The Morandi Bridge, opened in 1967, was seen at the time as the way forward for bridge building, using pre-stressed concrete and cable-supported spans. Sadly, on 14 August 2018, during a heavy storm, one of the cable-stayed towers and adjacent spans collapsed, killing 43 people on the bridge and in housing below.
Now, just two years on, a brand new bridge has been completed. Designed by architect Renzo Piano, the Genoa San Giorgio Bridge was built by 1,200 construction workers in just 15 months of 24/7 activity, working on the bridge despite strict lockdown conditions due to coronavirus. The only day work stopped was Christmas Day 2019.
According to RINA, the Project Managements Consultants for the project:
“The design of the bridge has been termed as a ‘statement in its understatement’ accentuating the beautiful valley between mountain and sea and it will be truly environmentally friendly by including photovoltaic panels for energy, water treatment processes, and ongoing structural monitoring, that will ensure ongoing sustainability and safety.”
The new bridge in numbers
The bridge stats are quite impressive, including:
- A continuous girder of 1,067 meters
- 19 spans supported by 18 reinforced concrete piles
- two lanes plus an emergency lane for direction of travel
- 17,000 tons of steel structural work
- 67,000 thousand cubic meters of reinforced concrete
Maintenance and monitoring
The Genoa San Giorgio Bridge has an innovative system involving four maintenance robots which run along the entire length of the bridge to detect any signs of weathering and wear. The damp, salty Mediterranean winds are a particular concern, so the bridge also features a dehumidifying system designed to limit corrosion. In addition,
“An almost invisible but capillary network of over 240 sensors, yet to be completed, will silently touch the pulse of the work, transforming any jolt or vibration, torsion or dilatation into numbers and algorithms, graphs and measurements in real time to monitor infrastructure security.”
These include accelerometers, extensometers, velocimeters, inclinometers and detectors for joint expansion.
A lighter touch
A series of metal fins with rows of photovoltaic panels to harness the Italian sunshine and power the bridge’s lighting. The bridge is also designed to reflect light down to the valley floor below, as DeZeen magazine explains:
“Each of the piers has an elliptical section designed to allow the light to ‘slip’ on the surface and help mitigate the impact on the neighbourhood below.”
This came from architect Piano’s vision for the bridge, as described by Renzo Piano Building Workshop:
“From an architectural point of view, the form described by the deck, which recalls the hull of a ship, is of great importance. The gradual reduction of the section towards the ends of the bridge attenuates the visual impact of the new infrastructure. In addition, the use of a light colour for the coating of the steel elements makes the bridge bright, harmonising its presence in the landscape.”
Load testing by lorry
Load testing of the structure involved an initial phase of 16 heavy trucks rumbling across the entire length of the bridge during phase zero of the preliminary assessment. A second phase involved 56 trucks weighing 44 tonnes each to further test the bridge, followed by static load tests. In a cautious approach, remote-controlled vehicles were used to test the eastern ramp.
Load cells and the new bridge
There is no doubt that load cells would have been involved at many stages in the construction of the bridge, including the transportation and lifting of new bridge sections from the port at Genoa to the bridge construction site. In total, 237 sections were transported, some weighing over 80 tonnes, to be assembled on the ground. Sections were then lifted 50 metres into position. As reported by Heavy Lift magazine:
“SPMTs were used to move the larger spans, which measured 100 m long and weighed approximately 2,000 tons (1,814.4 tonnes). For these lifting operations, a strand jack system was deployed, along with a 1,250-ton (1,134-tonne) capacity crawler crane.”
Could a similar collapse happen in the UK?
British engineers had seen the warning signs with the collapse of the Ynys-y-Gwas Bridge, a single span segmental post-tensioned bridge. This highlighted the need to make pre-stressed concrete more easy to inspect and that the steel parts of the structure were properly protected against corrosion. Construction of reinforced-concrete bridges may have discontinued, but Britain still has a historic stock of hundreds of reinforced concrete bridges for road and rail.
Monitoring systems using load cells
If you need to monitor loads continuously, reliably and remotely, call us. We have experience in designing load cell systems for a wide range of uses, from commercial testing to motor racing. We design and manufacture our own brand load cells here in the UK, so we can also get you the load cells you need quickly. Check out of our online shop for standard stock, or call us with your specific requirements.