Doomed from the start?
Due to inadequate support structures, failing to carry out suitable calculations, and not appropriately checking the designs, the collapse of the Pan-Island Expressway (PIE) viaduct project located in Upper Changi was foreordained.
The project checker’s failure claimed the life of 31-year old Chinese national Chen Yinchuan and injured 10 workers in the early hours of July 14, 2017.
Singaporean Leong Sow Hon, 61, pleaded guilty Monday (June 24) to one charge of failing to check the detailed structural plans and design calculations of the viaduct building works in accordance with regulations.
He further admitted to not assessing and reviewing the structural design in the plans and did not carry out the original calculations for all permanent corbels. These corbels are major structural components necessary to support the ends of the flyovers that comprise the 1.8km-long viaduct.
Another charge he pleaded guilty to was that of falsely certifying that he had not performed the necessary checks.
Destined to crash?
After the fatal incident, it was found that the calculations for the permanent corbels were inadequate.
Investigations revealed that eight of the 10 piers with permanent corbels were insufficiently designed, with five piers not being able to support the intended weight during the construction stage.
“Therefore, the five permanent corbels would have collapsed during the casting of the slab at the construction stage,” said the prosecutor.
The prosecutor added that while the remaining three piers can support the weight during construction stage, the corbels would eventually show significant structural cracks when there is full traffic load, followed by “sudden brittle failure leading to collapse.”
Because of the incident, the estimated completion date of the viaduct construction has been pushed back by at least two years from the first quarter of next year to the first half of 2022.
Leong was the first person involved in the case to plead guilty. The rest – including the qualified person who designed the building works and the builder Or Kim Peow Contractors – are set to claim trial.
The prosecution asked for at least nine months’ jail.
District Judge Hamidah Ibrahim said she intended to adjourn sentencing. The hearing continues.