Following the collapse of the westernmost pylon of a 51-year-old bridge in Genoa that killed 43 people, efforts to pinpoint the cause have centered on what was described as the bridge’s “unusual stay cables” design.

Crossing the Polcevera Valley, the 1.1-km-long viaduct included three cable-stayed sections on the east side, with spans ranging from about 142 m to 207 m. The westernmost pylon (span 9) collapsed during a storm before noon on Aug. 14. About 240 m of deck dropped some 45 m onto a highway, rail track and buildings.

Per a report in Engineering News-Record, Paris-based cable-stayed bridge engineer Michel Virlogeux—who studied the structure’s design and saw a video of the collapse—suspects cable failure. The bridge’s design was unusual in that it had a small number of stays, which provided no redundancy. Also, their prestressing created a “dynamic effect” when ruptured, hastening collapse, he said.

The report said that the stays of span 11 were reinforced over their full lengths with external steel plates in the 1990s, and that the tops of stays of span 10 were reinforced, but no retrofitting appears to have been made on the collapsed span 9. Following the collapse, the infrastructure and transportation ministry ordered an urgent review of an estimated 10,000 bridges older than 50 years.

The Asia America Gateway (AAG) undersea cable—a 20,000-km-long submarine communications cable system that connects South-East Asia with the mainland of the United States, across the Pacific Ocean via Guam and Hawaii—has reported its fourth service outage this year.

The Vietnam Post and Telecoms Group (VNPT) reports that the cable broke down on August 23, the fourth incident to date in 2018, affecting Vietnam’s international internet connections. It attributed the service break to a power leakage at a point about 250 km offshore the cable’s landing point in Vung Tau (Ba Ria-Vung Tau Province).

The AAG cable is notorious for its frequent breaks and outages since it started service in late 2009. Most of the outages have been located at the intra-Asia segments between Hong Kong and Singapore, with most problems occurring in the Vietnam section, while the segment between Hong Kong and the Philippines seems to have fewer problems.

The $560-million AAG cable handles more than 60% percent Vietnam’s international internet traffic. Since its debut, the cable has encountered a “very high” risk of rupture and been under frequent repair, affecting all service providers in Vietnam. The cable suffered technical errors at least five times in 2017.

Prysmian reports that it has entered into an agreement with Chinese contractor Talesun to supply some 3,600 km of cables for a new major solar park in Cauchari, Argentina.

A press release said that Prysmian will provide a range of instrumentation and control, low- and medium-voltage and solar cables from its Chinese plants in Tianjin and Yixing. The deal, to include more than 1,100 medium-voltage accessories and connectors from its Yixing plant, will also require 100 Pry-Cam Grids and one Pry-Cam Portable for monitoring to be supplied by Prysmian Electronics, and supervision services (KOM) for both MV Accessories and Pry-Cam supplied by the team in Argentina, it said.

Cuachari is the first project signed by China and Argentina within the “OBOR – One Belt, One Road” initiative, the release said. It noted that Talesun is acting on behalf of Shanghai Electric, the main contractor for the project, which will see the construction of a 315 MW photovoltaic plant. It is to be located in the Jujuy Province, close to the North-West border with Chile, and at an altitude of 4,100 m, it represents a significant solar resource. The solar park is expected to generate a monthly average of 55,073 MWh, which will be conveyed to the 345 kV line that links the Chilean town of Andes with the town of Cobos in the province of Salta.

“We leveraged the internal synergies within the Group with the close cooperation of the different regions and teams involved to fulfill the complex requirements of the project,” said Prysmian Group China CEO Matteo Bavaresco. “This is a milestone example of global integration and teamwork within Prysmian.”

The Lithuanian-Swedish submarine power cable, NordBalt, was shut down for what is expected to be two and a half months for planned repairs.

A story in The Baltic Course said that the repairs include the replacement of onshore cable joints that have been identified as the cause of frequent failures. It said that Lithuanian power transmission system operator Litgrid reports that 31 failures have been registered since the launch of the 700 MW NordBalt power cable in February 2016, including 12 incidents linked to cable joints. The repair work, expected to be completed by the end of October, will see 22 cable joints replaced on the Lithuanian side and 98 in Sweden.

The cable was provided by ABB, which in March 2017 was acquired by NKT. In a press release at its website, ABB outlined the project, which was described as the world’s longest HVDC Light® underground and submarine cable. “The NordBalt HVDC Light link is a joint project of the Swedish and Lithuanian transmission system operators (TSOs), Svenska Kraftnät and LITGRID AB. HVDC Light is an ABB technology for connecting transmission systems using submarine and underground cables. It offers several compelling benefits, including ‘invisible’ power lines, highly compact AC-DC converter stations, low cable and converter losses, and black start capability (the ability to rapidly restore system operations in the event of a systemwide power outage).”

The NordBalt project included “a 2 x 40 km HVDC Light underground cable on the Swedish side, a 2 x 13 km HVDC Light underground cable on the Lithuanian side, and a 2 x 400 km HVDC Light submarine cable across the Baltic Sea,” the report said. The ABB HVDC Light solution has a power rating of 300 kV. It includes two converter stations, “one at Nybro in Sweden and the other at Klaipeda in Lithuania, where the power is converted from AC to DC for transfer in the HVDC Light cable system. The Swedish power grid has a rating of 400 kV AC and the Lithuanian grid a rating of 330 kV AC; the two grids are asynchronous.”

Contacted by WJI, an NKT spokeswoman said that the owner of Nordbalt “has previously communicated that the line will temporarily be shut down due to cable joint repair. We ... (cannot) comment on any contractual terms, including repair costs.”