The engineer who prepared building work plans for the Pan-Island Expressway (PIE) viaduct that collapsed in July 2017 was yesterday sentenced to 86 weeks' jail, or slightly over one year and nine months, as well as a fine of $10,000.
In delivering her sentence, Deputy Presiding Judge S. Jennifer Marie said that the potential for harm in this case was high.
Indonesian Robert Arianto Tjandra, 46, the qualified person from subcontractor CPG Consultants, knew his team of engineers was inexperienced in designing bridges, but failed to give the team guidance or instructions.
He also failed to check the design assumptions made for the corbels, which are support structures, between affected vertical columns that collapsed. The viaduct rests on these vertical columns, called piers.
Even after he was aware of the errors in the calculations made by the engineering team, he failed to take the necessary remedial steps.
It was this reckless act that resulted in the collapse of the PIE viaduct, which killed Chinese worker Chen Yinchuan, 31, and injured 10 others. The 11 workers, who were working on the affected deck slab, fell to the ground from a height of at least 9m.
Arianto Tjandra, a Singapore permanent resident, had faced five charges under the Building Control Act and the Workplace Safety and Health Act - the highest among those who were charged.
On Nov 20, he pleaded guilty to three of the five charges, with the remaining two charges taken into consideration for sentencing.
He admitted to recklessly endangering the safety of others by putting up structural plans without checking on the design assumptions made for the corbels between the affected piers, and after knowing that the wrong design assumptions had been used, failed to carry out the necessary remedial works.
He also pleaded guilty to failing to take reasonable steps and to exercise due diligence to ensure that the building works were designed in accordance with the Building Control Act, as well as authorising strengthening works to a permanent corbel without seeking the necessary approval.
The court heard that Arianto Tjandra led a team of five design engineers who had no or limited experience with bridge design involving the design of the corbels used in the PIE viaduct.
None of the five design engineers knew how to do the calculations, nor did they make the correct calculations, said the prosecution.
The cases involving the main contractor Or Kim Peow Contractors, and its project engineer Wong Kiew Hai, 31, and project director Yee Chee Keong, 49, are still pending.