TWO STOREY SCHOOL BUILDING
BUILDING DIMENSION
 L = 7.5 m
 B = 25 m
 Total Building height, z = 3.2m + 3.2m + 2.0m = 8.4m
 Bay Length = 5.0 m
 Height of Truss = 2.0 m
2
 Roof Slope (θ) = tan−1 (5) = 21.8°
 Roof Mean Height, h = 3.2m + 3.2m + 1.0m = 7.4m
Dead Load
Roof


(Researched from the Internet)
Roof Covering = 0.08 kPa (Galvanized steel #20)
Roof Truss = (C.E. Fowler formula)
w = 0.4 + 0.04 L (L = 10 m = 32.81ft.)
w = 0.4 + 0.04(32.81ft.)
w = 1.712 lb. /ft2 = 0.082 kN/m2
Ceiling Frame
(CEILINGS, NSCP 2015, Table 204 -2)
 Plywood = 0.006 kPa/mm × 10 mm = 0.06 kPa
 Suspended Steel Channel
= 0.10 kPa
Total
= 0.16 kPa
Partition
(CONCRETE MASONRY UNITS, NSCP 2015, Table 204 -2)
 Concrete Hollow Block = 16.5 KN/m3 × 1m = 16.5 kPa
 Grout( spaced at 600mm with 100mm thickness) = 1.5 KN/m3× 1m =1.5 kPa
 Plaster = 0.24 kPa / side × 2 sides = 0.48 kPa
Total = 18.48 kPa
Floor Finish
(FLOOR AND FLOOR FINISHES, NSCP 2015, Table 204 -2)
 Ceramic or quarry tiles (20mm) on 13 mm mortar bed = 0.77 kPa
Live Load
(From minimum Uniform and Concentrated Live Load, Table 205-1, NSCP 2015)


Classroom = 1.9 kPa
Corridor Above Ground Floor = 3.8 kPa
Roof Live Load
(Roof Live Load, Table 205-3, NSCP 2015)
For roof slope less than 33%, for tributary area between 0 to 20 kPa = 0.75 kPa
ENCLOSURE CLASSIFICATION
Nomenclatures:
Ag
- gross area of that wall in which Ao is identified
Agi
- sum of gross surface areas of the building envelope (walls and roof) not
including Ag
Agt
- sum of gross surface areas of the building envelope (walls and roof)
Ao
- total area of openings in a wall that receives positive external pressure
Aoi
- sum of the areas of openings in the building envelope (walls and roof) not
including Ao
Aot
- sum of the areas of openings in the building envelope (walls and roof)
Agi FRONT = A wall + A roof (L roof × L top chord)
Agi FRONT = (6.4 ×25) + (27.5 × 5.385)
Agi FRONT = 160m2 + 148.09m2
Agi FRONT = 308.09m2
Agi REAR = A wall + A roof (L roof × L top chord)
Agi REAR = (6.4 ×25) + (27.5 × 5.385)
Agi REAR = 160m2 + 148.09m2
Agi REAR = 308.09m2
Agi RIGHT = A wall + A truss
Agi RIGHT = (6.4 ×5) + (1/2 × 2 × 10)
Agi RIGHT = 32m2 + 10m2
Agi RIGHT = 42m2
Agi LEFT = A wall + A truss
Agi LEFT = (6.4 ×5) + (1/2 × 2 × 10)
Agi LEFT = 32m2 + 10m2
Agi LEFT = 42m2
Agt = Agi FRONT + Agi REAR + Agi RIGHT + Agi LEFT
Agt = 308.09m2 +308.09m2+42m2 +42m2
Agt = 700.18 m2
Ao FRONT = A door 1 + A door 2
Ao FRONT = (9 ×0.9 ×2.1) + (2 ×0.9 ×2.1)
Ao FRONT = 17.01m2 + 3.36m2
Ao FRONT = 20.37m2
Ao REAR = A window 1 + A window 2
Ao REAR = (9 ×2 ×1.5) + (2 ×1.2 ×2)
Ao REAR = 17.01m2 + 3.36m2
Ao REAR = 28.2m2
Ao RIGHT = 0m2
Ao LEFT = 0m2
Aot = Ao FRONT + Ao REAR + Ao RIGHT + Ao LEFT
Aot = 20.37m2 + 28.2 m2 + 0m2+ 0m2
Aot = 48.57m2
Enclosure Classification:
(Front View)
Ag= 6.4m × 25m = 160m2
Agi= Agt - Agi FRONT
Agi= 700.18m2 - 308.09m2
Agi= 392.09m2
Ao= Ao FRONT
Ao= 20.37m2
Aoi = Aot - Ao
Aoi = 48.57m2 - 20.37m2
Aoi = 28.2m2
Open Building:
Ao > 0.8 Ag
20.37 m2 > 0.8 (160 m2) = 128 m2
20.37 m2 < 128 m2 (not ok)
Partially Enclosed Building:
Case 1:
Ao >1.1 Aoi
20.37m2 > 1.1 (28.2m2)
20.37m2< 31.02m2 (not ok)
Case 2a:
Ao > 0.37 m2 or 0.01 Ag
20.37m2 > 0.37m2 or 0.01 (160 m2) = 1.6 m2
20.37m2 > 0.37m2 (ok)
Case 2b:
Aoi / Agi = 28.2m2/ 392.09m2 = 0.072 < 0.20 (ok)
Therefore, the building is an enclosed building.
Enclosure Classification:
(Rear Side View)
Ag= 6.4m × 25m = 160m2
Agi= Agt - Agi REAR
Agi= 700.18m2 - 308.09m2
Agi= 392.09m2
Ao= Ao FRONT
Ao= 28.2m2
Aoi = Aot - Ao
Aoi = 48.57m2 – 28.2m2
Aoi = 20.37m2
Open Building:
Ao > 0.8 Ag
28.2m2> 0.8(160 m2) = 128 m2
28.2m2< 128 m2 (not ok)
Partially Enclosed Building:
Case 1:
Ao >1.1 Aoi
28.2m2>1.1 (20.37m2)
28.2m2>22.407 m2 (ok)
Case 2a:
Ao > 0.37 m2 or 0.01 Ag
28.2m2> 0.37 m2 or 0.01 (160 m2) = 1.6 m2
28.2m2> 0.37 m2 (ok)
Case 2b:
Aoi / Agi = 20.37 m2/ 392.09 m2 = 0.053 < 0.20 (ok)
Therefore, the building is partially enclosed building.
Enclosure Classification:
(Right Side View)
Ag= 6.4m × 5m = 32m2
Agi= Agt - Agi RIGHT
Agi= 700.18m2 - 42m2
Agi= 658.18m2
Ao= Ao RIGHT
Ao= 0m2
Aoi = Aot - Ao
Aoi = 48.57m2 – 0m2
Aoi = 48.57m2
Open Building:
Ao > 0.8 Ag
0m2< 0.8(32m2) = 25.6 m2
0m2< 25.6 m2 (not ok)
Partially Enclosed Building:
Case 1:
Ao >1.1 Aoi
0m2<1.1(48.57m2)
0m2<53.427 m2 (not ok)
Case 2a:
Ao > 0.37 m2 or 0.01 Ag
0m2< 0.37 m2 or 0.01 (32m2) = 0.32 m2
0m2< 0.32 m2 (not ok)
Case 2b:
Aoi / Agi = 48.57 m2/ 658.18 m2 = 0.074 < 0.20 (ok)
Therefore, the building is an enclosed building.
Enclosure Classification:
(Left Side View)
Ag= 6.4m × 5m = 32m2
Agi= Agt - Agi RIGHT
Agi= 700.18m2 - 42m2
Agi= 658.18m2
Ao= Ao LEFT
Ao= 0m2
Aoi = Aot - Ao
Aoi = 48.57m2 – 0m2
Aoi = 48.57m2
Open Building:
Ao > 0.8 Ag
0m2< 0.8(32m2) = 25.6 m2
0m2< 25.6 m2 (not ok)
Partially Enclosed Building:
Case 1:
Ao >1.1 Aoi
0m2<1.1(48.57m2)
0m2<53.427 m2 (not ok)
Case 2a:
Ao > 0.37 m2 or 0.01 Ag
0m2< 0.37 m2 or 0.01 (32m2) = 0.32 m2
0m2< 0.32 m2 (not ok)
Case 2b:
Aoi / Agi = 48.57 m2/ 658.18 m2 = 0.073 < 0.20 (ok)
Therefore, the building is an enclosed building.
Wind Load Computation:
Wind Load
*using MWFRS (Main Wind Force Resisting System) method
p = qGCp – qi(GCpi)
where: q = 0.613KzKztKdV2
a) Occupancy Category = Category III
b) Wind Speed, V = 270 kph (Figure 207A.5-1A, NSCP 2015)
𝑘𝑚
1000𝑚
1 ℎ𝑟
1 𝑚𝑖𝑛
= 270 ℎ𝑟 × 1 𝑘𝑚 × 60 𝑚𝑖𝑛 × 60 𝑠𝑒𝑐 = 75 m/s
c) Wind directionality factor, Kd = 0.85 (Table 207A.6-1, NSCP 2015)
d) Exposure Category = Exposure B (Section 207A.7.3, NSCP 2015)
(The area of the building is assumed to be in an urban area)
e) Topographic Factor, Kzt = 1.0 (Section 207A.8.1, NSCP 2015)
f) Gust Effect Factor, G = 0.85 (Rigid Building, Section 207A.9.1, NSCP 2015)
g) Enclosure Classification = Enclosed (Section 207A.10, NSCP 2015)
h) Internal Pressure Coefficient, GCpi = ± 0.18 (Table 207A.11-1, NSCP 2015)
i) Surface Roughness = B (Section 207A.7.2, NSCP 2015)
j) Velocity Pressure Exposure Coefficient, Kz = (Table 207B.3-1, NSCP 2015)
Height Above Ground Level
0 to 3.2
6.0
7.5
Exposure B
0.57
0.62
0.66
h = 6.4 m + ½ (2 m) = 7.4 m
z1 (0 to 3.2) = 6.4 m
z2 (3.2 to 6.4) = 6.4 m
Solving for 𝐾𝑧 and 𝐾ℎ :
Through Interpolation:
z = 3.2 m
𝐾𝑧1 = 0.57
z = 6.4 m
7.5 − 6.4
0.66 − 𝐾𝑧
=
7.5 − 6.0 0.66 − 0.62
𝐾𝑧1 = 0.63
h = 7.4 m
7.5 − 7.4
0.66 − 𝐾𝑧
=
7.5 − 6.0 0.66 − 0.62
𝐾𝑧 = 0.66
k) External Pressure Coefficient, Cp = (Figure 207B.4-2, NSCP 2015)
L/B
Cp
use with
Windward wall
All Values
0.8
qz
Leeward wall
7.5/25 = 0.3
-0.5
qz
Sidewall
All values
-0.7
qz
Windward Roof:
tan 𝜃 =
2
5
2
𝜃 = 𝑎𝑟𝑐 tan( )
5
𝜃 = 21.8°
Normal to
Ridge for θ ≥
10°
h/L
20°
21.8°
25°
≥1.0
-0.7
-0.18
Cp1
Cp2
-0.5
0
(h / L) = 7.4m /7.5m = 0.987 m say 1 m
Through Interpolation:
25 − 21.8 −0.5 − (−𝐶𝑝1 )
=
25 − 20
−0.5 − (−0.7)
𝐶𝑝1 = −0.63
25 − 21.8 0 − (−𝐶𝑝2 )
=
25 − 20
0 − (−0.18)
𝐶𝑝2 = −0.12
Leeward Roof:
Normal to
Ridge for θ ≥
10°
h/ L
≥1.0
≥ 20 °
-0.6
Solving for 𝑞𝑧 and 𝑞ℎ
q z1 (0 to 3.2) = 0.613 k z k zt k d V 2
q z1 (0 to 3.2) = 0.613 (0.57)(1)(0.85)(75)2
q z1 (0 to 3.2) = 1670.62 N⁄m2
q z1 (0 to 3.2) = 1.67 kN⁄m2
q z2 (3.2 to 6.4) = 0.613 k z k zt k d V 2
q z2 (3.2 to 6.4) = 0.613 (0.63)(1)(0.85)(75)2
q z2 (3.2 to 6.4) = 1846.47 N⁄m2
q z2 (3.2 to 6.4) = 1.85 kN⁄m2
q h = 0.613 k z k zt k d V 2
q h = 0.613 (0.657)(1)(0.85)(75)2
q z = 1925.61 N⁄m2
q z = 1.93 kN⁄m2
Table of Wind Load Computations:
Windward
Wall
0 to 3.2
Windward
Wall
3.2 to 6.4
Leeward
Wall
Sidewall
Windward
Roof
Leeward
Roof
p(kN/m2)
+ 0.18
Solution
qGCp – qi(GCpi)
1.67(0.85)(0.8) − [1.67(0.18)]
qh
-0.18
1.67(0.85)(0.8) − [1.93(−0.18)]
1.483
qz
qz
+ 0.18
1.85(0.85)(0.8) − [1.85(0.18)]
0.925
qz
qh
-0.18
1.85(0.85)(0.8) − [1.93(−0.18)]
1.6054
qh
qz
+ 0.18
1.93(0.85)(−0.5) − [1.85(0.18)]
-1.15325
qh
qh
-0.18
1.93(0.85)(−0.5) − [1.93(−0.18)]
-0.47285
qh
qz
+ 0.18
1.93(0.85)(−0.7) − [1.85(0.18)]
-1.48135
qh
qh
-0.18
1.93(0.85)(−0.7) − [1.93(−0.18)]
-0.80095
qh
qz
+ 0.18
1.93(0.85)(−0.63) − [1.85(0.18)]
-1.3615935
qh
qh
-0.18
1.93(0.85)(−0.63) − [1.93(−0.18)]
-0.686115
qh
qz
+ 0.18
1.93(0.85)(−0.12) − [1.85(0.18)]
-0.52986
qh
qh
-0.18
1.93(0.85)(−0.12) − [1.93(−0.18)]
0.15054
qh
qz
+ 0.18
1.93(0.85)(−0.6) − [1.85(0.18)]
-1.3173
qh
qh
-0.18
1.93(0.85)(−0.6) − [1.93(−0.18)]
-0.6369
q
qi
GCpi
qz
qz
qz
0.835
Maximum Pressure Computed:
Windward Wall (0 to 3.2) = 1.483 kPa
Windward Wall (3.2 to 6.4) = 1.6054 kPa
Leeward Wall = -1.3615935 kPa
Windward Roof = -1.3615935 kPa
Leeward Roof = -1.3173 kPa