The documentary video shows an extreme engineering works of constructing the Hong Kong International Airport. This project not only consists of new airport but also consists of super highways, tunnels and double Decker suspended bridges connecting to the main city. The construction of this project was definitely tough since only 7 years were given to complete the entire project. In fact, this project was estimated to be completed in 15 years.
There are several challenges faced during the construction stage. The main challenge is to construct the airport on a mountainous island. The mountains had to be removed and leveled. 200 million tons of rocks were removed by giant earth movers. To enlarge the surface area for the airport, reclamation works need to be carried out. The largest fleet of under water dredgers used to remove soft mud up to 120 meters the sea before reclamation works to ensure minimum consolidation settlement in the future.
The second challenge is to build a long tunnel through the sea. The construction method was to dig a basin and construct the concrete steel tunnel in sections. Once the tunnel sections were built, the basin will be flooded and the tunnel sections can be launched into designated location. After that, tunnel sections were to be laid 150 meters under water up to 1.6 km and capped with water tight seals to prevent water from entering. The seals were then removed carefully by hydraulic jacks.
Thirdly, there is an area with water width of 4.8 km where tunnels are not feasible due to heavy traffic on that route. The engineer proposed bridges to overcome the challenge. The bridges have to be long enough to span the islands and high enough to allow most gigantic ships below it. Two bridges with towers’ height of 60 stories were to be constructed. The most difficult construction method was practiced in this project where 75mm diameter cables (weigh up to 15000 tons) were built