TOTAL OVERHAUL: Ungka repairs to take more than a year—engineer

By Joseph B.A. Marzan

Motorists and commuters between Iloilo City and Pavia, Iloilo might continue to suffer traffic woes until 2024 as investigating and fixing the engineering issues of the P680-million Ungka flyover would take more than a year, according to an Ilonggo engineer on Tuesday.

Structural engineer Nilo Jardeleza told Bombo Radyo Iloilo that the repair would take very long, including government procurement procedures even as suggestions by the third-party consulting on the design would take more than one year.

Jardeleza even suggested an overhaul of the sinking portions of the flyover if only to assure its stability and safety.

Jardeleza attended the Regional Development Council-6’s (RDC-6) infrastructure committee meeting on Dec 19, 2022 as an invited expert, where he lamented the lack of publicly-displayed details and information on the flyover.

Likewise, he said that the vertical displacement or sinking of the flyover has become excessive, citing the National Structural Code of the Philippines (NSCP) for bridges, which limits allowable displacement of 50 millimeters or less.

“[Iloilo City Councilor] Ely Estante butted in and told me that he wasn’t interested in [the NSCP], but I told him that it was important, for us to know if the alignments had already exceeded the limit. For me, since we’ve seen the [visible] displacements, which means we have seen the limits,” Jardeleza said.

Jardeleza suggested redoing the foundations on Piers 4, 5, and 6 by burying them further together with a new group of board piles per foundation, as the original foundations and the 2.8-meter board piles buried 30 meters deep into the ground were no longer viable.

He cited that the Department of Public Works and Highways-Region 6 (DPWH-6) was unable to provide data as to how deep the board piles sank, although other experts said the depth should have been 49 to 50 meters.

It was also found out during the meeting that the flyover continues to sink and that the contractor, International Builders Corp., has resorted to jet grouting to arrest the movement.

Jet grouting involves injecting grout materials – usually cementitious, resinous, or solution chemical mixture – into the ground to improve soil mechanical and permeability properties.

The purpose of grouting can be either to strengthen a formation or to reduce water flow through it. It is also used to correct faults in concrete and masonry structures.

Jardeleza said that based on their engineering standards, solutions to the flyover’s issues were “simple but costly”, without needing to destroy the upper sections of the superstructure which includes the girders and the carriageways.

“We have to build the superstructure and adjust it back to the original level. Then, there needs to be a new soil investigation conducted. The piers, their caps, and the sunken board piles are no longer useful and should be demolished and replaced by new ones, which would be group board piles around the piers and the original board this time, and anchor them at the second-most strong layer, then those would be the new foundations,” he said.

“In the meantime, the superstructure should be suspended and would be eventually carried by the new piers. They should be placed with stands and used with jacks. It’s not retrofitting, but something brand new because the older foundation was already unviable and should just be buried underneath,” he added.

Monday’s committee meeting, which focused on the situation at the flyover in Pavia, resulted in an RDC-6 resolution urging the DPWH-6 to expedite the engagement of a third-party consultant by using the negotiated contracting process and to consistently provide periodic updates to the council via the Regional Project Management Council.

The flyover was fully opened to the public in the early part of September 2022, but it was closed again two weeks later after Daily Guardian first reported the sinking foundations of the structure.

The flyover is one of the legacy projects of former senator Franklin Drilon before he retired from politics after the May 2022 elections.