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Abstract

The carrying structure of the bridge over the Jiu River at Aninoasa consists in two parallel concrete arches with variable height of the cross section, sustaining a concrete deck through vertical concrete hangers. In the time period passed since the bridge was erected, some structural elements shown damages. In order to establish the technical state of the bridge, a technical appraisement was performed and according to this, the most exposed elements to the risk of failure are the hangers.

The purpose of this paper is to present briefly both, the method used to test the actual bridge carrying capacity in situ and the finite element model developed for the static and dynamic analysis of the structure.

In order to estimate the state of the structural elements, two ways were followed. In the first stage, a test project was carried out and in the second stage, a complete 3D finite element model was developed to analyze the bridge structure.

The test project has foreseen the loading of the bridge by heavy unloaded trucks, disposed in some positions on the deck and the measurements of the deck and arches displacements. The positions of the trucks were established in order to obtain the maximum values both for arches transverse displacements and vertical displacements of the deck. Using electro-resistive transducers the hangers elongations and strains values on their cross section were also measured. These measured values were compared with those obtained from the numerical calculations performed by using the complete finite element model. By means of the finite element model, also the response of the structure following the dynamic action of vehicles was investigated.

Abstract

The paper presents the main types of power boiler steam superheater loads together with relevant standards applicable to superheater calculations. In the case of horizontal superheaters, due to their thermal expansion and assembly errors which are the effect of non-uniform support of the hanger tubes, extra loads are generated on the coil pipes. An FEM analysis performed for a selected superheater structure indicates that maximum stress values and the location where the stresses occur depend on the method of support of the superheater tubes. It is shown that maximum stresses in this structural element can be reduced by introducing appropriate tension of hanger bars supporting the superheater hanger tubes.

Abstract

When observing the stability of suspended ceilings during operation, sometimes smaller failures are observed, up to disasters, even a few of considerable sizes and serious consequences. The aim of the article is to analyse the causes of damage to a suspended ceiling, with an area of approximately 500 m2, as well as testing and checking the applied construction elements. In situ destructive tests as well as tests at the AGH laboratory were carried out. The analyses were carried out in accordance with PN/EN 13964: 2014 (E). It was found that the designed ceiling system solution was correct. Whereas in the performance, an improper spacing of hangers, even by more than 70% of the permissible spacing, and forbidden lengths of brackets from C60 profiles, were applied. Also, about 55% of the connectors had too small diameters of the ends of the mandrels, which allowed for the sliding of broken head and a sudden loss of carrying capacity of the hanger.

Abstract

Road bridges with steel arches are used efficiently for medium and large spans. These solutions show advantages determined by the arches geometry, by the number and distributions of hangers and by the form and type of the arches bracing system.

The appearance of the welding as standard connection procedure for steel bridges, for road bridge decks two solutions are mainly used:

- the solution with a concrete slab acting together with the stringers and cross beams (the composite solution);

- the solution with orthotropic deck (the orthotropic deck consists in a network formed by the continuous longitudinal stiffeners and cross beams connected at the upper part by a steel plate).

In this paper a comparative study of the strength and fatigue checks performed on the new road bridge over river Argeşel near Mioveni in Argeş county is presented. The results are obtained using the Romanian standards STAS 1844-75 and SR 1911-1998 and the European norms SR EN 1990, SR EN 1993 and SR EN 1994. The deck was designed with two parallel steel arches, which are sustaining through vertical hangers a concrete slab connected with steel girders at the way level.

The aim of the paper is to outcome the safety factors obtained from checks performed on steel hangers using the Romanian standards with respect with those obtained using Eurocodes.

Abstract

In this paper, the dome of a tank in the Świnoujście LNG terminal is analysed. Some of the rafter ribs at the connection with hangers were not mounted during construction of the tank dome. Therefore, it has become necessary to estimate its response, which has been done with the aid of some computational models of the dome, that have been created in the finite element method environment. Different local models are studied, aiming to recreate possible outermost conditions of the tank dome response, i.e. with or without composite action between steel and concrete parts of the tank dome. Static calculations with material and geometric nonlinearities are carried out on the computational models, enabling the creation of a load capacity envelope of the rafter with or without ribs. The obtained results are then used to decide if repair works need to be done and whether the missing ribs should be welded.

Abstract

A space truss structural system is a three-dimensional arrangement of linear elements in a pyramid pattern forming a Double Layer Grid (DLG) system. Space trusses are an elegant and economical means of covering larger areas such as roof systems, in a wide variety of applications such as a stadium, aircraft-hanger, assembly hall, etc. The major problem encountered in using the space truss as a roofing system is the sudden failure of the whole structure due to critical buckling of the top chord member. Earlier research has shown that the optimal solution to overcome such a failure is by providing a small thickness of concrete slab over the space truss, so that the space truss with concrete slab (Composite Space Truss) will act as a floor system for the multi-storey building. For better ventilation and lighting in the building, the need for openings in the composite space truss is unavoidable; however, providing an opening in the concrete slab will reduce the load carrying capacity of the structure. The analysis of a composite space truss of size 30m x 30m with all possible locations of openings for four different support conditions was carried out using ANSYS in order to study the load - deflection behaviour. Further, the ductility factor and energy absorption capacity of the composite space truss with different locations of slab openings were compared.

Budownictwo, Vol. 6, 1997, 316–321. [5] Gjelstrup H., Georgakis C.T., Larsen A., An evaluation of iced bridge hanger vibrations through wind tunnel testing and quasi-steady theory , Wind and Structures, Vol. 15, Issue 5, 2012, 385–407. [6] Gjelstrup H., Georgakis C.T., Larsen A., A preliminary investigation of the hanger vibrations on the Great Belt East Bridge , Proceedings of the 7 th International Symposium on Cable Dynamics, Vienna 2007. [7] Górski P., Pospišil S., Kuznetsov S., Tatara M., Marušić A., Strouhal number of bridge cables with ice accretion at low flow

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value of multi-slice computed tomography coronary angiography over coronary artery calcium scoring in patients with suspected coronary artery disease. Eur Heart J. 2009;30(21):2622-9. 7. Writing Committee Members 2010 ACCF/AHA Guideline for Assessment of Cardiovascular. Circulation. 2010;122:2748-2764. 8. De Feyer JP, Nieman K. CCTA to guide revascularization for high-risk CAD: a cliff hanger. Eur Heart J. 2012;33:3011-3013. 9. Benedek Th, Bucur O, Pascanu I, Benedek I. Analysis of coronary plaque morphology by 64-multislice computed tomography coronary angiography

of tri-axial vibration data from helicopter transmission, Proceedings of 56th Meeting of the Society of Machine Failure Prevention Technology. Wen K. L. and Chang T. C. (2005). The research and development of completed GM(1,1) model toolbox using Matlab, International Journal of Computational Cognition 3(3): 42-48. Will T. (2005). Hanger matrix, two-thirds theorem , available at: http://www.uwlax.edu/faculty/will/svd/svd/index.html Żółtowski B. and Cempel C. (Eds.) (2004). Engineering of Machine Diagnostics , ITE Press, Radom, p. 1308, (in Polish). Yao A. W