Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
At most locations, there i s good agreement between measured and computed deflections. However, there i s a wide difference between measured and computed deflections along colisnn Line £. Computed deflections substant- iaJ.ly underestimate the measured deflection, and t h i s was also r e f l e c t e d i n the center-of-panel deflections discussed e a r l i e r . The high measured deflections were probably influenced by the diagonaJ. cracking caused by settlement of the structure p r i o r to tes t i n g . Column Loads. An equivalent frame an a l y s i s was also vised to calculate coltmin loads. Loads were determined for columns a t which the slab f a i l e d i n shear during each of the three t e s t s . I n addition, e f f e c t on column loads of settlement of the structure was evaluated. Column loads determined by the frame an a l y s i s for a 1 psf applied l i v e load are l i s t e d i n Table V I I I . These quantities are compared to nominal column reactions. Nominal reactions are based on the assumption that the column supports a loaded area bounded by the centerlines of adjacent panels. Column loads based on t h i s assianption would e x i s t i n the i n t e r i o r of a multi- panel slab subjected to a uniform load. The colvnnns chosen for comparison are those where shear punching f i r s t occurred i n each of the three t e s t s . I t i s seen that for Columns Ck and C5 there i s l i t t l e difference i n the computed column loads using different frames. For both columns, computed values Eire somewhat greater than nominal column loads. The r a t i o of com- puted to nominal loads ranges from I . 0 9 to I . 1 6 for Column C5 and l.lk to 1.17 for Coliann Ck. As expected load computed for Column E3 i s somewhat l e s s than the nominal value. As shown previously i n F i g . 15, considerable d i f f e r e n t i a l settlement seemed to have occurred each side of column Line h. Maximum settlement was at column Lines 1 and 7- Prom contours of deflection, l i t t l e d i f f e r e n t i a l settlement was noted along Column Line k. Ihe structure appeared to be supported mainly i n t h i s i n t e r i o r area. History of t h i s settlement i s 1- 32
TABLE V I I I COLUMN UNIT LOADS Column ⢠No. Frame Analysis No. Test No. Computed Column Unit Load,* Ib/psf Nominal Column Unit Load,** Ib/psf Computed Nominal C4 C4 C4 4a 4b C I I I 1057 1066 1031 908 908 908 l . l 6 .1.17 1.14 E3 E3 3 E I I I I 383 479 479 479 0.80 1.00 C5 C5 5 c I I I I I I 264 248 228 228 l . l 6 1.09 * From frame analysis ** From area bounded by panel centerlines not known. I n order to evaluate probable e f f e c t s on colvimn loads, i t was assumed that the structure was supported only beneath the two center bays between Lines 3 and 5* For t h i s support condition column loads r e s u l t i n g from settlement can be computed. Only the dead weight of the foundation slab was considered m these calculations since the reaction due to the weight of the roof slab i s calculated i n the same way as that due to l i v e loads. Load i n Column E3 induced by settlement of the structure was estimated by analyzing the frame shown i n Fig. 55. Since the frame i s symmetrical about column Line 4 only one-half of i t i s shown i n F i g . 55. F l e x u r a l s t i f f n e s s e s of the struct\ire along column Line C were used in the computations. Again an uncracked concrete section was used. Uniform load along the foundation was taken equal to the dead weight of the slab. This load was supported e n t i r e l y from below by a uniformly d i s t r i - buted load i n Span 3-4. Because of symmetry, end spans at Line 4 were consi- dered fixed. Dead weight of the 28-in. deep foundation slab was 350 psf. 1- 33
