According to information from the Management Board of Traffic Construction Investment Project of Tuyen Quang province, this unit has sent a report to the Ministry of Construction and the Provincial People's Committee about the collapse of the top of the civil traffic tunnel under package No. 20 on the evening of September 16.
Accordingly, the initial cause was determined to be the collapse of the formwork scaffolding system, leading to the collapse of the entire concrete and steel structure of the newly constructed tunnel top.
During the process of pouring reinforced concrete for the tunnel top at Km25+095 from 16:30 to 18:55. After pouring concrete, when cleaning up equipment under the tunnel, the entire scaffolding structure, formwork and reinforced concrete for the top collapsed.
According to the drawing, the tunnel has an aperture of 6.5 x 4.5 meters. The tunnel structure is made of 30Mpa reinforced concrete, the tunnel length is 30.5 meters. The left side of the route has been completed and the formwork has been removed to move on to the construction on the right side of the route.
At the time of the incident, the construction had been completed, with sufficient strength according to the design, and the reinforced concrete formwork for the tunnel bed and the first and second reinforced concrete for the tunnel body had been dismantled. At the same time, the pouring of reinforced concrete for the tunnel top had just been completed.
The contractor for the construction package is Cuong Thinh Thi Construction Investment Group Joint Stock Company (belonging to the Joint Venture of 168 Vietnam Construction Group Joint Stock Company and Cuong Thinh Thi Construction Investment Group Joint Stock Company).
In addition to human losses, material losses include the entire volume of reinforced concrete for the tunnel top (nearly 70.5m3 of concrete; 10.7 tons of various types of steel) and the entire scaffolding system and formwork for pouring concrete for the top of the residential tunnel.
Previously, as Lao Dong Newspaper reported, at around 7:00 p.m. on September 16, the Tuyen Quang - Ha Giang expressway underpass cover at Km25+095 in Tu Quan commune (Yen Son district) collapsed when the concrete pouring had just finished. The incident left one worker dead.
