The joint venture between the Cagayan de Oro City Water District (COWD) and its majority partner MetroPac Water Investments Corporation (MWIC) has started reaping dividends for Cagayan de Oro’s water system even before water starts pouring from consumers’ taps.
The exterior of Camaman-an Reservoir following its recent retroffiting and waterproofing
For starters, COWD’s Camaman-an Water Reservoir which has lain idle for over 20 years for lack of a water supply was turned over by Cagayan de Oro Bulk Water Inc. (COBI) to COWD last November 9, 2018 a full six months ahead of schedule and at half the cost compared to conventional methods.
The new pipeline and reservoir to improve water pressure and supply to the East Service area was originally planned for completion by June 2019.
Skilled workers on scaffoldings applying the 2nd layor of carbon fiber on interior walls
With a storage capacity of 5,300,000 liters, reservoir would boost water supply and pressure in barangays Camaman-an, Gusa, and Lapasan, specially within the Limketkai Center central business district.
The revamped facility would initially supply an additional 20 million liters daily (MLD) of treated potable water to benefit the East Service Area from Barangays Lapasan to Tablon, (including Camaman-an) during its first phase, to be augmented by an additional 20 MLD during the second phase. This would bring to 100 MLD the total bulk water supplied to COWD by COBI to 60MLD daily in the West Service Area 40 MLD daily to the East Service Area.
Skilled workers applying Tyfo_ SEH -25A glass fiber wrap on the reservoir floor as waterproofing material
Had the COWD chosen to demolish and reconstruct the Camaman-an Reservoir, it would have taken at least a year. Demolition would take 2-3 months and construction another 9-10 months. Total cost of the demolition and re-construction was estimated at P 50-60 million.
However, under its COBI partnership with MWIC, COWD was able to tap new materials and construction technologies which made it possible to complete the retrofitting and waterproofing of the original structure in only six months and at half the estimated cost of conventional methods at P26 million.
Skilled workers applying Tyfo_ SCH-7UP on interior walls
The contractor used the Tyfo® Fibrwrap® Composite Systems, instead of conventional/traditional concrete and steel methods for retrofitting and waterproofing the Camam-an Reservoir. Composed of E-glass/Carbon/Aramid/epoxy FRP composite materials, it is an efficient and innovative system for the repair and strengthening of structures.
Developed in the United States by FYFE Co. LLC and widely used in many thousands of projects since 1992, the Tyfo® Fibrwrap® System is a state-of-the-art, non-intrusive structural strengthening technology that increases the load carrying capacity (shear, flexural, compressive, seismic) of reinforced concrete, masonry and wooden structures.
Skilled workers applying Tyfo_ SCH-7UP on the bottom slab
It uses materials and technology derived from the aerospace industry to contain individual structural elements such as columns, beams, slabs, walls and tanks in an elastic ductile wrap that is also highly resistant against corrosive agents.
Weak columns, beams, walls, pipes of different shapes and sizes can be strengthened using the Tyfo® Fibrwrap® System. Because of the inherent nature of composite materials, the architectural and geometric shape of the concrete after repair can generally be preserved.
Bottom slab showing carbon and glass fibers applied on its columns
“Retrofitting using Tyfo Fibrwrap System enabled our contractor to finish the project in 6 months, including dewatering and desilting works inside the reservoir, as well as the waterproofing of its top slab, painting of outside walls and excavation,” said COBI General Manager Rodrigo O. Yabut.
MWIC tapped the services of the contractor EC Structural Composites, Inc. which had previously undertaken the repair, retrofitting and waterproofing of similar structures for its subsidiary Maynilad Water Services Inc. (MWSI) at its Caloocan Reservoir, Tondo Reservoir and Pumping Station, and Espiritu Water Reservoir.
A skilled worker applies Tyfo_SCH-7UP on a wall
Conventional Strengthening Methods like Concrete jacketing / Pressure grouting have been established and use relatively inexpensive materials, but is time consuming, labor intensive, fairly destructive, requires formworks to enlarge the existing section, causes additional dead loads and degradation of aesthetic features due to offsets from existing alignment.
Other conventional methods like steel plate bonding causes less headroom loss and are less destructive than concrete jacketing, but are bulky to set up, is likewise time and labor-intensive, requires the fabrication of custom-made steel plates which are difficult to lift and align in place, requires drilling and bolting in concrete which may cause additional distress, requires welding which is a possible fire hazard, and cause quality assurance problems.
Two layers of glass fiber were applied on interior walls as waterproofing lining
Similarly, the sprayed concrete method while being the fastest conventional method (no formworks needed) requires highly skilled (read: expensive) operators, produces a rough finished surface, messy rebound and high wastage of materials.
“FRP systems are non destructive process and easy to install, much lighter system with high strength to weight ratio, does not require heavy or special equipment, can be used in space constrained areas, incorporate different finishing coats, and can be applied underwater,” said Engr. Rustom Jamaji, Senior Vice President of Fyfe Asia PTE LTD. Asia Pacific.
Among other things, FRP systems increases bending strength of flexural elements, shear strength of beams columns and walls, vertical load capacity of columns, ductility under cyclic loading; improves the long-term durability of strengthened structures and does not corrode and can contain further corrosion, Jamaji added.
The system is about 15 times lighter than steel but its strength is approximately two to five times stronger than the yield strength of mild reinforcing steel. It is also only a few millimeters thick compared to conventions strengthening systems that can add 100mm to 150mm additional thickness, he noted.
Compared to mild steel which has an ultimate tensile strength (MPa) of 240-276 MPa and High Strength Steel with 410-500 MPa, FRP fiber has an MPa of 2,800-3,100.
To illustrate, one FRP strip 20mm wide x 1.3mm thick x 150mm long of TYFO Glass FRP weighing 0.006 kilograms can carry a load of 1,523 kgs, which is more than the weight of a mid-sized sedan which tips the scales at 1,430 kgs!
While FRPs are easy to install, they must be applied by trained applicators, although this is more than offset since the system usually takes about one third the time of a conventional retrofit using concrete and steel would take, thus saving labor costs and facility down time.
Furthermore, the system is water proof and can inhibit further corrosion in structures such as water tanks and jetties and piers.
The system has been used in over 80 countries in tens of thousands of projects such as buildings, bridges, water tanks, silos, pressure pipes, piers, industrial structures and for structures requiring blast mitigation.
Since 2001, the contractor has completed 21 similar projects for various clients including SMC La Tondeña Distillery, Pilipinas Shell Petroleum Corp., Bogo Water District, Bogo, Cebu, Santiago Water District, Isabela; and Subic Water & Sewerage Co.Inc.
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