MAASIN CITY, Southern Leyte—Years of finding a permanent solution to the perennial erosion problems that threaten the foundation of the country’s tallest bridge has finally come to an end.
The final fix: A Swiss engineering technology called rock netting.
“It takes Swiss technology to permanently eliminate the threat of erosions near the foundation of Agas-Agas Bridge, the country’s tallest,” Department of Public Works and Highways (DPWH) Southern Leyte District Engineer Ma. Margarita Junia said.
The Agas-Agas Bridge is a prestressed concrete beam bridge on the Pan-Philippine Highway connecting the towns of Mahaplag in Leyte and Sogod in Southern Leyte. The P1.024-billion bridge was constructed in 2006, cutting down driving time for motorists between Leyte and Southern Leyte. It was partially funded by the Japan International Cooperation Agency.
With a length of about 350 meters (1,150 feet) and a height of 292 feet (89 meters) above ground, Agas-Agas Bridge is considered the tallest column bridge constructed by the DPWH in the country.
The area where the bridge is constructed, though, is prone to landslides, especially during rainy days. During a prolonged downpour in January this year, landslides made the road impassable for two days.
Junia stated the installation of slope-stabilization control system will be a priority project of the DPWH field office next year to curb the perennial problem of erosions.
“The Swiss technology is seen as a permanent solution to rockfall and soil erosions near the bridge foundation,” she said.
Junia added their most recent inspection shows a problem on the slopes of Agas-Agas Bridge, which, if neglected, may weaken its foundation. She said the DPWH will need P100 million to prevent rockfall and erosion threatening to ruin the bridge.
Junia added the Southern Leyte field office will be the first in Eastern Visayas to pilot rock-netting technology developed by Swiss firm Geobrugg, a Switzerland-based world leader in design and fabrication of protection systems using high-tensile steel wire mesh and netting.
Junia and DPWH Eastern Visayas Regional Director Edgar Tabacon recently visited Switzerland to observe how the soil-stabilization system works.
Their systems provide highly sustainable solutions for securing unstable slopes or for strengthening existing retaining structures and other conventional materials. It also secures loose rocks, blocky rocks, rock spurs, overhangs or unstable rock formation with highly irregular surface structures.
Located in Kahupian village in Sogod town, the Agas-Agas Bridge is a 90-minute drive from Tacloban, the capital city of Eastern Visayas region. Sogod town is 62.4 kilometers from Maasin City.
Due to its panoramic view and tourism potentials, the DPWH proposed to former President Gloria Macapagal-Arroyo to turn the bridge into a venue for extreme sports, like bungee jumping, downhill skateboarding, zip line and rappelling.
On August 9, 2009, the President signed the construction of the bungee-jumping platform along the bridge, as well as other tourism amenities. The Agas-Agas Bridge zipline, known as “Zipline Leyte”, opened in April 2011. The twin zipline, one of the longest in the country at 880 meters (2,890 feet), glides diagonally above the bridge and the riverine below it. It was closed, though, after three years due to an accident involving a foreign national.