Cobertura de la trinchera ferroviaria de Hendaya

Un problema del ferrocarril al paso por las ciudades europeas es el efecto barrera generado, que impide su desarrollo más allá de las vías. Si se salta la barrera lo cierto es que ello se hace sólo en sitios concretos y el efecto psicológico de aislamiento persiste para los habitantes del entorno. Este trabajo presenta de manera sucinta los problemas de concepción, comprobación y vibraciones planteados por la estructura de cubierta de la trinchera ferroviaria de Hendaya, consistente en una losa de hormigón pretensado y luz variable de 20-40 metros, que resuelve el problema de aislamiento entre las dos partes de la ciudad. Su construcción ha sido posible gracias al acuerdo entre la SNCF e inversores privados y está permitiendo la construcción sobre ella de 6 edificios de viviendas y una residencia de turismo, la demolición del antiguo ?Pont-Vieux? y la construcción de un nuevo ?Pont-Vieux?, integrado completamente en la promoción inmobiliaria. An important problem put by the train in its passage by the cities of Europe generally and in France in particular is the effect barrier which builds up, preventing the cities from developing beyond. Even if this barrier is crossed, it is certain that the passage is restricted to concrete places and always acts as psychological barrier for the local residents. This article presents in a brief way the problems of conception, analysis and vibration of the cover structure of the railroad trench of Hendaye. This structure consists of a 20-40 meters span slab of pre-stressed concrete that solves the isolation problem of both parts of the town of Hendaye. Its construction was possible thanks to the agreement of the SNCF (French Railways)and some private investors, and is allowing the investors the construction on top of 6 residential buildings and a holiday residence, with demolition of the ancient “Pont-Vieux” and building of a new “Pont-Vieux”, which is completely integrated into the real-estate development. Special attention is given to the change of transverse cross-section of the slab during construction stages, which originates a redistribution of stresses, and to the long-term equilibrium of horizontal forces

Monitoring of Zarzuela Racecourse structure by means of no-destructive techniques for durability assessment.

Present paper describes some aspects of the restoration project recently undertaken in La Zarzuela Racecourse, designed by E. Torroja and Dominguez in 1934. Despite the good mechanical work of steel, it has started a deterioration process which has caused the corrosion of reinforcement by carbonation. It has been detected corrosion attack in some places due the breaking of the upper waterproofing membrane of the shell which enabled the water to remain long periods in the roof and therefore promoted corrosion of reinforcement. For the repair first an assessment of the degree of corrosion was made. The restoration project finally consisted in the injection of all the cracks in order to assure the joint work of the shell and the patching of the deteriorated zones. Profiting these works it was installed a monitoring system of corrosion sensors. Results of the recording are given in the paper

El patrimonio histórico de las obras públicas y su conservación: los puentes

There exists in Spain an important civil works historical patrimony to which attention has to be paid. &#13; Until the end of XVIII century the only technology to build durable bridges was the stone arch. In our century traffic necessities and technologies in bridge construction have changed significantly. This fact implies a change in mind about historical bridges and a decision between one of these possibilites: &#13; a)An adaptation to new necessities with a substantial transformation of the bridge even in its formal characteristics.&#13; b)A substitution by means of a new bridge. The old bridge looses its function and is abandoned until final destruction.&#13; The object of this paper is to study both options and problems which arise from them.<br><br>Existe en España un importante patrimonio histórico de obras públicas al que debe darse la debida atención en este aspecto.&#13; Hasta finales del siglo XVIII la única técnica utilizada para hacer puentes durables era la de arcos de piedra. En nuestro siglo las exigencias del tráfico y las técnicas de construcción de puentes han variado radicalmente. Ello supone una variación de actitud respecto de los puentes históricos y obliga a optar por una de estas dos posibilidades:&#13; a)Adaptarlos a las necesidades actuales del tráfico, lo que supone una transformación sustancial del puente con fuerte deterioro de sus cualidades formales.&#13; b)Sustituirlos por un nuevo puente. El puente antiguo se queda sin función y, por tanto, pierde su carácter de obra de ingeniería. En general se abandona totalmente, deteriorándose hasta su hundimiento.&#13; El estudio de estas opciones y de los problemas que se plantean en estos puentes es la intención fundamental del presente artículo