Cause of subsidence at Ngoc Hoi intersection has been determined

According to the report, through on-site inspection at the Ngoc Hoi roundabout, the Provincial Management Board of Investment and Construction of Agricultural and Transport Works recorded the phenomenon of subsidence, cracking and localized protrusion of the asphalt concrete surface with an area of about 15m². Phuc Son Group Joint Stock Company stated that in June 2024, at this location, there was a traffic accident that caused damage to the vehicle and required it to stop for repair (at the scene, damage and deformation of the steel railing were also recorded). During the repair process, the vehicle owner dumped grease and spilled solution on the asphalt concrete surface at the peeling location.

The subsidence location has been repaired by the construction unit, restoring the current state to ensure aesthetics and traffic safety.

On the morning of May 15, the Project Management Board, the Department of Construction coordinated with Phuc Son Group Joint Stock Company (investor), the construction contractor, the supervision consultant, and the design consultant to conduct a sectioning and excavation of the asphalt concrete layer at the subsidence and cracking location with an area of about 80 square meters to observe and visually evaluate the bridge deck. At the time of inspection, the relevant parties noted that the bridge deck was completely normal, with no cracks, peeling or unusual signs detected. After that, the relevant parties coordinated with BK-Central Construction Inspection Consulting Joint Stock Company to measure the strength and ultrasound of the bridge deck concrete at 5 locations to check the structural condition of the bridge girder concrete surface. The ultrasound results showed that the bridge deck was not structurally damaged, and the strength of the bridge deck concrete met the design requirements. From this result, Phuc Son Group Joint Stock Company, the supervising and design consultant, determined that the cause of subsidence and cracking was due to the reduction of adhesion between the asphalt concrete and the bridge deck, consistent with the phenomenon of chemicals or oil flowing down the asphalt concrete surface, leading to local damage to the asphalt concrete surface.

The investor and the construction unit have cleaned and treated the surface of the bridge deck; applied a layer of adhesive asphalt according to the correct procedure; laid a layer of geotextile mesh (geoglass mesh) to increase the connection; and constructed the asphalt concrete layer according to the approved design. Phuc Son Group Joint Stock Company has restored the asphalt concrete surface to ensure technical, aesthetic, and traffic safety for vehicles to circulate normally.

Van Ky

Source: https://baokhanhhoa.vn/xa-hoi/202505/da-xac-dinh-nguyen-nhan-vet-lun-tren-nut-giao-ngoc-hoi-0665a73/