SINGAPORE: An engineer overseeing works who did not report design flaws and cracks that appeared during the building of a viaduct was sentenced to 86 weeks' jail, or about a year and nine months, and fined S$10,000 on Monday (Dec 2).
A portion of the viaduct from Tampines Expressway to Pan-Island Expressway and Upper Changi Road collapsed in the early hours of Jul 14, 2017, and 11 workers on top of the structure fell at least 9m to the ground. One man was killed and several others injured.
Robert Arianto Tjandra, 46, was given the sentence on Monday after pleading guilty last month to three charges: Recklessly doing an act endangering the safety of others at work; failing to take all reasonable steps and exercise due diligence to ensure building works were in line with regulations; and authorising building works to be carried out without approval.
Two other charges were taken into consideration.
Tjandra was the qualified person to prepare building works for the project and supervise the carrying out of building works, and he had discovered errors in the design of the corbels and support structures meant to distribute the vehicular load two weeks before the fatal collapse.
He also learnt of structural cracks on the crossheads of numerous constructed piers, including Piers 40 and 41, where the collapse later occurred.
He realised that wrong effective width assumptions had been used in the design of both temporary and permanent corbels of the viaduct, through his omissions at the design stage.
As a result, many of the corbels had insufficient capacity to support the loads they were intended to bear.
However, instead of flagging what he had discovered, as he was required to do, Tjandra tried to conceal the design deficiencies from the Building and Construction Authority by getting additional rebars installed in the corbels without seeking required approval.
The prosecution team, made up of Kristy Tan, Yang Ziliang, Kelly Ho, Ho Lian Yi, Mark Yeo and Ho Jiayun, had asked for at least 22 months' jail and a fine of at least S$10,000.
They pointed out Tjandra's reckless acts - including his failure to consider his team's lack of bridge design experience, failing to give his team guidance or instruction on the proper method or effective widths to be used for the design of the corbels, and neglecting to prepare corbel design calculations himself.
"The Qualified Person (Design)’s role is one of the cornerstones of the construction industry," said the prosecutors, noting that the public depends on the person's attentive and careful performance his duties to ensure structural safety.
They said construction workers rely on this qualified person for the viability of the structures they work on.
"Deterrent sentences should be imposed to prevent future catastrophes arising from the negligent and even reckless performance of structural design," said the prosecution.
Five people and the main contractor Or Kim Peow Contractors were charged over their involvement in this case.
OKP was fined S$10,000 in July for carrying out unauthorised strengthening works on the support structures of the viaduct, but intends to contest another charge for the death and injuries caused in the collapse.
Engineer Leong Sow Hon was jailed six months in July for failing to make sure that the viaduct's supporting structures were sound.
The other cases are pending.