石材幕墙计算
本石材幕墙采用满槽式连接,抗折强度f gk=7N/mm2的天然花岗岩板,标高60米处幕墙为不利部位，该处石材最大分格为H(高)×B(宽)=500mm×2025mm。
1. 荷载的计算
风荷载标准值为
W k＝βgZ·μs1·μz·W o
＝1.691×1.2×1.355×.55
＝1.512KN／m2
水平分布的地震作用标准值为
q Ek＝βe·αmax·G／A
式中： G--石板自重标准值
G=γ石·H·B·t·1.05
=28×500×2025×40×10-9×1.05
=1.191KN
其中：γ石--石材密度，取28KN/m3
t--石板的厚度(mm)
A=B×H=2.025×.5=1.0125m2
则 q Ek＝βe·αmax·G／A
＝5×.08×1.191/1.0125
＝.47KN/m2
水平荷载组合设计值为
q =(1.4×W k＋1.3×0.6×q Ek)×10-3
=(1.4×1.512＋1.3×0.6×.47)×10-3
=.002N/mm2
2. 强度计算
(1)抗弯强度验算 Check bending strength
石材应力的设计值为 Design stress for stone is
σ =0.75×q×H2/t2
=0.75×.002×10-3×5002/402
=.23N/mm2≤f g=3.26N/mm2
其中：f g--石材抗弯强度设计值
In which,
f g is the design bending strength of stone
所以石材抗拉承载力满足要求。
Therefore, the tensile bearing capacity can meet the requirements.
(2)抗剪强度验算Check shear strength
在风荷载和水平地震作用下，石材受到钩板传来的剪力。
Under wind load, the stone is subject to the shear transferred by the hooking plate.
则钩板在石材中产生的剪应力设计值为
The design shear stress generated in the stone, which is caused by the hooking plate, is
τ=q·H/(t-c)
=.002×500/(40-6)
=.03N/mm2≤f s=1.63N/mm2
In which： f s--石材抗剪强度设计值design shear strength of stone
H--幕墙分格高(mm)grid height of curtain wall c--槽口宽度 notch width
所以石材抗剪承载力满足要求。
Therefore, the shear bearing capacity can meet the requirements.
(3)槽口处抗弯强度验算Check bending strength at notch
在风荷载和水平地震作用下，石材槽口处产生的最大抗弯强度设计值按照下式计算得：
Under the wind load and horizontal seismic load, the maximum design bending strength at the stone notch is calculated as follows:
σ=8·q·h r·H/(t-c)2
=8×.002×10×500/(40-6)2
=.07N/mm2≤0.7·f s=1.141N/mm2
式中： h r--槽口受力一侧深度(mm)
In which: h r--槽口受力一侧深度(mm)is the depth at the side subject to force.
所以槽口处抗弯强度满足要求。
Therefore, the bending strength at notch can meet the requiremnts.
(4)钩板承受的剪应力验算 Check shear stress of the hooking plate
在风荷载和水平地震作用下，钩板承受的剪应力设计值按照下式计算得：
Under the wind load and horizontal seismic load, the shear stress carried by the hooking plate is calculated as follows:
τ=q·H/(2·d)
=.002×500/(2×4)
=.13N/mm2≤125N/mm2
所以钩板的抗剪强度满足要求。
Therefore, the shear strength of hooking plate can meet the requirements.。