Technical information EL RANCHO snow construction

Technical information EL RANCHO snow construction

1.

Introduction

In this memo the maximum wind and snow load are calculated at which the strenght and stability are sufficient for the construction of an EL RANCHO

2.

Assumptions

2.1.

Description

The EL RANCHO consists of an inner and outer tent which is tensioned in a frame of circular wooden beams and steel connection elements.

2.2.

Geometry

2.3.

Materials and cross sections

2.3.1

Innertent:

• Material
  Tencate solair
• Type
  VA-46
• Weight
  420 g/m2
• Tensile strenght [N/5cm]
  1600/1200 (ketting/inslag)

2.3.2

Outertent:

• Material
  Heytex
• Type
  5671
• Weight
  650 g/m2
• Tensile strenght [N/5cm]
  2500/2500 (ketting/inslag)

2.3.3

Beams:

• Material
  rondhout
• Class
  C24
• Diameter
  ⌀100mm

2.4.

Applied codes and standards

The following Eurocodes are applied:

• • NEN-EN 133782
  • NEN-EN 1990
  • NEN-EN 1991-1-4
  • NEN-EN 1991-1-3
  • NEN-EN 1991-1-1
• Temporary contructions – Tents – Safety.
  Basic of structural design.
  General actions on structures – Wind.
  General actions on structures – Snow.
  Design and calculation of steel structures.

2.4.1

Load combinations

2.4.1.1

Fundamental – Ultimate limit state
For the verification on strenght/connection of the elements.

	One variabel load	Multiple variabel load
Unfavorable permanent load	1.35 x G + 1.5 x Q	1.35 x G + ∑ 1.35 x Q1
Favorable permanent load	1.0 x G + 1.5 x Q	1.0 x G + ∑ 1.35 x Q1

This means the following load combinations are calculated and checked
1. 1.0 x EG + 1.5 x Wind load
2. 1.35 x EG + 1.5 x Snow load

3.

Results

Wooden beams:
No wood strenght class is known, therefore the assumption of strenght class C24 is to be verified.

Maximum wind load:
The structure can be loaded with a maximum wind load of 0.36 kN/m2, which is in the reach of Beaufort scale 9. Therefore the strenght and stability ca be secured to Beaufort 8.

Maximum snow load:
A maximum snow load of S=0.42kN/m2 can be applied on the structure, which corrsponds to 42kg/m2 or about 20cm of fresh snow.

Normative section:
The wooden beams are normative for strenght of the construction. A reletively slender section on a large span combined with point loads from the innertent.

Anchorage / Verification of ground structure:
In this stage no checks have been done for the anchorage and connections of the ground structure, as well as the connections between the wooden beams. Also the satbility of the structure against sliding, lifting and overturning should be checked.