A treatise on architecture and building construction . most invariably been theseblocks that broke first; hence, it is very necessary to havethem extra strong, so as to equalize the strength of the dif-ferent parts forming the arch. Fig. 79 represents a form ofcombination construction; the inside blocks a are madesimilarly to those shown in Fig. 78; b is the skewback, hav-ing a flange extended under and protecting the beam, asindicated at c. These skewbacks have failed in some tests,and in later constructions have been replaced by those repre-sented in Fig. 78. 163. Another combination arch, w
A treatise on architecture and building construction . most invariably been theseblocks that broke first; hence, it is very necessary to havethem extra strong, so as to equalize the strength of the dif-ferent parts forming the arch. Fig. 79 represents a form ofcombination construction; the inside blocks a are madesimilarly to those shown in Fig. 78; b is the skewback, hav-ing a flange extended under and protecting the beam, asindicated at c. These skewbacks have failed in some tests,and in later constructions have been replaced by those repre-sented in Fig. 78. 163. Another combination arch, which is consideredvery strong and durable, is represented in Fig. 80; at rt- isshown the strongly braced skewback, having three or morewebs; at b, the inside blocks, laid end to end; at r, the side-method key; and at d, the beam protection, formed in twopieces, and separate from the skewbacks. The side andend surfaces of the blocks are corrugated, permitting the 8 MAvSONRY. 95 insertion of more mortar, and preventing the pieces slippingby each Fig. 80. 164. Weiglit.—The weight, of course, varies with thedepth and span of the arch. The depth ranges from 6 to 12inches in arches constructed on the side method, and fromG to 15 inches in those built on the end method. For ofhceand store buildings, a common depth is 10 inches, the floor-beams being spaced from 5 to 7 feet apart. It is preferableto have the blocks equal in depth to the beams, as it makesa lighter floor than when much concrete filling is weights and safe spans of both dense and porous tilingare given in Table 4: TABLE 4. WEIGHTS AND SPATSTS OF TILE ARCHES. DENSE TILE. POROUS TILE—END METHOD. Depth inInches. Span inFeet. Weight in Pounds per Square Foot. Depth inInches. Span inFeet. Weight in Pounds per Square Foot. G7891012 3i-4 4 -4i ?±2 t»2 5 -5f ^3 fil fii_7i ^2 2 22-2927-3230-3532-3734-4137-42 G IV i 8 9 10 12 15 3-5 Ql Kl^2~ 2 4^- G4.^ 5-7G - 871-10 21242730333743 96 MAvSONRY. § 8
Size: 2963px × 843px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, bookcentury1800, booksubjectarchitecture, booksubjectbuilding
