Projects and achievements
Prefabricated industrial warehouses
They undoubtedly constitute another of Fernández Casado's great achievements. Since the shortage of steel penalized the designs of metal trusses "Lattice (engineering)") after the Civil War, Fernández Casado developed with the company Huarte y Cía. prefabricated concrete solutions, some of them innovative and genuine, as an alternative that allowed the constructive advantages of steel construction to be reaped without having to use it. Furthermore, this industrialization and construction optimization fit very well into its engineering approach.
Within these realizations we can distinguish the cylindrical "Roof (construction)" roofs (Ensidesa warehouses in Avilés, 1952), the roof of the Madrid trolleybus warehouse (tri-articulated arches for 42 m spans, 1951), the Española del Zinc warehouses (1952), the Sociedad Ibérica del Nitrogen in La Felguera (1952) and the straight two-sided roofs. waters "Cover (construction)") or in sawtooth resolved with "Lattice (engineering)" trusses or porticos (ship for INTA assembly in Torrejón de Ardoz, 1946), Ensidesa lamination warehouse (1956) and the Intelhorce warehouses (1962).
Strict height bridges
One of Fernández Casado's first activities in the world of bridges was the study of solutions for common crossings required by roads in Spanish geography, especially in the Mediterranean area: wide channels or boulevards with great variability in flow, crossings very close to the ground to minimally raise the grade, crossings of streets or over the railway, etc. Although the strict name of the collection's title refers to the objective of minimizing the height of the bridge, probably the most significant thing is what it also represents a declaration of principles by its author: strict use of materials - as should correspond to an engineering activity -, formal minimalism - collecting the postulates of architectural rationalism - and minimal impact on the landscape - postulates that are decades ahead of the concerns of the Environmental Movement. For all this, the set of bridges in the collection, some of them not directly made by Fernández Casado, exemplifies his work and probably constitutes one of the best achievements of said engineer, if not the best.
On his own initiative he carried out a study - in a systematic and general way as he usually approached his work - of solutions for straight linteled sections of reinforced concrete, some hyperstatic, which were the solutions that were emerging at that time in Europe. He ordered them in a set of 10 series with the aim that they could be used by other non-specialist engineers.
The first four corresponded to portico solutions with one or three spans. From V to In several versions with more than three spans, the solution was repeated or combined with other models.
The cross sections are slab type in the odd collections and beam type in the even ones. The maximum spans covered by the first were 12 m and 20 in the second, later extended to 30 m.
The lintels are paneled up to the light room. This geometry is one of the distinctive features of Fernández Casado's designs, which he preferably used over curved variable edge solutions until the appearance of prestressed concrete, and which gives these works the formal cleanliness and the slender and serene appearance that is characteristic of the aesthetic approach of its author.
Several of the series were officially approved by the Ministry or used by other engineers in very diverse works throughout Spain. More than 50 of these structures were built, although the shortage of steel after the Civil War undoubtedly prevented greater use. Notable works within this group are the New Iron Bridge over the Manzanares River in Madrid (1932), the most beloved by Fernández Casado although it was never put into use, the Siles Bridge "Siles (Jaén)") over the Guadalimar River (1934), the El Pardo Bridge "El Pardo (Madrid)") over the Manzanares River (1935, demolished after the war), bridge over the river Guadalfeo in Salobreña (1944), San Ardyan bridge over the Besós river (1944), bridge over the Palmones river in Algeciras (1954).
arch bridges
Although his constructions are usually identified with lintel solutions, Fernández Casado also intensely studied the arch solution and used it in at least 15 bridges in addition to many unrealized projects. The result of his theoretical studies is another of his most widespread books, Calculus of Arcs.
In order to avoid the construction of the expensive formwork usually used in the construction of arches, he explored the possibilities provided by the prefabrication that he had already experimented with on the roofs. Due to the low power of the machinery available, to reduce the weight of the pieces he frequently used the solution of dividing the work into two or more knives.
Within these realizations several configurations were used:
During the postwar period, given the shortage of steel, mass concrete arches or arches with little reinforcement were used with some frequency, a solution that Fernández Casado called “anachronistic arches.” With this solution he carried out various works, including the bridge over the Tagus River in Fuentidueña de Tajo (Madrid) (1957, maximum span 32 m), bridge in Torquemada "Torquemada (Palencia)") over the Pisuerga River (1952/1960, maximum span 40 m) and bridge in Gibraleón over the Odiel River (1956, maximum span 34 m).
He used the thin arch and rigid deck solution in several aqueducts, where it is very suitable due to its uniform and constant load and in which the conduction box is used as a rigid lintel. The first constructions were two aqueducts for the Retorna waterfall, over the Najerilla river (1944) and over the Brieva ravine (1944), built with the Melán-Ribera rigid reinforcement technique. He later built the Cubillas reservoir aqueduct (1954) with prefabricated arches and the Gabriel y Galán Reservoir aqueduct over the Alagón River (1969) with a Maillart-type solution built on falsework with auxiliary metal arches.
This solution formally attracted him greatly although he only used it in two works, the bridge over the spillway of the Cubillas reservoir (1954), one of his most beloved creations, and over the Caudal river in Mieres (1969) carried out with his project office. To build them, he also used thin prefabricated knives mounted on an auxiliary central frame, on which the diaphragms and the upper slab were later made.
Buildings and roofs
Fernández Casado designed numerous building structures, mostly reinforced concrete works mostly resolved with reticular frameworks, in whose calculation he used the Cross method that he had developed. He also explored the possibilities of slabs on continuous supports on pillars with capitals ("mushroom slabs"), which he also used in some of his strict height bridges.
Most of these works were carried out for the company Huarte y Cía., in the post-war period, such as the Health Residences in Zaragoza, Barcelona, Gerona and Lérida (1946/1956), the Ministry of Air in Madrid (1948) by the architect Luis Gutiérrez Soto.
With the architects Muñoz Monasterio and Luis Alemany, he won the competition to build Real Madrid's new Chamartín stadium, current Santiago Bernabéu stadium, in 1947 with a variant construction solution with a reinforced concrete structure with new elements at the time. In 1955 he expanded the east stand, an excellent and light structure that has been visible until the last intervention carried out in the stadium in 2005 where an enclosure was installed.
With the architects José Antonio Domínguez Salazar, Ricardo Magdalena and Carlos de Miguel, he won the competition for the San Mamés stadium "San Mamés Stadium (1913)") in Bilbao, where he designed its famous roof, which was initially solved with concrete but was changed to its recognizable metal arch - one of his few works designed with this material - which still remains a distinctive element of the city.
With Huarte y Cía., and with his project company, he participated in the projects of some of the first tall buildings carried out during the 1960s and 1970s in Spain, such as the Torres Blancas by Francisco Javier Sáenz de Oiza and the Torres Colón by Antonio Lamela, both developed by Javier Manterola.
He did not lavish much on the lamellar roofs that were so widespread and successful among his contemporaries between the years 1930 and 1960 of the last century, probably because his approaches and interests fit better in lintel or reticular constructions. Although he studied some other projects, his only creations of this type are the cylindrical sheet roofs of the Barcelona Professional Training School (1962) and the HYTASA warehouses in Seville (1962).
He also carried out two works with hanging roofs, the INI pavilion at the Madrid Country Fair (1953) and the prestressed roof of the riding arena at the Villa de Madrid Country Club (1968) with the architect Domínguez Salazar.
Prestressed concrete bridges
At more than 50 years old, Fernández Casado embarked on the study of prestressed concrete, which already dominated construction in Europe in the second half of the century but which arrived late in Spain, to the certain disquiet of Fernández Casado himself,[2][4] as a consequence of its isolation since the end of the Civil War, which only accentuated the country's secular technical backwardness.
He was one of the main introducers and disseminators of this technique in Spain, and his two volumes of the book Reinforced and Prestressed Concrete Bridges were an obligatory reference in the country and in numerous Latin American countries, where his figure is still remembered for this reason.
His first contact with prestressing was not in bridges but in decks, using it in the triangulated beams of the Ensidesa rolling mills in Avilés in 1957.
Later with Huarte y Cía. won a competition for the reconstruction of bridges in Cuba in 1960, of which three were built, using prefabricated beam solutions with spans of up to 30 m.
In Spain, the first bridge he built was the bridge over the Río Tinto in Huelva, a deck of three spans of 30 m prestressed beams made by the company Entrecanales y Távora in 1960.
Another of his first works with prefabricated prestressed beams is the access pontoon to the Soto de Ribera Thermal Power Plant in Asturias, which was built by subdividing the beams into segments[13].
Fernández Casado's great contribution to the technique of bridges built by cantilever advancement - which he contributed decisively to introducing in Spain and some Latin American countries - was the development of construction with prefabricated voussoirs, taking advantage of the experience acquired in the projects of arches and prefabricated naves. To achieve this, he used an innovative solution with small, light voussoirs - the only ones possible to handle with the means of the time - so the panels were normally double. Its first applications coincide with the first works carried out in the world with this procedure that were carried out in the USSR. This technique was later widely used by French engineers in their achievements in the 1960s and 1970s.
His first work was the Almodóvar del Río bridge over the Guadalquivir with a span of 70 m, a pioneering work on a world scale in this type of construction. Given the success, he used it again in four other projects already developed within his project office with his collaborators: the Castejón bridge "Castejón (Navarra)") over the Ebro river in Navarra (1966/1968) with 101 m of span, Iznájar viaduct (1965), over the Guadalquivir basin in Seville (1972) and the Vados bridge over the Genil river in Granada. With the cantilever advance solution but with in-situ execution with an advance carriage, he also designed the bridge over the Priego ravine in the Iznájar reservoir (1970).
Dams
Although he studied and designed various vault dams, those with the greatest structural complexity, he only carried out the Retorna waterfall on the Najerilla River before the founding of his project office.
With his project office he built the Quéntar dam on the Genil River in Granada, 140 m high, and although other projects were competed for, they were not won and this line of work was finally abandoned.
Rehabilitation and reinforcement of historic buildings
Another of Fernández Casado's great interests was the study and conservation of historical heritage, both architectural and public works, the latter at a time when they were not usually considered worthy of any protection.
In his activity at the Bridge Headquarters of the Ministry of Public Works, he had the opportunity to direct or participate in numerous projects to reinforce or repair factory bridges such as the Orense Stone Bridge over the Miño River (1966) or the Simancas Bridge over the Pisuerga River (1967). He actively collaborated in the 1974 repair of the Segovia aqueduct, in which this notable Roman construction was reinforced with injections and bolts.
With his project office he collaborated in the repair and consolidation projects of other structures such as the Zaragoza Stone Bridge over the Ebro River (1980).
Cross of the Valley of the Fallen
The structure was calculated by Carlos Fernández Casado together with the engineer Ignacio Vivanco Bergamín and executed by Huarte y Cia, for which they worked at that time.