Reduction in Steel Rods Blamed for Construction Accident
The collapse of a pier head in the Bekasi-Cawang-Kampung Melayu (Becakayu) toll road project is alleged to have been caused by the reduced amount of steel rods used in the formwork.
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Kompas/Ryan Rinaldy
Construction workers walk through the Bekasi-Cawang-Kampung Melayu toll road project on Jl. DI Panjaitan in East Jakarta on Tuesday (6/3) after a 90-minute lunch break.
JAKARTA, KOMPAS – It is believed that neglect was not the only cause of the collapsed pier head in the Becakayu toll road project in Cawang, East Jakarta. The incident, which left seven workers seriously injured, was allegedly caused by a failure in the brackets that supported the formwork. The failure is believed to have been caused by a reduction of the number of steel rods used to bind the bracket from 12 rods to just four rods.
Up to Saturday, evidence of the pier head collapse could still be found at point PCB 34 of the overpass in front of the Nusantara Business Institute on Jl. DI Panjaitan in Cawang. The evidence was the steel rods that bent from too much load-bearing stress. The discovery that only four steel rods had been used to bind the brackets was enough evidence for pointing to the probable cause of the construction accident on Feb. 20.
The Improvement Method report that Kompas obtained from the Public Works and Housing Ministry shows that the original design of the construction project’s pier-head formwork uses 12 steel tension rods. The 12 steel rods, each 32 millimeters in diameter, are for binding the formwork’s brackets.
The design of these 12 steel rods is based on calculations of the bracket’s ability to support the combined weight of the materials used to build the pier head. The aggregate weight of each pier head is 3,201.8 kilo-newtons, or around 326 tons, which is the total weight of the brackets, formwork, shoring, the pier and the weight of the construction workers.
Reducing the number of steel rods reduced the brackets’ load-bearing capacity. The brackets’ load-bearing capacity was significantly reduced by reducing the number of steel rods from 12 to four, a reduction of more than 60 percent.
Project manager PT Kresna Kusuma Dyandra Marga (KKDM) also revealed its own finding that the number of steel rods in the brackets had been reduced. PT KKDM project leader Herarto Startiono said in Jakarta on Wednesday (28/2) that an on-site inspection had found that contractor PT Waskita had installed only four steel rods.
“Only four steel tension rods were installed where there should have been 12,” said Herarto.
Substandard
Herarto said PT KKDM also found that the steel tension rods used in the project did not meet the technical specifications. The steel rods that were installed measured only 19-25 mm in diameter, when the design called for steel rods measuring 32 mm in diameter.
“The 32-mm rods were available. [PT Waskita Karya] knows the [standard operating procedure], so why did they install smaller ones? We are still looking into who ordered this,” Herarto said.
PT Waskita Karya Division III head Dono Parwoto claimed that the toll road project only used four steel rods to bind a bracket. However, Dono said, the diameter of the steel rods that were used was 32 mm in keeping with the design.
Dono denied that Waskita had violated the technical specifications of the Becakayu toll road project. Dono said that one steel rod for the bracket cost Rp 5 million (US$350) and the bolts for tightening the rod cost Rp 200,000. The cost for one toll road formwork was about Rp 1 billion.
“It is impossible that we reduced the number of tension bars and bolts. How expensive are the bolts, anyway? No reduction is worth it when compared to the risks we’d face, when the cost of building one pier is already high. Reducing them could be fatal,” he said.
Dono said that the collapse of the pier head’s formwork was caused by untightened bolts on the brackets. “Perhaps this was a human error and one bolt was looser. It might have looked properly tightened from below. The tightness of the bolt is critical,” he said.
The police and relevant institutions remain tight-lipped on the cause of the accident. The East Jakarta Police, which is leading the investigation, has merely said that negligence may have been involved. PT Waskita project leader AA and PT Virama Karya head supervisor AS have both been named as suspects and charged with negligence.
Bandung Institute of Technology (ITB) construction expert Iswandi Imran said he believed that the number of steel rods used in the brackets could have been reduced. Iswandi was among the ITB experts who consulted on the Becakayu toll road project with the Public Works and Housing Ministry’s Construction Safety Committee.
