How to calculate the bearing capacity of the hotte

2022-09-22
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How to calculate the bearing capacity of glass

when supported on four sides, when t ≤ 6mm, wk=0. two α Majority

when t gt; At 6mm, wk= α (0. 2t1. 6+0. 8)/amax a few

when two opposite sides are supported, wk=0. one hundred and forty-two α T/l glass door

where, wk - standard value of wind load kpa

amax - maximum area of glass ㎡

l - allowable span of glass m

t - thickness of glass mm

α—— Adjustment coefficient

glass adjustment coefficient

glass type ordinary semi tempered tempered sandwich hollow wire embossing fire prevention

adjustment coefficient 1. 01。 62。 0~3。 00。 81。 50。 50。 63。 0~4。 5

b) example calculation

example 1. Hollow glass with outer tempering and inner floating method is adopted, and the size of 4 steel +a+5 is 1200 × 1800, what is the bearing capacity of glass

formula: wk attaches great importance to reducing carbon footprint, which has already become the resonance of the automobile manufacturing industry =0. two α

calculation and value: wk=0. two × 1。 five × 41。 8/1。 two × 1。 8=1。 68kPa。

analysis: ① when the tempered sheet is combined with float method, it is beneficial to calculate according to the sheet, otherwise it is unfavorable and the cost is high

② assuming that the two pieces are equal, the outside is tempered and the inside is float, which is not explained

③ jgj102 stipulates that the outer side is tempered, which is calculated according to the outer side tempering

example 2: laminated glass with 5mm thick outer fireproof glass and 4mm thick inner tempered glass is used, and its size is 1200 × 1800, what is the bearing capacity of glass

formula: wk= α (0. 2t1. 6+0. 8)/amax

calculation and value: wk=0. 8(0。2 × 91。 6+0。 8)/1。 two × 1。 8=2。 78kpa

analysis: ① at this time, the bearing capacity is very large, but the main function is fire prevention, and the cost is very high

② the adjustment coefficient of wind pressure resistance of tempered glass and monolithic fire-proof glass shall be determined by test

example 3: 15mm tempered glass with a size of 800 is used × 20 since the equipment is a fixed 2 equipped with a 00mm door, what is the glass bearing capacity

formula: wk=0. one hundred and forty-two α T/l

calculation and value: wk=0. one hundred and forty-two × two × 15/2。 0

analysis: ① the door glass has strict requirements and large thickness

② l takes the most unfavorable one as the long side, and the short side is 1. 94kPa;

③ glass damage is mainly tension damage, not pressure damage, so bending is the main contradiction

3. problems needing attention in calculation

a) the calculation formula of JGJ and 97 is the same, but the parameters change slightly

example: toughened glass from original 1. 5~3。 0 is changed to 2. 0~3。 0 and increase the adjustment coefficient of fireproof glass

b) glass for curtain wall shall still be in accordance with jgj102- ×××× The two are different and cannot be mixed

c) how to deal with the insulating glass composed of tempered glass and float glass with different thickness

outer tempering + inner float, when the two pieces are equal α Take 1. 5; When the outside is thin and the inside is thick, it is not a big problem to take a thin slice; It's not easy to use when the outside is thick and the inside is thin

d) when the service condition of laminated glass exceeds 70 ℃, α The adjustment factor is 0. 8 is reduced to 0. 6. Pay attention when using in the south

e) the adjustment coefficient of tempered glass and fire-proof glass gives a range. How to choose the value is best provided by the manufacturer, otherwise it is beneficial to choose a small value, including the combination of tempering and fire protection

f) tempered glass, which varies from place to place, is best provided by glass manufacturers and should bear the economic burden

analysis: ① ANSI is the parameter value provided by the glass factory, and the quality is guaranteed

② there is self explosion problem in tempered glass, which is about 8% in foreign countries, and greater than this value in foreign countries

silver cannot be replaced by other materials. ③ tempered glass also has assembly problems and profile deformation problems. The glass flatness is 2% 0, so it is advantageous to take the lower limit

g) glass calculation, there are also the following items, which are not within the scope of this time, but should be noted

such as glass disturbance, glass thermal stress, glass gravity, glass gap, glass thermal performance, underwater glass, etc

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