Ho Chi Minh City has installed steel frames and sprayed anti-slip glue on 918 bridge bearings on Metro Line 1 to ensure safety after an incident where some bearings fell and shifted three years ago.
The information was given by Mr. Nguyen Quoc Hien, Deputy Head of the HCM City Urban Railway Management Board (investor), on the morning of June 15 when mentioning the process of investigating the cause and fixing the bridge bearing problem on Metro Line 1 (Ben Thanh - Suoi Tien).
Mr. Hien said that the bridge bearings on the route fell and shifted due to the gap between the bearings and the support stones, leading to a decrease in contact area, affecting the friction force. This factor, combined with the expansion due to the temperature difference between the rails and the beams during construction, increased the possibility of the bridge bearings slipping. The conclusion was made after the general contractor and the consulting unit conducted monitoring and testing on all three aspects of design, construction and materials.
From October 2020 - the time the incident was discovered - to now, the metro line has had one bridge bearing fall and nine bearings move from their original position, out of a total of 1,910 bridge bearings in the project.
The steel frame system is installed to prevent the bridge bearings from shifting. Photo: MAUR
To overcome the problem, the contractor installed a steel frame structure at 918 bridge bearings on the route to prevent displacement, including in the event of an earthquake. Of the 918 locations mentioned above, 733 locations were sprayed with epoxy glue to fill the gap between the bearings and the support stones, ensuring friction.
According to Mr. Hien, the above measures have been assessed by independent consultants and approved by the NJPT consortium (the general consultant of the project) according to the quality management process. This is consistent with the opinions of experts in the working group participating in verifying the cause. However, to ensure absolute safety, the bridge bearing monitoring will continue to be carried out by the contractor until the acceptance and completion stages as well as during the warranty period.
Bridge bearings are the connecting parts from the bridge span to the abutment, acting as a load-bearing pad and reducing the force of the span structure transmitted to the abutment. Depending on the project, bridge bearings have many different types and designs, can be made of steel or elastic such as rubber, steel plate rubber...
Metro No. 1 train tested the elevated section in April 2023. Photo: Quynh Tran
Metro Line 1 started construction in 2012, with a total investment of over VND43,700 billion, and a length of nearly 20 km. The line extends from Ben Thanh Station to Long Binh Depot (Thu Duc City), including three underground stations and 11 elevated stations. The entire project is currently about 95% complete and is expected to be completed by the end of this year.
Gia Minh
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