NOTES ON FOUNDATIONS AND STRUCTURES IN RAILWAY DWELLINGS BUILT BETWEEN 1949-1989 (II)

At the end of the 1950s, with the development of capitalism, there was an unimaginable growth of large cities and therefore the need to generate mass housing. The 1960s was the decade of housing estates inspired by the most perverse functionalism, works carried out by the Ministry of Housing, by the Obra Sindical del Hogar (OSH) or subsidised housing such as that of the railway workers, which had no other aim than to provide cheap accommodation for the labour force that was arriving in the cities in waves (Grau, 1993). In the case of railway housing, this second period, 1965-1989, is characterised by workers’ cooperatives as the promoters of their housing.

Unlike the first period analysed in a previous entry, the substantial socio-economic change occurring in this second period gives importance to regulations, especially those of an urban planning nature and to the design and quality of social housing, as the only limit to speculation, and, although we can detect evolution with respect to the regulations existing in the previous period, their drafting is far removed from the theoretical studies of sociologists and architects, being basically driven by two motors: Increases in the social pressure of the user and the demand of capital for higher and higher capital gains. The result is poor, rigid and unimaginative regulations which, on a technical level, encourage the repetition of design solutions and, therefore, of construction solutions which become standards where cost and profitability are the basic premises (Paricio Ansuátegui, 1973).

With regard to technical regulations, the approval of the MV 101/1962 standard “Actions in building construction” put an end to the restrictions on the use of iron approved by the Decree of 11 March 1941 and this led to the substitution of reinforced concrete, in lattice structures, as the most widely used structural material to the detriment of brick, in load-bearing walls, which had been widespread in the previous period (Martínez-Corral & Cuéllar, 2020).

Thus, from the cooperative projects consulted to date, with regard to foundations, mainly surface foundation systems are used, consisting of isolated concrete footings with a grid on their lower face, in many cases without bracing or, in the best of cases, with perimeter bracing. It was usual to use footings with a trapezoidal section (Illustration 1). The 81 dwellings in General Salazar street, Bilbao, built by the Amézola railway cooperative in 1967, are one of the few cases with basements analysed to date. In special cases, given the characteristics of the supporting terrain, special foundations based on pile foundations are used, as in the case of the 226 dwellings in the south-west settlement of the Besós, built by the Barcelona Tramway employees’ cooperative in 1963.

Illustration 1. Detail of the footing in the 120 dwellings project of the “Sagrado Corazón de Jesús y Ntra. Señora de la Bien Aparecida” housing cooperative in the Cajo Sixto Obrador neighbourhood in Santander.

Source: Municipal Archive of Santander, ref. LL-1132 (1967).

The structures are, in most of the cases analysed, based on rectangular or square section columns and usual dimensions of 35 x 35 m, and reinforced concrete hanging beams, which implies less need for steel. The three phases of the houses built by the railway cooperative of “Nuestra Señora de Alarcos y San Rafael Arcángel”, in the district of Pío XII, in Ciudad Real, whose projects date from 1957 to 1960, opt for load-bearing walls based on solid brick masonry, reaching four storeys in height. Regarding the reinforcement, the specifications prescribed cold bending, tying by means of wire or concrete block and overlaps with lengths greater than 30 cm, welding the connecting wires between bars. The overlaps were of one diameter, admitting errors of half a diameter. We must point out that these minimum coverings, – think of the use of 8-10 bars-, are unacceptable nowadays and are one of the main causes of common pathologies in reinforced concrete elements in this type of housing.

Until 1961, plain steel bars were used in reinforced elements, and from that year onwards, corrugated steel reinforcement began to be marketed in Spain, with the resulting improvement in adhesion to concrete. In 1962, the Tetracero brand began to be marketed, which was the best known (Azpilicueta Astarloa, 2004). In the case of the stair platforms, the vault with 2 or 3 brick threads was replaced by inclined reinforced concrete slabs. In none of the cases studied are structural solutions based on standardised steel profiles used, although they had been frequently employed until 1936 (Lahuerta, 1965).

As for the floor slabs, in the cooperative projects analysed so far, there has been a change to one-way floor slabs made up of prefabricated type I joists instead of the in situ ribs that had been massively used until then in the so-called autarkic floor slabs. Specifically, “Castilla” joists, a company founded at that time by the civil engineer José Cámara Rica, is the one prescribed in all the projects analysed so far. For example, the detail of the slab used in the construction of the first phase of 104 dwellings of the Ciudad Real “Nuestra Señora de Alarcos y San Rafael Arcángel” cooperative has a slab depth of 18 cm, without detailing the upper slab of the slab, and where the joists are made with double threaded beams. The inner part of the slab is made flat by means of a single brick revolt, and the top surface is levelled by filling the gaps with concrete (Illustration 2).

Illustration 2. Section of the “Castilla” joist floor slab, in the project for the first phase of the Nuestra Sra. de Alarcos and San Rafael Arcángel railway cooperative housing in the Pío XII neighbourhood of Ciudad Real.

Source: AMF, project CR-5031-RL (1958).

Bibliography:

Azpilicueta Astarloa, E. (2004). La construcción de la arquitectura de postguerra en España (1939-1962) [Phd, E.T.S. Arquitectura (UPM)]. http://oa.upm.es/23197/

Grau, C. (1993). La Vivienda En España: 1970-1990. Universidad Politécnica de Valencia.

Lahuerta, J. (1965). Situación actual de la edificación en España. Arquitectura, 79, 43-50.

Martínez-Corral, A., & Cuéllar, D. (2020). Las soluciones constructivas en la vivienda durante el franquismo: El caso de la vivienda ferroviaria. Informes de la Construcción, Vol. 72, 558, e341, abril-junio 2020. https://doi.org/10.3989/ic.71047

Paricio Ansuátegui, I. (1973). Las razones de la forma en la vivienda masiva. Cuadernos de arquitectura y urbanismo, 96, 2-18.


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