Structural Mechanics

1. STRUCTURAL
CONCEPT OF
TRUSSES
MAKSIM MIKHAILOV L163330108

2. INTRODUCTION
Trusses are the key engineering feature in the emerging
civil engineering contest. Indeed, long span structures with
light weight is the main reason for the increase in the
demand of trusses in the construction industry. Since from
the usage of steel as a construction material, due to its
higher strength with lower mass, trusses took a major role
in the civil structures together with the advancement of
steel industry. Over the past years and even for now
considering aesthetic feature these trusses are made with
the timber planks as well. Roof trusses, bridges, electricity
and telecom towers and even the structural frames are
making use of these trusses as their integral structural
forms.

3. DEFINITION
Trusses are simply defined as triangulation of members to
make the stabilized structure. Triangulation is the stable
configuration mathematically. Generally, a truss has the
members called as top chord, bottom chord, vertical chord
and diagonal chord. The main functions of the trusses are
Carrying the loads from the over structures
Providing adequate lateral stability to the entire structure

5. TRUSS DESIGN
There are some basic assumptions in the designing process. It should be clarified
that the construction of the trusses should conform with the design assumptions
to avoid the unwanted failures due to the dispersion of the forces and loads.
Following are the assumptions in truss design.
Truss members will carry only the axial forces
The nodes i.e the connections of the members are designed as pinned joints so
that moments won’t be transferred to the members of the truss
All the external loads and the reactions are act only on the nodes
Generally, the truss should be in a plane.
Typically the members of the trusses are made as I sections, angles, T sections,
Tube sections, Square sections and channel sections. I sections are more
preferable as a optimized section in terms of the structural forces.

6. TYPES OF TRUSSES
Simple truss – indicates a single triangular truss. These
trusses are most often used as the roof trusses.
Planar truss – as the name implies it is a two dimensional
truss. If all the members and the nodes are in a planar
surface, then this truss is a planar truss.
Space frame truss – Contrast to planar truss, the members
and the nodes are located in the three dimensional space.
Electrical and telecom towers are the one of the simplest
example that we are seeing in the day to day life.

7. FORMS OF TRUSSES
Pratt truss Warren truss
North light truss
Vierendeel truss

8. KING POST TRUSS, BOWSTRING TRUSS, QUEEN POST
TRUSS, FLAT TRUSS, LENTICULAR TRUSS ARE SOME
OTHER FORMS OF TRUSSES IN THE USE OF THE
INDUSTRY.

9. REAL LIFE EXAMPLES

10. Thank you!