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PL
Celem artykułu jest zaproponowanie metody oceny podatnych połączeń spawanych kratownic o pasach wykonanych z ceowników i krzyżulców z rur prostokątnych. W metodzie tej nośność spoin określa się w zależności od wielkości siły osiowej, uwzględniając długości współpracujące spoin pachwinowych. Jak wykazano w artykule, zastosowanie w takich połączeniach cienkich spoin pachwinowych, o grubości dobranej do wytężenia pręta, jest dwukrotnie tańsze niż pełnościennych spoin czołowych. Ponadto przeprowadzona analiza cyklu życia wykazała, że zastosowanie cienkich spoin pachwinowych może zmniejszyć wpływ złącza spawanego na środowisko - o 73% pod względem emisji gazów cieplarnianych i o 70% pod względem zużycia nieodnawialnej energii pierwotnej.
EN
The aim of the article is to propose a new method for assessing the flexible joints of welded trusses with chords made of C-sections and braces made of rectangular hollow sections. In this method, the capacity of the welds is determined depending on the value of the axial force, taking into account the effective lengths of the fillet welds. As shown in the article, in such connections, the use of thin fillet welds with a thickness matched to the member's load is twice cheaper than the use of solid butt welds. Additionally, the life cycle analysis performed showed that the use of thinner fillet welds could reduce the overall environmental impact of the welded joint by 73% in terms of greenhouse gas emissions and 70% in terms of non-renewable primary energy consumption.
EN
Steel structures designed according to Eurocode 3 are executed in accordance with the provisions of the standard PN-EN 1090-2, which is referred to in Eurocode 3. In addition, the standard PN-EN 1090-2 refers to in its content a number of welding standards, e.g. PN-EN ISO 9692-1. These standards provide guidelines for welded connections, which should be applied in the case of joints connecting steel hollow sections. Analysis of above-mentioned provisions revealed that for fillet welds they are simultaneously fulfilled only if the inclination angles of the elements are in the range of 70°-100°. According to recommendations of PN-EN 1993-1-8 and EN 1090-2, the same weld type around the perimeter of the element connected to the chord of lattice structure is possible to execute only for inclination angle lower than 60°. Discrepancies between these standards also exist with regard to the interpretation of the dimension of the flare groove welds in connections of rectangular hollow sections with the same width. In addition, analyses of the recommendations for welding in cold-formed zones indicate that, for steel grades currently used for the production of cold-formed rectangular hollow sections, welding in these zones is not permitted only for profiles with wall thickness equal to 12.5 and 16 mm. The above-mentioned issues point out the need for mutual unification of standards for the design and execution of steel joints in hollow sections.
EN
With regard to the calculation of welds’ resistance in connections between hollow sections in EN 1993-1-8, very general information is given without any indication of specific calculation procedures. These recommendations are basically as follows: the resistance of the welds must have the value of the cross-section and assessment of the welds’ resistance based on the effective lengths is allowed in cases when forces in the braces are smaller than the resistance of the joint, but the detailed method is not specified. The objective of this paper is to present the most up-to-date information for the design of welds for overlap joints with reinforcing rib plates. The article presents the FEM analysis of the welds in the intermediate joint with the rib in a truss made of circular hollow sections. The conclusions from the analysis were presented.
EN
The hollow section welded joints require a number of actions before starting welding and appropriate supervision during this operation to achieve joints with adequate quality level, which should be confirmed by the post-completion tests. The execution of hollow section joints is associated not only with welding, but also with cutting and additional machining of edges. In some cases, weld surfacing is also applied to correct sections fit-up. Weld surfacing and thermal cutting can cause local hardening of connected elements. The welding has to be preceded by an assessment of the previous technological processes. The welded joints can be only executed on the basis of detailed Welding Procedure Specifications (WPS). It is advisable to manufacture - in accordance with previously prepared WPS - pre-production joints for testing, proving the ability of the welding personnel to execute welded joints with specified quality, using the available equipment. The quality of welded joints is proved by testing. A type of conducted tests, thus scope and type of welding defects possible to detect, depends on the weld type, wall thickness of connected elements and joint geometry. The authors’ experience indicates that the proper execution of the welded joint of hollow sections is difficult task, which often requires pre-production quality testing of the joints.
PL
W opracowaniu przedstawiono spotykany na obiektach budowlanych problem rozwoju korozji na wewnętrznych powierzchniach kształtowników zamkniętych eksploatowanych w środowisku zewnętrznym. Zachodzące wewnętrzne procesy korozyjne oraz towarzyszące im siły niszczące w związku z zamarzającą wewnątrz profili wodą powodują utratę nośności i obniżenie bezpieczeństwa eksploatacji, przez co przyczyniają się do powstawania stanów awaryjnych. Wiele ze stwierdzanych problemów związana jest z niepoprawnym projektowaniem i kształtowaniem elementów konstrukcyjnych, jak również zbyt optymistycznymi założeniami dotyczącymi stosowania technik uszczelniania. Wykonawstwo tego typu konstrukcji ma również znaczny wpływ na powstawanie uszkodzeń i zniszczeń.
EN
Problem of corrosion development on the inner surfaces of hollow sections exploited in the external environment is presented in the paper. Internal corrosive processes and destructive forces that sometimes accompany them as the result of the water freezing inside the profile, cause the loss of their bearing capacity and operational safety, thereby they create states of emergency. Many of mentioned above problems are associated with incorrect designing and shaping structural elements, as well as too optimistic assumptions about the use of sealing techniques. The role of execution of this type of construction also have a significant impact on the creation of damage and destruction states.
PL
W połączeniach kształtowników zamkniętych o przekrojach prostokątnych spoiny szerokobruzdowe są stosowane w wypadku łączenia prętów skratowania i pasów o tych samych szerokościach przekrojów. Na podstawie zaleceń dotyczących określania grubości spoin szerokobruzdowych przedstawionych w normie PN-EN 1993-1-8 zaproponowano wzory do obliczenia ich nośności.
EN
In rectangular hollow section joints, groove welds are placed in cases when the braces and the chord are the same width. In the paper on the basis of the comparison of thicknesses of such elements calculated according to EN 1993-1-8 the formulas to assess the resistance of groove welds were proposed.
PL
Przedstawiono propozycję sposobu obliczania nośności podstaw słupów o przekrojach zamkniętych prostokątnych wraz z przykładem obliczeniowym. Proponowana procedura bazuje na ogólnych założeniach normy PN-EN 1993-1-8. Ma ona charakter iteracyjny i obejmuje zarówno przypadki podstaw nieużebrowanych, jak i użebrowanych.
EN
Proposal for the calculation method of RHS column bases and design example has been presented. The proposed procedure is based on general assumptions of PN-EN 1993-1-8. The procedure is iterative and includes column bases with and without stiffeners.
EN
In calculating the resistance of welds within the connections between hollow sections in EN 1993-1-8, very general information is given without presenting specific calculations. The chief recommendations indicate that the resistance of the welds connecting the wall to the second element should not be less than the resistance of the cross section of the wall. In addition, assessment of the welds’ resistance based on the effective lengths is viable in cases when forces in the braces are smaller than the resistance of the joint, though the detailed method was not specified. The objective of this paper is to present the most up-to-date information about the design of overlap welded joints with a reinforcing rib plate.
EN
These joints are used when the designer and contractor anticipate difficulties during the construction of overlap joints. They were not included in the PN EN 1993-1-8 in full scale. Resistance assessment of such joints is presented in accordance with standard rules. The results were compared with the experimental studies carried out at the “Mostostal” Centre; while the former research activities and the legitimacy of the proposed method of assessing the resistance of these joints was confirmed. This is an example of an overlap joint calculation.
PL
Zastosowanie w konstrukcjach stalowych kształtowników o przekrojach zamkniętych cieszy się coraz większą popularnością. Wraz z powstaniem poradników projektowych CIDECT dostępne stały się narzędzia projektowe pozwalające na projektowanie połączeń spawanych węzłów spawanych z rur. Określenie nośności spoin w takich połączeniach jest złożonym problemem, ponieważ wymaga ustalenia długości efektywnych poszczególnych odcinków spoin, ich rozmieszczenia z uwzględnieniem podatności ścianek oraz rozdziału obciążenia na siły składowe działające na indywidualne odcinki spoin. Celem artykułu jest przedstawienie sposobu oceny nośności spoin w węzłach kratownic typu N z częściowym lub całkowitym nachodzeniem, o pasach wykonanych z rur prostokątnych lub dwuteowników i prętach skratowania wykonanych z rur prostokątnych.
EN
The use of hollow section structures has received considerable attention in recent years. Since the first publication of CIDECT additional research results became available, especially concerning design of welds between members of trusses joints. Estimation of resistance of welded semi-rigid joints is a complex issue because it requires determining of effective lengths of welds, their placement on the member walls with their different rigidity and distribution of components of the loads acting on each section of welds in various joint areas. The objective of this paper is to present the most up-to-date information to designers, teachers and researchers according design of welds for overlap N-type joints of trusses made of hollow sections.
PL
Przedstawiono wadliwą konstrukcję węzłów świetlików podłużnych hali przemysłowej, wykonanych z rur prostokątnych. Efektem tego były pękające w nich szyby. Analizie poddano pracę statyczną świetlików jako konstrukcji przestrzennych, współpracujących z konstrukcją dachu. Siły wewnętrzne w konstrukcji świetlików wyznaczono programem SOFiSTiK. Otrzymane w ten sposób siły ściskające lub rozciągające w ryglach świetlików, stanowiły odpowiednie obciążenia węzłów. Analizowano ponadto, z wykorzystaniem metody elementów skończonych (MES), zachowanie się pod wpływem wyżej wymienionych obciążeń, węzłów wykonanych z rur prostokątnych: wadliwie, poprawnie, a także według proponowanego sposobu naprawy. Było to konieczne, gdyż omawiane w pracy węzły konstrukcji świetlików, nie są ujęte w normie PN-EN 1993-1-8:2006 (/AC:2009 oraz /Ap2:2011). Węzły wykonane wadliwie pokazano na rys. 1., poprawnie – na rys. 8., a zgodnie z propozycją naprawy – na rys. 11. Natomiast zachowanie się węzłów wadliwych pokazano na rys. 6. i 7., poprawnych – na rys. 9. i 10., a wzmocnionych według wdrożonej koncepcji – na rys. 12. Referat zakończono wnioskami i zaleceniami odnośnie do naprawy i poprawnego konstruowania tego typu węzłów.
EN
Faulty structure of joints in longitudinal skylights in industrial building made of structural hollow sections is presented. Static analysis is taken into consideration as spatial construction and cooperating with roof structure. Internal forces in skylight bars were determined using SOFiSTiK software. Obtained in that way, compressive and tensional forces were used as proper nodal loads. Moreover, joints were modelled in commercial software Abaqus using finite element method (FEM) to obtain the behaviour under mentioned nodal loads made of rectangular hollow sections: faulty, correctly and according to proposed overhaul. It was necessary, because discussed skylight joints are not referenced to Eurocode PN-EN 1993-1-8:2006 (/AC:2009 and /Ap2:2011). Faulty joints are presented on Fig. 1, proper – on Fig. 8, according to proposed overhaul – on Fig. 11. On the other hand the behaviour of faulty joints is shown on Fig. 6 and 7, proper – on Fig. 9 and 10, according to proposed strengthened – on Fig. 12. Paper ends with conclusions and recommendations about repair and proper construction of that kind of joints.
EN
The basis for calculating of resistance of welded RHS connections is provided by codes and international guidebooks. In the matter of calculation of the resistance of welded joints, the European standard contains very general recommendations without specifying the detailed calculation procedures, which (the) designers could use in their work. Estimation of resistance of welded semi-rigid joints is a complex issue because it requires determining of effective lengths of welds, their placement on the member walls with their different rigidity, and distribution of components of the load acting on each section of welds in various joint areas. In this paper an approximate assessment is suggested of the resistance of the welded connection in the overlapped K type joints, made of rectangular hollow sections.
13
Content available remote Propozycja kratowych kładek dla pieszych z kształtowników zamkniętych
EN
The three truss footbridges for operating personnel made of cold formed hollow sections were constructed at "Kościuszko" Barrage on the Vistula near Cracow. Following good features of those structures the similar public footbridges were proposed. The 3,0 m wide footbridges were considered for the span lengths from 20,0 m to 45,0 m. The structures were analysed using FEM and structural components were proportioned according to ULS criteria. Deflections due to live loads and natural frequencies were calculated. Steel quantities per m2 of deck were compiled and costs estimated.
PL
Omówiono obliczanie elementów, spoin oraz węzłów, a także przygotowanie końców węzłów do spawania. Zamieszczono przykłady obliczania nośności węzłów.
EN
Design aspects of members, welded connections and member joints are dealt with together with technological aspects of preparation of member ends to be connected in joints. Numerical examples of the evaluation of the joint load bearing capacity are also presented.
15
Content available remote Experimental verification of welded hollow section joints
EN
The paper presents the preparation and execution of an experimental programme focusing on the verification of resistance in rectangular hollow section joints. The results obtained in experimental measurements are compared with joint resistance determined on the basis of standard regulations.
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