[1] Univ Politecn Madrid, Dept Ingn Civil Construct, ETS Ingn Caminos Canales & Puertos, C Prof Aranguren S-N, Madrid 28040, Spain
[2] Torroja Ingn, C Pedro de Valdivia 36,L20, Madrid 28006, Spain
[3] Univ Politecn Madrid, ETS Ingn Caminos Canales & Puertos, Dept Mecan Medios Continuos & Teoria Estructuras, C Prof Aranguren S-N, Madrid 28040, Spain