This PhD research will analyse the wind-structure interactions for membrane constructions and will assess their behaviour under wind loading, by numerically and experimentally determining and studying pressure coefficients (Cp-values) on the surface of doubly curved membrane constructions. The new knowledge will allow elaborating new insights that could contribute to new guidelines and the development of new innovative membrane structures.

Since the design and the application of tensile membrane structures developed fairly recently, a lot of expertise and research still has to be performed. Especially in the field of wind analysis accurate wind load determination has to be examined. Compared to conventional building typologies, these structures tend to be extremely vulnerable to wind because of the low self-weight-to-load-ratio. In general, conventional codes on wind design give upper bound values for the majority of structures, but the level of uncertainties increases as the building configuration deviates from the codified norms.

This master thesis forms an initial step in the experimental wind tunnel analysis on tensile membrane structures, and especially for the wind loading on hyperbolic paraboloid roof and canopy structures. The thesis is composed of 3 main parts. The first part illustrates the current Eurocode procedure for determining the wind loads on common building geometries. The key concepts for basic wind design are introduced according to the chronological calculation steps and evaluated for membrane canopy structures. The pressure coefficient distributions are discussed for flat and duo-pitch roofs and canopies, in order to evaluate the fabrication techniques of the models, validate the accuracy and precision of the measurements and to create a reference-testing field for the research on hyperbolic paraboloid roof structures. The second part focuses on the research for appropriate modelling and wind tunnel testing procedures for double curved canopy structures. A feasibility study on production process and material is performed based on most important model requirements and directories, among them the simultaneous pressure measurement on the upper and lower face of very thin roof structures. Three thin- shelled rigid roof structures are fabricated, i.e. a flat roof, a duo-pitch roof and a hypar roof, all equipped with removable walls to investigate the wind load on building roofs and open canopies. The third part displays the outcome of the experimental wind tunnel analysis. Wind tunnel testing is used in a first stage for validation of conventional building typologies in accordance to relevant codes and literature, and in a second stage for fundamental research of data on new membrane typologies. The recorded wind tunnel data is processed and evaluated for each test case. The models are tested under continuous rotation and for discrete angles of attack, as part of enclosed building envelope and as an open canopy itself. The rotation sequence is used to evaluate the wind pressure variation in function of the orientation, to define the most critic building orientations, and to assess the pressure alteration on the upper face of the roof for the open and enclosed state. The obtained pressure coefficient distributions for different angles of attack are visualised in charts and compared to EC1 – part 1.4 for flat and duo- pitch roofs and canopies, and to ‘Das Hängende Dach’, (Otto, 1954) for the hypar roof. Finally, the distributions for the hypar roof and canopy could be used for calculating wind loads on equivalent structures, and could form a basis for extensive research for the Eurocode on membrane structures.