f. Internal Pressure Coefficient , Gepi for Enclosed Building
Notes:
1. Plus and minus signes==s signify pressures acting toward and away from the internak surfaces ,
respectively.
2. Values of (GCpi ) shall be used with qz or qh as specified.
3. Two cases shall be considered to determine the critical load requirements for the appropriate
condition:
I.
A positive value of (GCpi ) applied to all internal surfaces
II.
A negative value of (GCpi ) applied to all internal surfaces
Step 4 : Velocity Pressure Exposure Coefficients , Kz and Kh:
1. The velocity pressure exposure coefficient Kz, may be determined from the following
formula:
For 4.5 m ≤ z ≤ zg
𝑧
𝐾𝑧 = 2.01 (𝑧𝑔)
For z ≤ 4.5m
2
𝑎
2
4.5 𝑎
𝐾𝑧 = 2.01 ( 𝑧𝑔 )
a
Table 207A.9-1 ( Terrain Exposure
Constant)
zg
Kz and Kh from table 207B.3-1
9.5
274.32
Diaphragm
Level
Height at each
diaphragm , z(m)
Kz
Kh(i.e., at z= h )
Roof
6th floor
5th floor
4th floor
3rd floor
2nd floor
21.3
17.8
14.3
10.8
7.3
3.8
1.174
1.13
1.08
1.017
.937
.816
1.174
1.174
1.174
1.174
1.174
1.174