According to Mr. Nguyen Ha Nam - former lecturer of the Bridge and Tunnel Department of the University of Transport - the cause of the Phong Chau bridge collapse was most likely due to the T7 bridge pier being swept away, causing two bridge spans to collapse, not the bridge pier collapsing as many people assumed.
As someone who has observed and participated in the research of Phong Chau bridge structure for many years, Mr. Nam commented: "Phong Chau bridge was built before 1995, at that time there was already bored pile technology (first used at Viet Tri bridge project, Phu Tho). However, at Phong Chau bridge project, piles were still used. After nearly 30 years, perhaps the position of bridge pier T7 has been severely eroded locally because it is located right in the middle of the narrow stream and bend of the river".
According to Mr. Nam, due to erosion, the bridge pier T7 was washed away, causing spans 6 and 7 to be washed away. Erosion is a long-term process that occurs with changes in the flow and natural and human factors.
Similar to the expert's assessment, the preliminary report of the Phu Tho Department of Transport also said that due to the impact of storm No. 3 causing floods, the Red River rose high, and the rapid flow changed the terrain and geomorphology of the riverbed in the Phong Chau bridge area, causing the collapse of pillar No. 7 and the collapse of 2 main spans of the bridge (spans 6 and 7).
According to PV's investigation, in 2013, Phong Chau bridge was repaired by replacing 4 beams with span 8 - T21m of normal reinforced concrete with 4 beams with span T21m of prestressed reinforced concrete; At the same time, fiberglass and carbon fiber were glued to reinforce T33 beams of spans 1,2,3,4.
The total cost of this repair is more than 15 billion VND.
By 2019, Phong Chau bridge was also repaired with the scale of handling erosion of pier No. 7; Reinforcing 8 C30 reinforced concrete bored piles, diameter D1200mm; pile tips embedded in bedrock; Combining with expanding the pier base with C30 reinforced concrete;
At the same time, dismantle and recover the damaged collision pillar in front of pillar number 7; Reinforce the collision resistance by rigidly connecting the two bodies of pillar number 7, reinforced concrete structure C30, height 1.2m.
In 2023, Phong Chau Bridge will continue to be repaired. Ngoc Viet Investment and Trading Company Limited, headquartered in Kim Bang District, Ha Nam, won this bid.
Phong Chau Bridge is a bridge across the Red River on National Highway 32C, located at Km 18+300 National Highway 32C, connecting Phung Nguyen commune, Lam Thao district with Van Xuan commune, Tam Nong district.
Phong Chau Bridge was built using old technology with a steel truss structure, 375.36m long. The project was inaugurated on July 28, 1995.
