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IBRACON Structures and Materials Journal • 2013 • vol. 6 • nº 3
Numerical and experimental study of a waffle slab designed to serve as a tennis court floor
3.2 TQS software
TQS
is a software developed by
TQS Informática Ltda.
for rein-
forced concrete structural design using the matrix analysis method
for grids. This system, formed by a set of modules, creates a da-
tabase on the entire construction, grouping geometries and loads,
managing the structural analysis, the transference and calculation
of stresses and the detailing of all the elements that constitute the
structure [9].
In the case of waffle slabs, the
TQS
software allows both linear
and non-linear grid analysis. In linear analysis, the reinforcement
is not considered in the determination of the cross sections stiff-
ness. Nonlinear analysis calculates the vertical displacements
considering the reinforcement used and the physical non-linearity
of concrete due to cracking, based on the recommendations of the
Brazilian Concrete Code (ABNT, 2004[10]).
This software allows the structural designer to enter user defined
values when determining stresses and detailing the reinforcement.
In the specific case of waffle slabs, the most relevant choices are
related to the structure´s flexibility. The user may change the tor-
sional and/or flexural inertia of the bars, as well as adjust the stiff-
ness of the connections between beams and columns.
In this investigation, however, no reduction on torsional or flexural
stiffness was used for the ribs or edge-beams. Additionally, the
connections between ribs and beams and/or beams and columns
were fully considered. This decision was made based on a para-
metric analysis, performed in a rectangular waffle slab, where the
stiffness of the elements were varied and the results were com-
pared to the ones obtained using the finite element program[7].
Given the necessary input data, the software automatically gen-
erates a numerical model of the slab, such as the one shown in
Fig. 10. A nonlinear analysis of the structure was also carried out.
However, in the case of nonlinear analysis, this computational pro-
Figure 10 – Grid model
Figure 11 – Total load applied, excluded self-weight
A
B