This paper deals with Preflex beams which are a very particular kind of composite structures, including a precasted concrete bottom flange, which is prestressed by means of pre-deflection of the steel beam. An important variant of this technology, adding prestressing with pre-strained cables to predeflection (Flexstress), is also considered. The concrete bottom flange increases significantly the stiffness with respect to instantaneous loads and it allows very slender designs. The case of a small span rail bridge is taken into account and the beam geometry as well as the material choice are optimized. These innovative solutions are then compared to a traditional composite design with the same slenderness ratio and with an existing rail bridge deck. Relevant cost savings seem to be possible, especially in the Flexstress case.

Preflex beams: Structural optimization and analysis of economic advantages / Mannini, C.; Morano, S.G.. - STAMPA. - (2006), pp. 835-836. (Intervento presentato al convegno 3rd International Conference on Bridge Maintenance, Safety and Management (IARMAS 2006) tenutosi a Porto; Portugal nel 16-19 July 2006).

Preflex beams: Structural optimization and analysis of economic advantages

MANNINI, CLAUDIO;MORANO, SALVATORE GIACOMO
2006

Abstract

This paper deals with Preflex beams which are a very particular kind of composite structures, including a precasted concrete bottom flange, which is prestressed by means of pre-deflection of the steel beam. An important variant of this technology, adding prestressing with pre-strained cables to predeflection (Flexstress), is also considered. The concrete bottom flange increases significantly the stiffness with respect to instantaneous loads and it allows very slender designs. The case of a small span rail bridge is taken into account and the beam geometry as well as the material choice are optimized. These innovative solutions are then compared to a traditional composite design with the same slenderness ratio and with an existing rail bridge deck. Relevant cost savings seem to be possible, especially in the Flexstress case.
2006
Proceedings of the 3rd International Conference on Bridge Maintenance, Safety and Management; Bridge Maintenance, Safety, Management, Life-Cycle Performance and Cost
3rd International Conference on Bridge Maintenance, Safety and Management (IARMAS 2006)
Porto; Portugal
16-19 July 2006
Mannini, C.; Morano, S.G.
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/632287
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