The steel structure of the junction of the North-South Elevated Road and the Beiheng Passage was completed on Sunday.
The 19-kilometer east-west passage will link Putuo, Changning, Jing’an, Hongkou and Yangpu districts. It will become part of the city plan to have three east-west and three north-south thoroughfares across the city to improve traffic flow.
The last section of the 168-meter steel box beam, which will support the passage over the North-South Elevated Road, was finished around 1am, avoiding disruption to traffic.
With the help of a super crane, the 1,475-ton beam was installed 30 meters above the ground over the Tianmu Road Roundabout, where the south-north thoroughfare will join the under-construction Beiheng Passage upon its completion by 2023.
The overpass project of the Tianmu Road Roundabout is constructed by the Shanghai SMI Highway Group and contracted by the Shanghai Construction Group, the two major constructors of the city. The project is dubbed a "bypass heart surgery" because of the delicate operations required in the central downtown with its heavy traffic flow.
Construction on the overpass beam started on July 14 to install the steel structure over the already three-layer traffic network.
To reduce disruption to the traffic on the Tianmu and the elevated roads as well as the roundabout, the constructors used a 28-meter-tall crane which has a 65-meter-long flexible arm with the capacity of up to 100 tons.
The base of the crane occupies only 13 square meters on Tianmu Road, which had not been closed.
The box-shape beam was installed by sections. Temporary supports were built and removed after the sections were welded together, according to the SMI group.
The final part of the work over the elevated road was built only after midnight after the closure of the elevated road for daily maintenance. The constructors spent four nights to link up the beam structure.
“The project marks the completion of the most difficult part of the Tianmu Road project for the passage,” said Wu Huaqi, a commander for the project. The constructors have overcome difficulties such as the dense overhead cables, limited space and busy traffic in the region, he added.
Under the current plan, the Beiheng Passage will run over the elevated road, while the roundabout will become a key intersection connecting the two major roads.
The roundabout was built in 1993 along with the North-South Elevated Road and has become a traffic bottleneck. The city's traffic authority installed traffic lights on the roundabout in 2007 to try to relieve the congestion, but it has hardly improved the situation.
Before the construction of the overpass beam, a renovation was carried out on the roundabout to not only connect the North-South Elevated Road with the Beiheng Passage, but also to solve the congestion on the roundabout. Two ramps were demolished and replaced by new ramps to join the south-north thoroughfare with the Beiheng in March 2019.
The work on the Tianmu Road Roundabout is scheduled to be completed by June 2021, when the western part of the Beiheng Passage will initially open. The whole project will be completed by the end of 2023.
Prefabricated structures and Building Information Modelling have been widely used during the project to reduce the impact on the environment and nearby residents.
The passage will reduce the driving distance between the Hongqiao airport and Shanghai Railway Station to 20 minutes from at least an hour currently, Wu said.
The heavy traffic flow on the Yan’an Road Elevated Road will also be reduced by 20 percent with the opening of Beiheng, he added.