1. 0 10-Feb-2013
Preliminary
calculation
SY VJ
Rev Date Revision Prepared by Reviewed by Submitted Approved
REV
0
ZAMIL
Architectural Industries
STRUCTURE DESIGN CALCULATIONS
Contract no: 3201
CLIENT: International building system
DOUBLE CONICAL SHADE
1) CENTRAL MAST (POST #2)
2) FLYING MAST WITH CABLE SYSTEM
MADINAH HOTEL PROJECT
PRELIMINARY DESIGN & REACTION
2. 1.0 Overview
This document covers the analysis and design of PVC conical shade.
1.1 Description of the Structure
The Structural steel & Fabric is modelled as 3D space frame in ixForten Software.
Fig: central mast - Rendered model
PROJECT:
DOUBLE CONICAL SHADE
MADINAH HOTEL
Contract No: DATE
10-Feb-13
Fig: Flying mast with cable system - Rendered model
3. PROJECT:
DOUBLE CONICAL SHADE
MADINAH HOTEL
Contract No: DATE
10-Feb-13
1.2 Modelling Approach
1.3 Design Criteria
The structure was designed using following codes and design procedures
Steel Design : BS 5950-1-2000
Load Data : BS 5950-1 & BS 6399-2,
The PVC/PTFE fabric and cables are modelled in FORTEN 4000 which is capable of form finding by
force density method and non liear structural analysis using Newton Raphson method . The first step in
the process of modelling is form finding . Form finding process involves applying pretension load on fabric
to obtain a sutable shape and to ensure that the normally very flexible structural elements remain stiff
under all possible loads. After obtaining a sutable shape fabric load are applied , Wind and live loads are
applied as surface load over the fabric mesh. The wind load on the fabric is consideres on the basis of
wind pressure coefficents on the basis of shape as per BS 6399.
1.4 Loading
a Dead Load
SelfWeight of steel and fabric considered by the software using selfweight command
b Live load :
Live load is considered on roof = 0.24 Kn/m2 (TABLE 1607.1 - IBC 2009)
4. Wind load calculation
Site wind speed
The site wind speed Vs for any particular direction should be calculated from where
Vs = Vb × Sa × Sd × Ss × Sp (Ref: 2.2.2 / BS 6399-2)
To determines a site wind speed, still corresponding to the hourly mean wind speeds at a height of 10 m
above ground in the standard exposure, from the basic wind speed by applying corrections for the
site altitude, wind direction and season.
Wind speed for the building location = m/sec (As per Madinah region)
Sb is the terrain and building factor = obtained from 2.2.3.3.
(by assuming closest distance to sea is 2 km)
Vb is the basic wind speed = / = m/sec
24.157
43.000 1.780
Contract No: DATE
- 10-Feb-13
TITLE: WIND LOAD CALCULATION
DESIGNED CHECKED
SYED
PROJECT: DOUBLE CONICAL SHADE
43.00
1.780
Vb is the basic wind speed = / = m/sec
Sa is an altitude factor (see 2.2.2.2); = 1 + 0.001∆s
∆s is an site altitude = m
Sa =
Sd is a direction factor (see 2.2.2.3); =
Ss is a seasonal factor (see 2.2.2.4); =
Sp is a probability factor (see 2.2.2.5). =
Vs = x x x x
Basic wind speed Vs = m/sec
Effective wind speed & Dynamic pressure
The effective wind speed Ve be calculated from
Ve = Vs × Sb
(by assuming closest distance to sea is 2km)
The value of the dynamic pressure qs of the standard method is given by
qs = 0.613Ve
2
(Ref: 2.1.2 / BS 6399-2)
1.000
24.57
1.000
24.157
17.000
1.017
1.000
43.000 1.780
1.000
1.000
24.16 1.017 1.000
qs = 0.613Ve
2
(Ref: 2.1.2 / BS 6399-2)
5. Contract No: DATE
- 10-Feb-13
TITLE: WIND LOAD CALCULATION
DESIGNED CHECKED
SYED
PROJECT: DOUBLE CONICAL SHADE
P = qs x Cp x Ca (Ref: 2.1.3.3 / BS 6399-2)
External surface pressure
The pressure acting on the external surface of a building Cpe is given by
A
E
B C F G
E
External Cpe values
A
0.25
17 24.57 1.74 42.75 1.12
Building
Height
(m)
Basic wind
speed Vs
Terrain and
Building factor
Sb
Effective wind
speed (m/sec)
Ve = Vs × Sb
Dynamic
pressure
(kN/m2
)
qs = 0.613 × Ve2
Pitch angle
in cone
-1.25
B
-0.72
C
-0.27
0.36 0.28
E F G
-0.99 -0.77 -0.47
19
A
conical structures
(Ref: Fig-20 / BS 6399-2)
Internal Cp value surface pressure (For enclosed building)
The pressure acting on the internal surface of the shade Cpi = -0.3 (Ref: Table-16 / BS 6399-2)
Cp = Cpe - Cpi
Cone angle
30
-1.07 -0.77
0.06 -0.02 -0.05
19
-1.55 -1.02 -0.57 -1.29
Cp - Values for conical structures
Pitch angle
in cone
A B C E F G
-1.1 -0.5 -0.2
-0.3
-0.7 -0.4 -0.4
60 0.8 0.8 0.8 -0.7 -0.7
0.8 0.5 0.4
30
-1.40 -0.80 -0.50 -1.00 -0.70 -0.70
0.50 0.20 0.10
-0.60
60 0.50 0.50 0.50 -1.00 -1.00
6. Contract No: DATE
- 10-Feb-13
TITLE: WIND LOAD CALCULATION
DESIGNED CHECKED
SYED
PROJECT: DOUBLE CONICAL SHADE
Ca is the size effect factor for external Ca = ( Fig-4, BS 6399-2)
WL case - I
WL case - II
WL case - I
WL case - II
WL case - I / II
0.840
Pressure, P = qs x Cp x Ca KN/m 2
19
-1.46 -0.96 -0.72
0.06 -0.02
0.09
30
-0.47
60 0.47 -0.94 -0.94
A B C E F G
-0.66
Load case Combination
LC-1 1.4 DL + 1.6 LL
LC-2 1.4 DL + 1.6 WL1
LC-3 1.4 DL + 1.6 WL2
LC-4 1.2 DL + 1.2LL + 1.2 WL1
LC-5 1.2 DL + 1.2LL + 1.2 WL2
For node number refer ACAD & staad file
LOAD CAMBINATION WITH PRETENSION