>>Costing 15.73 billion RMB (around US$20 billion) and measuring 55 km (34 miles)-long including connecting roads, the new Hong Kong-Zhuhai-Macau Bridge (HZMB) is the world’s longest sea crossing bridge. Following nine years of construction, the massive project is now open and connects the Chinese mainland to Hong Kong and Macau.<<

https://newatlas.com/hong-kong-zhuhai-macau-bridge-opens/56911/

PermeateFree said:

>>Costing 15.73 billion RMB (around US$20 billion) and measuring 55 km (34 miles)-long including connecting roads, the new Hong Kong-Zhuhai-Macau Bridge (HZMB) is the world’s longest sea crossing bridge. Following nine years of construction, the massive project is now open and connects the Chinese mainland to Hong Kong and Macau.<<

https://newatlas.com/hong-kong-zhuhai-macau-bridge-opens/56911/

seen some footage etc regards that in a documentary about bridges, nothing short of impressive

Someone was complaining it wasn’t financially responsible as they’d not make the cost back in regards to tolls but I’d have thought bridges are built because they are needed not to be a money maker.

Cymek said:

Someone was complaining it wasn’t financially responsible as they’d not make the cost back in regards to tolls but I’d have thought bridges are built because they are needed not to be a money maker.

Would a bridge like that see an economic change of some kind ?

I read that 18 people got killed making that bridge at different times during its construction.

Tau.Neutrino said:

Cymek said:

Someone was complaining it wasn’t financially responsible as they’d not make the cost back in regards to tolls but I’d have thought bridges are built because they are needed not to be a money maker.

Would a bridge like that see an economic change of some kind ?

yes

The region that is going to benefit from this bridge has a GDP of about 1.7 trillion USD per annum. If it removes barriers between Hong Kong, Macau and Guangdong even a little bit, it will pay for itself in short order.

PermeateFree said:

>>Costing 15.73 billion RMB (around US$20 billion) and measuring 55 km (34 miles)-long including connecting roads, the new Hong Kong-Zhuhai-Macau Bridge (HZMB) is the world’s longest sea crossing bridge. Following nine years of construction, the massive project is now open and connects the Chinese mainland to Hong Kong and Macau.<<

https://newatlas.com/hong-kong-zhuhai-macau-bridge-opens/56911/

It’s a long bridge but not a long span bridge, presumably bacause the water is not very deep.

> Hong Kong-Zhuhai-Macau Bridge (HZMB)

The Hong Kong–Zhuhai–Macau Bridge is a bridge–tunnel system, which consists of a series of three cable-stayed bridges and one undersea tunnel, as well as two artificial islands. It spans the Lingdingyang channel, which connects Hong Kong with Macau and Zhuhai, three major cities on the Pearl River Delta.

Images of the bridge on the web are conflicting, as if some were old proposals that were never installed.

Interestingly, they’ve opted to tunnel under the main shipping channel instead of bridging it. That makes good sense.

The bridge and tunnel together is only 29.6 km. The rest of the 55 km is only approach roads (on land). The largest bridge span is 460 metres. For comparison, the span of the old golden gate is 1,280 metres. Even the span of the Sydney Harbour Bridge is longer, at 503 metres.

On the topic of long-span bridges, I’ve been in two minds for about 30 years about the possibility of a suspension bridge with sloping hangers, setting up the slope to triangulate the bridge.

On the one hand, my mind says that it won’t be stiff because all the cables are bent under the force of gravity and a slight change in tension will cause them to straighten or bend more, allowing the bridge to flex.

On the other hand, my mind says that since all cables are prestressed in strong tension, it will be almost as stiff as a truss bridge for a tiny fraction of the weight.