Steel Roof Truss Span To Depth Ratio

25 t to 75 t crane 8 over 75 t crane 7.

Steel roof truss span to depth ratio.

05425 cold formed steel trusses roof truss spans every trussteel roof truss is a custom design based upon the unique load span bearing use and code criteria of a particular project. Most economical when the difference in slope between the top and bottom chords is at least 3 12 or the bottom chord pitch is no more than half the top chord pitch. Even though the overall bending effect is larger at mid span the chord member and web member stresses are smaller closer to the mid span and larger closer to the supports. Metal plate connected wood trusses hib 91 by permission of truss plate institute inc.

Roof floor truss manual 7 31 08 10 43 am page 11. Design of roof purlins 6 for efficient structural performance it is recommended that the truss span to depth ratio be kept between 10 to 15. Plate girder web thickness about depth 160. The architectural design of the building determines its external geometry and governs the slope s given to the top chord of the truss.

A brace should have a capacity in the order of 2 of the force in the main compression member or in the compression flange of a beam or girder. Or close to it in odd panel. 7 in the layout of truss systems it is more preferable in terms of economy and efficiency to have the shorter members in compression and the longer members in tension. General p roportions of steel structures.

Maximum span to depth ratio is 24 for parallel chord roof trusses for example a 24 deep parallel chord roof truss should not exceed a span of 48. The load span tables shown below demonstrate only a tiny subset of the possible combinations available with trussteel cfs roof trusses. A radius equal to the span will give a ratio slightly larger than the suggested minimum. The typical span to maximum depth ratios of pitched roof trusses are in the range of 4 to 8 the larger ratio being economical in longer spans.

For pitched trusses an effective depth to span ratio between 1 5 and 1 6 is recommended and a minimum of not less than 1 7 unless special consideration is given to deflection. The span to depth ratio of trusses ranges from 10 to 25 depending on the intensity of the applied load. Valleys and piggyback trusses must have verticals 4 o c. Flat the most economical flat truss for a roof is provided when the depth of the truss in inches is approximately equal to 7 of the span in inches.

For efficient structural performance the ratio of span to truss depth should be chosen in the range 10 to 15.