Extra consultant proposed for HCMC metro fault investigation

HCMC Management Authority for Urban Railways (MAUR) proposed to Japan International Cooperation Agency (JICA), which funds the metro project, that the additional consultant be independent of the consortium of Vietnam’s Civil Engineering Construction Corporation No. 6 (Cienco 6) and Japan's Sumitomo Corporation, contractor of the section where the incident had occurred.

Last October, one of the Elastomeric Laminated Bearing pads had fallen from its position between two beams on the elevated section in Thu Duc City of the metro line, which runs 19.7 kilometers (12.24 miles) from Ben Thanh Market in District 1 to the Suoi Tien theme park in Thu Duc.

These pads are made from high-purity elastomers that encapsulate layered internal steel reinforcing plates and are designed for use in bridge and building construction for beam support. The incident was detected after cracks were seen along the elevated section.

Then in January, another pad was found to have deviated from its position on the section as inspectors looked into the falling of the first. Later, four more pads along the section were found to have moved from their positions.

The MAUR said it had previously worked with competent authorities and closely with the contractor and general consultant of the project, NJPT, a consortium led by Japan's Nippon Koei, to speed up handling of the incident.

Currently, the contractor has completed necessary experiments and observations and sent its report to an independent consultant for verification.

Therefore, according to MAUR, adding another independent consultant would boost the legal process, and simultaneously, offer an objective basis for work acceptance.

In a preliminary conclusion submitted to the city administration last month, the MAUR said the pad incidents had been caused by temperature differences between the girder and track, with errors in construction having led to unsatisfactory friction between the contact surface of the pad and pier, and the low quality of pads.

The conclusions were made based on the results of periodic monitoring, reports from project contractors, and an independent consultant, it said.

The metro line No.1 project was approved in 2007 but work only began in 2012.

There have been several delays, and the MAUR said in September the route would be completed in late 2023 or early 2024 after one final delay due to the Covid-19 pandemic. It would be 91 percent complete by the end of this year, it stressed.

Costing more than VND43.7 trillion ($1.89 billion), including over VND38.2 trillion in official development loans from JICA, along with counterpart capital from the city budget, the line will have 14 stations, three underground and 11 on the surface, some elevated. For now, it is 88 percent complete.