How to calculate the carrying capacity of the glass
Release time:2017-08-08 22:51:42
1. Glass bearing state
Doors, windows, curtain wall in the wind pressure under two states:
One is four-sided support, apply to the doors and windows, curtain wall.
Second, two pairs of support, for glass doors and so on.
2. Glass bear wind load calculation
a) When T ≤ 6mm, Wk = 0.2α is the largest when t> 6mm, Wk = α (0.2t1.6 + 0.8) / Amax minority
Two pairs of side support, Wk = 0.142αt / L glass door
Where, Wk - wind load standard value kPa
Amax - the largest area of glass ㎡
L - glass permissible span m
t - glass thickness mm
α - adjustment factor
Glass adjustment factor
Glass type Ordinary semi - tempered steel interlayer hollow folder wire embossed fire
Adjustment factor 1.01.62.0 ~ 3.00.81.50.50.63.0 ~ 4.5
b) Example calculation
Example 1, the use of external steel, the float method of insulating glass, 4 steel + A +5 size of 1200 × 1800, seeking glass carrying capacity?
Formula: Wk = 0.2α
Calculated and value: Wk = 0.2 × 1.5 × 41.8 / 1.2 × 1.8 = 1.68kPa.
Analysis: ① tempered sheet and float combination, calculated by the sheet favorable, otherwise unfavorable, the cost is high;
② assume that the two films are equal, outside the steel, within the float, not to be confessed;
③JJJ102 is provided outside the steel, according to the outside of the calculation.
Example 2, the use of outer fire glass thickness of 5mm, the inner layer of glass 4mm thick laminated glass, the size of 1200 × 1800, seeking glass carrying capacity?
Formula: Wk = α (0.2t1.6 + 0.8) / Amax Calculated and value: Wk = 0.8 (0.2 × 91.6 + 0.8) /1.2 × 1.8 = 2.78kPa
Analysis: ① at this time carrying capacity is great, but the main role is fire, the cost is high;
② anti-wind pressure adjustment coefficient of tempered glass and monolithic fireproof glass shall be determined by experiment.
Example 3, the use of 15mm tempered glass, the size of 800 × 2000mm door, ask the glass carrying capacity?
Formula: Wk = 0.142αt / L
Calculated and value: Wk = 0.142 × 2 × 15 / 2.0
Analysis: ① door glass with strict requirements, and the thickness of large;
②L take the most negative for the long side, the short side was 1.94kPa;
③ glass damage is mainly tension damage, not pressure damage, so bending is the main contradiction.
3. The problems that should be noted in the calculation
a) JGJ113-2003 and 97 are the same, but the parameters change slightly.
Example: tempered glass from the original 1.5 ~ 3.0 to 2.0 ~ 3.0 and increase the fire glass adjustment factor.
b) Curtain wall glass still according to JGJ102- ×××× provisions, both in and out, not mixed.
c) tempered glass and float glass composed of hollow glass, and the thickness of the two different, how to deal with.
Outer layer of steel + inner float, when the two equal to take α 1.5; outside the thin thickness, take the sheet, the problem is not; outside the thin thin, it is not easy to use.
d) laminated glass when the use of more than 70 ℃ conditions, α adjustment coefficient from 0.8 to 0.6, the use of the South need to pay attention.
e) tempered glass, fire glass adjustment factor is given a range, how to value, preferably provided by the manufacturer, or take small value favorable, including the combination of steel and fire to be determined to be included.
f) tempered glass, different around the best glass manufacturers to provide, and to bear the economic responsibility.
Analysis: ① ANSI is the glass factory to provide parameter values, and to ensure quality;
② tempered glass has the problem of self-violence, foreign 8% 0 or so, abroad is greater than this value;
③ tempered glass, there are assembly problems, deformation profiles, glass flatness of 2% 0, which take the lower limit favorable.
g) glass calculation problems, as well as the following items, not within the scope, but should be noted.
Such as glass disturbance, glass thermal stress, glass gravity, glass gap, glass thermal performance, underwater glass and so on.