Abstract

Composite structures have not been able to compete in Spain with more conventional prestressed concrete bridges in the lower range of medium spans (30 - 90 m.). In this context, twin-girder sections are revealed as a more competent typology because of its sobriety, ease of construction and good structural performance.

At present the optimal character of the designs in structural projects is rarely challenged. The present study undertakes an in-depth analysis of the twin-girder section, involving a complete optimisation for the deck. To this end a specific 2D grillage model has been developed, integrating the composite and evolutive character of twin-girder decks, as well as the instability phenomena inherent to thin-walled structures.

Several conclusions are drawn after a parametric calculation using this model, regarding the optimum dimensions of all the variables that define the twin-girder section. These conclusions crystallise in a series of formulas that can be used as a design guide. 

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. "/jats:p""jats:p"The appearance of the welding as standard connection procedure for steel bridges, for road bridge decks two solutions are mainly used: "/jats:p""jats:p"- the solution with a concrete slab acting together with the stringers and cross beams (the composite solution); "/jats:p""jats:p"- 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). "/jats:p""jats:p"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. "/jats:p""jats:p"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. Document type: Article