The Alhambra is a palace and fortress complex built between the 9th and 16th centuries on the top of a steep hill facing the Albaicín quarter of Granada. Boasting some three and a half million visitors a year, it is, after the Antonio Gaudí-designed Sagrada Familia in Barcelona (4.5 million visits a year), the second most visited tourist attraction in Spain and it is also usually included in the list of the most popular in the world.

It consists of a military fortress, a medina quarter, several palaces and gardens and other buildings, mostly built by the sultans during Muslim rule over the Iberian Peninsula after moving their capital to Granada. This period ended with the conquest of the Nasrid Kingdom of Granada, the last territory held by the Muslims, by the Catholic Monarchs in 1492, the same year as the discovery of America by Christopher Columbus.

At this point, the complex passed into the hands of Christian monarchs who added some buildings, such as a Renaissance-style palace commissioned by Emperor Charles V in 1526 and the Church of Santa María, completed in 1618 on the site of an old mosque. After a period of neglect, the arrival of the Romantic era in the 19th century renewed interest in the complex and restoration works began. In 1898, ownership of the Alhambra was transferred to the Spanish state and shortly afterwards it was declared a national heritage site. In the early 20th century, the trust that today manages it was created, placing it under the auspices of the regional government of Andalusia, and, in 1984, it was listed as a Unesco World Heritage Site.

The palatine city

Despite the sprawl of the site, surrounded by two thousand metres of wall and thirty towers, and the variety of buildings of interest from different periods, what has made the Alhambra world famous are its palaces and gardens from the Muslim era and, in particular, the Nasrid dynasty. In spite of the characteristically low quality of construction materials used in Islamic architecture –stone, brick and wood– and the exterior sobriety, the beauty and artistic quality of the interior rooms make it unique. Its gardens and courtyards, adorned with pools, ponds and fountains –such as the famous fountain in the Court of the Lions, perhaps the most recognisable image of the complex– are also responsible for the Alhambra’s uniqueness and universal reputation.

It is located on an elevated site known as Sabika Hill that was initially used as a military post, probably beginning in Roman times. The first palace was built in the mid-13th century by the ruler Muhammad ibn Yusuf ibn Nasr, better known as Ibn al-Ahmar, a name from which the name ‘Alhambra’ is believed to be derived, although other theories suggest that the name means ‘red fortress.’ Though this is not the colour of the buildings, the name is attributed to the optical effect produced by the torch lighting at night during construction. Successive rulers continued to add palaces and rooms, and reinforced the walled military zone, the Alcazaba, which is notable for the Place of Arms, the Sail Tower, the Weapons Tower and the Adarve Gardens. The walled site can be accessed by several gates, the most important of which are the Gate of Arms, the Gate of the Poor Quarter, the Gate of Justice  and the Gate of the Seven Floors.

The citadel (medina), contained houses for nobles and commoners, as well as public baths (hammam), ovens, workshops, underground stores and water tanks. This is the location of the Generalife Gardens and Nasrid Palaces: the Mexuar, the Comares Palace, or Palace of Yusuf I, and the Palace of the Lions, or of Mohammed V. In this area –and not by chance, but to symbolise the triumph of Christianity over Islam–the Palace of Charles V, noted for its unusual circular courtyard, was erected three centuries later. Opposite the palaces is the entry to the Rauda, the royal cemetery, and the Generalife Palace, a house of recreation for the sultans of Granada, famous for its orchards and gardens, and adorned with fountains and irrigation ditches. These gardens include an exceptional construction: the Water Staircase, which features handrails containing channels to carry a stream of water.

Some of the most highly representative elements of Islamic architecture that abound in the Alhambra are its courtyards, some of the most notable of which are the Court of the Lions, with its famous fountain; the Court of the Wrought Iron Grille, with its balcony on the south side; the Court of Comares, or Court of the Myrtles, with its ditch flanked by hedges; and the Court of Lindaraja, over which
the viewpoint of the same name looks.

The palaces house the rooms and halls used by the sultans to receive foreign dignitaries, celebrate parties or impart justice, all with fabulous decoration covering the walls, arches, pillars and ceilings, and combining calligraphic elements, tiles and muqarnas (pieces of plaster similar to a honeycomb). Of these, some of the most notable are the Hall of the Ambassadors, where the sultan’s throne was located; the Hall of the Abencerrajes, the Hall of the Two Sisters
and the Hall of the Mocárabes, with its spectacular star-shaped vaults. In the Hall of the Kings, the ceilings are adorned with paintings, while in other rooms, such as
the Gilded Room, the ceiling is made of wood.

Other elements of great interest are its overlooks, which offer panoramic views of the city, such as the Queen’s Dressing Room, originating from the Nasrid period but modified during the Renaissance, and the Lindaraja  or Daraxa Viewpoint, which, in addition to its views, stands out for its sumptuous tiling.

According to data from the Santiago de Compostela Tourist Office, almost 263,000 pilgrims come to the city each year (in jubilee years, that number doubles to half a million). Of these, half are foreigners from across all continents. 85% are European, half of whom are Spanish, from every region, but mainly from Madrid, Andalusia and Catalonia. More than 90% go on foot, with the rest going by bicycle (9.6%, around 25,000 people), on horseback (326 people), and a small number in wheelchairs (71 in 2015). They all get their “compostela” or accreditation, for reaching their goal, which is issued by the Pilgrim’s Office. To get their certificate, pilgrims must travel the last 100 kilometres on foot or horse, or 200 kilometres by bike, and prove their achievement with the stamps that they receive for each stage, the only requirements needed to consider their journey complete.

This journey started in the Middle Ages, when the remains of St. James the Greater were discovered in the 9th century near the city. According to history and legend, this follower of Jesus preached in the land that we now know as Spain –a fact highlighted by scholars such as Beatus de Liébana– and then subsequently travelled to Palestine, where he was martyred, with his remains finally arriving in Galicia at the campus stellae, or field of the stars –whose name comes from the mysterious lights that attracted its discoverers– which, it is believed, gave ‘Compostela’ its name. When the Muslims invaded the peninsula, with the exception of the Kingdom of Asturias, the devotion to the Apostle quickly grew, and he was soon considered the patron saint of Spain.

Together with Rome and Jerusalem, Santiago became a great centre of Christian spirituality. The rise of pilgrimages, journeys with a sense of penance, the atonement for sin, fit with the medieval mindset in which spirituality was present in all areas of daily life. This was also in line with the concept of homo viator, human beings as “pilgrims” in earthly life, in transition to a spiritual and internal life that can only be attained by the cleansing of sin. So much so that forcing prisoners and criminals to go on the Camino de Santiago became a standard sentence in some European courts of the Middle Ages, although the pilgrimage was made by people of all social classes, including nobles, some of whom commissioned others to walk the route on their behalf.

These days the profile of the travellers is much more varied, and ranges from true pilgrims who more than anything are seeking an inner experience, to tourists, adventurers, and curious types, as well as every other possible combination. As a result, although participation in the Camino is free, there are many companies that offer all kinds of services –transport and storage of backpacks, suitcases and bicycles– and tourist packages that, in addition to walking sections, also include guided tours, airport, bus or train transfers, riding on horseback and even donkeys, hotels, gastronomy, etc.

And as was the case centuries ago, the Camino itself is an economic engine and cultural itinerary of the highest order, offering boundless artistic and natural riches. Although, in many cases, the routes leading to Santiago already existed before the discovery of the tomb of the Apostle, they prompted the entry and dissemination of cultural currents from the rest of Europe. After reaching its peak in the 12th and 13th centuries, the Camino went into decline, and it was not until the 1980’s that it started to regain its value, going on to become the huge phenomenon that it is today.

While the “French Route”, which crosses the Pyrenees through Roncesvalles, is the most popular route to reach Compostela from Europe, chosen by more than 66% of the pilgrims, there are more than a dozen routes throughout Spain. Virtually every region has its Jacobean route, many of which were forgotten and have been rediscovered thanks to the work of associations and scholars. In 2015, UNESCO expanded its ‘Heritage of Humanity’ classification, which the French Route had held since 1993, to include four other routes to the north of the country: the Coastal Route; the Inland Route of the Basque Country and La Rioja; the Liébana Route and the Camino Primitivo, which together total 1,500 kilometres.

At the same time, Spanish associations of friends on the Camino de Santiago –34 in total–, have studied, revived, and marked 12,000 kilometres of routes with yellow arrows, throughout Spain since the late 1980s, in addition to recruiting 700 volunteers known as “hospitaleros”, to work in around 40 free hostels, which were referred to in the past as “hospitales”. The pilgrims also have a further 400 places of paid accommodation managed by parishes, municipalities and other entities and institutions.

Four million passengers in 2016: this is the growth forecast for the Rafael Núñez airport in Cartagena de Indias according to SACSA, the concession company. Majority-owned by the Spanish company Aena Internacional, in 2011 SACSA embarked on a project to improve and expand airport facilities, both on ground and in the air, in order to adapt airport capacity to the growing demand. Ineco recently updated the airport’s Master Plan which plans for expansion work until 2020 and has also designed and coordinated construction work (see IT48). Five years ago, work began on passenger terminal building renovations and expansion; work then continued on the design and surveillance of work on the runway, aprons, the perimeter road and the new FBO terminal for general aviation services.

The increase in traffic at the airport is associated with the tourism and industrial activity in this city –located on the coastline of the Caribbean Sea–, whose characteristic, walled historic quarter has been a UNESCO World Heritage Site since 1984. The city stands out as a domestic holiday destination, and although the number of international arrivals has increased, the majority of the city’s air traffic is mainly domestic with connections to the capital, Bogotá, as well as to main cities such as Medellín and Cali. In terms of international flights, top destinations include southern Florida in the United States in addition to Chile, Venezuela and Spain.

In order to drive the tourism sector, the airport operator and local entities such as Corporturismo and the Cartagena City Council are committed to implementing additional long-distance routes both to North America –the city’s main source of outbound tourism– and to Europe –especially to Germany and Spain. Airlines are thus operating larger aircrafts, in turn requiring airports to provide greater capacity as well as increased safety and security –both operational and physical. Since all work must be carried out without interfering with airport operations, Ineco also conducted a study on the different stages of construction in order to minimise the effects as much as possible.

Greater passenger and aircraft capacity

Thus, the construction work that was carried out at Rafael Núñez airport met these requirements: the current terminal building which was expanded from 2011 to 2013 has grown from 10,491 m² to 19,370 m². Expansion of the international hall is currently under way. The runway in addition to the main and secondary (or ECO) aprons were repaved between 2013 and 2014 to repair damaged areas and to increase their load bearing capacity. The axis of the turnaround area was modified to make it easier for large aircrafts to move around, and signalling and traffic guidance equipment was also improved.

With regard to the runway, Ineco designed and coordinated the installation of an asphalt mix that had never before been used in Colombia: a discontinuous, BBTM-11 bituminous mixture (with additional fibres) in a 4-cm screed used on 1,740 metres of the runway’s 2,540 total metres. The asphalt not only improves friction conditions on the wearing surface, but it also facilitates drainage and prevents hydroplaning.

On both aprons, a P-401 bituminous hot mixture with a maximum aggregate size of ¾” was used with a BMIII modified asphalt, with varying thicknesses of 5 to 12 centimetres. The landing gear stop-way was also reinforced with 33-cm concrete slabs. Since there are fewer demands with regard to reinforcements on the perimeter road and pedestrian areas, a MDC-2 bituminous hot mixture with B60/70 asphalt was installed.

General aviation on the rise

In addition to the aforementioned interventions which are of vital importance in terms of aircraft safety, the increase in general aviation traffic was kept in mind. Private and military flights represent more than 90% of traffic at this airport, while the remaining percentage is represented by executive flights, school flights, etc. Although general aviation represents less than 1% of the total passengers who use this airport, it corresponds to 30% of airport operations and is expected to grow an average of 3.9% by 2020, totalling some 26,000 passengers and 14,000 operations.

Therefore, construction work was carried out on a new FBO general aviation terminal in 2014 (Fixed Base Operator, a company from the United States in this case), as agreed upon in the draft that had previously been drawn up by Ineco. The new terminal, located in the eastern part, boasts three different areas: airport authority, border control and entry/exit of passengers and baggage; a surveillance area that covers access areas both to and from air and ground, as well as security checkpoints; and a passenger waiting area.

The project included the construction of a new, stand-alone building with an electrical substation, a hydraulic pump room and a drinking water supply in addition to a handling office. Shared with the secondary apron, a new perimeter road was also constructed with direct access from Vía del Mar, the road that connects Cartagena de Indias with Barranquilla.

The growth forecast predicts that Rafael Núñez airport will see four million passengers in 2016

Ongoing work

Rescue and fire fighting services (RFFS) are fundamental elements when it comes to increasing an airport’s capacity. Aeronautics and airline regulations require that the capacity of these services must be rigorously determined by the size (total length and fuselage width) of the aircrafts that normally operate at the airport. Therefore, airports are categorised on a scale of 0 to 10; Rafael Núñez airport falls into category number 7, meaning that this airport would need a minimum of two fire-fighting vehicles, one fire chief and four firefighters.

Nonetheless, the new facilities designed by Ineco provide for the possibility, also foreseen in the regulations, of increasing these resources if, with prior notification, the airport needed to occasionally accommodate aircrafts corresponding to higher categories. For this reason, airport sheds have space for four vehicles: three fire engines and one light-weight commanding vehicle.

Seeing as this airport operates 24 hours a day, the RFFS requires staff to cover three shifts; thus, the new building has the appropriate facilities for said staff to rest in addition to offices, warehouses, technical areas and a car park. In front of this building there will be a paved clear zone that will allow for aircrafts to transition to the military area. Additionally, there will be two water deposits each containing 30,000 litres of water supply for the fire engines, and said fire engines will also be provided with a new access road, thus facilitating their arrival to the runway in under three minutes. Ineco is overseeing the construction work and is also monitoring compliance with the Operational Safety Plan.

Another ongoing project coordinated and monitored by the company includes the enlargement of the runway safety strip; in some areas, this strip does not meet the required distance of 75 metres between the runway axis and the border of the airport. To meet this requirement, ground is being gained from the area of vegetation by reinforcing it with 5-metre long micropiles.

The renovation work is part of the comprehensive restoration project drawn up by Ineco in 2008 which sought to remedy shortcomings while remaining consistent with the historic character of the architecture. These large, riveted iron structures were built as a result of the Industrial Revolution during the 19th century and are epitomised by the Eiffel tower. Spain lagged a bit behind other cities with regard to the use of iron in architecture and engineering as can be seen in countless examples from Paris, London, Amsterdam, Belgium and Germany in addition to Boston and New York in the United States.

With all of this, transport infrastructure in 19th-century Spain such as stations, bridges and viaducts requiring versatility, luminosity, spaciousness and low prices were easily adapted to the engineering of iron which was best received by engineers of that time period as well as by architects. Examples of riveted iron infrastructures in Spain include the Atocha and Delicias railway stations, the Catalonia Railway Museum, the Valencia railway station and the Aranjuez railway station –the main feature of this article. Furthermore, some quite representative buildings include Sabatini’s Royal Firearms Factory in Toledo and the Geological and Mining Institute of Spain, in addition to bridges and viaducts such as the prominent Triana Bridge.

Spanish transport infrastructure in 19th-century such as stations, bridges and viaducts requiring versatility, luminosity, spaciousness and low prices were easily adapted to the engineering of iron

Aranjuez station is one of the most characteristic vestiges of the industrial age of the 19th century. The earliest railway facilities at Aranjuez were built in 1851 for the line connecting Madrid with Alicante, popularly known back then as the ‘Tren de la Fresa’ (The Strawberry Train) and whose name is now in use once again for tourist services. This station also provides service to the C3 Madrid-Aranjuez commuter rail line. It is the second oldest railway line in Spain (the oldest is the Barcelona-Mataró line, 1943) and is one of the monuments of the Royal Sites of Aranjuez, a Unesco World Heritage Landscape Site since 2001. This line originally reached all the way to the Royal Palace. The original station faced towards the palace on grounds of the company’s prestige and the fact that they needed support from the monarchy. Nevertheless, this location caused so many problems affecting train traffic that it became necessary to build a new station with a completely different layout. The platform marquees are living proof of the iron beams and framework –signs of progress from that time period– that were used to construct public buildings such as stations, markets, factories, libraries and bridges.

The technique of riveting

The steel marquees, roofed by fibre cement and fluted glass, were built around 1851 to provide shelter over the station’s three platforms which were later renovated around 1980 in order to adapt them to the trains and general regulations at that time. As can be observed in the images, the marquees suffered from corrosion problems that affected their structural framework, foundation and ornamentation due to an unsatisfactory roof water drainage system, thus causing damage to the suspended wooden ceiling and corroding the metal. Rehabilitation and restoration of these marquees was a year-long, painstaking process that rediscovered the traditional technique of riveting.

Riveting is the process of joining together several metallic pieces (metal sheets and/or profiles) using rivets. Rivets are elements that are similar to screws –but without the thread– consisting of a cylindrical shaft called a shank or the body, and a head normally shaped like a spherical cap, such as the rivets utilised for the marquees at Aranjuez station. These rivets are manufactured from ductile, malleable and durable metals such as copper, aluminium, some alloys and mild steel, such is the case with the rivets presented herein.

Riveting is the process of joining together several metallic pieces using rivets –elements similar to screws but without the thread- consisting of a cylindrical shaft and a head

To join together metal pieces made from steel, rivets are used –also made from steel– whose quality and characteristics can vary. Holes are drilled just once, piercing through two or more pieces, after having assembled, clamped and tightly screwed said pieces together. Once the holes have been drilled, the pieces are separated from each other in order to eliminate metal scrap, remnants and sharp edges from the surface. The diameter of the holes, save for exceptional cases, is made 1 millimetre larger than the diameter of the body of the rivet. Selecting the length of the body of the rivet is very important: after the rivet is placed in a furnace and uniformly heated to a temperature between 950 and 1,050 ºC in order to allow for its moulding, the riveting process is carried out by introducing the heated rivet into the hole on the pieces which are to be joined together. The body of the rivet should be cast and forged in order to form the shop head of the rivet. This piece must completely fill the hole. To form the shop head, either a riveting machine applying uniform compression is utilised, or a pneumatic hammer with a riveting pin or a bucking bar is used, always held steadily in place. These tools –not the direct strike of a hammer– are used to form the rivet’s second head. Both the furnace and the riveting machine need to be located close to the area where the riveting is to take place so as to avoid significant cooling of the rivet before it is set into place. The pieces that are joined together must lie perfectly flush and tight against each other to ensure a union without bending or warping. Afterwards, the rivet is introduced into the pieces that are being joined together, and the body of the rivet is forged. This process is carried out using a pneumatic hammer and a bucking bar on the spherical head of the rivet.