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A rectangular solid steel beam with a width of 100mm and is usedas a roof purlin on simple span of 2.5m and a spacing of 400mm oncenter. The roof slope is 1:4. The roof dead load due to roofingmaterials (D) is 30 kPa (excluding self-weight) and a roof liveload (Lr) of 45kPa. Assume that the load passes through thecentroid of the section and plastic behavior. Determine thefollowing. Unit weight of Steel is 7850 kg/m3 and Fy=345 MPa. UseLRFD
(a) Determine the minimum depth of the steel beam
(b) Determine the minimum depth of the steel beam if the maximumpermissible flexural stress 125 MPa.
(c) If the sag rod is applied at the middle thirds, determinethe maximum flexural stress developed on the beam if the depth is400mm.
A rectangular solid steel beam with a width of 100mm and is used as a roof purlin on simple span of 2.5m and a spacing of 400mm on center. The roof slope is 1:4. The roof dead load due to roofing materials (D) is 30 kPa (excluding self-weight) and a roof live load (L) of 45kPa. Assume that the load passes through the centroid of the section and plastic behavior. Determine the following. Unit weight of Steel is 7850 kg/m³ and Fy=345 MPa. Use LRFD (a) Determine the minimum depth of the steel beam (b) Determine the minimum depth of the steel beam if the maximum permissible flexural stress 125 MPa. (c) If the sag rod is applied at the middle thirds, determine the maximum flexural stress developed on the beam if the depth is 400mm.