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EXPANSION OF SEA WALL AT THE PORT OF BARCELONA
PROPERTY       AUTORIDAD PORTUARIA BARCELONA
GENERAL DESCRIPTION OF THE WORKS.

The projected works correspond to execution of the extension of the East Breakwater in the Port of Barcelona, adopting the solution of a breakwater with banking.

The new East Breakwater extends the existing breakwater in the Port of Barcelona by 1,986.82m, comprising the following parts:

a) A first part towards the south, coinciding with the line of the existing breakwater. The length of this part is 928.88m.

b) A second part, also towards the south, forming an angle of 155.7º with the first. The length of this second part is 1,045.44m.

SECTION TYPE OF THE BREAKWATER.

The standard part of the breakwater is of a transverse section formed of the following units:

a) Prior dredging of softer material from the sea bed.

This consists in an excavation 3.00 m deep all along the line of the breakwater with a width at the lower base varying between 180 and 200m. The slopes of the dredging are 6:1 and the depth of the ditch varies between 21 and 25 metres below sea level.

b) Replacement of the dredged material by unclassified breakwater blocks.

The ditch dredged is filled by maritime dumping of unclassified breakwater blocks. Standard vessels for the purpose of marine dumping will be used. (Unit in progress at present)

c) Construction of the nucleus of the breakwater with unclassified breakwater blocks.

The nucleus is made by maritime tipping of unclassified breakwater blocks to level –4.00m, forming a slope 3:2 finished with earth tipping to level +2.00m. In this way, a working surface is obtained of 20m width.

The nucleus is made in three phases: the first to level – 11.50m, the second to level –4.00m and the third to level +2.00m.

d) Construction of the shelter for the nucleus with classified breakwater blocks of various sizes, as well as prefabricated blocks of solid concrete, respecting the necessary conditions of filtering and protection.

In parallel with the construction of the nucleus, maritime tipping is used for both the filters and protective layers, to levels –11.50m and –4.00m respectively. The layers above level –4.00m are made with earth, until the nucleus reaches level +2.00m. This will be done using cranes of the necessary dimensions for each of the types of breakwater blocks and other blocks used.

The filter consists of classified breakwater blocks of 150 to 300Kg, while the protection layers are formed of classified breakwater blocks of 500 to 1,000Kg on the lateral banks, classified breakwater blocks of 3,000 to 5,000Kg and blocks of 50t on the layers of the outer slopes and classified breakwater blocks of 2,000 to 4,000Kg and, only in the second part, blocks of 8t for the layers of the inner slopes.

As a footing to retain the 50t blocks, a trapezoidal berm is placed, formed of 8t blocks. This footing is made by maritime means.

The layer of 50t blocks presents a slope 1.75:1. That of the 8t blocks for sheltered waters has a slope of 3:2. The retention footing blocks have a slope of 2:1. e) Construction of the superstructure of the breakwater, formed of concrete paving topping the level +3.00m and a berm, also of concrete, topped at the level +12.00m.

As a finish for the two parts envisaged the breakwater end has to be constructed. This is obtained from the turning by 210º of a standard section of breakwater with slope, very similar to that used in the two parts, but where the outer protection blocks are now 80t and those at the foot of the layer are 12t. To respect the necessary filter conditions, the secondary layer below the 80t blocks is of classified breakwater blocks of 6,000Kg, and below this, two filters of classified breakwater blocks of 500 to 1,000Kg and 150 to 300Kg. The sequence of execution is identical to that for the rest of the breakwater.

From the description of the standard sections it is understood that a reduced number of works units are involved in the execution of the works, however the necessary quantities of these are very important. The following table sets out approximately the volumes involved in the execution of the works.

Dredging 1,250,000 m3
Unclassified breakwater blocks 10,000,000 t
Classified breakwater blocks 2,000,000 t
Concrete (blocks+berm+superstructure) 500,000 m3

The construction of the standard section is planned in 5 successive phases through the need to achieve a 90% consolidation in the land existing before continuing with the following phases; these phases are:

Phase 1. Dredging the ditch and filling it by maritime route with unclassified breakwater blocks to the natural level of sea bed.

Phase 2. Construction of the stabilising berms and the nucleus of the breakwater to level –11.50m, with the corresponding placing of filters and protection with the classified breakwater blocks of the berms.

Phase 3. Constructing the nucleus of the breakwater to level –4.00m. Placing filters and protection with the classified breakwater blocks of the berms. Placing concrete blocks in the footing layer and on the principal layer.

Phase 4. Construction of the breakwater nucleus to level +2.00 and the filter, classified breakwater blocks in the secondary protection layer and the placing of concrete blocks on the principal protection layer.

Phase 5. Construction of the superstructure.

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