Snow loads

Live loads which would be blown away by a blast wave or which would not increase the inertia of a supporting member should not be included in the mass calculation. Additionally, some judgment is needed to estimate the portion of a design live loads which is normally present. For example, snow loads in cold climates may be present for relatively long durations and a portion of this live load should be included in the mass calculation. Another example is a floor live load representing personnel and furnishings which should not be included in the mass calculation. 

Especially for tanks with a great diameter and for steel and wooden tanks truncated cone shaped tarpaulins are very useful, because they do not burden the tank wall very much. If the tank is empty, the tarpaulin must touch the center of the tank bottom in order to support bigger water or snow loads. With increasing contents the tarpaulin starts floating on the manure surface, fig.l. 

As the site is snowbound for about six months of each year, the treatment plant was designed to operate unattended for months on end. Unattended operation over short periods was demonstrated, though after the final inspection before winter the wastewater supply from the mine to the treatment plant was interrupted by rupture of the feed pipe under snow loading, which also crushed two sheds at the site. However, a flume packed with crushed limestone to neutralize mine drainage operated continuously through the winter under snowpack. 

MW KELLOCC SPEC IFICA T I f)N< U4I -F 2. SNOW LOAD SPECIFICATION ... 

Mechanical degradation—storms (wind, rain, hail, snow), loads Mechanical—stress, cracks, fracture, abrasion... 

Strength At ambient (74°F) flexural strength of GeoDeck is 2490 psi and flexural modulus is 323,000 psi. At— 20°F the figures are equal to 3530 and 564,000 psi, respectively (Tables 7.20 and 7.41). Because we consider a snow load, let us take a modest 32°F. Below this temperature GeoDeck is stronger and stiffer. A simple linear extrapolation (there is no reason to seriously doubt this assumption) shows that at 32°F flexural strength would be 2955 psi and flexural modulus 430,593 psi. 

Snow Load on a Heavy Duty GeoDeck Hollow Board (Width 8.10 in.. Depth 1.55 in.. Moment of Inertia 1.858 in.", and Support Span of 24 in.) Using the extrapolated to 32°F flexural strength values of 2955,2430 and 2820 psi (see above), one can obtain the ultimate uniformly distributed load at support span of 24 in. for the board equal to 1749 Ib/fF, 1438 Ib/fF, and 1669 Ib/fF, that is, 3.6-4.4 times higher than the required 400 Ib/fF potential snow load. 

Deflection Let us now consider deflection of a deck under such a snow load. For uniformly distributed load, the following equation for deflection at midspan is applicable ... 

Snow Load on a traditional GeoDeck Hollow Board (Width 5.5 in.. Depth 1.25 in.. Moment of Inertia 0.784 in.", and Support Span of 16 in.) At 32°F under the snow load of400 Ib/fF. and at the flexural modulus of431,000 psi, 445,000 psi, or 360,000 psi (the first was determined at 24-in. span under third-point load second was determined at 20-in. span under quarter-point load, and the third was determined at 15-in. span under center-point load, which is less accurate), the deflections would be equal to 0.039,0.037, and 0.046 in., respectively. For a support span of 16 in. (on center between joists), an allowable deflection is 16/180 = 0.089 in. This means that deflection under 400 lb of snow load is well within the allowable limit for all alternative experimental data. 

At-20°F the boards are about 20-30% stronger and 30-40% stiffer compared to that at 32°F. Flence, they are even more resistant to snow load compared to that at milder temperatures. 

Snow load, 272- 274 Snow on a deck, 272 Softwood fiber, 86, 100 Soil Block test, 431 Soil-block cultures, 434 Solar radiant exposure, 615 Solar radiation (UV light), 531 Solid board, 2, 16, 36, 267, 280, 281, 288, 311 Soundwall, 252, 269, 281-286 Bending moment, 282... 

In the course of remodelling the CargoLifter dockyard haU into the Tropical Island water park in Brand, Germany, the multi-layered fabric membranes (PVC-coated PES-fabric) in four of the arch planes were replaced with three-layered ETFE-foil cushions. The total area of the transparent foil cushions measures 20,000 m. Each ETFE-arch plane is formed by 14 foil cushions. The cushions at about 400 m were the largest ETFE-foil cushions built until then. For the first time an inner and an outer steel cable net were used to support the foil layers against wind and snow loads. 

Load-bearing behaviour of ETFE-foil cushions under wind and snow loads... 

The reverse of wind suction load is snow load. Snow pushes the outer layer down and the sag and forces in the outer layer are decreased. The inner layer will be strained under increasing internal pressure from snow load, sag, and forces will increase, too. Especially for high snow loads, the inner layer has to be supported by cables. Rgure 6.33 shows the principal load-bearing behaviour under snow load. 

Load-bearing behaviour of a two-layer cushion under snow load (according to Moritz and Schiemann (2008)). 

Tension tests according to DIN EN ISO 527 were carried out on the laminates with six tests per series to determine their tensile strength, the tensile e-modulus and the breaking point. Measurement of stretch characteristics was made using a video extensometer under standard weather conditions (23 2°C, 50 5% relative density) according to DIN 50014-23/50-2, i.e. three measurements, 0.01 mm exactness. For the determination of the force-tension range, the e-modulus was between e i = 0.05% and e"2 = 0.25%. Wind and snow loads were calculated as vertical loads. Other temporary loads have also been calculated as vertical pressure loads. An example for a rib type 350 is shown in Fig. 15.22. 

In Feuchtwangen snow loads are to be applied as Zone II according to DIN 1055-5 (07.2005). However, it is assumed that, since the roof is installed... 

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