Type of Trusses

1
Page 1 of 40
Chapter 3 Analysis of Statically Determinate
Trusses
? Type of Trusses ? Assumption for Design ?
Classification of Coplanar Trusses ? Methods of
Joint and Section ? Compound Trusses ? Complex
Trusses
2
Page 2 of 40
??????????? Trusses
Truss ??? ?????????????????????? Slender
member ???? ? ???? ??????????????????? members
???? Pin
Members ??????????????? ???? ????? Joint
???????????? Bolt ???? ????? welding ?????
3
Page 3 of 40
Type of Trusses
?????????????

• Bridge Trusses

• Roof Trusses

4
Page 4 of 40
Type of Trusses
?????????????

• Roof Trusses
• Scissors
• Howe
• Pratt
• Fan
• Fink
• Cambered Fink
• Warren
• Sawtoolh
• Bowstring
• Three-hinge Arch

Exit
5
Page 5 of 40
Type of Trusses
?????????????

• Roof Trusses
• Scissors
• Howe
• Pratt
• Fan
• Fink
• Cambered Fink
• Warren
• Sawtoolh
• Bowstring
• Three-hinge Arch

Exit
6
Page 6 of 40
Type of Trusses
?????????????

• Roof Trusses
• Scissors
• Howe
• Pratt
• Fan
• Fink
• Cambered Fink
• Warren
• Sawtoolh
• Bowstring
• Three-hinge Arch

Exit
7
Page 7 of 40
Type of Trusses
?????????????

• Roof Trusses
• Scissors
• Howe
• Pratt
• Fan
• Fink
• Cambered Fink
• Warren
• Sawtoolh
• Bowstring
• Three-hinge Arch

Exit
8
Page 8 of 40
Type of Trusses
?????????????

• Roof Trusses
• Scissors
• Howe
• Pratt
• Fan
• Fink
• Cambered Fink
• Warren
• Sawtoolh
• Bowstring
• Three-hinge Arch

Exit
9
Page 9 of 40
Type of Trusses
?????????????

• Roof Trusses
• Scissors
• Howe
• Pratt
• Fan
• Fink
• Cambered Fink
• Warren
• Sawtoolh
• Bowstring
• Three-hinge Arch

Exit
10
Page 10 of 40
Type of Trusses
?????????????

• Roof Trusses
• Scissors
• Howe
• Pratt
• Fan
• Fink
• Cambered Fink
• Warren
• Sawtoolh
• Bowstring
• Three-hinge Arch

Exit
11
Page 11 of 40
Type of Trusses
?????????????

• Roof Trusses
• Scissors
• Howe
• Pratt
• Fan
• Fink
• Cambered Fink
• Warren
• Sawtoolh
• Bowstring
• Three-hinge Arch

Exit
12
Page 12 of 40
Type of Trusses
?????????????

• Roof Trusses
• Scissors
• Howe
• Pratt
• Fan
• Fink
• Cambered Fink
• Warren
• Sawtoolh
• Bowstring
• Three-hinge Arch

Exit
13
Page 13 of 40
Type of Trusses
?????????????

• Roof Trusses
• Scissors
• Howe
• Pratt
• Fan
• Fink
• Cambered Fink
• Warren
• Sawtoolh
• Bowstring
• Three-hinge Arch

Exit
14
Page 14 of 40
Type of Trusses
?????????????

• Bridge Trusses
• Pratt
• Howe
• Warren(With Verticals)
• Parker
• Baltimore
• Subdivided Warren
• K-Truss

Exit
15
Page 15 of 40
Type of Trusses
?????????????

• Bridge Trusses
• Pratt
• Howe
• Warren(With Verticals)
• Parker
• Baltimore
• Subdivided Warren
• K-Truss

Exit
16
Page 16 of 40
Type of Trusses
?????????????

• Bridge Trusses
• Pratt
• Howe
• Warren(With Verticals)
• Parker
• Baltimore
• Subdivided Warren
• K-Truss

Exit
17
Page 17 of 40
Type of Trusses
?????????????

• Bridge Trusses
• Pratt
• Howe
• Warren(With Verticals)
• Parker
• Baltimore
• Subdivided Warren
• K-Truss

Exit
18
Page 18 of 40
Type of Trusses
?????????????

• Bridge Trusses
• Pratt
• Howe
• Warren(With Verticals)
• Parker
• Baltimore
• Subdivided Warren
• K-Truss

Exit
19
Page 19 of 40
Type of Trusses
?????????????

• Bridge Trusses
• Pratt
• Howe
• Warren(With Verticals)
• Parker
• Baltimore
• Subdivided Warren
• K-Truss

Exit
20
Page 20 of 40
Type of Trusses
?????????????

• Bridge Trusses
• Pratt
• Howe
• Warren(With Verticals)
• Parker
• Baltimore
• Subdivided Warren
• K-Truss

Exit
21
Page 21 of 40
Assumption for Design
??????????????????
1. ????????????????????????????? ??????????
???????????? ? ?????????????????? 2.
?????????????????????????????? Pined ????????????
Pin ???? Hinge 3. ???????????????????????????????
???????????????????? 4. ??????????????????????????
?????????????????????????
Tensile member
Compression member
22
Page 22 of 40
Classification of Coplanar Trusses
Trusses ??????? 2 ???? ??????? Statically
Determinate ????????????

• Simple Truss
• Compound Truss
• (Type1, Type2, Type3)
• Complex Truss

23
Page 23 of 40
Classification of Coplanar Trusses
Trusses ??????? 2 ???? ??????? Statically
Determinate ????????????
Type1

• Simple Truss
• Compound Truss
• (Type1, Type2, Type3)
• Complex Truss

Type2
Type3
24
Page 24 of 40
Classification of Coplanar Trusses
Trusses ??????? 2 ???? ??????? Statically
Determinate ????????????

• Simple Truss
• Compound Truss
• (Type1, Type2, Type3)
• Complex Truss

25
Page 25 of 40
Methods of Analysis
Methods of Joint
Method of Joint
??????????????? Truss ???????????????? (Method of
Joint) ?????????????????????????? ?????????????
??????? 2 ??? ???????????
26
Page 26 of 40
Methods of Analysis
Methods of Section
Method of Section
????????????????????? (Method of Section) ???
???????????????????? 2 ???? ?????????? ??????
????????????????????????????? ???????? ??????
27
Page 27 of 40
Example 3.1
Determine the force in each member of truss shown
in Fig.3-24a State whether the members are in
tension or compression.
28
Page 28 of 40
Compound Trusses
Compound Truss ?????????????????????????????
?????????????? Simple Truss ??????? 2 Simple
Truss ?????? ?????? Bars ???? Joint ????????????
?????????????????????? Method of Joint ???
Method of Section
29
Page 29 of 40
Example 3.2
Indicate how to Analysis the compound truss shown
in Fig.3-29a.The reaction at the supports have
been calculated.
30
Page 30 of 40
Example 3.2
??????????????????

• ??? Methods of Section ??????? Bar ???
• ????????? Simple Truss ??????? (HG)
• ??????? Simple Truss ???????? Take
• momemt ???? ????? Simple Truss ????
• ?????????
• ???????????? Simple Truss
• (Method of Joint or Method of Section)

31
Page 31 of 40
Example 3.3
Indicate how to Analysis the compound truss shown
in Fig.3-30a.The reaction at the supports have
been calculated.
32
Page 32 of 40
Example 3.3
??????????????????

• ??? Methods of Section ??????? Bar ???
• ????????? Simple Truss ??????? (HG)
• ??? Free Body Diagram ??????? ???
• ?????????? ???????????? Bar
• ???????????? Simple Truss
• (Method of Joint or Method of Section)

33
Page 33 of 40
Example 3.4
Indicate how to Analysis the compound truss shown
in Fig.The reaction at the supports have been
calculated.
34
Page 34 of 40
Example 3.4
??????????????????

• ??? Secondary truss ??????????????
• ??? Support ????????? B
• Main Truss ??????? Symmetry ???
• Load ??? Support ??? Secondary truss
• ???? Joint ??? Main Truss
• ????? member ????? (AE,CE) ???
• Secondary truss ?????? Method of
• Joint (A) ?? FAE ??? FCE ?????
• member ?????????

35
Page 35 of 40
Complex Trusses
Complex Truss ??????????????????
Determinate ???????????????????????? Simple Truss
??? Compound Truss ???????????????????????????????
member ?????????????????? ?? ?
??????????????????????? (???????????) ??????????
method of substitute member ???? method of
Supperposition ???????????????????? Method of
Joint ??? Method of Section ???????????
36
Page 36 of 40
Complex Trusses
Procedure for Analysis

• Reduction to Stable Simple Truss, Si
• External Loading on Simple Truss, si
• Supperposition , Si Si- xsi

37
Page 37 of 40
Example 3.5
Determine the force in each member of the complex
truss shown in Fig. Assume joint B, F and D are
on the same horizontal line. State whether the
members are in tension or compression.
38
Page 38 of 40
Space Trusses
????????????? ????????????????????????? Engineerin
g Mechanics (Static)
39
Page 39 of 40
Home Work III
1) Determine the force in each member of the
truss.State if the members are in tension or
compression
40
Page 40 of 40
Home Work III
2) The truss show in used to support the floor
deck. The uniform load on deck is 2.5 k/ft.
This load is transferred from the deck to floor
beams, which rest on the top joint of the
truss. Determine the force in each member of the
truss, and state if the members are in
tension or compression. Assume all members are
pin connected
41
Page 40 of 40
Home Work III
3) Determine the force in all members of the
complex truss. State if the members are in
tension or compression
500 lb
E
30?
D
F
30?
30?
12 ft
A
45?
C
45?
B
6 ft
6 ft