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Wind-Structure Interactions of Tensile Surface Structures
Training School COST Action TU1303
EUROMEM: From Uncertainties to Partial Safety factors Calibration
Nantes, 28 September – 01 October, 2015
Jimmy Colliers
Reliability of wind design for tensile surface structures
• SLS and ULS
• Collapses
Wind Structure Interactions of Tensile Surface Structures
Research Questions in Literature
Complex influence of wind loading on the structural behaviour: organic shapes, low self-weight, flexibility…
• The structural typology of membrane architecture is ignored by building regulations, even no information is
provided about preliminary design or about wind loads. Detailed investigations on the complex aerodynamic
behaviour of double curved structures are required. (Rizzo et al., 2011; Rizzo et al., 2012)
• The design wind force coefficients are influenced by the supporting system, the load conditions, the load paths,
the roof stiffness, the shape and the deformations of membrane structures. (Nagai et al., 2010) (Takeda et al., 2014)
• The wind induced response of a membrane structure as a result of the wind-structure cannot be accounted by
conventional analysis methods. Importance of aerodynamic damping and added mass should be further
investigated. (Sun et al., 2008; Xuanyi et al., 2013)
…
State of the Art document – Literature Review
Limited representative research
• Hyperbolic paraboloid roofs
(Otto, 1954; Rizzo et al., 2011; Rizzo et al., 2012)
• Conical or Horn shaped roofs
(Burton and Gosling, 2003; Elnokaly et al., 2004; Nagai et al., 2012, 2011, 2010)
• Specific case studies
(Baglin, 2002; Balz et al., 2004; Carradine, 1998; Michalski et al., 2004)
State of the Art document – Literature Review
State of the Art document – Literature Review
Approaches in Wind Design
Wind Loads (Cp-values) + Structural Finite Elements (FEA)
• Approximations based on Conventional Standards (Eurocode)
• Boundary Layer Wind Tunnel testing
• Computational Fluid dynamics
Appropriate wind pressure data is essential to provide confidence in the analysis and design process
Approximations based on Conventional Standards + Structural Finite Elements
• Pressure coefficient distributions of conventional building typologies
• No information about double curved surfaces
• Nature of textiles not considered
Conventional Standards are insufficient for tensile surface structures, dynamics actions, flexible deformations
State of the Art document – Literature Review
NBN EN 1991-1-4:2005 (BIN., 2005)
Design (Jan Roekens)
• Low-tech disaster shelter
S(p)eedkits – Clever Roof
Design (Jan Roekens)
• Low-tech disaster shelter
• Flat tarp of highly stretchable membrane (4m x 6m)
• Slightly anticlastic configuration
S(p)eedkits – Clever Roof
Wind Loading
• Static calculations (EASY) SLS and ULS
• EN 1991 – 1 – 4: Duo-pitch canopy
• Simple overall force coefficients
• Extensive pressure coefficient distribution
S(p)eedkits – Clever Roof
Wind Loading
• Longitudinal wind down (symmetric loading)
• Longitudinal wind up (symmetric loading)
S(p)eedkits – Clever Roof
Unloaded equilibrium state
Wind Loading: Simple force coefficients
Wind loading: Extensive pressure coefficient distribution
Wind Tunnel Testing + Structural Finite Elements
• Direct pressure measurements by pressure scanner (rigid models)
• Reaction measurements by load cell (rigid or aeroelastic models)
• Deformation measurements by optical sensors (aeroelastic models)
Wind Tunnel testing is complex and expensive
State of the Art document – Literature Review
a. Pressure scanner b. Load cell c. Optical sensors
Rigid models Rigid or Aero-elastic models Aero-elastic models
Three main wind analysis approaches on membrane structures (Nagai et al., 2011)
Computational Fluid Dynamics + Computational Structural Dynamics
• Multi-field problem
• Partitioned approach with reference updating strategy (Sun et al., 2012; Kupzok, 2009; Wüchner, 2006)
• CFD module: Incompressible Reynonds Average Navier Stokes (RANS) + Large Eddy Simulations (LES)
• CSD module: geometrically nonlinear elastodynamics
• Coupling module: Mesh-based parallel Code Coupling Interface (MpCCI)
Computational Fluid dynamics is sceptical approached
State of the Art document – Literature Review
Reliability of wind design for tensile surface structures
• How accurate is wind design while applying wind load estimations based on rough approximations referring to
conventional building typologies from existing codes?
• To which extend are we designing safe structures by relying on the conservative static approach and ignoring
the fluid-structure interaction due to flexibility of the structure?
Accurate wind load analysis has to be investigated, development of Eurocode Section
State of the Art document – Literature Review
Collating wind data for the basic shapes of tensioned membrane structures
• Launched: January 2015
CEN/TC 250; COST Action TU1303; TensiNews 28
• 5 subscriptions (4 BLWT – 1 CFD)
• Some relevant literature
• Closing deadline: September 2015
Analysis and dissemination of results
ROUND ROBIN exercise III
Data Forms
• Form 1: Test Setup
• Form 2: Model specifications
• Form 3: Wind data measurements
ROUND ROBIN exercise III
Wind tunnel test on a hypar canopy (Colliers, 2014)
Wind-Structure Interactions of Tensile Surface Structures
Behaviour under wind loading by numerically and experimentally studying pressure coefficients (Cp-values)
• WP1: Rigid flat and duo-pitch roof structures (EC1 – part 1.4)
• WP2: Rigid hyperbolic paraboloid roof structures (shape dependency of Cp values)
• WP3: Flexible hyperbolic paraboloid roof structures (materials and pre-tension)
• WP4: Hyperbolic paraboloid membrane structure (integrated numerical simulation)
• WP5: Evaluate the accuracy of the current approach in design
FWO mandate – PhD Thesis