The geological and erosive processes in the Lecrin Valley over millions of years have formed a very dynamic and complex relief of various fluvial basins. This factor has caused significant problems when establishing routes of communication through the Valley, a natural pass that links the city of Granada with the Coast and the Alpujarra and traditionally one of the most travelled routes of the entire province. Important communication routes passed through this area linking Granada with the Coast and the Port of Motril to achieve economic and social development. With the increased transport of goods and tourist development on the coast, road traffic demands have led to the creation of new, faster alternative routes with more audacious techniques in bridge building.
We could group them into different forms to facilitate analysis, however, it is better to group them by geographical area. This enables the traveller to observe them and understand the level of development of communications within the area. We shall distinguish 5 groups:
This valley is approximately 200m wide and 50m deep in which there are five bridges. Four are practically grouped within a few meters of each other located at the town entrance and another, the new motorway bridge, two kilometres further below the area of expansion of the town centre. This is the area with the most variety of technical solutions and we can find four different structural types:
It is the oldest bridge and represents basic technology of stonework construction taken from the river itself and cement. It has a single span (impossible to determine as it is semi-buried by the river bed sediment) with steep camber and is of undetermined origin. Its production, however, indicates that it may be Muslim and was constructed to span the river of the Royal Road or highway to the Alpujarra. It was in use until the mid 19th century, when the stone bridge of the road of Isabel II was constructed. Today the river does not pass underneath it and it is awaiting a significant remodelling that will affect both the bridge and the surroundings.
It was built in the mid 19th century when the Granada-Motril road was started during the reign of Isabel II. During this period, the old roads were replaced by modern and wider roads, where carriages could pass. The narrowest stretch of the river was chosen for its location taking into account the technical difficulties that still arose in 19th century when making a route of pass, with the outline of the road itself affecting the location of the bridge, sometimes with difficult curves and pronounced slopes of access.
It is a bridge of 104 m (373 feet) in length with a width of 7 metres without pavements. It has seven semicircular arches supported by robust prismatic pillars. Its masonry comprises ashlars, angles, cutwaters and coping stones. The parapets are made with brick buttresses, as well as the vault, facings and other, interposing masonry encaissements: the blocks are filled with quarried stones and cement. The arches were built with an arch centre as, during the construction period, there was little knowledge of using two simultaneously to counteract the horizontal forces of the arch on the columns. This is why the columns are so thick and robust. It suffered the consequences of the earthquake of 1884 which caused considerable damage and in the early 20th century the bridge was used without tarmac.
It was built with chrome steel at the Lecoog workshops in Belgium, to be installed on the railway line of Gor (Granada), where it was for 21 years and cost six million reales.
The poor consistency of the pillars caused engineers of the Ministry for Development to refuse permission to travel on it and then a royal order of February 1907 imposed the limitation which prohibited the passage of travellers aboard the train. They had to get off the train before crossing the bridge and walk the 463 meters to then get back on and take their seats; only the train driver and stoker passed with the train. To enforce the regulations passed, the Guardia Civil was charged with taking custody of the trains. In various articles published in the press during that time, the company was asked to adapt its timetables to not have to pass at night, sometimes with rain and snow, along a dangerous platform through impenetrable darkness.
The bridge was sold to the company Tranvías Eléctricos of Granada, dismantled in Gor and reassembled with a shorter length and in its current location by the German company Dourmounde Unión. It was inaugurated on July 18,1924 by the sub-secretary of Public Works, General Vives. Resistance tests were carried out on July 3, 1924 and one of the three motor cars used ran over an employee, killing him immediately.
Initially, the electrical railway project was to connect Granada and Motril along a narrow electrical railway, although the project remained in Durcal where the tram line arrived at a station that, converted to a park, continues to the entrance of the town. Next to this station there was a cable railway service to complete the journey to Motril port. This cable railway operated until 1958 and the tram line of passengers continued to make the journey from Granada-Dúrcal (one hour journey time) until 1974 when a regular bus service was installed. In 1976, the railway line was dismantled and the bridge was about to be dynamited by FEVE, however, the delegate of the General Board of Fine Arts, Vicente González Barberán managed to prevent this and it was finally ceded to the Regional Government in 1983 for its preservation. In 1999 it was cleaned, painted, illuminated and access improved.
Like all railway bridges it is not just a cantilever viaduct. It is built using metallic beams in meshwork linked by rivets, with a total length of 199.93 meters, distributed in three spans. The two tronco-pyramidal columns of meshwork stand at 25.50 m high, with concrete pedestals made to boost the columns as the Gor ravine, where it was previously located was shallower than the valley where it currently stands.
The first was built during 1980 to meet the need to modernise the stretch of the N 323 and avoid crossing Dúrcal passing to the east of the town.
The bridge is made of pre-tensed concrete voussoirs strengthened with reinforced framework. It is 218 m long, on 2 separated columns 106 m. (maximum span) and 12 m wide (with 7 m of road, hard-shoulders of 1.5 m., pedestrian pavements separated by a safety barrier and with metallic railings on the edges).
The 2 columns are parallel prism-shape of 1x5 m rectangular section (in h-shape) and 95 metres high. The deck bridge was based on successive voussoirs of variable section concreted in situ that were laid alternately on each side of the columns to counteract expansion if both sides did not advance at the same time. The procedure was completed linking the decks of each side of the columns with the final voussoir giving the bridge its definitive strength.
The second bridge, that of the coast motorway ,runs approximately 2Km below the spot where the four previous bridges are located.
The viaduct of 305 metres in length, has two separate decks, one for each carriageway measuring 13.50 metres wide each, both supported by the same column in Y-shape. The four central spans measure 53.50 metres each and 43.50 m at the ends and the maximum column height is 80 metres.
Its basin starts at the Pico del Caballo collecting the waters from the Sierra de Nigüelas. Its flow is not abundant as it supplies several irrigation channels and regularly suffers from the effects of the dry season, especially in the summer months, however, sometimes it can flood after local storms.
During different periods of the year, the river was forded by the routes that crossed it. When the road was planned during the reign of Isabel II, experts deemed that a bridge was not necessary to cross the river as it was hardly a torrent. Therefore, the road dropped to the river bed and once crossed the route continued downstream along the left side until exiting by the current brick factory of the Ravine of el Pleito.
This remained the case until Natalio Rivas, a distinguished politician from Granada in the early 20th century, passed through it. The minister had the misfortune of getting his wheels stuck in the turbulent River Torrente and found it impossible to get out. He had to ask the locals for help, which they did as long as he promised to order the construction of a bridge. And thus we have this beautiful triple-arch platform.
In compliance with the principles of good construction, the ashlar stones were adopted for all angles, edges, vaults and imposts. Furthermore, the work has a general impost and ashlar masonry that limits its height and that runs the entire length of the bridge. The finishing is faced masonry in the main body and ashlar masonry for the coping (coping stone). For all the factory fillings in general, the ordinary masonry was adopted facing it only on abutment, column and wall faces.
The motorway bridge (formed by two independent decks) was carried out at two different times. The first deck was executed when the new stretch of the N. 323 was carried out to avoid crossing towns and villages. The carriageway had three lanes: one in downwards direction and two in upwards direction (one crawler lane). At the beginning of the 21st century construction began on the second viaduct that runs parallel to the first.
The construction system was very similar in both: first a series of columns were erected on which a series of parallel prefabricated beams were placed (three on the first viaduct and four on the recently built viaduct). On top of them prefabricated deck bridges were also placed to form the platform. To adapt the oldest viaduct, the entire platform had to be resurfaced to raise it a little and increase the curve. On March 14, 2002 it was inaugurated.
The regional road was carried out at the beginning of 20th century. It was then that the Valley left the bridle paths behind and modernised. The road required several bridges, which at that time were the pride of the area and that at times we don’t appreciate enough.
The first bridge is found at the entry to Melegís. It is that of the Ravine of los Hijones (Gijones). It is a single semicircular arch pontoon bridge in line with the type of construction at that time: The masonry cross springers, the intrados and the coping stone of the parapet are all made with ashlars. The abutments and the rest of the arch offer ashlar masonry on a stone base collected from the surrounding land.
On leaving the village we find new bridge over the River Torrente. A few meters further along, at the entrance to Restábal, is another bridge over the River Grande (union of the River Dúrcal and the River Santo). Both bridges are practically identical as they were built at the same time and in the same way, therefore we can comment on them together.
The bridges have two arches that rest on the centre of a pillar with stone ashlar cutwaters. The cross springers and intrados are also made of stone and the rest of the bridge is faced. The intrados has a series of jutting corbels used to support the arch centre at the time of construction. There are stone parapets with coping stones in the upper part of the carriageway.
It is a strategic place as it is a narrow and deep opening one hundred meters deep and is very difficult to surround. Evidently, there has been a bridge in Tablate for centuries, however, there was not only one, but many successive bridges on which today we call Tablate Bridge: "Some burnt -says Alarcón-, others flew, and all drenched in the blood of the Phoenicians, Carthaginians, Romans, Goths, Arabs, Moriscos, Austrians and French, and of course Spanish from all centuries". Due to its strategic and key position, Tablate has been the backdrop throughout history of numerous combats, significant battles, in which it was necessary to subordinate the campaign plan to this perpetual topographic phenomenon.
In this area we find four bridges:
1.- The old bridge. The first references we have on the existence of the bridge are directly linked to the conquest of the Kingdom of Granada, with the Castilian troops having to cross it when the Alpujarra was conquered in 1491. Then during the Mudejar revolt of the Alpujarra of 1500, the bridge was destroyed to stop the Castilian armies from accessing it easily, wherefore once conquered repair works started in earnest.
In 1502 the Catholic Monarchs, at the request of the council of Granada, took certain measures regarding its importance for communication between the Alpujarra and the Lecrin Valley and the plains of Granada. To obtain sufficient funds and start the works each person who crossed the bridge was ordered to pay a toll of 1 maravedí for him or herself and for each large animal during a period of three years. The aim of this levy was not only to rectify the damage caused by the mudejar revolt but any surplus was destined «for the repair of roads of the Alpuxarra ».
All towns and villages affected by its destruction were involved in the works together with the city of Granada, each one contributing according to the use of the bridge and obtaining funding from their own assets.
On January 10, 1569 this spot was the backdrop for the most significant skirmish of the War of the Alpujarra against the Moriscan uprising of Aben Humeya. On this day the Marquis of Mondéjar visited the bridge with an army of 2,000 soldiers and 400 horses. The 3,500 rebels, as told by the chronicles of Diego Hurtado de Mendoza, broke the bridge and entrenched themselves on the other side of the gorge, in the safety that it would be impossible to cross. To their surprise, however, as told by the historian, and thus transcribed by Alarcón, a Franciscan brother crossed the gorge:
"A Franciscan brother called Fray Cristóbal Molina led the soldiers by example and instilled terror in the Moriscans. With a crucifix in his left hand, a sword in his right hand, his habit gathered around his waist and a shield on his back. He reached the pass, supported on a long wooden plank, he jumped and when they all expected him to fall, they saw him safe and sound on the other side. Two soldiers followed him: one fell and died; the other was more fortunate. They rearranged the wood to shelter from the fire of the harquebusiers, helping the others pass and finally repelling the Moors and consolidating the bridge with planks and stones allowing the entire division to pass with horses, carriages and artillery and it camped in Tablate".
At the end of 16th century or in early 17th century it was rebuilt and then underwent subsequent repairs over the centuries. In 19th century Pascual Madoz indicates that its state was «ruinous»
Giving a short description of the bridge we shall say that it is located at a narrow pass of the Tablate ravine, not built directly on the riverbed but on a step formed in the ravine walls at a certain height and that acts as a base for the abutments that in turn act as pillars elevated above the area of passage.
The masonry abutments are bound with lime cement and can be differentiated into two sources. It has a semicircular arch that is made of masonry with external ashlar work although currently it has lost some of its arch-stones, especially in the keystone area, where it is supported directly on the rock. The intrados has regular medium-size rough ashlars. The arch sits directly on the abutments and the entire space silted up with different building materials. On the outside are what remains of rendering on both sides.
The primitive bridge initially passed at a much lower level than the current one as shown by a first line of sluices or drains. In subsequent periods (possibly in 18th century) remodelling increased the level of pass with a body of masonry that reaches the second line of sluices. At the time of Isabel II it was found in such a poor state with collapsed walls and the outside part had given way, that to avoid ruin it had to be supported with iron keys.
In 2002 the Ministry of Public Works undertook the essential restoration of the bridge and its surrounding area.
2.- Bridge of the Road of Isabel II. It was built in 1859 below the existing bridge and is 18.4 m high, 39.8 m long and has a 16.7 m diameter. The arch, interior facing of the abutments, foundations, imposts, pavement and parapets are all ashlars; the rest is brick, rendered masonry on the exterior and ordinary on the blocks.
The gorge sinks down 40 m, however, luckily it was possible to rest the abutments on two outcrops of rock. Two large areas have been levelled at both the entrance and exit of the bridge, which considerably reduced the height and cost of this work.
The hermitage built at the end of this bridge was built relatively recently in 1957, due to an initiative by the RACE (Real Automóvil Club de España –Royal Motoring Club of Spain) to honour the Granadine patron saint, the Our Lady of Sorrows, which never lacks fresh flowers and oil lanterns lit in her honour.
3.- Access bridge to the Lanjarón road. It is a metal framework bridge with beams and upper braces. It has a single span and measures 115 metres in length. It was inaugurated in 2002 forming part of the entire motorway and as the new access to the Alpujarra road to avoid a stretch of very difficult curves on the old road.
4.- Motorway bridge. In reality there are two bridges. One downwards and another upwards. The first was outlined in 1994 and devised to ease congestion of the national road 323 and later inaugurated on July 21, 1995. The second was later built and inaugurated on March 15, 2002 with the motorway stretch from Dúrcal-Ízbor
It crosses a riverbed that is 100 metres deep over land of winding geography, problematic geology that has a propensity to rock slides and in an area of high seismic risk.
The Tablate bridge, in the words of its creator, Javier Rui-Wamba, was conceived and constructed as planned, with two metal arches of 142 metres span, based on foundations that rest on each side of the gorge. The arches have parabolic geometries with a central deflection of 25 metres. Each arch is constituted by a rectangular caisson of 2 metres edge and 1.20 m. wide, with diaphragms and internal strengtheners. Transversally, the arches are linked by beams to the caisson of rectangular section, forming a rectangular Vierendeel-type structure, which ensures its transversal stability against traffic and seismic actions. On the arches there are 14 pairs of square metal pillars at a maximum height of 25 metres, and they decrease as they approach the key of the arch. The pairs of pillars rising from the foundations are braced with “Saint Andrew” crosses to give the structure transversal strength.
The reinforced concrete deck is integrated with the longitudinal and transversal beams, forming an element of horizontal strength and is supported on the reinforced concrete abutments with foundations on the land.
Provisional points were installed for the assembly of the bridge which facilitated the assembly of the semi-arches, leaving a central voussoir 30 cm.wide, which was finished by welding after having adjusted the geometry of the arches. As the assembly of the beams advanced from the abutments towards the centre of the arch, the pre-slabs were laid and the rest of the deck surface was concreted.
Until the mid 19th century, the Royal Road passed further up through Pinos del Valle towards Venta de la Cebada. But in the kingdom of Isabel II it was decided to change the outline to where it is today. The Ízbor or Acebuches pass was considered a strategic point as demonstrated by the fact that there used to be a police surveillance point at the tunnel mouth.
There was a bridge at the end of 18th century or early 19th century that was used only for mule trains and that could not be used for the new stretch of the Isabel II highway (due to the enterprising genius of the Count of Montijo, during his administration between 1845 to 48) because of its low lying situation and poor building quality. It served well, however, during the construction of the new works, acting as scaffolding for the placement of the arch centre and for other necessary operations during the construction of this road. It was later demolished.
The new bridge comprises a large arch with a 23-metre span and a further three spans of 7.17 m. each. In order to gain as much height as possible all the arches are semicircular in shape. Thus the greatest span of the large arch has a height of 13.53 m; and for the main pillar of the small arches a height of 10.54 m which was used to calculate the thickness. To increase stability the thickness of the keystone, pillars, adjacent walls and abutments was increased to give a solid perspective.
The total width adopted for the entire work is 6.80 m. with the parapets occupying 0.80 m., therefore there are only 6 metres of road, which is sufficient width for this difficult pass, although less than that affecting the road at all points; and it is clear that the only reason for this was due to economics.
Ashlars were adopted for all angles and edges leaving on these the precise toothing for good bonding of other materials. Likewise, the ashlar masonry was adopted for the entire vault and was the only admissible material. The small arches are brickwork due to their smaller dimensions; using only ashlar masonry on the facades, and brickwork on the rest of the vault. And in order to ensure its perfect resistance, the best bricks were used that were manufactured in the tile factory of Béznar, located 8km from the works and those made in la Solana were rejected.
The abundance of good limestone found near the works led to the adoption of this for facings; as although this production is more costly than regular masonry, it is also more solid, on the other hand, small sacrifice, conciliating its decoration with prudent economics and the desired strength.
Ordinary masonry was used for all the backing, facing only the abutments, pillars and adjacent walls. The faced masonry aprons of the bridge are continuous but on reaching the walls they are interrupted with a safety barrier; and it continues after a series of pavements interrupted by more safety barriers.
The improvements of the N. 323 road required a new pass over the river as the narrow bridge and bordering tunnel could not meet new demands of increased traffic and vehicle size. An iron bridge was made that is practically a clone of those of Tablate ,therefore we are not going to place too much emphasis on it.
The outline of the motorway involved the construction of five new viaducts. The first of them “Viaduct of Rules” starts in the area of the current bridges, crosses the river Izbor and runs along the tail end of the reservoir to the confluence of the river Lanjarón. It measures 950 m in length and has two clearly differentiated constructive origins. The first three spans are of successive projection (voussoir) built “in situ” and the rest of the bridge with pillars of up to 75 m. in height, it was carried out with arch-centre and spans of 55 m. Its section comprises a central caisson beam and lateral slabs supported by prefabricated braces.
The following viaduct called “La Loma” is a bridge of 480 m. and 12 spans with reinforced concrete deck and mortar box beams of 40 m span supported on a single pillar with heights of up to 45 m. It is located in a highly unstable area wherefore the pillars have deep foundations based on 6 piles of diameter 2,000 and depth of up to 45 m.
The third viaduct called “Viaduct of the Guadalfeo” is a metal meshwork bridge of 585 m. in length, built “in situ” and placed by thrust. It has 2 central spans of 140 m., with pillars of up to 95 m. in height. Said bridge shall hold a world record for metal bridge with spans of 140 linear meters. The steel structure weighs 10,000 tonnes.
The “Viaduct of Miranda” of 360 m. in length is similar to that of la Loma, with the reinforced concrete deck and beam of 40 m. span.
Finally, we have another singular structure: the “Viaduct of el Vizcaíno” of 170 m. 2 spans and single pillar and built using a metallic caisson with metal braces, constructed “in situ” and placed using hydraulic jacks.
We do not want to finish this article without mentioning another series of bridges that are also in the region and which we have failed to mentioned, mainly because they are smaller in size (except small gorges) and to save repetition.
The majority are located along the old Isabel II highway: Acequias (ravine of el Pleito), Talará ravine, Chite ravine, Béznar (Quete ravine, Canales ravine) there is also another along the Royal Road (Calavera ravine). There are other bridges from Restábal to la Venta de la Cebada. The roads to Albuñuelas also have bridges which tend to be simpler.
We must not forget that bridges are of great historical and monumental value that we must recognise, value and respect.
Autor: Placido Molina Molina