Changi viaduct collapse: LTA-appointed checker who failed to review structural plans jailed 6 months

LTA-appointed accredited checker Leong Sow Hon, 61, had failed to check on the 10 permanent corbels – a type of weight-bearing structure – that were under his purview. (PHOTO: SCDF)

SINGAPORE — A Land Transport Authority (LTA)- appointed accredited checker (AC) who failed to inspect the structural design of a viaduct in Changi that collapsed was jailed six months on Thursday (4 July).

Part of the 1.8km-long Pan-Island Expressway (PIE) viaduct along Upper Changi Road East collapsed at about 3.30am on 14 July 2017. The accident killed one worker, Chinese national Chen Yinchuan, and left 10 others injured.

While the segment of the viaduct that gave way was not under Leong Sow Hon's purview, investigations found that he had not checked on the 10 permanent corbels – a type of weight-bearing structure – that had been assigned to him.

The 61-year-old engineer’s failure to evaluate, analyse and review the structural design of the permanent corbels would have led to five corbels collapsing at the construction stage and three more failing had the viaduct been opened to the public.

As an AC, Leong was also required to submit independent calculations and analyses of the structure but did not do so between 18 November 2016 and 13 June 2017.

While his failure to check the design plans formed the basis of one charge, a separate charge of falsely certifying that he carried out an evaluation, analysis and review of the plans of the building works in accordance with regulations was taken into consideration for his sentencing.

Leong had claimed on 26 July 2017 that he had performed original calculations at the submissions stage and had checked the permanent corbels. However, he was unable to provide evidence of original calculations when asked.

He admitted on 21 September 2017 that no calculations had been done.

The prosecution had called for nine months' jail for Leong, citing the potential for harm had the project carried on. Leong's lawyer, Tai Chean Ming, had sought a fine of $25,000, pointing out that his client was not involved in the section of the viaduct that collapsed.

In passing the sentence, District Judge Hamidah Ibrahim said that the potential for harm in Leong’s lapses was high and that, if the viaduct had been constructed as intended, its eventual collapse would have put workers and members of the public at risk.

She added that, as an AC, Leong should have taken and discharged his statutory duty seriously. As the leader of a team, any responsibility in the matter also ended at him.

Leong intends to appeal against his sentence.

Others implicated

Construction firm Or Kim Peow (OKP) Contractors and four other individuals – group managing director Or Toh Wat, employees Yee Chee Keong and Wong Kiew Hai, and consultant Robert Arianto Tjandra – were charged on 30 May last year.

All parties are claiming trial to breaches under the Workplace Safety and Health Act and the Building Control Act and have yet to been dealt with by the court.

Both the firm and Or are accused of failing to take measures to ensure the safety and health of the firm’s employees by failing to adequately assess risk when they became aware of cracks that had formed on the corbels.

They had also allegedly failed to stop all work on the viaduct after discovering fresh cracks had formed on the corbels, which led to the fatal incident.

OKP and Or were also both charged for allegedly carrying out unauthorised strengthening works on a corbel without the approval of the Commissioner of Building Control, and for failing to notify the Commissioner of the contravention of a section the Building Control Act.

Yee and Wong were each charged with one count of recklessly committing an act, which endangered the safety of others. They are accused of failing to halt all works on the viaduct section when cracks were discovered in the corbels supporting the section upon which the workers were casting a deck slab.

Both men were also charged with one count of intentionally obstructing the course of justice by deleting a WhatsApp conversation between each other which contained photographs and information potentially relevant to criminal investigations.

Yee also faces one count of permitting unauthorised strengthening works without the approval of the Commissioner of Building Control.

Tjandra faces one count of recklessly committing an act that endangered the safety of others. He allegedly put up structural plans without checking the design assumptions made for the cracked corbels.

He also allegedly did not carry out the necessary remedial works to rectify the inadequate design, even after knowing that the corbels could not support the deck slab while it was being concreted.

Tjandra was also accused of failing to ensure that the building works relating to the permanent corbel structures were designed in accordance with the provisions of the Building Control Act and regulations, and accused of failing to notify the Commissioner of Building Control of the contravention of a section in the act.

He is also accused of authorising strengthening works without approval from the Commissioner of Building Control and of falsely certifying that the structural plans and design calculations were prepared in accordance with the Building Control Act and regulations.

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