President Ferdinand Marcos Jr. has said that the 60-meter-long span of the 990-meter Cabagan-Sta. Maria Bridge in Isabela province that collapsed on February 27 suffered from a “design flaw,” noting that it was the only “suspension bridge in the world” he’d seen that was ”not supported by cables.”
An engineer has been identified and has owned up as the structural designer of the now-useless P1.22 billion bridge, a national government project that started during the administration of the late president Benigno S. Aquino III administration.
His name? Alberto C. Cañete, 68, a civil and structural engineer and president of Cañete Structural Investigation. The contractor for the project is R.D. Interior Jr. Construction.
In a phone interview with Rappler on Saturday, March 8, Cañete insisted that it was an overloaded dump truck, carrying boulders, that caused the collapse of one of the spans of the bridge which has 12 arches.
“It’s not a design problem but an overloading problem,” he said.
The truck that was allowed to pass through the bridge had a gross vehicle weight of 102 tons — or way above the 54-ton capacity (two 10-wheeler trucks carrying 27 tons on each side) of the bridge. Cañete said incidents such as what happened in Isabela will continue unless the weight limits of the country’s bridges are strictly followed.
So, which is it: design flaw or overloading?
Cañete is a product of the Philippine Science High School, and has a Bachelor of Science degree in Civil Engineering from the University of the Philippines (UP). He also has 24 semester units of post-graduate work in Structural Engineering in UP. He opted, however, to continue his education via a scholarship in the US, particularly in Virginia Polytechnic Institute and State University, where he completed his Masters in Engineering.
In the Philippine engineering community, Cañete is known as a “bridge expert” or “bridge engineer.” Bridge engineering is a subspecialty field of structural engineering. Cañete has identified some of the projects which he has worked on including:
Bridgetowne Bridge. This is located in the Gokongwei Group’s Robinsons Land Corporation’s Bridgetowne Destination Estate, a mixed-used, 32-hectare real estate project in Pasig City and Quezon City.
Bridgetowne Bridge’s original arches (seen above) were covered and augmented with artificial arches (as seen in the photo below) designed by the late National Artist Francisco Mañosa as architect and Cañete’s group for the structural design of the enhancement.
Parklinks Bridge. This 110-meter, 4-lane bridge in Parklinks Estate, a 35-hectare mixed-use project of Ayala Land and Lucio Tan’s Eton Properties, connects Pasig City and Quezon City.
Structural designers for Parklinks Bridge were Systra Philippines and Systra Korea, but Cañete was hired by Makati Development Corporation to design the methodology to construct the bridge, particularly for erecting the 50-meter-high arch and launching the bridge’s beams and girders across the river.
Manna East Bridge. This is a 34-meter “reinforced concrete tied arch” bridge of the Gotianuns’ Filinvest townscape project in Teresa, Rizal.
Sacobia Bridge. This 894-meter, 6-lane bridge in New Clark City, Pampanga, is a project of the Bases Conversion and Development Authority.
Cañete pointed out a basic error in what the President said, which is that the Cabagan-Sta. Maria Bridge is NOT a suspension bridge but a “tied arch bridge.”
This explains why it has no suspension cables but uses “hanger connections,” which failed when the heavy trucks crossed the bridge. Suspension bridges mainly use cables to support the bridge, while arch bridges’ main supporting elements are the arches, according to the simplest definition provided by Brittanica on bridge engineering.
“Ang arko ang nagdadala ng buong tulay and you have hangers na nakatali sa bridge deck (It’s the arches [not suspension cables] that carry the bridge and you have hangers at the bridge deck),” Cañete said.
So, when the President expressed surprise that it’s the only suspension bridge he’d seen without suspension cables, it’s probably because he doesn’t know the difference between a tied arch bridge and a suspension bridge, Cañete said.
The well-traveled President is probably more familiar with suspension bridges such as the the Golden Gate Bridge in San Francisco, California, USA, or some suspension bridges in England, United Kingdom where he studied.
Cañete has served as president of the Association of Structural Engineers of the Philippines Incorporated (ASEP), a 64-year-old group established in 1961 which seeks to advance the field of structural engineering by, among others, advocating public safety. He takes credit for the second volume on bridges of the National Structural Code of the Philippines (NSCP), also known as the “bridge code.” ASEP has been the author of the NSCP, which guides engineers on structural engineering design and construction.
Cañete has also authored four books on structural engineering, including the Design of Bridge Superstructures. His Principle of Concrete Design and Principles of Steel Design are textbooks for structural engineering students. He described these two as his “legacy books” to help students better understand the subject in the Philippines.
He has had more than 30 years experience in bridge structural design and has worked on various public works projects when he was with the DPWH from 1980 to 1990. In the last six years when he was with the DPWH, he was section head of the Bridge Division of the DWPH’s Bureau of Design.
In 1990, he was tapped by then-Polytechnic University of the Philippines (PUP) president Nemesio Prudente to be the dean of the state university’s College of Architecture and Engineering. He was also director of the Special Projects Office of PUP in charge of infrastructure projects in all PUP campuses.
He has taught at PUP (before he was tapped as dean), and in the graduate schools of Pamantasan ng Lungsod ng Maynila (PLM), University of the Philippines (UP), and De La Salle University (DLSU).
The semi-retired engineer still lectures at the PLM Graduate School of Engineering in Manila on Saturdays, and is a now a structural consultant specializing in bridges and ports for local and international consulting projects.
Meeting with ex-DPWH Secretary ‘Babes’ Singson
Cañete told Rappler he presented in 2012 the design for the Cabagan-Sta. Maria Bridge to then-Public Works and Highways Secretary Rogelio “Babes” Singson, an industrial engineer.
“Nilapit ko sa kanya, pinapprove ko sa kanya personally (I went to him personally to have it approved),” he said. Construction started in November 2014 and completed on February 1, 2025. Part of the bridge collapsed just 26 days after it opened or on February 27 at 8 pm at the 3rd span (from Cabagan side) of the 12-arch bridge.
The engineering community in the Philippines is a small one, and Cañete said Singson knew that he was “bridge expert” so it was easy to have the structural design approved.
Cañete said he also personally knows current DPWH Secretary Manuel Bonoan, and that they were supposed to have had a meeting last Monday, March 3, about the collapsed bridge, but the meeting did not push through due to a conflict in schedules.
Aside from overloading being the immediate cause of the collapse of the bridge, Cañete suspects that the DPWH in Region 2 did not follow the right processes in building the bridge. He said the regional office in Cagayan Valley, to cut costs, may not have hired construction management and supervision consultants whose job is to make sure that everything is followed to the letter.
So, why is the President taking a strong position on the Cabagan-Sta. Maria Bridge’s design being flawed in addition to the obvious problem of overloading? [READ: EXCLUSIVE: Did Bongbong Marcos lie about Oxford, Wharton?]
The most logical explanation is because he’s essentially a politician, and since the Cabagan-Sta. Maria Bridge was one of the achievements trumpeted by the Rodrigo Duterte administration, it’s now a showcase of Duterte’s overhyped Build, Build, Build infrastructure initiative, even though the project’s construction spans three administrations.
Hopefully, an independent, third-party probe into the bridge’s structural design, construction, retrofitting, as ordered by Bonoan, will be able to come up with the real score and determine who are liable for the collapse, which clearly should include the owners and operators of the overloaded trucks.
This will likely take several months and by then, the controversy may have died down, and the 2025 mid-term elections would be over. In the meantime, expect the political circus to continue. – Rappler.com
