Demolition and reconstruction works of the road bridge at Mulino di Galò (Ellera). Final/Executive Design, safety coordination, construction management, works accounting and acceptance testing.

Project objective

The objective of the project is the demolition and reconstruction of the road bridge at Mulino di Galò (Ellera, Albisola Superiore) over the Sansobbia stream, permanently and safely restoring access to the dwellings on the right bank (Cian, Parvin, Mulino d’Alto), replacing the temporary structure installed after the 1992 flood event and upgrading the roadway tie-ins on both banks.
The solution is based on hydraulic compatibility (freeboard and conveyance coherent with the basin planning), urban-planning consistency and landscape integration within a protected area, with a construction staging that safeguards the riverbed and manages interferences safely. The overall safety of the area will require, downstream of this intervention, the definitive arrangement of the Sansobbia riverbed and embankments: separate works, not included in this design scope.

Main works

The main work is a lower-deck steel superstructure with a slight “hogback” profile (slightly convex roadway), single span, with plate-girder main beams and rolled-section cross-beams, and a composite reinforced-concrete slab on predalles with shear connectors. The deck is supported on new reinforced-concrete abutments with fixed/movable bearing scheme and buffer/expansion joints, and is connected by approach walls that optimise road elevations and barrier integration. Drainage works are included (transversal and longitudinal drains), together with the safety upgrading of Via Parvin by means of reinforced-concrete walls at the slope toe and barriers consistent with those at the bridge edges. Construction phases include pre-assembly of segments, safe launching/erection with temporary works and bypass channels to protect flow conveyance, followed by reinstatement of the riverbed and pavements. The crossing is designed to convey the design flood, in consistency with the additional hydraulic works planned at reach scale.