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Test I I . Test I I was divided i n t o two parts. I n Part A, the three panels along the edge of the b u i l d i n g between column Lines 2 and 5 were loaded. This part of the t e s t ended with a shear f a i l u r e at Column E 3 . I n Part B, Panel 4,5-D,E and the adjacent h a l f of Panel 3,4-D,E were loaded. Part B was tenninated a f t e r the slab f a i l e d i n shear at Column Elt-. Part A of Test I I l e d t o a deflection of the waffle slab at 3^7 psf applied load (added dead plus 1 . 0 l i v e load) as shown i n Fig. 3 5 . I t can be seen t h a t deformation outside the loaded panels was small. Along the middle of the slab between Lines D and E, deflection at midspan between columns and at panel centers was about equal; deflec- tions at the centers of loaded panels were only s l i g h t l y higher than those at column s t r i p midspan. Such a defle c t i o n pattern indicates e s s e n t i a l l y one-way action of the loaded panels. Deflections of the edge beam along column Line E were about twice those of the column s t r i p s along column Line D. The edge beam was 3 0 . 3 7 5 - i n * deep, 6 - 3 7 5 i n . deeper than the slab, and had a width of 4 5 i n . This extra depth was not s u f f i c i e n t t o compensate f o r the smaller e f f e c t i v e width of the slab along column Line E. Load-deflection curves were l i n e a r u n t i l load exceeded 4 9 9 psf (added dead plus approximately 1 . 5 l i v e loads). Cvirves f o r def l e c t i o n at the middle of the loaded panels are shown i n Fig. 3 6 . A f t e r t h i s load stage, deflections i n Panels 2,3-D,E and 3,U-D,E increased s i g n i f i c - a n t l y with load. I n p a r t i c u l a r , load-deflection curves became nearly- horizontal f o r Locations 5 1 and 5 9 i n Fig. 2 2 as loading approached added dead plus two l i v e loads. Strain records also indicated distress at Column E 3 . Load-strain relationships changed markedly at an applied load of 56O psf (added dead plus I . 7 l i v e loads). Gages i n Panel 3,4-D,E showed a decrease 1 - 2h
i n s t r a i n at t h i s load. Load-strain curves for Gages 66 and 68 shown i n F i g . 37 are t y p i c a l . (Location of the gages i s shown in Fi g . 24.) However, Gages 42 and 37 continued to indicate increased s t r a i n . These gages were on negative moment reinforcement across Line D. Since decrease i n s t r a i n was exhibited by gages in both positive and negative moment, regions, the pattern of changing s t r a i n indicated r e d i s t r i b u t i o n of moments. I t i s evident that i n i t i a t i o n of the shear f a i l u r e at Column E3 reduced the column reaction. This increased the amount of negative moment i n the slab along column Line D. Shear f a i l u r e a t Column E3 occurred when the applied load reached 607 psf. This load i n t e n s i t y i s equal to added dead plus about 1-9 l i v e loads. A view of the failiare zone at Column E3 a f t e r the t e s t i s shown i n F i g . 38. The diagonal cracks extended from the junction of the column and edge beam to the top of the slab at an angle measured to be about 35° from horizontal. Deflections a f t e r f a i l u r e had occurred and the load was removed are shown in Fi g . 39- I * i s apparent that r e s i d u a l deflections were sub- s t a n t i a l . Part B of Test I I was conducted to evaluate shear strength at Column E4. This column was sim i l a r i n location and in dimensions to Colimin E3. Colimn E3 was 12 x 32 i n . i n plan, while Column E4 was 12 x 24 i n . Deflections and st r a i n s were measured, but t h i s information i s used only for q u a l i t a t i v e purposes. The proximity of the f a i l u r e at Column E3 precludes t h e i r use as a true indication of behavior of a monolithic reinforced concrete structure. Load was applied i n one increment to 607 psf, the load at which f a i l u r e occurred at Column E3 i n Part A. Load was then Increased i n increments of about 40 psf. When an applied load i n t e n s i t y of about 728 psf was 1-25
