ILOILO City – The Department of Public Works and Highways (DPWH) Region 6 reaffirmed the effectiveness of its jet grouting procedure on the Ungka flyover’s 16 piers, including Abutments A and B, in Barangay Ungka II, Pavia, Iloilo.
The P680-million flyover is undergoing rectification costing P300 million more due to vertical displacement or subsidence.
Engr. Sanny Boy Oropel, the DPWH-6 director, assured the public that the flyover will be safe and stable when it opens at full capacity on December 25, with reinforced piers following intense jet grouting undertaken.
The grouting, guided by data and scientific studies, have significantly strengthened the piers, which were previously affected by subsidence, said Oropel.
The Ungka flyover stretches from Barangay Ungka, Jaro, Iloilo City to Barangay Ungka II, Pavia. Straddling the major intersection of the Sen. Benigno Aquino Jr. Avenue and President Corazon Aquino Avenue in Barangay Ungka II, it is meant to ease traffic congestion in this crucial point that leads in and out of Iloilo City.
Oropel issued the assurance following concerns raised by Ilonggo structural engineer Nilo Jardeleza, who questioned the sufficiency of DPWH-6’s rectification work, especially on piers 4, 5, and 6.
“Our recent studies show no further tendency for subsidence. The jet grouting has shown promising results, and all our statements are based on verified data,” said Oropel, emphasizing that the corrective actions are aligned with recommendations from Abinales Associates Engineers + Consultants, DPWH-6’s third-party consultant that was paid some P13 million to conduct a geotechnical study on the flyover.
The four-lane, 453.7 lineal meters long Ungka flyover was constructed beginning January 2020 and opened to traffic on the first week of September 2022. But this was closed two weeks after due to vertical displacement.
Engr. Adam Abinales of Abinales Associates recommended intense jet grouting to reach the hard strata beneath all 16 piers and abutments of the flyover.
Jet grouting was applied to a depth of 54 meters on piers 1 to 4. Initially, four additional bored piles were advised for piers 4, 5, and 6, but DPWH-6 later deferred this plan as jet grouting alone reached the hard strata, rendering additional piles unnecessary, said Oropel.
The contractor, International Builders Corporation (IBC), implemented jet grouting on piers 4, 5, and 6 in 2023, at their own cost. A seismic survey by DPWH-6 confirmed that the soil density around these piers has improved, allowing jet grouting as the primary method in the ongoing Phase 2 rectification efforts.
The consultant’s final report recommended against additional bored piles, citing positive results from the Multichannel Analysis of Surface Waves (MASW) survey.
Oropel reported no further settlement in the flyover’s piers from September 2023, when the structure was initially opened to traffic, through November 2024.
The piers undergo regular monitoring through seismic testing, conducted by DPWH’s engineering and geological teams. Temporary shoring is also in place to ensure that the superstructure’s weight is fully supported.
Despite reservations about allowing traffic on the flyover during jet grouting operations, DPWH-6 opened the right lanes upon requests from local government officials and residents to alleviate heavy traffic below the flyover.
Oropel assured that, upon the full opening on December 25, he will be the first to cross the flyover, with the agency conducting regular surveys to monitor any structural movement.
Currently, DPWH-6 and the contractor are working 24/7, installing geofoam on the superstructure’s uneven surface, and continuing jet grouting on remaining piers, including piers 7, 8, 9, and 10, to meet the December 25 deadline.
By the time DPWH-6 fully reopens the Ungka flyover to traffic, the cost of the Ungka flyover will have ballooned to P980 million — P300 million higher than its original cost./PN
