SCR tunnel needs water-proofing

Poor maintenance led to the accumulation of water at a portion of the South Coastal Road (SCR) tunnel causing it to leak, Cebu City structural consultant Ariel dela Cruz said last week.

However the leaks don’t affect the tunnel’s stability, he added.

In his inspection report, dela Cruz said regular maintenance is needed to clear the tunnel’s surface drain of silt and allow water to drain properly.

“The failure of the installed waterstop will eventually lead water to penetrate the (tunnel) joints. It’s advisable to repair it using polyurethane injection resin which is a waterproofing technique (to plug and seal) the cracks,” his report stated.

Mayor Michael Rama received dela Cruz’s report last March 7. The consultant recommended that the city government tap the water-proofing contractor to help fix the leaks.

The tunnel has a 10-year water-proofing warranty. Marie Nillama, information officer of the Department of Public Works and Highways-Central Visayas (DPWH-7), said the tunnel leak doesn’t affect its structural stability.

She said DPWH Regional Director Ador Canlas instructed Cebu City Engineering District head Nicomedes Leonor to address the tunnel leak.

Mayor Rama said the city government was ready to handle the tunnel’s maintenance if the DPWH-7 agrees to transfer funds for the structure’s maintenance to the city.

Overflowed

The subway (tunnel) was built using a P9 billion loan from the Japan International Cooperation Agency (JICA) and is one of the major components of the Japan-funded Metro Cebu Development Project Phase III (Cebu South Coastal Road).

It is the last remaining section of the entire Cebu South Coastal Road Project.

The four-lane, one kilometer long tunnel connects S. Osmeña national  road in the northern part of Cebu City with the South Coastal Road.

The SCR also connects to the Cebu South Road. Rama earlier called on city engineer Kenneth Carmelita Enriquez following reports on the presence of cracks and water leaks on its walls reported by motorists.

Engrs. Mario Montejo, Joshua Monsanto, Waltham Obenario and Larry Villegas said the tunnel’s leak resulted from water which accumulated and overflowed from the tunnel’s weep holes

The tunnel’s weep holes at the bottom end section of its wall and adjacent to the sidewalk are used to catch water seepage.

Dela Cruz’s inspection report mentioned vertical linear cracks and water leaks on the eastern side of the tunnel wall’s construction joints.

Buildup

He also mentioned moisture on the tunnel’s construction joints and the presence of silt on the surface drain especially at the foot of the tunnel.

The cracks measuring less than 2mm each won’t affect the tunnel’s stability, dela Cruz said.

“The cracks resulted from the buildup of hydrostatic pressure caused by accumulated rain or seawater,” dela Cruz said.

“These are typical occurrences when large vibrations or lateral movements are present since the bonding capacity of these joints are considered as (the) weakest point in construction,” the city structural consultant said.

Dela Cruz said the cracks would indicate defects on the waterstops installed on the tunnel’s construction joints.  with Chief of Reporters Doris C. Bongcac