Ponte Edificio Merlata Bloom, Milan
ELEVATED CROSSING OF THE ROAD JUNCTION IN THE CASCINA MERLATA MALL
The structure allows for the crossing of the road junction connecting the East and West areas of the Merlata Mall multifunctional center; the structure features two levels, the first floor is used for commercial retail while the cover houses a pedestrian garden.
The first deck is supported by a row of two span continuous girders with a composite steel-concrete section set at 5.80 center lines with supports constituted by steel box beams bearing on reinforced concrete support structures (columns for the edge beams and diaphragms for the central box beam)
The layout of the structures is constrained by the position of the lateral supports which have to follow the edges of the adjacent buildings and by the already built foundations of the central piers.
The superstructure is independent from the side buildings and therefore it does not interact with these constructions; the longitudinal displacements of the deck are bypassed by deck and roof special joints located at the edges along the side buildings.
The whole structure is restrained by means of two multidirectional supports placed between the two central diaphragms and the box beam and by eight supports in laminated neoprene (4 per side) located between the two lateral box beams and the eight reinforced concrete supporting piers.
Because the axis of the central support is not orthogonal to the direction of the girders the relevant spans feature variable lengths between a minimum of 35m and a maximum of 44.5m and the depth of around 3 m.
The reinforced concrete slab above the steel beams is composed by self-supporting predalles acting as formworks in the casting phase and connected by means of Nelson studs welded on the upper flange of the steel section; the relevant total depth is equal 25cm.
The cover above the bridge deck is constituted by a composite steel-concrete structure that supports the pedestrian garden on the roof and the arched wooden arches with glass finishing; this level is supported by H-columns and is braced by a system of X-shaped pipe struts which assure the necessary stability.
The steel beams are laid in a main and a secondary direction and develop the composite behavior with the concrete slab by means of Nelson studs; the 15 cm deep concrete is cast over corrugated steel sheets used as lost formworks.