The article analyses the impact of wind suction on roof coverings glued with polyurethane adhesives to flat roofs, i.e., roofs with an up to 20% slope. The impact of the cyclical wind was simulated in fatigue tests, gradually increasing the test pressure in repeated sequences until the first delamination occurred. The tests were carried out for eight test sets, with concrete and trapezoidal sheets used as a construction substrate, on whose surface thermal insulation layers were glued with polyurethane adhesive; the thermal insulation layers were EPS (expanded polystyrene) and PIR (polymer mainly of polyisocyanurate groups), respectively, followed by flexible sheets, i.e., a laminated PVC membrane (polyvinylchloride) and an EPDM (terpolymer of ethylene, propylene and a diene with a residual unsaturated portion of diene in the side chain)-type rubber-based membrane. The test results were compared with the functional requirements determined with computational simulation methods for the maximum wind load values on the example of wind loads for Poland. The tests confirmed that some polyurethane adhesives could ensure the operation of flexible sheets used as flat roof coverings that are failure-free from the point of view of resistance to wind suction.

This manuscript provides an overview of the most commonly-produced bitumen roofing sheets, focusing on the types of reinforcements used for their production and the reinforcements’ effects on the durability of tensile mechanical properties of roofing sheets under thermal loads. The paper includes the analysis of working conditions of roof coverings in the mid-European transitional climate, i.e., exposed to temperatures passing through 0 °C for three seasons in a year, periodic exposure to negative temperatures reaching −15 °C and positive temperatures up to +70 °C, justifying the above-mentioned emphasis on thermal load. It draws attention to technical problems related to the cooperation of roofing sheets with roofing substrates, with particular emphasis on concrete substrates. For the purposes of the work, the analyses were carried out with regard to the assessment of the service life of roof coverings made of various reinforcements working in conditions of variable temperatures and thus exposed to the transfer of thermal movements of substrate plates. The analyses also included the impact of different coefficients of thermal expansion of the materials in contact with other materials within roof coverings on the incidence of damage to cover layers. Particular attention was paid to the conditions resulting from the production process of roofing sheets effect on the durability of roof coverings made of these materials. Additionally, there were set directions for further work to calculate the impact of stresses, arising in layers of roof coverings during their operation in changeable negative and positive temperatures, on the incidence of mechanical damage to these coverings.

With the large panel buildings being widely used, effective protection of buildings against the destructive effects of extraordinary loads becomes an important issue. Therefore, the article delves into the history of developing standards that regulate design basics of buildings made of large-scale elements. The article deals with characteristic properties such as spatial stiffness by using a system of rigid transverse and longitudinal walls. The author emphasizes that a characteristic feature of the design of large panel buildings is the presence of monolithic joints between prefabricated elements in the ceiling and wall slabs. The article identifies the components that play an important role in ensuring sufficient reliability of large panel system buildings. The article stipulates methods of accounting for accidental loads in designing large panel system buildings and covers application methods. The article covers the guidelines for protecting large panel buildings against progressive collapse. The authors outline that the local destruction of a load-bearing wall in the zone adjacent to the outer edge is extremely dangerous due to a progressive collapse, and that is why it is important to take into account progressive collapse in structural design. The article contains basic design recommendations for protecting large-panel buildings against the effects of extraordinary loads. In conclusion, the authors opine that the methodology of protecting large panel buildings against the effects of a progressive collapse may be used for assessing the state of a structure damaged due to warfare. In the case of war damage to large-panel buildings occurring in Ukraine, due to the extent of the destruction, the article recommends developing procedures aimed at reliability assessment with partial use of the methods described in the article. On top of that, the catalog of strengthening solutions for each large panel system should be developed and available in case if reconstruction is needed. У зв'язку з широким використанням великопанельних будівель ефективний захист будівель від руйнівного впливу екстремальних навантажень стає важливим питанням. Тому в статті розглядається історія розробки стандартів, які регулюватимуть принципи проєктування будівель з великих елементів. У статті розглядаються такі характерні властивості, як просторова жорсткість за допомогою використання системи жорстких поперечних і поздовжніх стінок. Автор підкреслює, що характерною особливістю проєктування великопанельних будівель є наявність монолітних швів між збірними елементами в плитах стелі і стін. У статті вказані компоненти, які відіграють важливу роль для забезпечення достатньої надійності великопанельних будівель при їхньому проєктуванні. У статті розглядаються методи обліку навантажень при виникненні аварії під час проєктування великопанельних будівель і сфера застосування цих методів. У статті конкретизовані та проаналізовані настанови щодо захисту великопанельних будівель від прогресуючого обвалення. Через локальне руйнування несучої стіни в зоні, прилеглій до зовнішнього краю, що є надзвичайно небезпечно через можливість прогресуючого обвалення, автор наполягає на тому, що локальному руйнуванню необхідно приділяти особливу увагу при проєктуванні будівлі. У статті містяться основні проєктні рекомендації щодо захисту великопанельних будівель від впливу екстремальних навантажень. У висновках автор висловлює думку, що методологія захисту великопанельних будівель від наслідків прогресуючого обвалення може використовуватися для оцінки технічного стану об'єкта, пошкодженого в результаті бойових дій. У випадку пошкодження великопанельних будівель внаслідок війни в Україні, в залежності від масштабу руйнувань, у статті рекомендується розробити послідовні принципи оцінки надійності об'єктів з частковим використанням методів, описаних у статті, а також розробити каталог рішень щодо посилення великопанельної системи будівлі у випадку можливості проведення реконструкції.

Residential buildings near transport corridors are exposed to traffic-induced vibrations that can affect their safety. This paper presents a dynamic diagnosis of a masonry building located near a grade-separated junction. The study aimed to determine whether traffic-induced vibrations were responsible for the diagonal cracking of plaster observed in a dormer wall. The methodology included simultaneous acceleration measurements on the ground and building, traffic recording, 3D laser scanning for geometric reconstruction, and finite element modelling with soil–structure interaction. Time history and modal analyses were performed for various soil stiffness values. The results show that vibrations are predominantly attenuated at the soil–building interface, whereas soil flexibility markedly lowers the fundamental (lowest) natural frequencies of the building. The effect of soil stiffness on wall shear stress was more significant than that of dynamic action in load combinations. A comparison of the principal stress trajectories with the observed cracking patterns suggests that the damage was primarily due to the support condition of the wall. Traffic-induced vibrations are not the main cause of the observed damage. The integrated diagnostic procedure was effective in distinguishing vibration effects from other structural factors and was useful in assessing building safety.

Numerous artificial sources of acoustic waves have been described in the literature, which are designed to replicate the process by which actual damage occurs in a given material. Knowledge of the velocity with which an acoustic wave propagates is important here, both in order to correctly locate the signal source and to determine the degree of material degradation or the location of damage that has already occurred in the medium. This work presents the results of laboratory tests comparing two sources of artificial waves in terms of determining their parameters: the Hsu–Nielsen source and a sensor with the Auto Sensor Test function. The AST function allows the sensors to send and receive an elastic wave and is used to calibrate the sensor before, during, or after the test. In this study, the impact of the positioning of the sensors on the element being tested, their spacing, and the distance of the wave source from the sensor on selected parameters of the recorded waves are analyzed: velocity, amplitude, energy, rise time, waveform shape, and wavelet maps. This work demonstrates that a sensor with the AST function can be an effective alternative for the Hsu–Nielsen source in diagnostic studies.

Wydawnictwo SIGMA-NOT wydaje czasopisma fachowe informuj?ce swoich czytelnik?w o najnowszych osi?gni?ciach naukowych i nowoczesnych rozwi?zaniach technicznych w Polsce i na ?wiecie, popularyzuje problemy techniczne oraz poszerza wiedz? i kultur? techniczn?.