11:00-12:00 – DESIGN CODES, STANDARDS & GUIDES – LOADING - SPEAKER ALAN WHITE 

Temporary Structures – Structural Loading

This part of the seminar will be a presentation of :AWD Alan Malachy EuanLoading to the various codes
Member and material capacities
Software simulation
Effects of Overloading

There are 5 different methods given in codes and guides for the calculation of the wind loading on a structure.

(Rudi's comment: This is an area which has been highlighted at the seminar asneeding action. For engineers the situation is simple, we work to the latest codes and guidance).

Slide 4
CP3 Chapter V Part 2 : 1972
BS 6399 Part 2 1997
BS EN 1991-1-4: 2005
BS EN 13782 2005 Temporary structures –Tents
IStructE Guide Temporary Demountable Structures

Slide 5
The site I am examining in this example is Balado in Fife in Scotland  as shown on the map. It is the location of T-in-the-Park. The results from the design codes will be compared for a 10m high structure.

Slide 6
BS 6399 Part 2 1997
This is a suggested method in the IStructE guide for structures that were fabricated after 2001
At Balado in Fife in the wind Speed is 23m/s. It is not comparable with CP3

Slide 7
Explain the issues of older structures and how they fit in with the new regulations and guidance. Explain the difference between the old BS6399 and new codes. Explain the changes in loading With the introduction of the European Standard BSEN 13782:2005, Temporary Structures – Tents – Safety, and the ISTRUCTE Temporary Demountable Structures, Guidance on Procurement, Design and Use, 3rd edition, the ever growing numbers of multi thousand capacity tents at events, and ever larger stages, this seminar becomes even more vital to understand that guidance.

Slide 8
BS EN 1991-1-4: 2005
This is the current standard for the design of wind loads
At Balado in Fife the wind speed is 24.5m/s

Slide 9
BS EN 13782: 2005
This is also a suggested method in the IStructE guide. It is a design code specifically for the design of Tents but in the scope it states: "The field of application of this European Standard covers all kind of temporary covered structures."
This suggests a reference wind speed of 28m/s for design and a wind pressure of 0.6kN/m2 for a 10m high structure.

Slide 10
IStructE Guide Temporary Demountable Structures.
This is the design method in the IStructE guide for tents and marquees following the MUTA method.
This suggests using the BS 6399 wind speed with a single variable.

Slide 11
Wind speeds and pressures comparison

Slide 12
Wind coefficients
The pressure that is applied to a surface by the wind depends on:
Wind speed
Wind direction
Slope of surface.
Area of surface
The pressure is calculated using coefficients of pressure Cp

Slide 13
Wind coefficients
The coefficients of pressure Cp have been derived in NDN Membrane for elements depending on the angle of the wind and the slope of the surface of the element

Slide 14
Wind coefficients

Slide 15
Snow and Access Loads

Slide 16
Snow and access loads
The application of snow loads to a temporary demountable structure is a subject open to a lot of debate.
Will snow lie or build up?
Is the structure heated?
If men are used to brush snow off structure, what load should be applied?

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