Method for manufacturing a composite girder and so manufactured girder

摘要

A method for manufacturing a composite girder including one or more vertical cores of steel plate, associated and cooperating with one or more horizontal slabs or flanges of concrete. At least one of the horizontal slabs or flanges is made from high-performance concrete in order to allow mutual forces or co-actions to be imposed between the several components of the girder which are much higher/stronger than the mutual forces/co-actions which can be imposed by way of other methods and materials. If the composite girder is at least partially manufactured at the prefabrication factory, according to the present method, the starting element will be an I girder preflexed or inflexed with welded connections; the I girder will be positioned on the prefabricating bench imposing such constraints as to straighten the girder, then in a suitable position steel cables are installed prestressed between external anchoring points, and the concrete casting is carried out in a flange in which the cables are associated with high-performance concrete. After setting is complete, the auxiliary constraints are cut and removed. In such a way, the by now set concrete, by being integral with the iron girder thanks to the iron reinforcer elements and welded connections and with the cables by adhesion, causes the several components to mechanically cooperate and the composite beam to be endowed with much better characteristics.