have not survived to this day retaining their original arrangements and structural elements. Renovations and repair work in the past were often carried out using materials of uncertain quality, with repair work of different qualities and without detailed analysis or methodology, based only on the experience of the former builders. In historic structures, the character of the work of individual structural elements has often changed due to significant material degradation, the poor quality of repair work, or the loss of adequate support. When load transfers change, internal forces are redistributed, and, as a result, the static scheme changes. This article presents an overview of identified defects affecting the change in static schemes in historical building structures built in the 18th century, using the example of a historic building with a large number of aforementioned defects. The process of assessing the technical condition of the facility is presented, in which non-destructive testing (NDT) methods were used. Detailed computational analyses were carried out for the wooden roof truss structure, which had partially lost its support.
M. Mackiewicz, J.R. Krentowski, P. Knyziak, and R. Kowalski
Elsevier BV
Maciej Wardach, Janusz Ryszard Krentowski, and Monika Mackiewicz
Elsevier BV
M. Mackiewicz, J.R. Krentowski, P. Knyziak, and M. Wardach
Elsevier BV
J.R. Krentowski, P. Knyziak, and M. Mackiewicz
Elsevier BV
Abstract The work concerns the procedure of examination and assessment of the condition of external curtain walls used in typical prefabricated residential construction systems at the end of the 20th century in Poland. External partitions were formed from a concrete structural layer, thermal insulation made of expanded polystyrene or mineral wool with variable thickness and a layer of textured concrete. The insulating and texture layers were attached to the structural panel through connectors known as “hangers”. The durability of the exterior barrier, planned at the design stage for 50 years, is determined by the effectiveness of the execution of both concrete layers’ connections. The technical condition of more than one hundred buildings assembled in the large-panel technology was carried out after 35-50 years of operation, usually prior to the thermo-renovation of the buildings planned by the users or before the end of the designed period of use. Various research techniques were used, non-destructive testing has allowed to limit the required number of destructive tests. The test results, assessing actual physical and mechanical parameters of the materials used for the construction of connections, permitted to build calculation models and verify the effort state of structural elements. As a result of the research, calculations and analyses, a concept of effective reinforcement of threatened connections was developed. In addition, recommendations regarding effective testing of interlayer connections that are difficult to reach were formulated.
Tadeusz Chyży and Monika Mackiewicz
MDPI AG
The conception of special finite elements called multi-area elements for the analysis of structures with different stiffness areas has been presented in the paper. A new type of finite element has been determined in order to perform analyses and calculations of heterogeneous, multi-coherent, and layered structures using fewer finite elements and it provides proper accuracy of the results. The main advantage of the presented special multi-area elements is the possibility that areas of the structure with different stiffness and geometrical parameters can be described by single element integrated in subdivisions (sub-areas). The formulation of such elements has been presented with the example of one-dimensional elements. The main idea of developed elements is the assumption that the deformation field inside the element is dependent on its geometry and stiffness distribution. The deformation field can be changed and adjusted during the calculation process that is why such elements can be treated as self-adaptive. The application of the self-adaptation method on strain field should simplify the analysis of complex non-linear problems and increase their accuracy. In order to confirm the correctness of the established assumptions, comparative analyses have been carried out and potential areas of application have been indicated.
T. Chyży and M. Mackiewicz
Elsevier BV
An original function describing the occurrence of indoor gas explosion in residential buildings has been presented in the paper. The function has been developed in order to simplify the description of explosion occurrence with its principal parameters, pressure and dynamics, being retained. It is a self-adaptative function, which means that its time function depends on the condition of construction elements, mainly decompressing areas called vents. The function consists of two parts. One is the phase of explosion pressure increase and the second is the decompression phase described by the fvent. modifier. The multiplication of the explosion pressure increase function and the fvent. modifier provides a final description of a pressure function for a vented explosion. The proposed function dependence enables an efficient dynamic analysis of three-dimensional models of building structures by means of the FEM.