Philippines: Ans: Revealing a response to the unprecedented floods of the past three decades, a new program of refurbishment has been unveiled.

Yasuyuki Nomura, project manager of Toyo Construction Co., gives an explanation at a construction site in Marikina, Tokyo, on Oct. 2. (Mainichi/Tomoaki Takeshita)The Japan International Cooperation Agency (JICA), together with the Toyo Shimizu Special Construction Joint Venture, CTI Engineering International (CTII), and the Department of Public Works and Highways (DPWH), recently opened the construction site of the Pasig-Marikina River Improvement Project Phase 4 to the media for the first time. published on The visit was also attended by Mr. Takeo Sakamoto, Director of JICA Philippines Office, and Mr. Cresile Damo, Project Manager of DPWH.
The project, which started in 1999, will be completed as a JICA project in Phase 4. Aiming to put the facility into service in December 2013, once construction is complete, the river that runs through the Tokyo metropolitan area will have the capacity to withstand a major flood that occurs once every 30 years.

▽ 1 million to 30,000
Yasuyuki Nomura, project manager of Toyo Construction, who was appointed in 1992 and has worked for a total of 19 years in the Philippines, said, “The river width, which is currently 50 to 60 meters, will be widened to 80 to 90 meters. If the amount of water is about 100,000, the water level of the river will be 1 meter lower than before the widening. I explained while pointing.
CTII is a simulation that compares the disaster mitigation effects of the Pasig-Marikina River Improvement Project up to Phase 3 and the Mangahan Floodway, which was completed in 1988 with Japanese loan assistance, with and without the project. It is carried out.
According to it, if a typhoon equivalent to Typhoon Ulysses in 2020 (with an average rainfall of 302.3 mm/24 hours in the basin) hits the Tokyo metropolitan area, the estimated number of victims would be 1 million and the amount of damage would be 13 if the project had not been implemented. 100 million dollars, and the flooded area was 54 square kilometers, while calculations based on the project effects showed 30,000 victims, 200 million dollars in damage, and 10 square kilometers of flooded area. It is estimated that the number of victims will be reduced by 97%, the amount of damage will be reduced by 85%, and the flooded area will be reduced by 81%.
“Phases 2 and 3 have increased the river flow capacity of the most downstream repaired section from about 700-800 cubic meters per second to about 1,200 cubic meters per second,” said Kazuto Suzuki, CTII Senior Engineer.
On the other hand, when the construction of the Phase 4 section is completed, the current discharge capacity of about 1,200 to 1,500 cubic meters per second will increase to 2,900 cubic meters per second.”
▽ Hinomaru technology plays an active role
The exposed site is the riverbank of the Marikina River near SM Marikina in Marikina City, the metropolitan area. At the site gate, there are illustrations and letters that require workers to wear safety equipment such as helmets, dust masks, and safety gloves. Once inside, you can see rows of wavy metal plates neatly lined up a few meters along the river. It is the piled steel sheet pile, which is the first stage of the bank protection work.
The work consisted of placing steel sheet piles for the new riverbank, constructing a flood wall at a distance from the riverbank, excavating and dredging, and riprap work to strengthen the embankment. Currently, 8,600 steel sheet piles are being driven into the plant.
This project is a yen loan through STEP, and Japanese technology shines everywhere. The method of combining hat-shaped steel sheet piles and H-shaped steel developed in Japan was adopted for the first time in the world in the Pasig-Marikina River Improvement Project. It is highly rigid (hard to deform) and can be transported more efficiently than conventional steel pipe sheet piles, making it an economical construction method.
The vibratory hammer construction method combined with the water jet to drive it in is also a unique Japanese technology. Pile can be driven into hard bedrock, and low vibration and low noise impose less burden on neighboring residents. This technology is suitable for construction in densely populated areas around rivers.
However, such “things” are not the only Japanese technology. Nozomu Kobayashi, a 38-year-old construction manager at Shimizu Corporation, pointed out that the most difficult part of river improvement work is piling steel sheet piles. The steel sheet piles were produced with a length of 21 meters while strictly observing the verticality within the required standards for each sheet and measuring the river width accurately to the design value (80 to 90 meters) while following the curved river. We have to go deep into the ground.” It is also an important role of Mr. Kobayashi to convey such accurate construction to the Philippine employees.
During Phase 3 of the Pasig River rehabilitation project (2012-2018), we hit a point that even a water jet could not penetrate. “For that part, we made a special sheet pile and penetrated the hard ground first, and managed to complete the construction.” For these achievements, Mr. Kobayashi received the Minister of Land, Infrastructure, Transport and Tourism Encouragement Award for Outstanding Engineers in Overseas Infrastructure Projects in 2009.

▽A place for technology transfer
Project Manager Nomura said, “In Phase 3, there will be about 700 people, including workers. In Phase 4, there are currently about 300 people, but we plan to hire about 700 people during the peak construction period.” .
The work of welding hat-shaped steel sheet piles and H-shaped steel is subject to quality inspection by a third-party organization at the request of DPWH. We have achieved high quality by further training Philippine engineers who have national qualifications and clearing in-house tests.
Mr. Nomura also emphasized the importance of communicating Japan’s safety management culture. “In the workshop, we have introduced Japanese-style safety management methods such as morning assembly, radio exercises, and monthly safety meetings, as well as Japanese corporate culture such as 5S (sorting, setting in order, cleaning, cleanliness, and discipline). The philosophy, ‘good, fast, cheap, safe and clean,’ is the point I want to convey to Hijin.” (Tomoaki Takeshita)