Mill Building Frame Analysis: Distribution of Lateral Loads

In recent years, few papers have covered the subject of mill buildings. In one of the papers,1 a programmable solution for mill building columns was given using the equations proposed in the Murray-Graham stepped column model. It dealt with a truss-column system with knee braces or parallel chord trusses where both chords were connected to the columns, providing a partially fixed condition at the truss column interface. Not all mill buildings have knee-braced roof trusses because of the lack of clearances and other restrictions. This paper is an analysis of such mill buildings. Also, it is an attempt to relate the stiffness of trusses and columns in a mill building with knee braces and to develop a method of analyzing such frames. It deals only with the distribution of horizontal loads acting along the transverse direction. The horizontal loads, either external loads or those induced from vertical loads, are carried by the frame or bent along a transverse row. The analysis, involving trusses and columns, is on the basis of a plane frame, i.e., loads on a frame in a row are carried by that frame only and not shared by adjacent rows. This assumption is more valid for wind loads than for localized crane wheel loads (localized compared to the length of the building). However, in this paper it is assumed bottom chord bracing, which makes it possible for adjacent rows to share crane-induced loads, is either not present for the entire length of the building or not effective enough.