Widespan Membrane Roof Structures:Design Assisted by Experimental Analysis M.Majowieckil IUAV Facolta di Architectura University of Venice,ITALY majo@mail.asianet.it Summary.Wide span structures are today widely applied for sport,social,indus- trial,ecological and other activities.The erperience collected in last decades identified structural typologies as space structures,cable structures,membrane structures and new-under tension-efficient materials which combination deals with lightweight structural systems,as the state of art on long span structural design.In order to increase the reliability assessment of wide span structural systems a knowledge based synthetical conceptual design approach is recommended.Theoretical and erperimen- tal in scale analysis,combined with a monitoring control of the subsequent perfor- mance of the structural system,can calibrate mathematical modelling and evaluate long term sufficiency of design. Key words:Wide span structures,snow and wind loading,experimental analysis, reliability 1 Introduction Considering the statistical results of [1],the unusual typologies,new materials and the "scale effect"of long span structures,several special design aspects arise as: the snow distribution and accumulations on large covering areas in function of statistically correlated wind direction and intensity; the wind pressure distribution on large areas considering theoretical and exper- imental correlated power spectral densities or time histories; rigid and aeroelastic response of large structures under the action of cross- correlated random wind action considering static,quasi-static and resonant con- tributions; the time dependent effect of coactive indirect actions as pre-stressing,short and long term creeping and temperature effects; the local and global structural instability; the non linear geometric and material behaviour; reliability and safety factors of new hi-tech composite materials; 173 E.Onate and B.Kroplin (eds.).Textile Composites and Inflatable Structures,173-194. 2005 Springer.Printed in the Netherlands.Widespan Membrane Roof Structures: Design Assisted by Experimental Analysis M. Majowiecki 1 IUAV Facolt`a di Architectura ` University of Venice, ITALY majo@mail.asianet.it Summary. Wide span structures are today widely applied for sport, social, indus￾trial, ecological and other activities. The experience collected in last decades identified structural typologies as space structures, cable structures, membrane structures and new - under tension - efficient materials which combination deals with lightweight structural systems, as the state of art on long span structural design. In order to increase the reliability assessment of wide span structural systems a knowledge based synthetical conceptual design approach is recommended. Theoretical and experimen￾tal in scale analysis, combined with a monitoring control of the subsequent perfor￾mance of the structural system, can calibrate mathematical modelling and evaluate long term sufficiency of design. Key words: Wide span structures , snow and wind loading, experimental analysis, reliability 1 Introduction Considering the statistical results of [1], the unusual typologies, new materials and the “scale effect” of long span structures, several special design aspects arise as: - the snow distribution and accumulations on large covering areas in function of statistically correlated wind direction and intensity; - the wind pressure distribution on large areas considering theoretical and exper￾imental correlated power spectral densities or time histories; - rigid and aeroelastic response of large structures under the action of cross￾correlated random wind action considering static, quasi-static and resonant con￾tributions; - the time dependent effect of coactive indirect actions as pre-stressing, short and long term creeping and temperature effects; - the local and global structural instability; - the non linear geometric and material behaviour; - reliability and safety factors of new hi-tech composite materials; 173 E. Oñate and B. Kröplin (eds.), Textile Composites and Inflatable Structures, 173–194. © 2005 Springer. Printed in the Netherlands