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1
Content available Development of roundabouts empirical capacity model – case study of Hungary
Al Hasanat Haitham, Janos Juhasz
Zeszyty Naukowe. Transport / Politechnika Śląska
|
2023
|
z. 120
5--17
EN
Roundabouts are commonly used worldwide because they offer several advantages over traditional intersections. The capacity that a roundabout can handle is an important factor in ensuring smooth traffic flow at a particular location. Therefore, various models have been developed to describe traffic conditions and driver behaviour at different sites or countries. However, existing models cannot be directly applied to other countries without proper calibration of the models to ensure an accurate estimation of capacity. In this study, five roundabouts in Hungary were selected to develop a general capacity model and compare it with international models. First, all sets of entry and circulating data were obtained from video recordings of each roundabout entry. These data were used to develop a model for each entry and then for each roundabout separately. Finally, all the data sets from all sixteen entries were used to develop a general capacity model (GM). The general capacity model (GM) was compared with the Highway Capacity Manual (HCM) 2016, the Brilon-Bondzio, and the Brilon-Wu models. The maximum capacity of the general capacity model (GM) was 1390 pcu/h, slightly higher than the maximum capacity of the HCM 2016 model of 1380 pcu/h. The percentage differences between the generated general capacity model (GM), HCM 2016, Brilon-Bondzio, and Brilon-Wu models were +0.71%, +12.4%, and +10.7%, respectively.
2
Content available Evaluation of a capacity increase in AG milling of copper slag
Can N. Metin, Mercan Orberk
Physicochemical Problems of Mineral Processing
|
2023
|
Vol. 59, iss. 6
art. no. 175181
EN
The verification of the desired capacity increase in the grinding circuits is performed by simulation studies as they suggest accurate and fast alternatives compared to expensive and labor-intensive methods, particularly for the evaluation of situations that require investment. In this study, simulation was used to evaluate the alternatives that can be made to increase the capacity from 38.86 tph to 90 tph in a grinding circuit where copper slag is autogenously milled. The slag sample was characterized by drop weight and abrasion tests to describe the breakage in autogenous (AG) milling. The performances of the existing circuit and equipment were determined by a comprehensive sampling study, and modeling studies were carried out to form the basis of the simulations. Simulation scenarios were evaluated as investment free and investment requiring alternatives. In the investment free option changing fresh feed size distribution was examined however, capacity could be increased up to only 42 tph. In investment option, increasing the mill motor capacities was simulated and 90 tph target throughput was provided. This result was validated in the plant by replacement of mill motors of AG and pebble mill for 1000 kW and 750 kW, respectively.
3
Content available remote Modernizacja śluzy na stopniu wodnym Januszkowice – betonowanie obiektów
Synowiec Katarzyna, Tałaj Michał, Golda Artur, Saferna Marcin
Inżynier Budownictwa
|
2023
|
nr 7-8
86--91
4
Content available The Capacity and Effectiveness of Screening People and Baggage with the Use of New Technologies: Standard C2
Uchroński Piotr, Kozuba Jarosław, Letun Magdalena, Brzeska Katarzyna
Safety & Defense
|
2022
|
2
72--81
EN
One of the basic elements inseparably connected with air communication is the security control of persons and luggage which is performed by certified OKBs entered on the list of the President of the Polish CAA. An area of ​​interest is the security check of hand baggage passengers take with them on board the aircraft. This control is carried out based on current legal regulations in the field of civil aviation security and is designed to detect prohibited and dangerous items hidden in the passenger's luggage specified in these legal acts. Due to the fact that the catalogue of these items is not included in an enumerative way, the security control operator assesses the possibility of using any item other than that specified in the document in terms of the possibility of making an act of unlawful interference. However, the skills of the security control operator are only one of the elements affecting the effectiveness of the security check being performed. The technical background and degree of technical sophistication are no less important in the control process. This paper aims to indicate possible organizational solutions to be applied in practice, which have a measurable impact not only on the effectiveness of the security control performed but also on the throughput at the security checkpoint, which in turn determines the operational readiness of the entire airport. The authors, through empirical studies carried out at airport security checkpoints equipped with different technical and technological solutions, quantitatively indicate the benefits of using new technologies and the possibility of choosing the organization of work at the security checkpoint, depending on the needs arising from the nature and number of flight operations.
5
Wątpliwości dotyczące nośności stropu z płyt kanałowych obciążonego siłą skupioną
Jeziorski Miłosz, Derkowski Wit
Inżynieria i Budownictwo
|
2022
|
R. 78, nr 5-6
263--268
PL
W pracy przedstawiono wybrane aspekty projektowania stropów z płyt HC, obciążonych siłą skupioną, w świetle obowiązującej normy EN 1168 oraz licznych publikacji. Przeprowadzono analizę porównawczą, w której obliczeniową nośność płyty porównano z wybranymi badaniami eksperymentalnymi takich stropów, przeprowadzonymi w Fińskim Instytucie Technicznym. Wykazano wiele niejasności i wątpliwości co do sposobu obliczania elementów pracujących w złożonym stanie naprężenia, które wciąż wymagają naukowego wyjaśnienia.
EN
The article presents selected aspects related to the design of hollow core slab units that are able to distribute concentrated loading to adjacent slabs. Provisions of EN 1168 as well as literature are presented and discussed. A comparative analysis has been performed in which calculated capacity of a slab has been compared to selected experimental results obtained from slab field tests done in Technical Research Centre of Finland. The outcome of analysis illustrated various ambiguities and questions that correspond to the state of the art knowledge regarding the considered subject.
6
Content available Analiza ruchu drogowego wraz z koncepcją przebudowy skrzyżowania drogi DK78 z łącznicą węzła Zabrze Północ w Zabrzu
Kołodziejczak Michalina, Olma Anna
Drogownictwo
|
2022
|
nr 11-12
405--410
PL
W artykule przedstawiono wyniki obliczeń przepustowości i oceny warunków ruchu istniejącego i projektowanego ronda węzła „Zabrze Północ” w Zabrzu. Porównano je do wyników symulacji ruchu w programie PTC VIISSIM oraz zaobserwowanych i określonych z pomiarów warunków ruchu. Przedstawiono koncepcję przebudowy ronda zapewniającą większą przepustowość skrzyżowania i korzystniejsze warunki ruchu.
EN
The article presents the results of capacity calculations and the assessment of traffic conditions for the existing and planned roundabout at the Zabrze Północ junction in Zabrze. They were compared to results of the traffic simulation in the PTC VISSIM program and the observed and determined traffic conditions measurements. The concept of reconstruction of the roundabout was presented, ensuring great er capa city of the intersection and more favorable traffic conditions.
7
Content available Train headway optimisation using virtual blocks
Irlik Maciej
Zeszyty Naukowe. Transport / Politechnika Śląska
|
2021
|
z. 112
75--84
EN
Although the implementation of a new Automatic Train Protection (ATP) system increases the safety level, it also exerts some impact on the blocking time in block sections, and consequently, on the headway between trains. At the same time, ATP systems introduce a train positioning system based on odometry calculation and reporting back to the trackside system. This paper describes the concept of using virtual blocks based on train position reporting in the ATP system for purposes of non-occupancy determination. Virtual blocks can be used to reduce headways on railway lines without increasing the number of trackside signalling devices. Preliminary capacity assessment was performed to calculate the average headway depending on the signalling system with reference to a case study.
8
Content available Effect of train position reporting on railway line capacity
Folęga Piotr, Irlik Maciej
Transport Problems
|
2021
|
T. 16, z. 2
59--72
EN
Over the recent years, an increase in the demand for passenger and freight rail transport services has been observed. This is mainly owing to the policy objectives related to the use eco-friendly means of transport and the investment causing the quality of rail services to grow. Along with the growing demand for rail transport, a problem of railway capacity utilisation has emerged. Although the implementation of the new Automatic Train Protection (ATP) system increases the safety level, but under some scenarios, it may decrease the headways between trains. At the same time, the ATP systems enables train positioning based on odometry calculation and reporting it to the trackside system. This paper proposes a solution that involves application of virtual block sections which use the train position reporting feature of the ATP system for the determination of non-occupancy. Virtual blocks can successfully reduce headways in railway lines without increasing the number of trackside signalling devices. The capacity assessment proposed under the study was performed to calculate the average headway depending on the signalling system configuration.
9
Content available remote An attempt to determine capacity of movements from minor entries in case of congestion on the major street
Gasz Krzysztof
Roads and Bridges - Drogi i Mosty
|
2021
|
Vol. 20, no. 2
95--113
EN
The article presents the author’s own method of determination of capacity of movements from minor entries at an unsignalized intersection, when turning vehicles join the queue of vehicles on the main street, generated due to the influence of an adjacent signalized intersection. The proposed method of capacity calculation consists of four steps. First, the length of lane vacated by the vehicles leaving the signalized intersection was calculated. Second step consisted in determination of capacity of the right-turn movement joining the queue.In the following step, capacity of the left-turn movement joining the queue was calculated. The last step consisted in calculation of the time in which the intersection is blocked by vehicles moving ahead in the queue.
PL
W artykule przedstawiono autorską metodę określenia przepustowości relacji podporządkowanych na skrzyżowaniu bez sygnalizacji, dołączających się na jezdni głównej do kolejki pojazdów spowodowanej działaniem sygnalizacji świetlnej na kolejnym skrzyżowaniu. Zaproponowany sposób obliczenia przepustowości tych relacji składa się z czterech etapów. Na początku obliczono długość pasa zwalnianą przez pojazdy opuszczające skrzyżowanie z sygnalizacją świetlną. W drugim etapie określono przepustowość relacji prawoskrętnej dołączającej się do kolejki pojazdów. W kolejnym kroku obliczono przepustowość relacji lewoskrętnej dołączającej się do kolejki pojazdów. Ostatni etap to obliczenie czasu blokowania skrzyżowania przez pojazdy poruszające się w kolejce.
10
Content available Performance Investigation of High-Speed Train OFDM Systems under the Geometry-Based Channel Model
Do Viet Ha, Trinh Thi Huong, Nguyen Thanh Hai
International Journal of Electronics and Telecommunications
|
2021
|
Vol. 67, No. 3
451--457
EN
The high-speed of train (HST) in combination with the high carrier frequency of HST systems leads to the severe inter carrier interference (ICI) in the HST orthogonal frequency division multiplexing (HST-OFDM) systems. To avoid the complexity in OFDM receiver design for ICI eliminations, the OFDM system parameters such as symbol duration, signal bandwidth, and the number of subcarriers should be chosen appropriately. This paper aims to propose a process of HST-OFDM system performance investigation to determine these parameters in order to enhance spectral efficiency and meet a given quality-of-service (QoS) level. The signal-to-interference-plus-noise ratio (SINR) has been used as a figure of merit to analyze the system performance instead of signal-to-noise ratio (SNR) as most of recent research studies. Firstly, using the non-stationary geometry-based stochastic HST channel model, the SINR of each subcarrier has been derived for different speeds of the train, signal bandwidths, and number of subcarriers. Consequently, the system capacity has been formulated as the sum of all the single channel capacity from each sub-carrier. The constraints on designing HST-OFDM system parameters have been thoughtfully analyzed using the obtained expressions of SINR and capacity. Finally, by analyzing the numerical results, the system parameters can be found for the design of HST-OFDM systems under different speeds of train. The proposed process can be used to provide hints to predict performance of HST communication systems before doing further high cost implementations as hardware designs.
11
Content available Modelling of work of the rotor-type blade pump with revolving stator
Dmytriv V. T., Lanets O. S., Dmytriv I. V., Horodetskyy I. M.
International Journal of Applied Mechanics and Engineering
|
2021
|
Vol. 26, no. 4
17--28
EN
In the article, the analytical dependences of modelling the cell cross-sectional area between two adjacent blades of a rotary blade pump and capacity for a pump with fixed and rotating stators are given, and analytical dependences are derived to model the power necessary to overcome the friction forces of the blades. The forces acting on the radially placed blade of a rotary pump with a fixed stator (non-rotating or stationary) and a rotating stator are analyzed. Design and technological parameters that influence the pump capacity and power are taken into account. The power required for the movement of the pump blade without taking into account the compression of the air has the opposite character of the change as to the pump capacity The capacity of a rotary pump with a rotating stator is three times higher than that of a stationary stator. The rotary pump with a rotating stator, with six radially spaced blades, consumes 0.854 [kW] less power to overcome the blade friction of 1313 kW The results of modelling of the pump work are given.
12
Content available The capacity of the Sanna river in conditions of the reliable flow and the control discharges of the weir in Zaklików
Michalec Bogusław
Geomatics, Landmanagement and Landscape
|
2021
|
no. 1
57--68
EN
The aim of the study was to determine the capacity of a selected section of the Sanna river, designated below the lower site of the weir in Zaklików. The capacity calculations included the conditions of flood water discharge, i.e. the reliable flow and the control flow, determined in accordance with the Regulation of the Minister of the Environment on technical conditions that should be ensured for the hydrotechnical structures and their locations. The paper presents the consequences of changes in the regulations regarding the determination of building type, for which reliable flow and control discharges are determined. These modifications in the regulations have an impact on changes in the determination of the probability value for water discharges related to the analysed weir. The calculation of the capacity of the tested section also took into account its technical condition, specifying the variant of calculations for the lack of maintenance works, i.e. for the current state and for the state after maintenance works, consisting in mowing vegetation on slopes and shaping the surface of river bottom, removing pits and shallows. The results of the calculations of capacity of the measured cross-sections showed that the performance of maintenance works will convey the flow of a Q3% reliable flow in the Sanna river, while the Q1% control flow will not fit into the riverbed and will cause inundation of the adjacent areas.
13
Content available Koncepcja przebudowy węzła drogowego Golden Glades w Miami na Florydzie. Cz. 2, Analiza wielokryterialna, wrażliwości i przepustowości
Tkaczyk Maciej, Kowalski Karol, Dąbkowski Paweł
Drogownictwo
|
2021
|
nr 4
101--113
PL
Analiza wielokryterialna jest często stosowaną metodą wyboru optymalnego rozwiązania przedsięwzięcia. W prezentowanej analizie zastosowano cztery kryteria: funkcjonalno-ruchowe, kosztowe, środowiskowe i społeczne oraz możliwości etapowania. Analiza wrażliwości jest prostą techniką analityczną pozwalającą na badanie wpływu zmiany kryteriów analizy wielokryterialnej na ostateczny wynik wyboru koncepcji. Analiza odpowiada na pytanie czy wybrany wariant przedsięwzięcia jest „stabilny”, tzn. odporny na zmianę wcześniej założonych kryteriów. Analiza przepustowości pozwala ustalić poziom swobody ruchu i wyznaczyć liczbę pasów ruchu.
EN
Multi-criteria analysis is a common method of choosing the optimal solution for specific project. Four criteria were used here: functional-utility, cost, environmental and social, and staged capabilities. Sensitivity analysis is a simple analytical technique that allows to study the impact of changing the criteria of multi-criteria analysis on the final outcome of the concept selection. It answers the question whether the chosen option of the project is “stable”, that is resistant to the change of previously established criteria. Capacity analysis allows to determine the level of service and the number of lanes.
14
Content available Pseudo-static test of steel-glulam composite beam-to-column exterior joints
Duan Shaowei, Liu Xinglong, Yuan Jian, Wang Zhifeng
Archives of Civil Engineering
|
2021
|
Vol. 67, nr 1
147--161
EN
Steel-glulam structure is a new type of composite structure,glulam have lateral support effect on steel plate, that can prevent premature buckling of steel plate and improve the stability of steel structure. In order to study the influence of column’s cross-section form on the seismic performance of steel-glulam composite beam-to-column exterior joint, the column’s cross-section form was taken as the basic variable (glulam rectangular section , H-beam section and H-beam-glulam rectangular section were used respectively). The pseudo-static tests of three composite beam-to-column joints were carried out to observe the different failure modes, and obtain the mechanical performance indexes. The experiment results demonstrated that: The energy dissipation capacity of beam-to-column exterior joint composed of glulam column was the worst, the ultimate bearing capacity and stiffness were the lowest. The ultimate bearing capacity of the exterior joints formed by the H-beam column and the H-beam-glulam composite column were both high, and their ductility coefficients were similar, while the former had better energy dissipation capacity.
15
Content available Udrażnianie węzłów tramwajowych w awaryjnych sytuacjach ruchowych
Molecki Adam
TTS Technika Transportu Szynowego
|
2020
|
R. 27, nr 3-4
32--36
PL
W kręgu inżynierów ruchu i szerzej – osób zajmujących się ruchem drogowym na co dzień, ogólnie znanym faktem jest możliwość zwiększenia przepustowości na skrzyżowaniach z sygnalizacją świetlną poprzez wydłużenie cyklu sygnalizacji. Metoda ta jednak nie jest zwykle skuteczna w odniesieniu do komunikacji tramwajowej. W artykule omówiono dlaczego tak się dzieje i jakie kroki można podjąć, gdy na skutek awarii sytuacja ruchowa wymusza zwiększenie przepustowości w ruchu tramwajowym.
EN
Traffic engineers or generally - people working with road traffic, it is generally knows that on the intersections with traffic lights the way to increase capacity is extend the signal cycle. However, this method is usually not effective for tram traffic. The article discusses why this phenomenon occurs and what steps can be taken when, as a result of a failure, the situation makes an increase of tram traffic capacity necessary.
16
Content available Assessment of Security of Water Supply for Benissa Municipality, Spain Employing the Shannon-Weaver Model
Miazga Maciej, Królikowska Jadwiga
Rocznik Ochrona Środowiska
|
2020
|
Tom 22, cz. 2
593--604
EN
This publication is a presentation of the methodology to determine the degree of diversification and allocation of water resources in water supply systems; with a differentiated level of need based on the example of the municipality of Benissa Spain. The article shows a frequency of the changes and factors that affect the functioning of the water supply system. Moreover, its presents the calculation of the diversification indices for the selected water supply system while the methodology offers the possibility of evaluating the diversification of water resources in two parameters according to an adapted form of the Shannon-Weaver index.
PL
Publikacja przedstawia metody wyznaczenia współczynnika dywersyfikacji i alokacji zasobów wodnych dla systemu zbiorowego zapotrzebowania wody cechującego się zróżnicowanym jej zapotrzebowaniem na przykładzie miasta Benissa w Hiszpanii. W pracy przedstawiono obliczenia stopnia dywersyfikacji zasobów wodnych, metodą dwu-parametryczną, wg zaadaptowanego wskaźnika Shannona-Weavera.
17
Content available The mechanism of fractured porosity formation in heterogeneous rocks under irreversible volume-stress deformation
Bondar Halyna, Yevdoschuk Mykola
Nafta-Gaz
|
2020
|
R. 76, nr 5
287--290
EN
The paper deals with the study of the deformation, strength, and reservoir properties of rocks under various stress conditions, typical of great depths. The effect of all-round compression causes a change in the elastic, plastic, and strength characteristics of rocks. Some features of fracture formation and development in inhomogeneous solids under tension and compression were determined. The irreversible deformation mechanism of rocks under an uneven volume stress was considered. The irreversible deformation of rocks combines two types of deformation–intergranular slip, which produces the development of micro-fracturing, and intracrystalline slip, which mainly develops only at high pressure. The typical types of rock damage for uneven triaxial compression (transcrystalline and intercrystalline damage) were investigated. The phenomenon of loosening and increasing the volume as a result of irreversible deformations is mainly caused by the simultaneous formation of intergranular micro-cracks and micro-shifts along grain boundaries. As a result of these micro-dislocation combinations, macroscopic shift planes are formed, followed by irreversible deformation. On the surfaces of deformed samples, slip lines often appear; these are the traces of these macroscopic shift planes. Rock samples deformed due to high pressure are presented. The slip plane traces are clearly visible on the samples’ surfaces. It has been stated that under conditions typical of 8–10 km depths, irreversible deformation occurs with decompaction of their structure, increasing the coefficients of porosity and permeability. The effect of rocks deconsolidation caused by stress can be so significant, that in some cases may even increase the volume of voids by 1.5–2 times. The processes of dissolution and leaching of chemically unstable elements are of great importance in determining the filtration capacity and reservoir properties of deep-lying rocks, affected by irreversible deformation changes. Different dependences of volume growth, decompaction intensity coefficient, and permeability coefficient on the overall compression under uneven triaxial stress–which was based on the data of sandstone and marble–have been illustrated. The volume growth is quantitatively determined with the help of the decompaction intensity coefficient, and it is correlated with the collector and filtration capacity of rocks.
PL
Artykuł dotyczy badań odkształcenia, wytrzymałości oraz właściwości zbiornikowych skał w różnych warunkach naprężenia typowych dla znacznych głębokości. Wpływ ściskania obwodowego powoduje zmianę właściwości sprężystych, plastycznych i wytrzymałościowych skał. Określono niektóre cechy tworzenia i rozwoju pęknięć w niejednorodnych ciałach stałych pod wpływem rozciągania i ściskania. Rozważano mechanizm nieodwracalnego odkształcenia skał pod wpływem niejednolitego naprężenia objętościowego. Nieodwracalne odkształcenie skał łączy dwa rodzaje odkształcenia: poślizg międzyziarnowy, powodujący rozwój mikropękania, oraz poślizg międzykrystaliczny, który rozwija się tylko przy wysokim ciśnieniu. Badano rodzaje zniszczenia skał typowe dla niejednolitego trójosiowego ściskania (zniszczenie śródkrystaliczne i międzykrystaliczne). Zjawisko rozluźniania i zwiększenia objętości w wyniku odkształceń nieodwracalnych jest powodowane przez jednoczesne tworzenie mikropęknięć międzyziarnowych oraz mikroprzesunięcia wzdłuż granic ziaren. W wyniku tych kombinacji mikrodyslokacji tworzone są makroskopowe płaszczyzny przemieszczenia, a następnie odkształcenie nieodwracalne. Na powierzchni próbek odkształconych często pojawiają się linie poślizgu, które są śladami tych makroskopowych płaszczyzn poślizgu. Zaprezentowano próbki skalne odkształcone z powodu wysokiego ciśnienia. Na powierzchni próbek widoczne są wyraźnie ślady płaszczyzn poślizgu. Stwierdzono, że w warunkach typowych dla głębokości 8–10 km występuje odkształcenie nieodwracalne z rozgęszczeniem ich struktury, zwiększeniem współczynników porowatości i przepuszczalności. Wpływ dekonsolidacji skał powodowany przez naprężenie może być tak istotny, że całkowicie usuwa konsolidację skał, powodowaną przez naprężenia efektywne, a w niektórych przypadkach może zwiększyć objętość pustek nawet 1,5–2 razy. Procesy rozpuszczania i ługowania elementów niestabilnych chemicznie mają duże znaczenie dla określenia zdolności filtracji oraz właściwości zbiornikowych skał zalegających głęboko pod wpływem nieodwracalnych zmian odkształcenia. Zilustrowano różne zależności wzrostu objętości, współczynnika intensywności dekompakcji i współczynnika przepuszczalności od całkowitego ściskania pod wpływem niejednolitego naprężenia trójosiowego, oparte na danych dla piaskowca i marmuru. Wzrost objętości jest ilościowo określony za pomocą współczynnika intensywności dekompakcji i jest skorelowany z właściwościami filtracyjnymi skał.
18
Content available El-Nino effect on reservoir capacity reliability: Case study of Sumi dam, Sumbawa Island, Indonesia
Andawayanti Ussy, Yasa I. Wayan, Bisri Mohammad, Sholichin Mochamad, Sulianto
Journal of Water and Land Development
|
2020
|
no. 44
1--7
EN
Reservoirs have a very important function in providing multi-sector water requirements. In the future, reservoirs not only serve to store and available water can also be used as disaster mitigation instruments. The completeness of hydrological measurements in reservoirs can be expanded more widely for climate change mitigation. The reliability of the reservoir capacity varies greatly depending on the El-Nino character that occurs among them El-Nino is weak, moderate, strong and very strong. The El-Nino characteristic is very influential on the period of water availability, the increase of evaporation capacity and decrease of reservoir capacity. Analysis of the reliability of the reservoir volume due to El-Nino using the Weibull equation. The deficit reservoir was calculated using the concept of water balance in the reservoir that is the relationship between inflow, outflow, and change of storage at the same time. Based on the results of the analysis showed that the evaporation increase and the decrease of reservoir capacity had a different pattern that is when the evaporation capacity started to increase at the same time the reservoir capacity decreased significantly. The correlation coefficient between evaporation capacity increase and decrease of reservoir water capacity are consecutively –0.828, –0.636, and –0.777 for El- Nino weak, moderate and very strong respectively. At the reservoir capacity reliability of 50% reservoir has a significant deficit. When weak El-Nino the deficit is 2.30∙106 m3, moderate: 6.58∙106 m3, and very strong 8.85∙106 m3.
19
Content available Preliminary study of shaping the railway track geometry in terms of their maintenance costs and capacity
Gołębiowski Piotr, Kukulski Jacek
Archives of Transport
|
2020
|
Vol. 53, iss. 1
115--128
EN
In Poland, due to the increase in investments made by railways in recent years, and thus the increase in the replacement value of transport infrastructure, the need for expenditure on infrastructure maintenance will increase in the next 30 years, or the development of the developed transport network will degrade. As part of the overall discipline of resource management, subdiscipline has emerged - infrastructure asset management. As part of the management of railway transport infrastructure, the demand for cheaper maintenance costs will grow. The cost reduction of infrastructure maintenance is possible through meticulous assessment of its condition, rational selection of locations and scope of repairs at the assumed risk level, as well as at the stage of preparation of new construction or modernization projects taking into account aspects of later maintenance. For some time, we have been observing the accumulation of knowledge (methods, programs, procedures) in the country and abroad enabling optimization of infrastructure condition assessment and programming of its maintenance. The implementation of these solutions may result in a more rational use of funds for infrastructure maintenance and not disturb its smooth functioning in operation. The article discusses aspects that should be considered in the design process of railway infrastructure. Particular attention was paid to the durability of steel components of the railway superstructure, maintenance costs as well as aspects related to the capacity of the track node. An example of dependence of selected values of radial arcs depending on their durability and maintenance costs was presented. It was proposed to change the track layout at the Warszawa Srodmiescie passenger stop planned for reconstruction. Calculations of kinematic parameters for various configurations of railway turnouts were performed. Also, calculations of the capacity for the existing track system solution as well as the proposed track system after reconstruction of the analysed Warszawa Srodmiescie railway station were also carried out.
20
Content available Formulae for buckling load bearing capacity of glass structure elements
Gwóźdź M.
Archives of Civil Engineering
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2020
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Vol. 66, nr 2
353--368
EN
Development of contemporary building industry and related search for new aesthetical and functional solutions of monumental buildings in the centers of large cities resulted in the interest in glass as a structural material. Attractiveness of glass as a building material may be derived from the fact, that it combines transparency and aesthetical look with other functional features. Application of glass results in modern look of building facades, improves the indoor comfort without limiting the availability of natural daylight. Wide implementation of the new high performance float flat glass manufacturing technology, in conjunction with increasing expectations of the construction industry relating to new glass functions, has led to significant developments in glass structures theory, cf. [1, 3, 4, 5, 9, 10]. Many years of scientific research conducted in European Union countries have been crowned with a report CEN/TC 250 N 1050 [2], compiled as a part of the work of European Committee for Standardization on the second edition of Eurocodes - an extension of the first edition by, among others, the recommendations for the above mentioned design of glass structures, in particular modern procedures for the design of glass building structures. The procedures proposed in the pre-code [2] are not widely known in Poland, and their implementation in the design codes should be verified at the country level. This task is undertaken in this paper.
PL
Rozwój nowoczesnego budownictwa i związane z tym poszukiwanie nowych rozwiązań w zakresie estetyki i funkcjonalności budynków reprezentacyjnych w centrach dużych miast, stało się przyczyną zainteresowania szkłem. Atrakcyjność szkła jako materiału budowlanego wynika z faktu, że łączy ono w sobie przeźroczystość i estetyczny wygląd z innymi cechami użytkowymi. Jego zastosowanie nadaje nowoczesny wygląd elewacjom budynków i polepsza komfort przebywania w pomieszczeniach, nie ograniczając przy tym naturalnego oświetlenia dziennego, Wdrożenie nowej, wysokowydajnej technologii produkcji szkła płaskiego float, w powiązaniu z rosnącymi wymaganiami budownictwa, dotyczącymi nowych funkcji szkła, doprowadziło do znacznego rozwoju teorii konstrukcji szklanych, por. prace [1, 3, 4, 5, 9, 10]. Wieloletnie badania naukowe prowadzone w krajach Unii Europejskiej zostały zwieńczone opracowanym dokumentem CEN/TC 250 N 1050 [2], zredagowanym w ramach prac Europejskiego Komitetu Normalizacyjnego nad drugą edycją Eurokodów. W wydaniu tym zaproponowano poszerzenie pierwszej edycji między innymi o rekomendacje w/z projektowania konstrukcji szklanych, a w szczególności o nowoczesne procedury w zakresie obliczania konstrukcji budowlanych szklanych. W Polsce zaproponowane w prenormie [2] procedury nie są powszechnie znane, a ich implementacja do norm projektowania wymaga przeprowadzenia weryfikacji krajowej, co podejmuje niniejsza praca.
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