SINGAPORE: On the morning of July 14, 2017, an early morning signal of a piece of viaduct under construction was received, in which one worker was killed and 10 people were injured.
A month before the incident, employees of Builder or Kim Pew (OKP) contractors were aware of the cracks in the support structures, but did not inform Robert Arianto Tajandra, the project's registered professional engineer.
The second time the cracks were found, Tajundra ordered an investigation and learned of the flaws in Corbel's initial design – support structures meant to distribute vehicle loads – but did not report OKP.
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On the day of the incident, the project engineer noticed cracks on curbs in the viaduct's section that later collapsed, and sent his photos to the project director, but none of them stopped construction.
Part of the case was that OKP and three other accused persons will prosecute on the collapse of the viaduct from the Tampines Expressway to the Pan Island Expressway and Upper Changi Road East, it was revealed in court at the start of the trial. Thursday (August 1).
Charges by the builder and three men
The three individuals fighting the charge are: Tajandra, 46, who was hired by CPG Consultants and worked as a qualified person to design and oversee the project; Wong Kyu Hye, 31, a project engineer working for OOP; And P KP Project Director Ye Chi Kyung, 49.
Tajendra faces the highest charges – four charges under the Building Control Act and one charge under the Workplace Safety and Health Act.
Wong and Ye face every charge of recklessly endangering the safety of everyone on the part of the viaduct – between p૦ to 41૧ – when they discovered cracks on the corbels on the day of the incident but failed to close all operations.
Both men have also been accused of deleting the WhatsApp conversation between the two, holding photographs of cracks on Corbels in the 40 and 41 range, and obstructing the way of justice.
Builder OKP, appointed by the Land Transport Authority, faces a single charge under the Workplace Safety and Health Act for failing to take the necessary steps to ensure the safety and health of its workers casting a deck slab.
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The prosecution, led by deputy public prosecutors Christie Tan and Yang Ziliang, detailed in its opening address how various parties involved in the project dealt with potential problems in construction.
Just months before the cracks
The viaduct was designed 1.8 km long, with 50 spans between the piers and each splice divided into eight flyovers.
The section that was broken into the flyover, between Pierceand૦ and 41૧, was .543.m long. This was also the longest in this flyover. The failed curbles were the support structures connecting the columns between the piers to the columns, and the ends of each guard rested on a corbel.
The prosecutor said the cracks were found in Corbels just over a month before the incident. On June 16, 2017, Pierre 41 found cracks in Corbel's face after Occupy personnel launched a precast girder between Pirates 40 and 41.
Yeh was allegedly aware of these cracks. OKP's technical director and noted commercial engineer Yang Chun Kang evaluated the cracks on the site and learned that it was structural cracks due to bearing failure.
The builder joined the two plinths – the certs that rest on top of the corbels – in one piece to raise the contact surface based on Mr Young's recommendation.
However, Okapi did not inform Tajundra of the cracks.
More cracks were found later that month, this time on the corbels of Pier 42. OKP The project engineers of Goh E Hui saw the cracks on June 30, 2017.
Mr Goh immediately reported the cracks to Yen. Mr Young returned to the site again and evaluated the cracks, finding them to be constructive cracks again. He tells Yen to ask Trasandra to check the adequacy of the design of the crossheads.
After telling Tajund about the cracks, Tajandra made a site inspection on July 3, 2017 and instructed the design engineers of CPG to investigate the adequacy of the corbel design for the entire project.
The initial corbel design was not flawed
It is the case of the complainant that the CPG design engineers discovered in early July 2017 .The wrong corbel width assumption was used in the design of the corbels, which was later used in the break-in period.
They incorrectly assumed that the effective width of the corbel was longer than it should have been, and as a result of this error, the capacity of many corbelles was insufficient for the load they carried.
The complainant said that Tajundra did not make these mistakes at the time of the initial design. However, CPG design engineers conducted an investigation, and they became aware of them in early July 2017, after not telling OKP about the design flaws.
The complainant claimed that he had not redesigned the corbels in pillars 40 and 41.
Trondra did not say exactly what the error was, citing other steps
However, Tajundra took other steps. On July 5, 2017, he sent Yen a revamped construction sequence for deck slab casting works for 40 and 41 of 41 gal. He instructed to make 12 props under each crosshead on both piers, and the OKP. Directed to cast 50 percent. During the first stage casting, the deck slab length was instead of 75 percent, which was done for the deck slab, among other pillars.
Prior to the second phase of casting, Tassandra also instructed the OKP to drop the precast girders at the crosshead so that the load would not go to the corbel but to the crosshead which has been cited in the precast girder.
Although he improved the construction order in three ways, Xander did not inspect the installation of the props and remotely checked for four days before the crash by exchanging WhatsApp WhatsApp messages with Ye.
He also served as O.A.P.P. Also provided a series of instructions for inserting additional rebars into other curbs, which the builder had made.
Taking steps after cutting, involves the structure
On the day of the incident, Okpi began casting a first-stage deck slab for the segment between Pierce 40 to 41 at 1.30am.
The cracks were visible on curbs at 2.5.3am, at 2.5am. They were spotted by project engineer Wong, CPG resident engineer Shivnath Shenthan, OKP's security supervisor Victor Tan and LTA site supervisor Syed Mohammad Farik Fashil Syed Salim Altas. General Chat Chat Lounge
Wong called a guy named Ye, who was not on the site and sent him photos of the cracks via WhatsApp. Other employees at the site, including Mr Fariq, urged Wong to stop casting works.
However, they continued.
At 3:30 in the morning, curbs on the pillars of iers૦ and at૧ were overturned, resulting in the structure being broken and concrete flowing between the two pillars that morning.
After the accident, Wong and Yeo deleted the conversation "in no hurry to bury their responsibility," the prosecuting party said.
Warning Signs to Unleashed Place Workers in Danger
The prosecution on Thursday told the court in its opening address that there were warning signs that were unnoticed before the collapse.
"If the work had been stopped immediately, the workers would have been out of danger," the government lawyers said.
Instead, 31-year-old China national Chen Yinchuan was pronounced dead at the scene at 435 in the morning, and 10 other workers suffered injuries to the spine, pelvis and limb fractures and to friction.
The prosecutor wants to call expert witnesses to confirm that the overloading at 40 and 41 was due to Corbel's failure, and that the design had failed, because Corbelles was not built for banding and shear. Inspired by the load during casting of the deck slab.
Tajandra is defended by a team of lawyers for King and Ten, led by senior adviser Lee Enjing Bang, while Wong and Ye are represented by Tan King and Cheh's lawyers, led by senior adviser Chelva R. Raja.
OKP has appointed a Wong Partnership team as a lawyer, led by senior consultant Alvin Yio.
The hearing is set to begin this afternoon.