The bridge is a mega seaborne corridor linking Hong Kong, Zhuhai and Macau. It measures 55 km in total – including a 35.5-km main bridge and a 6.75-km underwater tunnel in the waters between Hong Kong and Macau. The infrastructure – engineered to withstand shocks of a magnitude-8 earthquake and gusty winds of a category 16 typhoon – is currently the world’s longest of its kind and is designed for a service life of 120 years.

The bridge is a mega seaborne corridor linking Hong Kong, Zhuhai and Macau. It measures 55 km in total – including a 35.5-km main bridge and a 6.75-km underwater tunnel in the waters between Hong Kong and Macau. The infrastructure – engineered to withstand shocks of a magnitude-8 earthquake and gusty winds of a category 16 typhoon – is currently the world’s longest of its kind and is designed for a service life of 120 years.

One-Hour Connectivity

The bridge has reduced travel time between Hong Kong, and Zhuhai and Macau from three hours to just half an hour thus helping to form an economic cluster in the Pearl River Delta region.

A Marvel of Engineering

The bridge is an engineering marvel made possible by a series of innovative applications of science and cutting-edge technology. The bridge is a piece of world-class mega infrastructure and has set a number of world records for its breakthroughs and architectural achievements.”

The Artificial Island: An Unprecedented Challenge

The construction of bridges and tunnels entailed in the project required engineering effort of the highest caliber. In particular, large man-made islands have been created using an innovative technique of reclamation; a perimeter is formed with 120 giant steel cylinders placed directly onto the seabed before filling the center area with rocks. Each cylinder measures 22.5 meters in diameter (as large as a basketball court), 55 meters in height (as tall as an 18-storey building), and 550 tons in weight (as heavy as an Airbus A380 double-decker airliner).

The Tunnel: Longest, Deepest & Immersed

The project adopted a bridge-island-tunnel design – including two artificial islands with a land area of ​​100,000 square meters and a 6.7 km underwater tunnel. This offshore tunnel is the first of its kind in Mainland China; it is also the world’s longest, deepest and most difficult to construct piece of immersed architecture.

The Bridge: Designed to Last and Withstand Catastrophic Impacts

The bridge – which architects worldwide have labeled an engineering marvel bordering the limits of current technology – is designed to withstand shocks of a category-16 typhoon or a magnitude-8 earthquake. With an expected service life of 120 years, it exceeds the average of older designs by 20 years, and is considered to be among the most innovative of bridge constructions globally.

Emergency Response Time

The artificial islands are equipped to serve as rescue platforms in cases of an emergency. Should an accident occur inside the tunnel or on the bridge itself, rescue personnel will arrive within 3 and 5-7 minutes, respectively.

Plenty of Airflow & a Strong Mobile Signal

Circulation of air inside the tunnel is facilitated by a series of overhanging fans, injecting fresh air and extracting automobile exhaust fumes simultaneously. The installation of communication lines, meanwhile, ensures uninterrupted voice and data transfer for mobile phone users. Even without a personal mobile handset, a driver or passenger is able to call for help in a situation of distress by pressing one of the many one-button emergency assistance devices provided in  the tunnel.
 

China’s Swift Progress

The underwater tunnel – from the installation of the first section (E1) on May 2, 2013 to the final joint completed on May 2, 2017, along with 34 rounds of “deep-dive” construction – is a masterful engineering achievement. It marks China’s swift progress in the delivery of mega infrastructure projects as reflected in a number of record-breaking achievements. These include the successful installation of ten tunnel sections within a year, sometimes two sections in 2-3 weeks, and doing so within a tolerance measured in millimeters.

420,000 Tons

The bridge was constructed using 420,000 tons of steel – ten times the amount used for the construction of the Beijing National Stadium (aka the Bird’s Nest), or 60 times the weight of the Eiffel Tower.

6.7 KM

It is 6.7 km in total length and composed of 33 individual sections. Each section weighs roughly 80,000 tons and is larger than an aircraft carrier.

120 Years

The estimated service life is 120 years, 20 years more than any existing sea-crossing bridge in the world, a task deemed difficult due to harsh conditions pertaining to high temperature, high humidity and high corrosion.  

Underground Cut

Instead of relying heavily on the Open Cut method, excavation was mostly carried out using the the Underground Cut technique which allowed the immigrant checkpoint at Gongbei port, near Macau, to remain functional. This avoided disrupting port traffic and inconveniencing some 300,000-500,000 daily commuters. The Open Cut process would have taken four years.

The challenges associated with the Gongbei tunnel construction included:

References:

Technology Explained: The Hong Kong-Zhuhai-Macao Bridge (港珠澳大橋的「科技密碼」) by Feng Hua (馮華) People’s Daily (人民日報) Jan. 16, 2018

Eight Years in the Making, Lingding Channel-Spanning Hong Kong-Zhuhai-Macao Bridge Breaks Numerous Records (港珠澳大橋歷時8年跨越伶仃洋 創多個世界之最) China Central Television News Channel (央視新聞) July 7, 2017

Hong Kong-Zhuhai-Macao Bridge Withstood Beaufort Force 16 Storm (港珠澳橋16級風中穩如泰山), hk.news.yahoo.com, Sept. 17, 2018