Structural_________ Basics_____-2016.ppt

Structural_________ Basics_____-2016.ppt

1. STRUCTURAL BASICSSTRUCTURAL BASICS
Structural SystemsStructural Systems

Md. Sohel Rahman
Executive Engineer
PWD Design Division-4
Public Works Department (PWD)
Government of Bangladesh

2. What is Structural Engineering?
◦Analysis and Design of Structures that
support and resist Loads acting in the
structures

3. What is Structural Design?
◦Process of determining material,
appropriate structural system and size
of structural elements to resist forces
acting in a structure

4. Structural Engineer to do
Determine appropriate structural system for
a particular case
Determine forces acting on a structure
Select material for construction
Calculate size of members and connections
to avoid failure (collapse) or excessive
deformation

5. Structural Engineer must ensure their
design to satisfy
Safety
◦Design Criteria
◦Serviceability
Durability
Economy

6. Forces Acting in Structures
Forces induced by gravity
◦Dead Loads (permanent): self-weight of
structure, partition walls, fixtures and
attachments
◦Live Loads (transient): moving loads (e.g.
occupants, vehicles)
Forces induced by wind
Forces induced by earthquakes
Others

7. Forces Acting in Structures
Vertical: Gravity Lateral: Wind, Earthquake

8. Structural Systems
A particular method of assembling and
constructing structural elements of a building so
that they support and transmit applied loads
safely to the ground without exceeding the
allowable stresses in the members and within
all serviceability limits.
-Group of structural elements form a load path
through which the acting loads can be
transferred safely to the ground.

9. Typical Vertical Load path
Slab
Beams
Columns
Footings

10. Commonly used Vertical Load transfer
Systems
Load Bearing Wall System
(viz. Masonry Wall Structure)
Frame Structure
Flat Plate Structure
Folded Plate Structure
Shell Structure
Truss Structure
Arch Structure

11. Example of Vertical Load transfer
Systems
Brick Structures

12. Example of Vertical Load transfer
Systems
Frame Structure
ElevationPlan

13. Example of Vertical Load transfer
Systems
Flat Plate
Plan

14. Example of Vertical Load transfer
Systems
Folded Plate

15. Shell Structures
Example of Vertical Load transfer
Systems

16. Truss Structures
Example of Vertical Load transfer
Systems
Truss

17. Arch Structures
Example of Vertical Load transfer
Systems
Arch

18. Commonly used Lateral Load transfer
Systems
Moment Resisting Frame
Frame-Shear wall System
Flat Plate-Column System
Flat Plate-Shear wall-Column System
Tube Structure

19. Moment Resisting Frame OR Rigid Frame
Example of Lateral Load transfer
Systems
Rigid Joint
ElevationPlan

20. Non Rigid Frame
Example of Lateral Load transfer
Systems
Hinge Joint
This frame can not resist lateral Loads

21. Shear wall Structure
Example of Lateral Load transfer
Systems
Shear wall
Elevation
Edge column
Interior gravity
frames

22. Coupled Shear wall Structure
Example of Lateral Load transfer
Systems
Coupled Beam
Elevation
Edge column
Interior gravity
frames

23. Frame-Shear wall System OR Dual System
Example of Lateral Load transfer
Systems
Moment Resisting
frames*
Shear walls
Core
*Minimum 25% of lateral load shall be resist by the frames.

24. Flat Plate- Column System
Example of Lateral Load transfer
Systems
Plan
Elevation
Effective slab width

25. Flat Plate- Shear wall System
Example of Lateral Load transfer
Systems
Flat Plate
Shear walls
Core
Column

26. Tube Structures
Example of Lateral Load transfer
Systems
Concrete floor
framing
Closely spaced
perimeter columns
Deep spandrel
Interior
Column

27. Basic Strutural Systems as per BNBC

28. Basic Strutural Systems as per BNBC

29. Drift Limitation: In general

30. Building Diaphrams

31. Balanced Stiffness

32. Structural Systems for Concrete Building
0
9
Perimeter tube and interior
core walls
10Exterior diagonal tube
11Modular tubes
NUMBER OF STORIES
10 20 30 40 50 60 70
No. SYSTEM
6
Widely spaced perimeter
tube
80 90 100 110 120
7Shear wall - frame
8
Closely spaced perimeter
tube
4
5
Flat Slab and Shear Walls
Flat Slab, Shear Walls and
Columns
Coupled Shear walls and
beams
Rigid frame (Moment
Resisting Frame)
Flat Slab and Columns1
2
3

33. Structural Systems for Concrete Building
N
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F
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W
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F
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A
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H
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A
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W
A
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F
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T
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I
N

T
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B
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STRUCTURAL SYSTEM OF TALL BUILDINGS

34. Example of framing
TOILET block
TOILET
OFFICECOMPUTER
STORE
P .A
DIRECTOR
LOUNGE
TOILET
OFFICE
TOILET
TOILET
OFFICEOFFICE
UPDN
UP
DN
LOBBY
LIFT LIFT
STA IR
FIRE STAIR
LOBBY
20'-2
1
2
"
15'-5" 15'-5" 15'-5" 15'-5" 15'-5" 15'-5" 11'-9"
1
5
'-
1
"
1
0
'-
1
1
12
"
1
1
'-
3
"
TYPICAL FLOOR PLAN

35. SummarySummary
To determine the appropriate Structural
System is the primary task for structural
designing
There may be alternative structural
systems for a particular structure but the
structural engineer has to select the
appropriate one

36. A guideline to finalize structural system
Most of the cases some gridlines and columns are
shown by the Architect. Make a framing system
according to the architect’s suggestion. Check whether
this framing system can satisfy the structural
requirements or not.
Find out the alternative framing systems available for
the structures which satisfy the structural
requirements.
Choose the appropriate framing i.e., Column, Beam,
Shear wall (if necessary) which meet the followings
◦Satisfy all structural requirements
◦Satisfy the functional criteria
◦Maximize performance
◦Minimize project cost.

37. Consult with the architect about your proposed
framing system.
With the consent of the Architect finalize the framing
(structural) system of the project.
That is the starting of all structural
calculations and as well as the starting of
architectural working drawings

38. Thank you very muchThank you very much