pptx

1. WHAT ARE TRUSSES ?
• IN ARCHITECTURE AND ENGINEERING, A TRUSS IS A STRUCTURE WHICH
COMPRISES OF ONE OR MORE TRIANGULAR UNITS MADE BY STRAIGHT ENDS
JOINED AT POINTS CALLED NODES. EXTERNAL FORCES AND REACTIONS ONLY ACT
AT NODES AND THE RESULT IN THE MEMBERS OF THE TRUSS WHICH ARE EITHER
TENSION OR COMPRESSION.
HOWE TRUSS
QUEEN POST TRUSS
NAMITA GUPTA
HARSHIT SINGHAL
HARSHI GARG
T
Y
P
E
S
O
F
T
R
U
S
S
E
S

2. ROOF TRUSSES
• A TRUSS IS ESSENTIALLY A TRIANGULATED SYSTEM OF STRAIGHT
INTERCONNECTED STRUCTURAL ELEMENTS.
• THE MOST COMMON USE OF TRUSSES, WHERE SUPPORT TO ROOFS, THE
FLOORS AND THE INTERNAL LOADING SUCH AS SERVICES AND SUSPENDED
CEILINGS ARE READILY PROVIDED.
• THE MAIN REASON FOR USING TRUSSES ARE:
1. LONG SPAN
2. LIGHTWEIGHT
3. CONTROLLED DEFLECTION
4. OPPURTUNITY TO SUPPORT CONSIDERABLE LOADS
T
Y
P
E
S
O
F
T
R
U
S
S
E
S

3. T
Y
P
E
S
O
F
T
R
U
S
S
E
S

4. DIFFERENT USES OF TRUSSES
T
Y
P
E
S
O
F
T
R
U
S
S
E
S

5. T
Y
P
E
S
O
F
T
R
U
S
S
E
S

6. T
Y
P
E
S
O
F
T
R
U
S
S
E
S

7. T
Y
P
E
S
O
F
T
R
U
S
S
E
S

8. FLAT TRUSS
• A TRUSS WHICH HAS THE TOP CHORD PARALLEL TO THE BOTTOM CHORD
OVER THE WHOLE LENGTH OF THE TRUSS.
• THE MOST ECONOMICAL FLAT TRUSS FOR A ROOF IS PROVIDED WHEN
THE DEPTH OF THE TRUSS IN INCHES IS EQUAL TO THE 7% OF THE SPAN OF
THE INCHES.
T
Y
P
E
S
O
F
T
R
U
S
S
E
S

9. TYPES OF FLAT TRUSS
• HOWE TRUSS
• PRATT TRUSS
• WARREN TRUSS
T
Y
P
E
S
O
F
T
R
U
S
S
E
S

10. T
Y
P
E
S
O
F
T
R
U
S
S
E
S

11. NATIONAL COMPOSITES CENTRE, BRISTOL
• WARREN TRUSS : ALSO CALLED AS EQUILATERAL TRUSS.
T
Y
P
E
S
O
F
T
R
U
S
S
E
S

12. NATIONAL COMPOSITES CENTRE, BRISTOL
T
Y
P
E
S
O
F
T
R
U
S
S
E
S
•IN THIS TYPE OF TRUSS, DIAGONAL MEMBERS ARE ALTERNATIVELY IN TENSION AND
COMPRESSION
•THE WARREN TRUSS HAS EQUAL LENGTH COMPRESSION AND TENSION WEB MEMBERS ,
AND FEWER MEMBERS THAN A PRATT TRUSS.
•FOR LARGER SPANS, THE MODIFIED WARREN TRUSS MAY BE ADOPTED WHERE
ADDITIONAL RESTRAINT TTO THE INTERNAL MEMBERS IS REQUIRED ( THIS ALSO
INCLUDES SECONDARY STRESS.

13. UNIVERSITY OF MANCHESTER
T
Y
P
E
S
O
F
T
R
U
S
S
E
S
PRATT TRUSS IN UNIVERSITY OF MANCHESTER
•PRATT TRUSS ARE USUALLY LONG SPAN
BUILDINGS RANGING FROM 20 TO 100 m
IN LENGTH.
•IN A CONVENTIONAL PRATT
TRUSS, DIAGONAL MEMBERS ARE IN
TENSION FOR GRAVITY LOADS.
PRATT TRUSS :
WARREN TRUSS PRESENT IN
STAIRCASE STRINGER

14. PRATT TRUSS ( GRAVITY EFFECTS)
•THIS TYPE OF TRUSS IS USED WHERE THE GRAVITY LOADS ARE PREDOMINANT.
•THIS TYPE OF TRUSS IS ALSO USED WHEN THE UPLIFT LOADS ARE ALSO
PREDOMINANT.
T
Y
P
E
S
O
F
T
R
U
S
S
E
S

15. FLAT TRUSS ROOF CONSTRUCTION
T
Y
P
E
S
O
F
T
R
U
S
S
E
S

16. SCISSOR TRUSS
• SCISSOR TRUSS IS A KIND OF TRUSS USED PRIMARILY IN BUILDINGS, IN
WHICH BOTTOM CHORD MEMBERS CROSS EACH OTHER, CONNECTING TO
THE ANGLED TOP CHORDS AT A POINT INTERMEDIATE ON THE TOP
CHORD’S LENGTH, CREATING AN APPEARANCE SIMILAR TO AN OPENED
PAIR OF SCISSORS.
• SCISSOR ROOF TRUSS CAN PARTICULARLY BE FOUND IN CATHEDRALS.
• ADVANTAGE : THE CEILING GETS VAULTED AND WE GET MORE SPACE IN
THE ATTIC.
T
Y
P
E
S
O
F
T
R
U
S
S
E
S

17. T
Y
P
E
S
O
F
T
R
U
S
S
E
S

18. CRESCENT TRUSS
• IN THIS TRUSS, THE UPPER CHORD AND THE DIAGONALS ARE IN COMPRESSION
WHEREAS THE LOWER CHORDS AND THE RADIALS ARE IN TENSION
• COUNTER BRACES ARE REQUIRED TO RESIST THE WIND PRESSURE.
• This truss can be made of wood, the chords being built up of planks bent to the
curve and firmly bolted together. The radials should be of wrought iron or steel
rods.
T
Y
P
E
S
O
F
T
R
U
S
S
E
S

19. CRESCENT TRUSS
DISADVANTAGES :
1. NOT AS SUCH FREQUENTLY USED.
2. NOT ECONOMICAL
3. NOT USED FOR LARGE SPANS.
T
Y
P
E
S
O
F
T
R
U
S
S
E
S

20. T
Y
P
E
S
O
F
T
R
U
S
S
E
S

21. • The Airbus production hall in Toulouse covers 200000 m2 of floor
space and is 45 m high with a span of 117 m. It consists of 8 m
deep lattice trusses composed of H sections. Compound column
sections provide stability to the roof structure. The building is
shown in Figure 2.5 during construction. Sliding doors create a 117
m 32 m opening in the end of the building. Two parallel rolling
cranes are installed each of 50 m span and 20 tonnes lifting
capacity.
Airbus Industrie hanger, Toulouse,
France
T
Y
P
E
S
O
F
T
R
U
S
S
E
S

22. T
Y
P
E
S
O
F
T
R
U
S
S
E
S

23. • This production hall is 85 m in length, 40 m wide and 24 m high with full
height doors at the end of the building, as shown in Figure 2.6. The roof
structure consists of an inclined truss. Because of the lack of bracing in the
end walls, the structure was designed to be stabilised through the
columns assisted by in-plane bracing in the roof and side walls.
Industrial hall, Krimpen aan den Ijssel,
Netherlands
T
Y
P
E
S
O
F
T
R
U
S
S
E
S

24. T
Y
P
E
S
O
F
T
R
U
S
S
E
S
WARREN TRUSS

25. Scissors truss
A scissors truss is a kind of truss used primarily in buildings, in which the bottom
chord members cross each other, connecting to the angled top chords at a point
intermediate on the top chords' length, creating an appearance similar to an opened
pair of scissors. Scissors trusses are used almost entirely in building construction to
support a pitched roof, where a sloping or raised ceiling surface is desired

26. Scissor trusses
Scissor trusses are designed with a
slope on the outside and inside. The
bottom chords are angled to create
vaulted ceilings. There are variations of
this design to create numerous unique
ceilings. Parallel chord trusses allow for
greater interior clearance in buildings.
The offset scissor truss has a bottom
chord that features a flat and vaulted
portion. The partial scissor truss is
similar, except that the bottom chord
slopes up in one direction while the
remaining portion is flat.

27. Conventional scissors truss
Conventional scissors trusses
are hard to detail for high
performance at the edge of the
roof near the outside wall,
because there’s only a small
space for insulation, and any
ceiling penetrations are close to
the roof sheathing in a difficult
area for workers to access. The
author’s crews use a custom
baffle made of one-inch rigid
foam to help contain dense-
packed insulation.

28. Raised-Heel Scissors Truss
For a practical,
high-
performance
solution, the
author’s
company
devised a raised-
heel scissors
truss that’s
detailed to work
well with a

30. • Scissor trusses were commonly used in roof
framing to accommodate interior vaulting,
domes and coves, or whenever the center of
the ceiling beneath was designed to rise
higher than the wall plates of the building

31. • ST. PAUL’S
EPISCOPAL
CHURCH (1822),
Windsor,
Vermont. With a
span of 50 ft.
and a roof pitch
of 6:12, St. Paul’s
is a successful
example of an
American-style
scissor truss
used in a
Neoclassical
rather than a
Gothic design.

32. The scissor chords
foot their principal
rafters and join
opposing principal
rafters near the
latter’s midpoints, the
whole assisted only by
a single kingpost. The
scantling sizes are
large: the scissor ties
are 7x13, the principal
rafters 9x11 and the
kingposts 9x12.

33. The role of the kingpost in this scissor
truss is fourfold:
With the flat pitch of the roof and low rise of the
vault, the scissor beams are long and subject to
sagging because of ceiling and self-weight, and
possibly subject to compressive buckling. The
kingpost, trapped and supported at the top by
the principal rafters, is in tension, holding up
both scissor chords where it intersects them
near their midpoint.

34. The kingpost provides the basis for longitudinal
bracing of the roof system, achieved by braces
rising from the kingposts to a five-sided ridge.

35. Scissor Trusses in Saint Catherine's
Church

36. BRIGHTON STATION, UK

37. CURVED STEEL ROOF TRUSSES
The curved steel roof trusses
are designed in such a way so
that they can fit into each
project without a problem.
They can easily be cut in order
to fit into any location or roof
type, and the length of the
roof isn’t a problem. Usually,
these steel trusses are smaller
than other materials, and they
can be quite lightweight too,
which means that moving the
trusses from one place to
another is a lot easier than
expected.

38. CURVED TIMBER ROOF TRUSSES
A great benefit brought by
the curved timber roof
trusses is that the
wood definitely offers a lot
of durability. This is very
important for the trusses
that do not have a normal
shape, such as the curved
ones. When it comes to
pricing, the curved timber
roof trusses can be a little
more expensive than the
curved steel roof trusses, it
all depends on the materials
used for the truss.

39. BENEFITS OF CURVED TRUSSES
• Ease of installation is crucial
as well, because unlike many
other trusses, these are easy
to install and come with a
highly reliable installation
method.
• The pricing is also right here,
because it’s not needed to
pay a lot in order to have a
different
• No high transportation costs,
as the size and design makes
them easy to move from one
place to another.

40. BENEFITS OF STEEL TRUSSES OVER
WOODEN
• These curved wood roof trusses are harder to implement than
the steel ones, and depending on the density of the wood used
there, they can also be heavier. But this more than makes up for
it when it comes to the natural look that the entire truss
provides. Of course, aside from the looks, the curved wood roof
trusses are designed with a lot of durability in mind.
• Both these and the metal ones need a professional to work with
them, because the process of creating a truss is a little harder
than expected, which means that a non-professional can easily
do a bad job and that’s something that should definitely be
avoided at all costs, which is crucial.

41. MOSCOW STADIUM
Capacity 81,000
(60,000 with
proposed
extra
platform for
athletics)
[1]
Record atten
dance
102,538
(Soviet
Union–Italy,
13 October
1963)
Field size 105 by 68
metres
(114.8 yd
× 74.4 yd)
Surface SISGrass
(Hybrid
Grass)

42. AIRPORT VILLAGE, HYDERABAD

43. IGI AIRPORT , NEW DELHI