Does anyone know the rationale behind this - W/50 slope? Example: 1/4:12 roof pitch = 1.19 degrees. W = 60 eave to ridge, W/50 = 1.2. Slope is less than 1.2 so surcharge is added. Same roof, W =55, W/50 = 1.1. Slope is now greater than 1.1 thus surcharge is not required. Seems there is a...
Underhung hoist or bridge crane. The rail is supported at the top flange. There are no other supports. The required horizontal force is applied at the bottom flange. As such it either bends the web or puts the section in torsion. But the supports being at the top rail only do not give much...
Plan on an extension to which we can brace the top of the runway. I do not like the cantilevered column either, but not sure of alternatives. Have preliminary design with column taking all load (no sharing). Large column to resist moment and limit deflection to h/400. With sharing should be...
Thanks for the quick response. Existing structure is PEMB designed as a warehouse, no accounting for crane. Owner has instructed that crane be independant of building. Found other posts on the sharing or lack thereof of the horizontal force accross the bridge. Will apply load without sharing...
Looking at a crane system independant from the building structure. No clearance to brace overhead from runway to runway so columns will be cantilevered to resist horizontal forces perpendicular to runway. Is the bridge and the trolley mechanism strong enough such that the horizontal forces...
The equation for Avo is based on a large concrete section and uses the edge distance to calculate the area. Looking at a foundation such that the edge distance is very large compared to the depth. In calculating Av it will be limited by this depth. Thus the ratio of Av / Avo used in eq. D-20...
A concrete beam spans between two other concrete beams. Can it be designed as a simply supported beam? Bottom steel designed for beam moment, top steel provided for stirrups, concentrated loads to supporting beams. Or should it be designed as contimuous? Top steel to resist moments at...
