Penchala tunnel safe

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HAIRLINE cracks that have appeared on the wall of the Penchala tunnel on the Penchala Link Expressway about 20m on the west-bound entrance after the Bukit Kiara toll plaza are “surface peelings and not a structural defect.”

Sistem Penyuraian Trafik KL Barat Sdn Bhd (Sprint) assistant general manager and engineering department head Francisco Anthony Doss assured motorists that the surface peelings were common in tunnels and did not pose a danger to road users.

“The primary lining is reinforced concrete of about 150mm thick. We have monitored the peeling over the past one-and-a-half months.

“Our observations and engineering tests show that what had formed were just hairline cracks,” he said.

Report in black and white: Doss (right) and Shah Rizal discussing a report on the surface peelings at the Penchala tunnel.

Doss said behind the hairline cracks was a secondary lining that was 400mm to 500mm thick with water proofing material.

“There are anchor bolts holding the whole structure. We monitored the surface peelings for about 45 days as we wanted it to stabilise.

“Our men have injected concrete epoxy into the cracks to keep moisture from seeping through and to reinforce the waterproofing membrane.

“Markers have also been put in place for further monitoring efforts,” he said.

The RM150mil tunnel is the widest of its kind in Malaysia covering 710m of the 5.5km Penchala Link Expressway that connects Sungai Penchala to Mont Kiara in the Klang Valley.

Surface peeling: Cracks that appeared on the left side of the Penchala Tunnel.

Unlike other highway tunnels which used tunnel-boring machines, the Penchala tunnel was bored by using the slower rock-explosion method, due to the unstable rock condition at the site.

Litrak Group head of communications Shah Rizal Mohd Fawzi said the three-lane tunnel was built with numerous safety features like strain gauges, piezometers to monitor stress on the structure, smart lighting and close-circuit television cameras that allows for constant monitoring.

“Moisture that flows out from the wall panels are within permissible limits. There is no unusual water pressure built up along the tunnel.

“The tunnel’s structural integrity and safety is intact. We conduct monthly inspections to detect any visual abnormalities since the tunnel was opened to traffic in February 2004,” said Shah Rizal.