A treatise on architecture and building construction . curing rigid connections be-tween the columnsand beams, and alsobetween the col-li umns themselves ind i if e r e n t are left onsuch columns towhich the carpenteris to seat and anchorthe ends of his beamsand girders; whenthese brackets arecast with a fillet, as shown at d, Fig. 96, the carpentersimply notches the under side of his beam, as for the caps andanchors above described. If a rolled-iron or steel I beamis used instead of a heavy wood girder, the carpenter will becalled upon to sheath the beam in wood to protect it,
A treatise on architecture and building construction . curing rigid connections be-tween the columnsand beams, and alsobetween the col-li umns themselves ind i if e r e n t are left onsuch columns towhich the carpenteris to seat and anchorthe ends of his beamsand girders; whenthese brackets arecast with a fillet, as shown at d, Fig. 96, the carpentersimply notches the under side of his beam, as for the caps andanchors above described. If a rolled-iron or steel I beamis used instead of a heavy wood girder, the carpenter will becalled upon to sheath the beam in wood to protect it, andunless iron brackets are provided to seat the floorbeams on,he will also be required to provide a wooden ledge, as shownat e, Fig. 96, on which the beams are set and secured. 339. The methods of sheathing iron girders with woodand of securing floorbeams to them are numerous, anddepend entirely on the purpose of the building and theeconomy of its construction. Under most circumstances, anexposed iron beam, such as is shown at c, will not stand the. Fig. 96. 9 CARPENTRY. 141 heat of a fierce fire as long as a wooden girder of equalstrength, such as is shown at b^ in Fig. 90. The iron beamabsorbs the heat and soon becomes so hot as to bend in themiddle, thereby throwing walls and columns out of plumb,and finally causing a collapse of that entire part of the build-ing in which it is located. A wood girder does not absorb the heat, and when exposedto flames takes fire very slowly, commencing with the lowercorners, or edges, and gradually burning up towards thecenter until it breaks through and precipitates its superim-posed load to the floor, or cellar beneath. If its ends are supported on a cap, such as shown in Fig. 95,or upon a bracket, as at d, in Fig. 96, it will probably as it falls, and inno way endanger thefloor above, as theburning material hasbeen carried down withthe girder and is far-ther away from thenext tier above thanbefore the floor , the
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Keywords: ., bo, bookcentury1800, booksubjectarchitecture, booksubjectbuilding
