The memorial bench is at Tampines Tree Park because Mr Heng used to visit the park often with his family.
His widow, Mrs Sally Heng, 45, and children Daniel, 20, and Joann, 18, attended the ceremony with former colleagues and friends.
Mr Phornamdaeng, who has not seen Mr Heng's family for four years, said: " I'm happy that his children have grown up and are so well behaved... It's sad they had to grow up without Ah Heng, but I'm glad that they have grown up well."
The 2004 Nicoll Highway collapse is one of the worst construction accidents in Singapore's history.
The steel support for the tunnel that was being built for the Circle Line collapsed and the highway caved in, resulting in a 30m-deep cave-in that spread across six lanes of Nicoll Highway.
Construction foreman Heng Yeow Peow, 40, lost his life helping his workers escape the chaos of the collapse by shepherding them to safety.
Mr Suphathip Sanya, 37, and Mr Kabkaew Suriphon, 52, two of the eight workers whom Mr Heng helped to rescue from the MRT tunnel, said that all they remember of the day was the sound of beams falling.
The last thing they heard was Mr Heng shouting for them to run to the surface.
Mr Suruphon said in Thai: "I remember panicking, and climbing up the ladder.
"By the time we got out, we were exhausted because we had run 100m out of the tunnel and climbed 35m up the ladder to the surface."
Mr Heng was one of four men who died in the accident.
His body was the only one never found as rescuers had to call off the search due to the unstable ground.
Mr Heng was posthumously awarded the Medal of Valour during the 2004 National Day Awards.
This article was first published on June 19, 2014.
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