Lenteng Agung Road Subsides, Experts Suspect Foundation Soil Issues

JAKARTA, KOMPAS.com - Construction expert Davy Sukamta suspects that the subsidence of Lenteng Agung Raya Road in Jagakarsa, South Jakarta, is not solely due to corroded underground concrete structures but may also involve issues with the underlying soil.

According to Davy, in culvert and box culvert construction, the strength of the foundation soil is a critical factor determining structural resilience.

“If there’s subsidence, there are two possibilities: either the soil itself sinks, causing the structure to collapse,” Davy told Kompas.com on Friday (29 May 2026).

“The foundation soil must be strong for the structure to be stable,” he added.

Davy also questioned claims that the underground structures were deteriorated due to age.

He stated that the term “corroded” for concrete needs verification.

“Concrete that’s described as corroded is typically defective from the pouring stage. If it wasn’t corroded initially but suddenly becomes so, that’s unusual,” Davy explained.

He noted that concrete damage usually occurs due to water seepage causing rust on steel reinforcements or prolonged exposure to aggressive chemicals.

“If the deformation is gradual rather than sudden and localised, it’s likely due to soil settlement,” he said.

Therefore, he recommended direct inspection of the road’s subsurface structures to determine the primary cause.

“It would be best to dig and inspect the area. At the edges, when they excavate, they can check the condition. Whether it’s dangerous or not,” Davy added.

Previously, a section of Lenteng Agung Road towards Depok collapsed on Thursday (28 May 2026) around 11:30 PM WIB.

Jagakarsa Water Resources Agency (SDA) Head Sartono said a 3-metre culvert beneath the road is suspected to have weakened due to age.

As a result, the asphalt and underlying soil collapsed, forming a 16-metre-long and 3-metre-deep hole.

As of Friday afternoon, traffic towards Depok was restricted to a single lane.