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381 IBRACON Structures and Materials Journal • 2013 • vol. 6 • nº 3
P. F. SCHWETZ | F. P. S. L. GASTAL | L. C. P. SILVA F°
gram considers only the sum of all loads applied on the structure,
including its self-weight. This load can, however, be divided into a
number of stages to be defined by the user. Hence, in this study,
the results originated only from the consideration of the additional
dead load were obtained through the difference between two dif-
ferent analyses: one applying the sum of self-weight load, addition-
al dead load and masonry applied straight on beams and the other
applying only the self-weight and the masonry load on the beams.
4. Analysis of the results
This study presents the results obtained in the numerical analyses
and those measured experimentally regarding the additional dead
load applied as indicated in Fig. 11. Slab deflections and distribu-
tion of bending moments are compared using numerical and ex-
perimental results obtained along slab lines indicated as Line A
and Line B as shown in Fig. 6.
4.1 Vertical displacements
Fig. 12 and 13 present deflection along slab lines A and B obtained
with the nonlinear analyses of the structure as well as the values
obtained experimentally.
A similar behavior is verified between numerical results of the two
models and the experimentally measured data, showing that both
numerical design strategies are fairly able to represent actual waf-
fle slab deformed behavior.
4.2 Bending moments
In order to compare the numerical results with the ones obtained
experimentally, the measured strains had to be transformed into
bending moment estimates, considering the equilibrium of internal
forces in the instrumented cross-sections [11].
Three values of bending moments were determined for each sec-
tion, as shown in Fig. 14:
n Experimental uncracked section with calculated εs: Bending
moment is calculated considering the uncracked cross-section,
with the reinforcement strain inferred from a strain gradient de-
fined from the experimental strain values measured;
n Experimental uncracked section with measured εs: Bending
moment is calculated considering the uncracked cross-section,
but takes into account the measured reinforcement strain. This
estimate of the bending moment cracking onset concerns con-
crete contribution between cracks (tension stiffening effect);
n Experimental cracked section: Bending moment is cal-
culated considering a cracked section with measured rein-
forcement strain.
Figure 12 – TQS, SAP and experimental:
deflections along line a shown in Fig. 6
Figure 13 – TQS, SAP and experimental:
deflections along line B shown in Fig. 6
Figure 14 – Strains used to determine experimental bending moments for (a) Uncracked section
with εs deduced, (b) Uncracked section with εs measured and (c) Cracked section
A B C