Tubular Steel Roof Truss | Trussed large span Constructions

Tubular Steel roof trusses are used for large span constructions such as factories, industry worksheds, shopping malls, huge exhibition centres, multiplexes etc. They are generally used for spans as large as 25-30m.

There is a similar kind of a truss called “Tubular Steel Monitor Roof Truss“. There are projections on the roofs called “Monitors” to admit daylight into the space.

Tubular Steel Roof Truss
Tubular Steel Roof Truss

  • It is in two halves with bolted joints at P and Q, the remaining joints being 5mm fillet welds made in the workshop.
  • The main tie member rises 130mm from L to N to counteract any appearance of sag that would be evident if it were horizontal.
  • A bend a N reduces the midspan height to 2m so that the half truss is a manageable size for transportation.
Tubular Steel roof Truss
Tubular Steel roof Truss
Details of Tubular steel roof truss
Details of Tubular steel roof truss
  • The eaves detail L is given at G, where the rafters and the main tie tubes are fillet welded to an end plate.
  • The site connection to the column is with 16mm diameter bolts using an angle cleat, a further angle bracket at the top is used for the purlin attachment . Small plates are welded to the purlin for this purpose, this purlin also acts as a sheeting rail for the side cladding.
  • The roof covering in this thickness of asbestos sheeting which should have bitumen bonded glass wool insulation between the sheets.
  • The ridge joint at E show plates which are welded to the rafters, these are bolted to the four site bolts.
  • The plates are used to connect vertical end tubes of the two halves of the truss.
  • The corresponding joint at Q of the tie member is given at J and K, the two bottom holes in the circular plate are used to fix a longitudinal tie at right angles to the trusses, the two holes above these can also be used to fix braces against the gable walls of the building in the end bays.
Steel truss on Terrace
Steel truss on Terrace

Advantages of Tubular Steel Roof Trusses

  • Structures designed for material handling equipments (e.g., a bridge and a tower crane) where weight savings may be very substantial economic consideration.
  • 30% to 40% less surface area than that of an equivalent rolled steel shape. Therefore, the cost of maintenance, cost of painting or protective coatings reduce considerably.
  • The moisture and dirt do not collect on the smooth external surface of the tubes. Therefore, the possibility of corrosion also reduces.
  • The ends of tubes are sealed. As a result of this, the interior surface is not subjected to corrosion. The interior surface do not need any protective treatment.
  • They have more torsional resistance than other section of the equal weight.
  • They have a higher frequency vibrations under dynamic loading than the other sections including the solid round one.

30 thoughts on “Tubular Steel Roof Truss | Trussed large span Constructions”

  1. actually i need a particular design example for a tubular truss in this post i was just able to know the fundamental concepts but is it possible to know a complete design regarding tubular truss???

  2. There are numerous variables that must be considered to determine the weight limit of a steel truss. Some factors include the span length, the amount of lateral bracing, acceptable movement and bending and bowing.

  3. I need a detailed sketch showing the design of a tubular steel truss to span 16 m.Spacing of the trusses is 2.4 m c/c.Roofing with aluminium trafford sheets 22 gauge.Maximum load per sq.m of roof is 150 kg.Shall I get a suitable structural design ?

  4. can a roof trus be built for a hip style roof with a free span of 62 ft? Prefer pitch of 2/12. What spacing would be required for normal loading, Metal standing seam roof would be utilized

  5. Very useful deta collection for students of architecture like me as we r not awair of these topic , thanks to share the knowledge, looking more for north light trusses construction & its details, built with morden technology, hope to get the response very soon.

  6. Hi!

    I’m currently sourcing photos for a publishing company, specifically for a high school textbook. Would it be possible to purchase any of your images to use in the text book? Specifically one of the tubular steel roof trusses.

    Thank you!

    Kind regards,


  7. Dear,

    we want to construct one coal shed of size 250 mtr x 50 mtr and Ht 10 mtrs, is it advisable to go for tubler truss or warner truss, as span is 50 mtr column to column.

  8. Hello Edward,
    Is it advisable to have diagonal members directly welded to top and bottom chord members without gussets in a tubular truss?What are the conditions like thickness of tubular truss members for direct welding?

  9. we are a construction company in Uganda,kampala we have done a couple of steel roof projects,however i would like keep me posted with new design and its an opportunity for me to learn more

  10. need a detailed sketch showing the design of a tubular steel truss to Length 60 m.Spacing of the trusses is 10 m Width Roofing .Shall I get a suitable design ?

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