Road Repair at Least in Five Days

KOMPAS/BAHANA PATRIA GUPTA

An aerial view of Jalan Raya Gubeng in Surabaya, East Java, Wednesday (19/12/2018). Besides the installation of asbestos walls as a safety measure on the road section which collapsed on Tuesday evening, traffic rerouting has also been conducted to facilitate the traffic flow.

SURABAYA, KOMPAS – A sinkhole has appeared on Jl. Raya Gubeng due to subsidence in Surabaya, East Java, causing the road to be closed for at least five days for the first recovery phase. This means the repairs could take more than a week to allow time for investigators and experts to determine the cause of the subsidence.

A day after the sinkhole appeared on Wednesday (12/19/2018), authorities had cordoned off the area of subsidence so police and experts could investigate. The sinkhole is 100 meters long, 25 meters wide and 20 meters deep.

East Java Police chief Insp. Gen. Luki Hermawan had ordered the nearby construction project to be stopped for inspection. State lender Bank BNI, which has a branch located not far from the sinkhole, was advised to move important documents, digital equipment, money and other valuable assets for safekeeping by the police.

“A forensic team from the National Police [has arrived] to investigate. Meanwhile, an expert research team will also help uncover the incident,” Luki said. Eleven staff, supervisors and project managers of the construction project were being questioned.

Mudji Irmawan Arkani, who is on Surabaya municipality’s expert team, said several buildings in the surrounding area were safe from the threat of collapse. Some sections of fence at a number of buildings had collapsed because of their shallow foundations. Meanwhile, the nearby Elizabeth bags and accessories outlet and BNI building were relatively safe, because they stood upon deep foundations.

Duration of repair

It has been estimated that it would take 3-5 days to repair the road. The government’s current priority is to fill the sinkhole so the road can be reopened as the investigation continues.

“Usually, it will take three to five days to [reopen the road], although [the repairs] would not be permanent. The important thing is for the road to function,” said highways director general Sugiyartanto of the Public Works and Housing Ministry (PUPR).

Public Works and Housing Minister Basuki Hadimuljono made a similar statement, and that the investigation into the incident would continue. “Regarding sanctions, we are waiting for recommendations from the Construction Safety Committee,” he said.

Mudji said that the most important thing at present was to install steel sheets to retain the embankment. The sinkhole would then be filled with construction materials, namely sand and rock, and packed down.

The next step would be paving, testing and finally, reopening the road. “If the steel sheets arrive

today, the installation can take five days. The process will take three weeks at the soonest until the road can be used again,” he said.

The road subsidence is located within the city limits and is not on a national road.

To date, the cause of the road subsidence remains unknown. However, it has been confirmed that the sinkhole’s appearance was preceded by a sudden collapse on Tuesday (12/18) at 9:30 p.m. of the east retaining wall at the Siloam Hospital construction site.

The causes of the subsidence are being investigated. “All possibilities, including the alleged construction error or negligence, will be investigated,” said Luki.

Siloam Hospital Surabaya general affairs manager Budijanto Surjowinoto said that the project operator of the new hospital facility was PT Nusantara Konstruksi Engineering. The contractor was coordinating with PT Bina Marga, the Surabaya municipal administration and relevant authorities to secure the area around the project site.

Separately, the head of the Soil Mechanics Laboratory at the November 10 Institute of Technology, Indrasurya Mochtar, said the collapse of the east retaining wall was unique, especially as the north, west and south retaining walls were still standing.

He said the incident was not triggered by natural causes like land subsidence or a land surface collapse, and that it was more related to the retaining wall’s inability to resist active lateral pressure from earth, water and other loads.

Seismic records also do not indicate any faults in the bedrock, but only from local activity. “It is more appropriately called land subsidence, not liquefaction, because there is no phenomenon of liquefying soil at the scene,” said Earthquake and Tsunami Center head Triyono of the Meteorology, Climatology and Geophysics Agency (BMKG). (ETA/BRO/HRS/TAM/NIK)