Scouring and erosion control measure and bank protection for Mora Bridge in Timor-Leste

2015.09.30

Route Name                         :   National Route A02

Work title                             :    Grant aid cooperation project: bank protection plan for Mora bridge

Location                               :    Zumalai City, Cova Lima District, Timor-Leste

Duration                               :    January 21, 2014 to September 15, 2015

Implementing body              :    Ministry of Public Works, Government of Timor-Leste

[Outline of facilities]

  • Pier foundation protection: 2 sites (protection with steel sheet piles + foot protection with large concrete blocks)
  • Abutment foundation protection: 1 site (slope protection with large concrete blocks + foot protection with large concrete blocks)
  • Bank protection (left bank: 102m; right bank: 578m; height: 5.0 – 6.7 m; impermeable steel sheet pile base + gravity type retaining walls + foot protection with large concrete blocks
  • Auxiliary facilities (terracing at 4 sites and intake at 1 site)

 

Mora Bridge on National Route A02 is a truss bridge crossing the 400 m wide Mora River. The structure consists of two bridges: a new bridge (220 m long constructed with Japanese grant aid in 2011 and an old bridge (180 m long) constructed during the period of Indonesian rule.

 

Repeated flooding in recent years eroded the river banks in both the upstream and downstream of Mora Bridge and scouring of the abutments and piers of the old bridge, exposing the base section, seriously compromising the stability of the bridge.

 

The project involved planning for countermeasures against the scouring and erosion of the abutments and piers of the old bridge and river banks with Japanese grant aid in order to secure safe transport functions of the national road.

 

For the piers, steel sheet piles were inserted around the piers and concrete blocks were placed in front to deal with possible lowering of the riverbed. For the abutments, gabions were placed around them and the frontal slopes were covered with concrete blocks to develop a structure which could resist flood-induced erosion. For the riverbanks, free-standing gravity type retaining walls were erected in consideration of reducing the burden of the maintenance cost. This project demonstrated the Japanese approach to disaster prevention, constituting a useful reference for the desirable direction for the national land conservation policy of Timor-Leste. The results of the project, including shortening of the construction period by two months, have been highly praised by both the Ambassador of Japan and the Government of Timor Leste.

 

The completion ceremony held by the Ministry of Public Works of Timor-Leste at the site of Mora Bridge was attended by the Ambassador, chief representative of the JICA Timor-Leste Office, consultant and the contractor on the Japanese side and the Minister, Vice-Minister and Director-Generals of the Ministry of Public Works, Deputy Speaker of the National Parliament and four members of the National Parliament on the Timor-Leste side. With additional attendance of local residents and television as well as newspaper journalists, the ceremony was a splendid event. Representing EJEC, Vice-President Furukawa and two others attended the ceremony.