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2022 ◽  
Vol 20 (4) ◽  
pp. 093-114
Author(s):  
Viktar Tur ◽  
Andrei Tur ◽  
Aliaksandr Lizahub

The article presents the simplified implementation of alternative load path method based on the energy balance approach. This method should be used to check the global resistance of a damaged structural system after the occurrence of an accidental event. Basic assumptions of simplified analytical models for modelling resistance of horizontal ties in a damaged structural system, taking into account the membrane (chain) effects, were presented. An approach to modelling the dynamic resistance of a damaged structural system based on the energy balance method is described. Calculated dependencies for checking the robustness of a prefabricated multi-storey building with hollow-core slabs after the loss of the central column are proposed and considered using an example. On the considered example, a comparison of the required tie sections area with the dynamic resistance designed using the energy balance method (EBM) and according to the current standards, and a statistical assessment of the reliability of the load-bearing capacity models are carried out. In the end, a brief algorithm for the simplified calculation of the dynamic resistance of a damaged structural system is proposed.


Author(s):  
Viktar TUR ◽  
Andrei TUR ◽  
Aliaksandr LIZAHUB

Within the framework of traditional approaches to checking for resistance of reinforced concrete buildings and structures to the progressive collapse development, membrane (chain) forces in a damaged structural system are calculated separately, without considering its non-linear bending behavior during the formation of the plastic hinges and without checking the possibility of achieving large deflections.The authors propose an approach to modelling a nonlinear quasi-static reaction of a damaged structural system in an accidental design situation. This approach considers non-linear bending and the resistance of reserved horizontal ties, considering their ultimate ductility. The authors verified the proposed approach based on the results of experimental studies by others researchers.An example of the application of the proposed approach in assessing the robustness of a structural system made of precast concrete with a sudden removal of the central column is considered. In accordance with the provisions of the energy approach, an analysis is made of the contribution of individual resistance mechanisms to the total quasi-static and dynamic resistance of the damaged structural system.We show that the proposed calculation model adequately describes the behavior of a damaged structural system in an accidental design situation, and therefore to carry out parametric studies and check the robustness of building structures.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
José Hurtado-Aviles ◽  
Joaquín Roca-González ◽  
Konstantsin Sergeevich Kurochka ◽  
Jose Manuel Sanz-Mengibar ◽  
Fernando Santonja-Medina

Introduction. Axial vertebral rotation (AVR) is a basic parameter in the study of idiopathic scoliosis and on physical two-dimensional images. Raimondi’s tables are the most used method in the quantification of AVR. The development of computing technologies has enabled the creation of computer-aided or automated diagnosis systems (CADx) with which measurement on medical images can be carried out more quickly, simply, and with less intra and interobserver variabilities than manual methods. Although there are several publications dealing with the measurement of AVR in CADx systems, none of them provides information on the equation or algorithm used for the measurement applying Raimondi’s method. Goal. The aim of this work is to perform a mathematical modelling of the data contained in Raimondi’s tables that enable the Raimondi method to be used in digital medical images more precisely and in a more exact manner. Methods. Data from Raimondi’s tables were tabulated on a first step. After this, each column of Raimondi’s tables containing values corresponding to vertebral body width (D) were adjusted to a curve determined by AVR = f (d). Third, representative values of each rotation divided by D were obtained through the equation of each column D. In a fourth step, a regression line was fitted to the data in each row, and from its equation, the mean value of the D/d distribution is calculated (value corresponding to the central column, D = 45). Finally, a curve was adjusted to the obtained data using the least squares method. Summary and Conclusion. Our mathematical equation allows the Raimondi method to be used in digital images of any format in a more accurate and simplified approach. This equation can be easily and freely implemented in any CADx system to quantify AVR, providing a more precise use of Raimondi’s method, as well as being used in traditional manual measurement as it is performed with Raimondi tables.


2020 ◽  
Vol 69 (1) ◽  
pp. 71-102
Author(s):  
Horogszegi Tamás

Tradition had it that the rectangular Romanesque hall with a central column in the royal and later archiepiscopal palace on Castle Hill in Esztergom was the birthplace of King Saint Stephen, although it was already clear in the 19th century that this part of the building dated from after the 11th century. Nevertheless, in view of the salient role of the castle in the cult of Saint Stephen, the prince primate and archbishop of Esztergom (1867–1891) János Simor (1813–1891) had the Romanesque room converted into a chapel in 1873–74, a thousand years after the birth of the state and church founder king. The reconstruction was planned by József Lippert, the chief architect of the prince primate who planned in this capacity, among other things, the transformation of the interior of the cathedral and the construction of its vestibule, the primate’s palace, and the purist reconstruction of Pozsony cathedral. The transformation of the hall with the central column included a new aperture, walling up of a niche, erection of an altar, and embellishing of the walls and vault with neo-Romanesque frescoes imitating the Byzantine style painted by the brothers Karl and Franz Xaver Jobst (fig. 3). The completed chapel became a neo-Romanesque Gesamtkunswerk down to the smallest detail, a venue of cult and memory.The decisive part of the painted decoration was the cycle of the salient episodes in St Stephen’s life on the vault arches: 1. Apparition of St Stephen protomartyr to Sarolt, wife of prince Géza (fig. 7). 2. The baptism of Vajk (fig. 11). 3. Bishop Astrick shows the crown brought from Rome to St Stephen (fig. 15). 6. Offering of the country to God (fig. 23). The paper reviews the iconographic antecedents of the scenes and the respective source texts, mentioning so-far unpublished works (figs. 13, 22). In addition to several other findings, it could be concluded that unlike in the period from the 17th to the mid-19th century when the depictions of King St Stephen were imbued with currently topical political implications, the images of the Esztergom cycle are free from such readings. The painters of the frescoes ordered by archbishop Simor mainly used recognized schemes and panels aligning themselves with the iconographic tradition, and therefore the novelty of the decoration which contemporary accounts emphasized must have been their neo-Byzantine style. A few decades later, however, this style must have appeared obsolete, nor did it have followers in its time, either. Apart from the demonstration of iconographic motifs, the direct models of the scenes cannot be determined even for such an extremely rare theme as Sarolt’s dream. That is at the same time proof of the invention of the painters and that is what ranges their work among the important achievements of post-Compromise painting: the ingenious use of motifs of mostly familiar scenes (identified by captions as well) and their arrangement in a new composition in the chosen or required style, with the prudent use of the semi-circular shape of the picture field when need be. It is important to note that no other picture cycle was created of St Stephen’s life in the second half of the 19th century. Moreover, some of the scenes have demonstrable linkage to stations in the life path of archbishop Simor, which must have influenced the finalization of the programme.During the archaeological excavations and reconstruction on Castle Hill in 1934–1938 the historicist elements of the hall with a central column were removed (fig. 4). Until how, research thought the painted decoration by the Jobst brothers had perished and were only known in reproduction. However, it must have been removed by Mauro Pellicioli or an assistant of his who had been invited to Hungary from Milan by Tibor Gerevich. I chanced upon the removed frescoes in a remote storeroom of Esztergom cathedral in 2011 with Veronika Nagy.


2020 ◽  
Vol 11 (4) ◽  
pp. 513-519
Author(s):  
R. R. Andreychuk ◽  
V. P. Kolomiychuk ◽  
A. V. Odintsova

The most usual fruit type in the family Саmpanulaсеае is an inferior multi-seeded capsule. In Саmpanula and related genera, A. Kolakovsky determined a new type of capsule, characterized by a specialized organ, axicorn. Some types of axicorn capsules were determined depending on the way of dehiscence. In Campanula, capsule dehiscence is called axicorn-fissuricidal mode, while in Asyneuma – axicorn-valvate mode with scaliformis valves. The precise differences between slit and valve so far have not been identified. In this connection, we performed the study of the inner fruit structure and dehiscence in Asyneuma canescens intending to compare the results with those for Саmpanula species. Anatomical fruit structure was studied under a light microscope on temporary preparations of transversal and longitudinal sections. For the first time, the obtained data provide precise characteristics of the inner fruit morphology, the anatomy of the fruit wall, and dehiscence mode in A. canescens. The survey revealed predominance in the ovary of a synascidiate zone with axile placentation. In the anatomical structure of the fruit wall, there we found a parenchymatous mesocarpium, non-lignified exo- and endocarpium, and lignified elements of fruit – axicorns, located in the small upper part of the septa. Fruit dehiscence in A. canescens occurs in two steps. First, during early flower development, narrow-oval dips are formed on the septum radii; during the fruiting period, a hippocrepiform slit at the lower margin of each dip develops. At this time axicorns detach from the central column of the ovary following a curved direction, meaning the formation of the septifragal slit. During the second stage, the longitudinal slits are formed from the lowest point of the hippocrepiform slit to the fruit base. These slits facilitate seed release from the capsule. Fruit in A. canescens we define as an inferior trilocular syncarpous capsule with two-stage, hippocrepiform and laminar dehiscence. Our study confirms resemblance of anatomical structure and dehiscence mode of fruit in A. canescens and species of the section Rapunculus of the genus Cаmpanula with erect capsules. We consider it inexpedient to accept the new fruit type for A. canescens, because differences compared with species of Cаmpanula are derivative and concern the small size of the axicorn slit and the appearance of additional slits only.


2020 ◽  
Vol 54 ◽  
pp. 119-127
Author(s):  
Giuseppe Casula ◽  
Francesco Cuccuru ◽  
Maria Giovanna Bianchi ◽  
Silvana Fais ◽  
Paola Ligas

Abstract. The use of Non-Destructive Testing (NDT) applied to construction materials allows to highlight and characterize their features, especially in the case of old buildings. The multi-technique high resolution 3D modelling described here is aimed to investigate the conservation state of the central column of a colonnade in the ancient church of Saints Lorenzo and Pancratio, dating to about the second half of the thirteenth century and located in the old town of Cagliari (Italy). This column was considered of interest because its longitudinal axis deviates from its ideal position and it appears the most deteriorated. In this work we describe the integrated application of 3D diagnostic methods, i.e. Terrestrial Laser Scanner (TLS), close range photogrammetry (CRP) and ultrasonic tomography supported by petrographic investigations. They were used to improve the diagnostic process of the conservation state of the investigated column. The TLS technique was supported by CRP to obtain a natural colour texturized 3D model of the column. The geometrical anomaly maps derived from the data of the TLS-CRP survey show the presence of some anomalies worthy of attention. Starting from the 3D reconstruction with previous techniques we planned and implemented a 3D ultrasonic tomography. Ultrasonic tomography proved to be a successful tool in identifying internal defects, as well as the presence of voids and flaws within the materials through the analysis of the propagation of ultrasonic waves. The integration of the three non-invasive techniques supported by petrographical analyses demonstrates its potential in reducing ambiguities since each technique brings its clue to the overall diagnostic process.


2020 ◽  
Vol 09 (04) ◽  
pp. 276-282
Author(s):  
Gregory I. Bain ◽  
Sathya Vamsi Krishna ◽  
Simon Bruce Murdoch MacLean ◽  
Parth Agrawal

Abstract Background Kienbock's disease, in spite of an uncertain natural history, is known to cause lunate compromise, leading to central column collapse, carpal instability, and degenerative arthritis of the wrist. Joint leveling procedures are performed in the early stages of Kienbock's disease to “unload” the lunate. Capitate shortening is the preferred procedure in Kienbock's patients with positive ulnar variance. Description of Technique We describe the rationale and a simplified technique of capitate shortening in early Kienbock's disease. This is a single-cut osteotomy with single-screw stabilization. Patients and Methods We have performed this technique in three cases. We present a case of a 26-year-old male who presented with a 1-year history of pain in his right wrist. Radiology performed demonstrated lunate sclerosis. Diagnostic arthroscopy revealed healthy articular surfaces. Single osteotomy capitate shortening was performed with an oscillating saw and fixed with a single cannulated compression screw. A shortening of 1.5mm was obtained with this technique. Results At 1- to 2-year follow-up, all three patients had considerable pain relief but did not have a complete resolution of pain. There was a significant improvement in function and grip strength. There have been no cases with infection, nonunion, avascular necrosis or a need for a salvage procedure. Conclusion The simplified technique of capitate shortening is easy to perform, less traumatic to the capitate vascularity, and leads to good short-term functional results.


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