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The work concerns issues related to the diagnostics of moisture in historic buildings. Moisture content is one of the basic physical properties of materials. Excessive and undesirable growth of moisture in masonry causes considerable damage to masonry wall assemblies. It reduces the load-bearing capacity of structural elements, causes difficulties with heating and contributes to the development of mould and fungi. The article describes diagnostic procedures, provides available drying methods for walls in buildings and the applied method of renovation based on the example of damage caused by moisture in an examined historic facility.

Current trends towards saving energy and designing sustainable buildings result in most designers focusing on achieving the best thermal parameters, thereby neglecting a careful moisture analysis. Excessive moisture content in building partitions degrades the mechanical properties of materials, reduces thermal insulation properties (which leads to an increase in the demand for thermal energy) and worsens the microclimate in rooms. Modern digital solutions help create appropriate models of partitions that work for many years in good environmental conditions. According to the analysis of air parameters, 1 m3 of air at 20 °C contains approx. 17.3 g of water. When the temperature of the air reaches the dew point temperature, water vapour condenses. The dew point depends on air temperature and relative air humidity; for instance, at the same air temperature of 20 °C, the dew point temperature at 40% relative air humidity is 6 °C, whereas at 90% relative humidity, it is over 18 °C. This means that the higher the value of relative humidity in the room at a certain temperature, the lower the temperature that will cause condensation. The article presents a numerical analysis of the insulation work of flexible materials within the layers of ventilated partitions in an 8-year simulated period of varying environmental conditions. The aim of the article is to analyze different models and variants of ventilated partition operation with respect to the advisability of using a vapour barrier to avoid the problem of destruction of thermal insulation and finishing layers of a ventilated roof.

This article presents different types of commercially available roof waterproofing membrane systems used on roofs with large surface area. It deals with the causes of deterioration of such membranes due to environmental factors and describes the tests used to detect leaks and determination of the severity of deterioration of polymeric membranes taking into account the properties declared by their manufactures. The last part of the article is a case study comparing a brand new membrane with a membrane after 27 years in service.

The article presents a current view on the issue of supplying utilities to land regarded differently than merely technical solutions. The authors offer an insight to the issue of the technical supplying of urbanized areas, treating such infrastructure as a determinant of the coexistence of buildings and transfigurations of the urban fabric. Using selected examples of novel means of identifying existing solutions of the underground technical infrastructure (canals, sewage and stormwater networks, transportation and communication tunnels, building in additional contemporary of installations of logical networks or unidentified remains of past development), the need to carry out additional analyses and prepare a new, or update-change the existing local spatial development plan were identified. It was noted that The construction of underground infrastructure corridors ought to be the key, preceding the issuing of building permits, the commencement of activities by developers as well as administrative conditions. The underground infrastructure has an influence of the dynamics as well as quality of spatial transformations of urbanized areas.

W artykule przedstawiono dawne popularne zabezpieczenie drewna konstrukcyjnego ze względu na wilgoć i owady. Ekotoksyczny olej kreozotowy jest do dnia dzisiejszego stosowany jako środek zabezpieczający konstrukcje, które stykają się z gruntem, wodą i powietrzem. Kreozot, stosowany do impregnacji podkładów kolejowych, podrozjazdnic oraz mostownic, a także słupów linii energetycznych uznano za bezprogowy czynnik rakotwórczy i sklasyfikowano jako substancję rakotwórczą kategorii 1B. Obecnie w kraju podejmuje się próby neutralizacji tego materiału celem ochrony środowiska. Celem artykułu jest wykazanie, że dawne impregnowane elementy drewniane nie powinny dostawać drugiego życia, choć ich budowa i struktura nadal nie uległy destrukcji pomimo ich długoletniej eksploatacji. W artykule przedstawiono różne metody neutralizacji, porównano strukturę drewna zdegradowanego i bez śladów destrukcji po wieloletnim działaniu impregnatu.

W artykule przedstawiono podstawowe przepisy regulujące politykę energetyczną w Unii Europejskiej oraz dochodzenie do aktualnego stanu certyfikacji energetycznej. Zwrócono również uwagę na aktualne akty prawne regulujące tę kwestię w Polsce. Przedstawiono także najbardziej charakterystyczne świadectwa energetyczne obowiązujące w wybranych krajach w Unii Europejskiej. Starano się określić główne zasady obowiązujące w danym kraju oraz politykę energetyczną, jaką poszczególne kraje preferują.

The use of layered or hollow floors in the construction of buildings obviously reduces the self-weight of the slab, and their design requires some expertise. In the present work, a sensitivity analysis and numerical homogenization were used to select the most important characteristics of bubble deck floors that have a direct or indirect impact on their load capacity. From the extensive case study, conclusions were drawn regarding the optimal selection of geometry, materials, and the arrangement and size of air voids in such a way as to ensure high stiffness of the cross-section and at the same time maximally reduce the self-weight of the slabs. The conducted analyses showed that the height of the slab and the geometry of the voids had the greatest impact on the load-bearing capacity. The concrete class and reinforcement used are of secondary importance in the context of changes in load-bearing capacity. Both the type of steel and the amount of reinforcement has a rather small or negligible influence on the bubble deck stab stiffness. Of course, the geometry of the voids and their arrangement and shape have the greatest influence on the drop in the self-weight of the floor slabs. Based on the presented results of the sensitivity analysis combined with numerical homogenization, a set of the most important design parameters was ordered and selected for use in the optimization procedure.

Niniejszy artykuł ma być próbą poszerzenia wiadomości na temat Tadeusza Staniewskiego (1873–1940) na podstawie zbiorów Archiwum Państwowego w Poznaniu i wielkopolskiej prasy. W 1919 r. objął stanowisko burmistrza w podpoznańskim mieście Swarzędz. Piastował je przez 9 miesięcy. Ponownie wybrany burmistrzem w 1929 r., pełnił tę funkcję do 1939 r. Ta dekada to okres powolnego rozkwitu miasta. Swarzędz zyskał reputację „stolicy polskiego meblarstwa”. W swoim mieście Tadeusz Staniewski cieszył się uznaniem jako kupiec i człowiek oddany działalności obywatelskiej. Zwolennik Narodowej Partii Robotniczej, po zamachu majowym przyłączył się do secesyjnej grupy NPR-Lewica, popierającej Józefa Piłsudskiego. Następnie stał się członkiem Bezpartyjnego Bloku Współpracy z Rządem. Później wspierał działalność Obozu Zjednoczenia Narodowego. Z szacunkiem odnosił się do przedstawicieli ugrupowań opozycyjnych. Mimo że w Radzie Miasta Swarzędza zdobyli przewagę zwolennicy endecji, Tadeusz Staniewski utrzymał się na stanowisku burmistrza. Na szczególną uwagę zasługuje jego działalność charytatywna i zaangażowanie na rzecz zwalczania bezrobocia na terenie miasta. Public activity of Tadeusz Staniewski in Swarzędz in the years 1918–1939 The article presents the activity of Tadeusz Staniewski (1873–1940), a merchant and social activist, in the town of Swarzędz, near Poznań, in the years 1918–1939. The following sources were used for the purpose of writing this article: the collection of the State Archive in Poznań, as well as articles in Greater Poland press, mainly in periodicals. In 1919, Staniewski became the mayor of Swarzędz and held this position for nine months. In 1929, he was yet again elected mayor, but this time held this position for a decade. For the town, this was a time of a gradual rise to prosperity. Swarzędz became known as the “furniture capital of Poland”. In his town, Tadeusz Staniewski was a respected merchant and a dedicated civil servant. He was a supporter of the National Workers’ Party, and after the May coup, he joined one of its factions — the Left, which supported Józef Piłsudski. Later, he became a member the Nonpartisan Bloc for Cooperation with the Government. In subsequent years, he supported the activities of the Camp of National Unity. His attitude towards the representatives of the opposition remained respectful. Even though the representatives of the National Democracy gained majority in the Swarzędz City Council, Tadeusz Staniewski kept his position as mayor. His charitable activity and commitment towards combating unemployment in his town are particularly noteworthy.

Wind action belongs to loads that are environmentally variable. Wind action is included in the basic combination of loads, whereas hurricane wind action is classified as a unique combination. Due to large gusts of wind, the roof coverings of large-scale buildings are exposed to detachment of their cover layer. The article presents the effects of over-normative wind, which occurred on January 19, 2018 and was named the cyclone Frederic/David. The purpose of the article is to show that in design of roof coverings made of large-format materials, such as membranes, it is crucial to accept wind load values properly in order to ensure a right spacing between fasteners. The presented results might be an important contribution to the debate on the necessity for increasing the fundamental value of the basic wind velocity in the perimeter and corner zones of large-format roofs.

The non-linear analysis of hollow-core concrete slabs requires the use of advanced numerical techniques, proper constitutive models both for concrete and steel as well as particular computational skills. If prestressing, cracking, crack opening, material softening, etc. are also to be taken into account, then the computational task can far exceed the capabilities of an ordinary engineer. In order for the calculations to be carried out in a traditional design office, simplified calculation methods are needed. Preferably based on the linear finite element (FE) method with a simple approach that takes into account material nonlinearities. In this paper the simplified analysis of hollow-core slabs based on the generalized nonlinear constitutive law is presented. In the proposed method a simple decomposition of the traditional iterative linear finite element analysis and the non-linear algebraic analysis of the plate cross-section is used. Through independent analysis of the plate cross-section in different deformation states, a degraded plate stiffness can be obtained, which allows iterative update of displacements and rotations in the nodes of the FE model. Which in turn allows to update the deformation state and then correct translations and rotations in the nodes again. The results obtained from the full detailed 3D nonlinear FEM model and from the proposed approach are compared for different slab cross-sections. The obtained results from both models are consistent.

In the article, a comparative analysis of the effects of selected substances applied to create secondary horizontal damp proof courses of masonry walls by means of the chemical injection method on the properties of masonry mortar was carried out. Particular attention was given to the influence of impregnation on the hygric properties of mortar. The resistance to destructive factors accompanying the dampening of masonry wall structures was also subjected to observation.

The determination of mutual correlation between thermal and humidity-related parameters at locations with difficult geometry is still a challenge for designers. External partitions operating in adverse environmental conditions must exhibit specific parameters protecting against condensations and destruction, in order to ensure the operation safety of the entire structure. Both the research, as well as construction reality have shown that thermal bridges are the critical locations of buildings. The Investors often interfere with the design process creating hard-to-accept boundary conditions. Lack of knowledge and experience often results in the formation of construction defects and failures.

Modern materials and construction solutions draw more and more attention to ecology and building certification. Among the criteria appearing in revitalization, an important element is bringing plants back into heavily urbanized areas. In its natural form, this is not possible to carry out everywhere, often requiring large amounts of space. Nowadays, however, there are a number of green roofs and green wall systems, allowing “greener” construction without making significant changes in the urban environment. The article includes a presentation and analysis of selected solutions of biological surfaces known as green roofs and green walls, specifying various solutions and their most important features. The case study focuses primarily on material and design solutions, as well as the potential benefits, risks and limitations in their use. Plants structures on the surfaces of vertical and horizontal partitions continue to be a very interesting alternative to take into account when applying for grants, such as LEED or BREEAM certificates.

As climate changes progress we are dealing with violent and excessive environmental actions. However, the impacts of loads acting on a building object caused by unlikely phenomena such as: fire, explosion, flood, vehicle impact, plane impact, excessive snowfall, and excess wind gusts are still being ignored when analyzing the structure of building objects in the combinatorics of loads. The paper presents a multi-criteria approach to accidental actions and analyzes design situations and load combinations in relation to accidental actions. The existing legal acts were used to define the concept of a construction disaster. The authors verified, on the basis of applicable legal acts and design guidelines, individual analysis strategies for ensuring the safety of building objects and divided them into consequence classes of structural damage. They collected and analyzed the number of construction disasters which occurred in Poland between 1995&ndash, 2019 (25 years) based on the data from the General Office of Building Control. The number of disasters was divided by voivodeships and causes and supplemented with the data on the number of people injured. The article presents the direction of research development that could be undertaken in order to eliminate future catastrophes caused by the omission of the analysis of the impact of accidental actions at the design stage. Statistical analyses were carried out to show whether land use, population density, and weather factors (wind) affect the number of recorded disasters. It has been shown that regions that have preserved the sustainable development of their territories are less vulnerable to disasters resulting from extreme weather events.

The moisture content in historical masonry walls, particularly on the ground floor, caused by i.e. lack of damp insulation, is a phenomenon of common occurrence. It is usually analysed in terms of mycological changes, thermal insulation and frost damage. The paper discusses the influence of the increased moisture content on the weight and load bearing capacity of the structure. The determination of moisture content in masonry elements, performed during the inspection of the building, provides information from which an increase in the structure's weight can be defined. Reliable tests for the moisture content and compressive strength of masonry and mortar components are invasive, and the number of testing in historical buildings should be limited to the minimum necessary to preserve their vintage nature. As a result, the received overall picture of the work of masonry may not be consistent with its actual state since historical buildings could have been rebuilt or repaired, and consequently, contain masonry conversions made of various materials with different properties. Absorbability can serve here as an example as it is a factor that disrupts a reliable determination of load bearing capacity values of masonry structures. The article attempts to determine the change in load bearing capacity of a moist masonry structure compared to the original - in the air-dry state - for various types of historical masonry and mortar components. The main influence analysed was due to capillary action, whereas the effect of other sources of moisture, i.e. salinity, was excluded.

Reinforced concrete structures are frequently designed and executed in such facilities as: halls, warehouses, factories, multi-family buildings, single-family buildings, tanks, silos and many others. For this type of structures, it is particularly relevant to provide an appropriate thickness of concrete lagging, which aims at protecting reinforcement against corrosion, and to design it with appropriate spacing allowing the in-between space to be filled with a concrete mix. A frequent problem met while making reinforced concrete structures is such a density of reinforcing bars, particularly within structural nodes, that there is no possibility of filling the space between them with a concrete mix or it is not possible to vibrate the concrete mix in order to prevent segregation of mixture components. Structural nodes are points where special attention should be paid to careful compaction of concrete mixes and application of measures that prevent concrete from adhering to molds. The case study illustrates two structural nodes connecting a column with a bolt, located in a wall with a column-transom structure. During the modernisation works carried out in the production hall there were exposed two structural nodes completely unfilled with a concrete mix and with visible reinforcing bars that showed little buckling and the onset of corrosion. The columns, due to their location in the general static scheme of the wall, were subjected to compression or locally compressed and affected by bending. Particularly unfavourable was the fact that the columns did not feature the concrete lagging in the compression zone of the element. Removal of concrete lagging in the compression zone always results in decrease in the bearing capacity of a structure. It can be concluded that due to faulty workmanship the columns had a lower load bearing capacity than anticipated in the building permit design. The paper provides software-derived guidelines for repairing reinforced concrete columns so as to obtain the value of load bearing capacity equal or higher than expected in the design and on the assumption that repair works would be carried out on columns subjected to loading.

Dampness in basement walls caused by capillary rise of water from the ground, as well as possible resulting damage, is very unfavourable phenomenon. This problem mainly concerns historical buildings and other structures erected before 1920, and the destruction is caused by lack, damage or technical wear of insulation. However, it can also arise in relatively new buildings where insulation was made incorrectly (or was not made at all). Creating a barrier that interrupts the capillary rise of moisture in the existing wall, i.e. secondary horizontal hydro-insulation is perceived as one of the most difficult, from a technical point of view, tasks in the field of building protection against water and dampness. The so-called mechanical methods are seen as the safest. Assuming that the works will be flawlessly planned and executed, a durable layer, impermeable to water and thus completely inhibiting the capillary transport of moisture, is formed in the cross-section of the wall – in many cases resulting in highly efficient isolation as "in a new building" 1[1]. However, due to practical limitations, mechanical methods are used much less frequently than injection schemes. By injection, injection technology or chemical injection is meant the introduction of injection fluid into the masonry, with the following three distinguishable ways of applying an injection agent: penetration, pressure and pulse in the form of an aerosol. The technology must ensure equal distribution of an injection agent within the entire wall cross-section, and its principle of operation is to create a continuous layer interrupting capillary rising to obtain (after some time) an area with regular dump in the masonry zone above the membrane. Injection methods, although widely used, are associated with a greater risk of partial or complete failure. The universality of application combined with the risk of failure has encouraged the search for a parameter to assess the effectiveness of secondary horizontal insulation. A suitable parameter is the AQ coefficient (from German - Abdichtungs Qualitat) based on the capillary water absorption coefficient, proposed by Venzmer et al3. The article presents research results on the effectiveness of chemical injections performed in reference walls made of ceramic bricks. The membrane was made using three different injection agents: formulation based on silicates (mixture of silicates and alkaline methyl silicates), silicon micro-emulsion and silane-based injection cream. In the injection zone, the drill cores were taken to perform capillary water absorption coefficient measurements. In order to obtain reference samples, additional drills were made above the impregnation zone protected with the injection agent. Both the measurements made and the calculated AQ coefficients proved the effectiveness of the abovementioned injection agents.