Efficient sizing of rigidly fixed portal frames under different static loads

This work considered the height to span ratio (h/L) ratios that would give the most economical design for portal frames under different static loads. The equations for minimum depth for each section of the portal frame were first developed. These were used to formulate the equation for the volume of the frame. The volume of the frame was taken to be proportional to the cost of the portal frame. The usefulness or benefit of the frame was computed as the ratio of the frame's cross-sectional area to its perimeter. The economical height to span ratio (h/L) for any kind of load were the ratios that gave the least cost/benefit value. These values were found to depend on the ratio of the load to the grade of portal frame material w/σ and the thickness b of the portal frame.