Parametric Study of Framed Truss Systems forLarge Span Industrial Structures

Abstract

-Use of high strength steel (300-350MPa) framed trusssystems is increasing in the current scenario instead of
conventional mild steel (250 MPa) truss systems as it is structurally more efficient and has less depth requirement. Also due
to development of good and efficient connection technologies,large industrialroofing systems are now using closed form
tubular sections instead of traditional angles, channels and I-sections. The roof slope of the framed truss is kept in the range
of 5
o
-7
o
as against 10o
-15o
for conventional trusses thereby reducing the exposed area for wind loads. As a result of above
factors, framed trusses proves economical as compared to conventional trusses. But on the other hand use of lighter sections,
results in increased deflection which needs attention. Lack of sufficient guidelines in Indian design codes, needs investigation
in design parameters of framed trusses. So to optimize the design of framed trusses, influence of design parameters such as
truss depth at eave and at ridge level, roof angle and number of panels have been studied to assess their impact/influence on
the ridge deflection and self-weight of truss. It is observed that increasing the truss depth at eave proves economical in
controlling ridge deflection rather than increasing the sizes of member. The results are presented in graphical form.