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Details

Plan for the reconstruction of the bridge over the river Magra that collapsed on 8 April 2020, connecting Albiano Magra and Caprigliola on S.S. 330 “Buonviaggio”
Structural tipology:
Beam Bridge

Design level:
Construction Management Support, Executive plan
, Final design plan
, Technical and economic feasibility plan


Location

SS 330 “Buonviaggio”

Principal

ANAS S.p.A

Contracting company

Sales SpA & Italscavi di Pratelli Alvaro & C. Sas

Fincantieri Infrastructure (metal works)

Fagioli SpA (transportation and hoisting)

Team

Politecnica Ingegneria ed Architettura Soc. Coop.
Technital S.p.A.
Matildi+Partners srl

Activities

Technical and financial feasibility plan,

Final design plan (deck)

Executive plan (scaffolding)

Assistance to construction management

Time Period

2021 – 2022

Extent and spans

291 m | 57+90+90+54

New Bridge over the River Magra

The new deck

The new deck

The new deck

The new deck is a continuous truss in a composite steel-concrete system with a four-span 57+90+90+54 twin-beam truss layout.

The concrete slab accommodates the road platform and two lateral bicycle and pedestrian paths, for a total width of 15.90 m; it is frame worked on the main beams, which are 10 m apart, and on the intermediate pin beam.

Construction efficiency

Construction efficiency

Construction efficiency

The beams vary in height from a minimum of 2.50 m at the span to a maximum of 5.40 m at the central pier and employ S460 steel, which is suitably utilised to contain the weight of the main members and thus simplify installation.

The same aim has led to dramatic simplification of the deck structure, with diaphragms arranged at a typical spacing of 13 m; only in the vicinity of the piers, where the lower platform of the beams is compressed at high levels of tension, are there inverted V-shaped stabilising struts.

Rapid assembly

Rapid assembly

Rapid assembly

The need to minimise construction time, which interferes with the river hydraulics with their very short run-off times, prompted research into a fast assembly procedure: the entire metal deck was assembled in just four macro-segments, essentially corresponding to the four spans of the bridge, laid with coupled SPMTs.

The launch of the metal deck was then completed in four steps, which lasted only a few hours in total. The first of these involved the macro-segment between piers P2 and P3, which was 102 m in length and weighed almost 530 t, including the metal predalles and internal inspection walkway.

Photo gallery

A visual narrative depicting our rigorous work on the design, construction and testing of the infrastructure as a new roadway serving the entire community.