As Italian officials put the number of victims killed by the collapsed Polcevera viaduct in Genoa at 43, some engineers suspect that the 51-year-old bridge’s unusual stay cables may have played a role.

The bridge operator Autostrade per l’Italia SpA had invited bids for a contract to reinforce stays on the collapsed section, but work had not yet commenced.

Following the collapse, the infrastructure and transportation ministry ordered an urgent review of an estimated 10,000 bridges older than 50 years.

穿过波尔切拉山谷（Polcevera Valley），长1.1公里长的高架桥包括东侧的三个缆线，跨度从约142米到207 m不等。

在8月14日中午之前的暴风雨中，最西端的塔倒塌了，几乎没有警告。大约240 m的甲板将约45 m的甲板掉到了高速公路，铁轨和建筑物上。

研究了该结构的设计和崩溃的视频后，巴黎的缆车桥工程师Michel Virlogeux可疑电缆故障。

Because of the late Riccardo Morandi’s unusual design, the bridge’s small number of stays provided no redundancy. Also, their prestressing created a “dynamic effect” when ruptured, hastening collapse, he believes.

Morandi’s design included rigid assemblies of cantilevering decks, each supported at the ends by two stays from 90-m-tall A-frame pylons. Four concrete struts inclining outward from the pier base provide additional support for each cantilever. Drop-in girders between the cantilever ends complete the deck. Each stay comprises around 300 strands that were prestressed after placement to share loads with the deck props. The cables were then encased in approximately 1 m of concrete, which was prestressed to remain in crack-free compression under live loading.

在1990年代，用外部钢板在其全长上加强了SPAN 11的停留时间。只有Span 10的顶部的顶部得到了加固，但是在倒塌的SPAN 9上似乎没有进行翻新。

Viaduct operator

Autostrade per l’Italia was about to start reinforcing pylons 9 and 10 when the collapse occurred. In May, the firm invited bids for a 784-day contract valued at $23 million to supplement those stays with new cables.

AutoStrade驳斥了政府关于忽视的指控。该公司声称，其符合国际标准的结构，并每年投资11亿美元。

The transportation ministry has threatened to cancel the company’s concession, which includes 2,855 km of highways, and impose a $170-million fine.

Following the collapse, government ministers ordered an initial review of all critical infrastructure to be done by Sept. 1. Deputy foreign minister Guglielmo Picchi says the government is prepared to make needed “massive investment.”

能扭转这一趋势,意大利pending on transportation infrastructure fall to 60% of the West European average, according to the Organisation for Economic Cooperation and Development. The cost of necessary upgrades could reach “tens of billions” of dollars, according to the Institute of Construction Technology of the National Research Council.

While more than 10,000 heavily loaded Italian bridges are over 50 years old, no official inventory exists, says institute director Antonio Occhiuzzl.