History
The project
The passage of the Deva estuary had historically been carried out by means of a barge that gave continuity to the bridle path that from Urazandi, going up through Laranga, reached Motrico, which was later complemented in 1791, by the Camino Real, which through Sasiola, passing through the port of Arribiníeta, over Mount Calvario, unites Motrico with Mendaro and Deva. In 1855, the road between Deva and Sasiola was built, providing road transport to the entire western area of the Gipuzkoa coast and the eastern coast of Biscay, especially to the important fishing port of Ondárroa.
In 1866, the coastal section between Deva and Motrico was inaugurated, in which the bridge over the Deva estuary is located. It consists of three arches and a drawbridge that allows the passage of boats upstream, to the Maxoe and Berria fish markets where the stowage work was carried out. Since its inauguration, the geology of that area of the coast has created problems in the road infrastructure, with frequent landslides and collapses of the road and damage to the bridge. Already in 1883, a sinkhole caused the collapse of the second pillar of the bridge (looking downstream), it was repaired again in 1892, with problems continuing on a recurring basis.
After the construction of the road between Munlasoro and Sasiola, which would ultimately be the national highway N-634, the construction of a coastal highway is proposed to link the town of Deva with the neighboring Motrico, thus giving continuity to a coastal highway that would link the two Basque capitals, Bilbao and San Sebastián. In 1862 the authorities of both towns asked the Provincial Council to build the new road. In March 1862, the then mayor of Deva, Juan Unzueta, met with the deputy director of roads of the Provincial Council of Guipúzcoa, Santiago Sarasola, to propose the project, in which they had already located the bridge and provided that it would make way for boats. On July 10, the project received approval from the General Meetings of the province held in Azpeitia, although proposing a passage over a cheaper boat bridge.
In the drafting of the project, the location of the bridge was initially proposed in the Arzabal area by the so-called "Casa Campo" (location later used for a new access bridge), higher than the Maxpe and Berria boat loading and unloading markets, thus avoiding the drawable section as there is no longer the need for the passage of boats. That location was rejected by the Deva city council, which intended to bring the bridge closer to the urban center. Finally, it was decided to locate the infrastructure between the Aguirre Palace, on the Deva side, and the place called Bruyako aitza (Bruya rock) on the Motrico side.
The town councils of Deva and Motrico constitute commissions to agree on the details of the project and open a popular subscription for the financing of the new road. An independent subscription is made in each town.
In April 1863 Julián de Andonaegui, mayor of Motrico, informed the mayor of Deva that the Provincial Council of Guipúzcoa had appointed Antonio Cortazar, interim director of Public Works, to draft the project which was presented on July 18 of that same year and put up for auction.
The project proposes six sections of work for the construction of all road infrastructure, including the bridge over the Deva as well as access to the port of Motrico. The total budget amounts to 1,105,270 reales (vellón), of which 261,861.92 reales correspond to the bridge. It was awarded to various contractors for 988,870 reales and was finally realized for 1,739,893.51 reales without including the cost of the drawbridge section of the bridge.
The construction
The sections corresponding to the road works are awarded to contractors from Motrico, and the bridge is awarded to the contractor Luis Emparanza from Cestona. The direction falls to Santiago Sarasola, with José María Arbulu as his assistant. The settlement of the work was carried out on May 22, 1866 and amounted to 396,555.34 reales without including the drawbridge section.
Now that the bridge works are advanced, the Deva city council requests that several modifications be made; increase the width by one meter (from 2 to 3 meters) of the upper gate, the construction of four stairs, one in Urazandi, another in the "Cruz" (Salbarreta) and another towards 'Arrangasi" for the public service and several rings are placed in the buttresses of the bridge for moorings for boats. The proposed modifications are rejected by the Provincial Council. The bridge was inaugurated on December 18, 1866.
672.45 m³ of limestone were used in compact and homogeneous ashlar carved with a bushhammer from the Latzurregi, Maxpe and Milluaitz quarries.
The drawbridge
To allow the passage of boats to the fish markets located upstream, a drawbridge was built. This section was designed and built independently from the rest of the work. In the spring of 1866, with everything finished, it had not yet been defined what the moving part would be like. On May 31, 1866, the Guipúzcoa council commissioned the construction of the moving part to the French company Cabocller y Grimaull, which did so based on a design by the works director Antonio Cortázar. The cost was 14,000 French francs.
It was a metal bridge with two independent lifting leaves, each sitting in a part of the section to be covered where, using a set of counterweights, they pivoted, rising, leaving free passage. Built in Paris, it reached San Sebastián by rail and, from there to Deva, by sea to its location.
On October 7, 1866, the pieces that make up the bridge were received and the metal structure began to be assembled. The frame and board were made of oak wood. By December it was ready for use, enabling the complete inauguration of the infrastructure on the 18th of that same month. The total cost of the drawbridge section was budgeted at 31,272.37 reales, ultimately rising to 99,138.74 reales de vellón.
When the transit of goods through the estuary disappeared, mainly coal, the drawbridge ceased to make sense, its last opening was in 1941, and it was dismantled in 1951 (the date of 1956 is also given) and replaced by a concrete vault clad in stone.
Closure to road traffic
In Deva, the bridge was located right next to the railway track at the very entrance to the station. The road formed a level crossing with the railway route that created significant circulation problems. This, together with the measurements of the bridge that did not allow the smooth passage of vehicles, led to the decision to look for a new alternative for crossing the estuary.
In 2007, after the inauguration of the new link between the N-634 and the GI-638, located 1 km upstream and that crosses the river and the railway line with a tubular bridge with a single span of 110 meters of span supported by an upper arch to avoid supports in the channel and a 300-meter-long tunnel,[3] ownership was transferred to the municipalities of Deva and Motrico and it was closed to road traffic. leaving it only for pedestrian use.
On January 10, 2012, the Camino de Santiago as it passes through the autonomous community of the Basque Country was classified as a Qualified Cultural Asset, with the category of Monumental Ensemble, by decree 2/2012, of January 10, of the Basque government.
In 2016, on its 150th anniversary, a small restoration was carried out. In July 2018, the central pillar collapsed, rendering it unusable. After its recovery in 2021, it opens again to the public on May 26, 2022.
Foundation problems
The bridge was designed to remain in service on a carriage and stagecoach route, which passed to motor vehicle traffic as the century progressed, maintaining service. The geology of the area where it is located is conducive to subsidence and landslides and the bed of the estuary is muddy in nature and the bedrock is 40 meters deep. The technical solution adopted in the 1863 construction project was to establish a settlement of wooden piles driven into the bed of the estuary until the bedrock was reached. These piles, approximately 30 cm in diameter, supported a grid of wooden beams on which the pillar sits.[4] This problem has been a constant in the life of the infrastructure. In 1883, a sinkhole occurred in the bed of the estuary that affected the pillars of the bridge, exposing the wooden pile structure. After covering the pillars with a large amount of breakwater, the sliding of the pillars was not stopped.
In 1892 Inocencio Elorza carried out a study of the situation, clarifying the problem of the foundation of the bridge and the inconvenience, for new interventions, that the breakwater represents. Elorza proposes making a type of concrete wedge based on the breakwater stones that supports the pillars. The situation of the bridge with two pillars sinking and deforming it, led to the proposed works being approved and carried out. That same year, the settlement and firmness work on the pillars was carried out and the following year the comprehensive repair of the bridge.
In 2001, new problems were detected with the foundation.
On July 5, 2018, the central pillar collapsed, closing the passage both above and below it.[5] The collapse of the central pillar occurred when, due to the action of the currents and tides, the wooden piles that supported the second pillar were discovered. and with it the stability of the vaults it supported.
Bridge rehabilitation
The infrastructure, although already closed to road traffic, is the main passage that connects the homes on the left side of the Deva estuary with the town of Deva; its closure created a serious mobility problem. Furthermore, given its degree of protection as a monument, the authorities decided to recover it in the most respectful way possible with its technical and construction characteristics. The council commissioned the companies Injelan and Fhecor to carry out an action study. On July 24, a technical inspection of the bridge foundation was carried out where the failure problem centered on the deterioration of the wooden piles due to the attack of the xylophagous teredo navalis was seen and determined. Given the possibility that the other piles would suffer similar episodes, it was decided to reinforce them, underpinning them with micropiles of steel tubes filled with cement slurry.
To stabilize the structure, which was threatening to collapse, a large metal formwork was used to support the vaults by hanging them, thus preventing their possible total collapse, in addition to enabling pedestrian passage over it. These works, carried out urgently, consisted of the so-called first phase.
On October 7, 2020, an agreement was signed between the municipalities of Deva and Motrico and the Provincial Council of Guipúzcoa for the rehabilitation. In it, the council was responsible for the cost of the recovery and restoration of the infrastructure with an initial budget of 7 million euros, as the Department of Culture of the Provincial Council of Guipúzcoa is responsible for the conservation, improvement and restoration of cultural heritage that resides in the province.
The bridge recovery works began in April 2021 after being awarded to the joint venture formed by the companies Construcciones Moyua and Harri under the technical direction of the Fhecor-Injelan joint venture. The works lasted 13 months and the infrastructure was reopened in May 2022.
The rehabilitation project was based on the premises of maintaining the falsework installed in the first phase of emergency action to guarantee pedestrian passage, during most of the work, and acting on pile 2 without proceeding to its dismantling. To this end, the following actions were carried out: the underpinning of pile 2 to its original quota, the complete dismantling of vaults 2 and 3, the restitution of the upper geometry of pile 2, the reconstruction of vaults 2 and 3 and in addition, the underpinning of the abutment foundation 1 and pile 3.[6] The original stone blocks were used and those that were replaced or added were made with stone. coming from the Lastur quarries where the original stone had been taken.
On November 29, 2021, the stripping was carried out, the operation lasted 4 hours and the key descended 10 mm in an arch with a span of 14 meters. After that, the rest of the infrastructure was completed and a typical pavement of an urban environment was available, not looking for what the bridge may have had originally. On May 26, 2022, it reopened and entered service again.