There was nothing unusual about the early morning construction work at the site where part of the structure collapsed yesterday. The Land Transport Authority explained that the timing had been scheduled.

To facilitate the works, a slip road from the Pan-Island Expressway to the Tampines Expressway (TPE) and Upper Changi Road North and East was closed between 1am and 5am on several days in the past three months.

The Straits Times understands that some roadworks have to take place in the early hours of the morning as it might be the only available time for certain major operations such as concrete casting.

Closing the slip road at night would allow heavy equipment to deliver construction materials to the work site without disrupting daytime traffic.

Pre-dawn works are a common practice in the construction industry, though there may be some additional challenges, such as the lack of light.

Singapore Contractors Association president Kenneth Loo said: "Certainly, there are more challenges to working at night, but it is possible to plan for them, for example by scheduling night shifts and having flood lights."

For works occurring at night, there will be stricter noise control requirements to reduce disruption to residents.

Fatigue levels of those working in these shifts should also be accounted for, as outlined in the Workplace Safety and Health Guidelines on Fatigue Management.

Ng Jun Sen