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Solutions for certain rectangular slabs continuous over flexible ...

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SOLUTIONS FOR CERTAIN RECTANGULAR<br />

SLABS<br />

according to the assumptions of the solution, will transmit no load.<br />

Its effect will then be to twist the stringers.<br />

35. Rectangular Slab, Having Two Opposite Edges Simply Supported<br />

and Two Edges Stiffened, Loaded by Symmetrical Concentrated<br />

Loads Placed on the Center Line Normal to the Stiffened Edges.-The<br />

slab is shown in Fig. 38 where it will be noted that the axes have been<br />

FIG. 38<br />

rotated and shifted from the position given in the corresponding<br />

solution of Section 17. The purpose of the change is to put the<br />

solution into a <strong>for</strong>m which, <strong>for</strong> small values of b/a, can utilize the<br />

well known solution <strong>for</strong> an infinitely long slab, having a span 2b = s,<br />

simply supported on the edges x = + b, and supporting the given pair<br />

of concentrated loads. For all values of b/a the solution may, however,<br />

be stated in a <strong>for</strong>m which contains, in part, the solution of<br />

the <strong>rectangular</strong> slab, simply supported on four edges, and carrying<br />

the given loads.<br />

Consider the portion of the slab between the limits x = ±v.<br />

The deflection, wi, is given by the sum of Equations (94) and (96)<br />

provided that proper correction is made <strong>for</strong> the position of the pair<br />

of loads and <strong>for</strong> the changed axes. One finds<br />

Pa 2 1 1<br />

wi - 1 { [b, + (1 + av) e-"'] cosh ax<br />

n 3 -N ) s..c<br />

(192)<br />

where bi and cl are given in Appendix B.<br />

- (c, + e- ") ax sinh ax } cos ay

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