This section is from the "Architectural Iron And Steel, And Its Application In The Construction Of Buildings" book, by WM. H. Birkmire.. Also see Amazon: Architectural Iron And Steel, And Its Application In The Construction Of Buildings.
All cast-iron, wrought-iron, or wrought-steel columns shall be made true and smooth at both ends, and shall rest on iron bed-plates, and have iron cap-plates, which shall also be made true. All iron or steel trimmer beams, headers and tail beams shall be suitably framed and connected together, and the iron girders, columns, beams, trusses and all other ironwork of all floors and roofs shall be strapped, bolted, anchored and connected together, and to the walls, in a strong and substantial manner. Where beams are framed into headers, the angle irons which are bolted to the tail beams shall have at least two bolts for all beams over seven inches in depth, and three bolts for all beams over twelve inches in depth, and these bolts shall not be less than three quarters of an inch in diameter. Each one of such angles or knees, when bolted to girders, shall have the same number of bolts as stated for the other leg. The angle iron in no case shall be less in thickness than the header or trimmer to which it is bolted; and the width of, angle in no case shall be less than one third the depth of beam, excepting that no angle knee shall be less than two and a half inches wide, nor required to be more than six inches wide. All wrought-iron or wrought-steel beams ten and a half inches deep and under shall have bearings equal to their depth, if resting on a wall; twelve-inch beams may have a bearing of ten inches, and all beams more than twelve inches in depth must have bearings not less than twelve inches if resting on a wall. Where beams rest on iron supports, and are properly ties to the same, no greater bearings shall be required than one third of the depth of beams. Iron or steel floor beams shall be so arranged as to spacing and length of beams that the load to be supported by them together with the weights of materials used in the construction of the floors shall not cause a deflection of the said beams of more than one thirtieth of an inch per linear foot of span; and if said beams are unsupported laterally by floor arches between them, or otherwise, they shall be tied together at intervals of not more than eight times the depth of the beam.
Under the ends of all iron or steel beams where they rest on the walls, a stone or cast-iron template must be built into the walls, said templates to be eight inches wide in twelve-inch walls, and in all walls of greater thickness to be twelve inches wide, and such templates, if of stone, shall not be in any case less than two and one-half inches in thickness and no template shall be less than twelve inches long.
All iron lintels shall have bearings proportionate to the weight to be imposed thereon, but no lintel used to span any opening more than ten feet in width shall have a bearing less than twelve inches at each end, if resting on a wall, but if resting on an iron post, such lintel shall have a bearing of at least six inches at each end by the thickness of the wall to be supported. If the posts are to be party posts in front of a party wall and are to be used for two buildings, then the said posts shall not be less than sixteen inches on the face by the thickness of the wall above, and if the party wall be more than sixteen inches thick, then the posts shall be the thickness of the wall on the face. Intermediate posts may be used, which shall be sufficiently strong, and the lintels thereon shall have sufficient bearing to carry the weight above with safety, as in this title provided. When the lintels or girders are supported at the ends by brick walls or piers they shall rest upon cut granite or bluestone blocks at least twelve inches thick, or upon cast-iron plates of equal strength by the full size of the bearings. In case the opening is less than twelve feet, the stone blocks may be six inches in thickness, or cast-iron plates of equal strength by the full size of the bearings may be used. In all cases where the girder carries a wall and rests on brick piers of walls, the bearing shall be sufficient to support the weight above with safety. No cast-iron lintel or beam shall be less than three quarters of an inch in thickness in any of its parts. Iron beams or girders used to span openings more than sixteen feet in width, upon which walls rest, or on which floor beams are carried, shall be of wrought iron and of sufficient strength ; or cast-iron arch girders may be used having a rise of not less than one inch to each foot of span between the bearings, with one or more wrought-iron tie rods of sufficient strength to resist the thrusts, well fastened at each end of the girder. All lintels or girders placed over any opening in the front, rear or side of a building, or returned over a corner opening, when supported by brick or stone piers or iron columns, shall be of iron and of the full breadth of the wall supported.