Physical Model Tests for the Construction of the Coruña Outer Port Large Breakwater (Spain)

Introduction: The paper will present the tests conducted at CEDEX Large Wave Flume, to study the Coruña Outer Port breakwater construction stages, with the aims: (A) define temporary protections during construction and (B) determine the waves at which works must be stopped for the workers’ safety.

It is a 3,354 m long rubble mound breakwater with 40 m maximum depth, with 150 t cubic blocks on the seaward (2:1 slope), a filter with two 15 t block layers and 1 t stone and a riprap core. The back side is composed of 50 t blocks (1.5:1 slope). It is crowned with a parapet at 25 m.

Tests characteristics: (A) Temporary crown protections

Five construction stages were studied, involving one of the two layers of 150 t blocks and several layouts

The scale was 1:28.5, the peak period Tp = 20 s and the significant heigh Hs, increasing m by m, from 7 m up to the crown protection failure.

(B) Wave height at which the works must be stopped.

Seven construction stages were studied with the crown at 10 m, starting with the core protected by 1 t armour stone and ending with the final section. Criterion for the temporarily works stop was: ending the activity when the water reached the work platform.

The scale was 1:27.5. The waves were generated increasing Hs by 0.2 m.

Results: (A) Temporary protections

Stage 2 performed best. It failed for Hs = 11 m and Tp = 20 s. Failures occurred for the other stages for Hs = 9-10 m.

(B) Wave height at which the works must be stopped.

The first overtopping was for Hs = 1.35 m at Stage 1, with 5.0 m water level and Tp = 21 s.

The breakwater has performed as expected, withstanding storms: 10/3/2008, 20/1/2009, 9/11/2010 and 15/2/2011, with Hs and Tp from 10 to 12 m and 13 to 17 s, remaining undamaged, except for certain temporary protection, according to the tests. Several videos, model tests and construction, will be included