Port accessThe works are included in one contract with a global estimated cost of 74 million euros and a European Union subsidy.
The stabilisation works lasted 34 months and have required up to 330 blasting operations.
A new technical and environmental-friendly system comprising a tunnel and two wells was used to clean up debris from the old quarry.
The works on the Port of Bilbao Central Pier and those on the stabilisation of the old Punta Lucero Quarry, which the Port Authority has been carrying out since late November 1916, will be completed in this month of September, three months previous to the original schedule.
Considering technical, environmental and economic advantages – and due also to the fact that they coincide in time –both works were included in the same contract. The global estimated cost of the works is 74 million euros. The European Commission will contribute 20% as part of its Connecting Europe Facility (CEF) Programme, with the Port Authority providing the rest from its own funds. Of the total cost, approximately 11% corresponds to the quarry stabilisation works, that is, some 8 million euros.
The works were awarded by public tender to, and carried out by the temporary consortium formed by Trabajos y Obras (SATO) – Construcciones Adolfo Sobrino, S.A – Excavaciones Viuda de Sáinz S.A.,
First stage of the Central Pier
The new dock has been named the Central Pier – due to its position in the zone sheltered by Zierbena Breakwater and its secondary breakwater- and supposes total exploitation of the same.
In the first phase, 334,000 m² of surfaces were reclaimed from the sea and 1,281 metres of berthing were created together with 21-metre depths. The surfaces obtained will amount to somewhat more than half of the 600,000 m² of the completed pier.
During these works the following actions were carried out:
- The construction of 22 caissons 25m high, 55m long and 17m wide.
- Obtaining and depositing 1.5 million mᶟ of filling, 50% of which proceeded from the remains of the stabilisation works on the old Punta Lucero quarry.
- Sand extraction from the furthest zone of the Port domain, specifically opposite Punta Lucero breakwater. In this second phase, 6.5 million cubic tonnes were used to fill in the new dock esplanades.
The sand infills from the marine deposit, like the Pier Project itself, have their Perceptive Environmental Study (AZTI, October 2011) and the corresponding favourable Declaration of Environmental Impact of 17 April 2013. These infills suppose less than 15% of the total sandbank in this zone.
The works on the new infrastructure will be completed in September 2019, while fitting out works will be completed throughout 2020.
Stabilisation works on the old quarry
The works to stabilise the old Punta Lucero Quarry were carried out in order to contain rock landslides and subsidence produced in recent years. To guarantee the efficiency and durability of the works, and after the undertaking of several studies and receiving assessment from specialised firms, it was decided to “comb” the area, from the highest to the lowest levels by small, controlled blasting and other auxiliary works. In all 325 blasting operations were carried out, with an average of 10/15 per month, while a further five are calculated to be needed in this month of September.
Pre-warnings for each blasting operation were sounded for those port facilities near the works area and the works were supervised by the Basque Government Direction of Energy, Mines and Industrial Administration.
The blasting technique used was the same as that employed on Road BI-625 where it links with Motorway AP8 at the Arrigorriaga –Zaratamo connection, and that in the Old Quarter of Toledo.
The old Punta Lucero Quarry in the town of Zierbena was exploited from the 1970s until about 20 years ago to provide material for the Extension Works of the Port of Bilbao. Since then, nothing has been extracted, as borrow required for port infrastructures has been obtained either from commercial quarries near the Port, or from other nearby works.
The quarry mainly looked stable and did not pose any problems except in one very specific area due to the position and slant of rock slabs and the constant progressive deterioration resulting from rains and temperature. Landslides in this area forced the closing of the road beneath for safety reasons, as well as the placing of concrete blocks to prevent rocks rolling down the side from reaching the petrochemical deposits.
These measures were provisional, and actions had to be taken in order to offer a permanent solution to the area by providing the necessary safety for the correct development of port activities for both lorry traffic along the road and liquid bulks storage.
Taking into consideration these facts, it was decided to carry out a previous study of the zone, and a later development of the same in order to establish the alternatives that would stabilise the side, bearing in mind such factors as safety and durability. The alternatives of supporting the side using embedded anchors and safety netting were rejected due to their mid- and long-term performance, so it was decided to undertake stabilisation by creating a new profile with an approximate height of 170 metres along the side and providing 15-metre high slopes and 5-6-metre berms in order to guarantee long-term safety and durability, as mentioned above. Such “re-profiling” was carried out by blasting and produced 900,000 mᶟ of surplus material which was withdrawn and deposited in the Central Pier.
