Department of Public Works and Highways (DPWH) is eyeing the use of a more durable type of sheet pile protection in the repair of the collapsed portion of Arnedo Dike.
The agency is proposing the shift to Z-type sheet piles from the U-type that were originally installed.
DPWH Pampanga 1st District Engineer Almer Miranda explained that Z-type sheet piles have an extra piece of steel protruding which helps increase its bending resistance compared to U-type sheet piles.
In 2016, U-type sheet piles were installed in the slope/bank protection to serve as main barrier against the impact of the flowing water along the Sto.Tomas-Sta. Rita Road in the San Luis section of the Arnedo Dike.
However, residents said a portion of the infrastructure began collapsing at some point in 2019.
“The steel sheet piles, along with the concrete pile cap, tilted towards the river. This caused a major depression on embankment materials and triggered the collapse of one lane of concrete adjacent to the pile cap,” Miranda explained.
DPWH received reports that the situation worsened after the onslaught of Super Typhoon “Karding” in the province.
Upon order of DPWH Regional Director Roseller Tolentino, Miranda immediately sent an inspection team onsite on October 21 to gauge the extent of damage and plan the needed repair works.
During the inspection, it was found out that the length of the damaged portion has extended to 63-meters or around 39.9 percent of the total project length.
It was also discovered that the materials used are already non-compliant to the standard design followed nowadays.
DPWH likewise disclosed that the project contractor failed to incorporate a “deadman” or an anchor in the infrastructure.
This means that no object provided a pulling support for the sheet piles or resistance against the confined earth.
Aside from the use of Z-type sheet pile, DPWH is also proposing the updated analyzation of other factors that may affect the integrity of the infrastructure.
These include the checking of the soil condition and scouring effect to achieve the correct depth of penetration.
Installation of “deadmen” or anchors and thickening of the concrete road must also be ensured. (CLJD-PIA 3)