Bangkok: The Thai Industrial Standards Institute (TISI) has confirmed that the T-mark on rebar does not compromise structural integrity and can be safely used in construction, including tall buildings. This assurance comes amid concerns following the collapse of the Office of the Auditor General's building.
According to Thai News Agency, Assoc. Prof. Dr. Samit Songpiriyakit, President of the Civil Engineering Branch at the Engineering Institute of Thailand under the Royal Patronage, stated that the T-mark on rebar has been used reliably in the construction industry for over 20 years. He emphasized that the T-mark indicates the manufacturing method, which involves a specific cooling and reheating process to harden the steel's outer surface.
Dr. Samit explained the process, highlighting that T-mark steel is cooled with water mist and reheated, while non-T-mark steel cools naturally and is chemically strengthened, making T-mark steel a more cost-effective option. He noted that engineers have long been aware of these differences, and project bids often include discussions on using T-mark steel due to its cost benefits.
To ensure quality, steel arriving at construction sites undergoes rigorous testing for maximum stress, elongation, and bending capabilities. These tests are conducted by accredited institutions such as the Steel Institute and universities. Despite concerns, historical inspections have shown no instances of substandard steel, although lightweight steel has occasionally failed to meet standards.
Dr. Samit also addressed the recent building collapse, stating his belief that steel was not the primary factor, though the exact cause remains undetermined.
Mr. Kritsada Chanjamrassaeng, Vice President of the Thai Contractors Association under Royal Patronage, discussed the implications of the confusion over T-mark steel. He noted that some government agencies have advised against using T-mark steel, impacting contractors who have stockpiled it, potentially causing supply issues and price increases for non-T steel. He acknowledged that steel from the collapsed building did not meet standards but affirmed that generally, 90% of steel does comply with requirements.