Note the haunch at the eave. This is provided to take the large bending moment which occurs there and also to provide the depth required to take all of the bolts transferring the moment between the rafter and the column. Note the bolts connecting the column to the rafter and the 45 degree stays which help to develop a moment between the purlins and the rafter. The eaves detail on the left is the simple one as used on this case study. The one on the right is often used to hide the roof pitch and thereby to give the impression of a higher specification building.
Care has to be taken with the possible build-up of snow in the valley.
Note the relationship between the main steel sections, the purlins, the cleats connecting the purlins to the main steel and also the two layers of cladding. The roof sheets have been fixed. Note the proportion of roof lights. Too much and the building will overheat, even in winter, too little and it will be dark. In time, the sheets will become dirty and the illumination will diminish.