Introductory lecture on types of structures and loads for under

1. Chapter 1Chapter 1

2. Chapter 1
Types of Structures & Loads

3. Introduction
• Structure refers to a system of connected parts used
to support load, such as Buildings, Bridges,
towers, Stadiums, ……………. etc.
Chapter 1 Dr. Mohammed Arafa Structural Analysis I

4. Introduction
• Structural Analysis involves the prediction of the
performance of a given structure under prescribed
loads and/or other external effects, such as
support movements and temperature changes.
• The fundamental purpose of a structural analysis
is to determine the magnitudes of force and
displacement for each element of a design system
for a given set of design loads.
Chapter 1 Dr. Mohammed Arafa Structural Analysis I

5. Structural Elements
• Tie Rods

6. Beams
• Type of Beams

7. Columns
• Columns

8. Type of Structure
• Trusses

9. Cables and Arches

10. Cables and Arches

11. Frames
• Frames members are subjected to axial, shear and moment

12. Surface Structures

13. Loads
 Codes
a) General Building Codes
Specify the requirement of minimum design load on structures
1. ASCE
2. UBC
3. IBC

14. Loads
 Codes
b) Design Code
Used to establish the requirement for the actual structural design
1. ACI
2. AISC
3. AASHTO

15.  EuroCode
EN 1990 Eurocode 0: Basis of Structural Design
EN 1991 Eurocode 1: Actions on structures
EN 1992 Eurocode 2: Design of concrete structures
EN 1993 Eurocode 3: Design of steel structures
EN 1994 Eurocode 4: Design of composite steel and
concrete structures.

16.  EuroCode -Continue
EN 1995 Eurocode 5: Design of timber structures
EN 1996 Eurocode 6: Design of masonry structures
EN 1997 Eurocode 7: Geotechnical design
EN 1998 Eurocode 8: Design of structures for
earthquake resistance
EN 1999 Eurocode 9: Design of aluminum
structures

17. Dead Load
Consist of the weight of the various structural members
and weight of any object that permanently attached to the
structure

18. Dead Load

19. Dead Load

20. Dead Load

21. Dead Load
10cm
20cm
3m
1.0m
1.0m
The floor beam used to support the 2 m width of lightweight plain concrete
slab having thickness of 10cm. The slab serve as a portion of the ceiling for
the floor below, and therefore its bottom is coated with plaster. Furthermore,
an 3m high, 20 cm thick lightweight solid concrete is directly over the top
flange of the beam. Determine the loading on the beam measured per one
meter of the length of the beam
Solution
From Table 1-3
Lightweight concrete 0.015 kN/m2 per (mm)
15 kN/m3
Plaster on tile or concrete 0.24 kN/m2
From Table 1-2
Masonry, Lightweight solid concrete 16.5kN/m3
Concrete Slab (0.015)(100)(2) = 3kN/m
Plaster Ceiling (0.24)(2) = 0.48 kN/m
Block Wall (16.5)(0.2)(3) = 9.9 kN/m
------------------------------------------------------------
Total load = 13.38 kN/m

22. Live Load
• Building Loads
• Highway Bridge Loads
• Railroad Bridge Loads
Can vary both in their magnitude and location

23. Live Load

24. Where
L Reduced design live load per square meter supported by the member.
0L Unreduced design live load per or square meter area supported by the
member.
LLK Live load element factor. For interior columns KLL=4
TA Tributary area in square meters.
2
37.2 mLL Ti K Af 
Live load Reduction
 For some types of buildings having very large floor areas
 Many codes will allows a reduction in the uniform live load for a
floor, since it is unlikely that the prescribed live load will occur
simultaneously throughout the entire structure at any one time
0
4.57
0.25
LL T
L L
K A
 
  
 
 
In ASCE 7-10

25. Live load Reduction
0
0
50% for members supporting one floor
40% for members supporting more than one floor
L
L
L

 

2 2
0 4.8 kN/m (480kg/m )
The structures used for pu
No re
blic
duction is a
assembly,gar
llow
ages,or ro
ed
ofs
if
if
or
L 

26. A two-story office building shown in the photo has interior
columns that are spaced 8m apart in two perpendicular
directions. If the (flat) roof loading is 0.95 kN/m2. Determine
the reduced live load supported by a typical interior column
located at ground level.
Example
8m
8m
8m8m

27. Example
The interior column has a tributary area or effective
loaded area of AT= 8x8=64m2
KLL AT > 37.2m2
A ground floor column supports a roof live load of
FR= 0.95x64= 60.8 kN
This load cannot be reduced since it is a roof load.
For the first floor, the LL is taken from table 1-4
L0=2.4 kN/m2.
2
0
4.57 4.57
0.25 2.4 0.25 2.4 0.536 1.29 kN/m
4 64LL T
L L
K A
   
             
1.29
The load reduction here is 100% 53.8% 40%
2.4
The Floor load 1.29 64 82.6
The Roof load 0.95 64 60.8 (NoReduction in Roof load)
60.8 82.6 143.4
F
R
R F
F kN
F kN
F F F kN
  
  
  
    
8m
8m
8m8m

28. Wind Load
)(N/m613.0 22
IVKKKq
pressureWind
dztzz 
qz= velocity wind pressure at height z above ground level.
V The velocity of the wind measured 10 m above the ground
I Importance factor depends upon nature of the building
Kz The velocity pressure exposure coefficient which is function of height
Kzt a factor that account for wind speed increases due to hills and
escarpments for flat ground Kzt=1.0 (topographic factor)
Kd a factor account for direction of wind when subjected to load
combination
Chapter 1 Dr. Mohammed Arafa Structural Analysis I

29. Wind Load
)(N/m)( 2
pihp GCqqGCp
BuildingEnclosedforpressureWind


30. Wind Load
)(N/m)( 2
pihp GCqqGCp
BuildingEnclosedforpressureWind

G Gust factor, which equal 0.85 for rigid structures.
Cp a wall or roof pressure coefficient
(GCpi ) internal pressure coefficient which depends upon the
type of openings in the building. For fully enclosed
buildings GCpi = 0.18

31. Wind Load
)(N/m613.0 22
IVKKKq
pressureWind
dztzz 

32. fph AGCqF
SignsforpressurewindDesign

Wind Load

33. Snow Load
gte IpCCF 7.0

34. Earthquake Load
The total design base shear in a given direction:
IBC-03WCV s
   
1
/ /
0.044
DS D
s
E E
DS
S S
C
R I R I T
S
 

R = Response modification coefficient
IE = Seismic occupancy importance factor
T = Fundamental period of vibration
Equivalent Lateral Force Analysis
V = Total Design Base Shear
Cs = Seismic Response Coefficient
W = Total seismic dead load

35. Earthquake Load
Dynamic Force Analysis

36. Hydrostatic and Soil Pressure
Other natural Loads

37. Structural Design
• LRFD (Load and resistance factor design)
Load combination example:
1.4( )
1.2( ) 1.6( ) 0.5( )
1.2 1.6( ) (1.0 0.8 )
1.2 1.6 1.0 0.5( )
1.2 1.2 1.0 1.6 1.0 0.2
r
r
r
U D F
U D F T L H L or S or R
U D L or S or R L or W
U D W L L or S or R
U D F E H L S
U
 
     
  
   
     
 0.9 1.2 1.6 1.6
0.9 1.2 1.0 1.6
D F W H
U D F E H
  
   

38. Structural Design
Where:
D= Dead load.
L = Live load, except roof live load.
Lr = Roof live load.
E = Earthquake load.
W= Load due to wind
F = Load due to fluids
H= Load due to lateral earth pressures
R = Rain load.
S = Snow load.
T = Load due to temperature, shrinkage,
creep, differential settlement