Reliability-based analysis of tensile surface structures designed using partial factors

The design of tensile surface structures is based on expert judgement. A standardized design approach as for traditional buildings is not yet available for tensile surface structures. To achieve a partial factor framework similar to that for traditional buildings (i.e. within the frame of the Eurocodes), research into structural reliability calculations for tensile surface structures is needed. This paper studies a hyperbolic paraboloid cable-net structure. The structure is designed using partial factors of which the partial factor for the material is investigated in more detail. Therefore, the cable-net is designed according to three material safety factors: 1.2, 1.5 and 2.0 and the reliability index is calculated for the catenary and arching cables for each structure subjected to either snow or wind load. As expected, an increase of the material safety factor results in an increase of the reliability index. If the structure is designed according to the Eurocode for a consequence class 2 and a 50 year reference period (material safety factor: 1.5, EN 1993-1-11) the reliability index of the cable-net proves to be 7.36 which is almost twice as high as the target reliability index 3.8 suggested by the Eurocode for the reliability based design