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1. Introduction
The researches about the behavior of precast concrete structures
are very important for the modernization of the Civil Construction
Industry, mainly to improve the quality, productivity and to promote
the rationalization on sites.
After the Second World War, the precast concrete structures were
so much used to reconstruct the Europe. In this period, new meth-
ods and constructions techniques that emphasize the rationaliza-
tion and the productivity became necessary to boost the prefabrica-
tion. The large-scale and the few available workers were the main
reasons for the development of the precast concrete structures.
The use of precast concrete structures is increasing in Brazil. The
reason for this growth is the efficiency of this type of structure to
meet the market requirements that are the compliance with dead-
lines and technical quality. These requirements are important for
buildings mainly which have large spans, for example, industrial
buildings.
The main difference between precast concrete structures and the
traditional reinforced concrete structures is the presence of con-
nections. Therefore, the study of the connections behavior stands
out in the field of precast concrete structures. The connections be-
havior has an important role because it is responsible for transmis-
sion and redistribution of the stress. The ABNT NBR 9062 [1] is the
Brazilian Code that governs the design and construction of precast
concrete structures. This code has received many contributions
from several studies involving the behavior of connections with the
intention of spreading the technical knowledge obtained and usual
the use of this type of structure.
The connections are regions that have a complex behavior. In
these regions occur stress concentrations and for this reason the
connections deserve a special attention of the researchers and
the designers. In general, the connections between precast ele-
ments do not behave exactly as they are considered in the struc-
tural analysis. The designers consider that the connections allow
or prevent entirely the relative displacements between the con-
nected elements, which do not happen. What happens is that the
connections have an intermediate behavior and must be called as
semi-rigid. However, the development of this type of connection is
extremely important to enable the use of precast concrete system
in multistory buildings.
2. Analysis of semi-rigid connections
The connections have been defined as “semi-rigid” in the study of
precast concrete structures since the 1980s. This term has been
used since 1930 to designate connections in steel structures and
now it is becoming common among researchers in the field of pre-
fabricated structures.
Several types of studies on precast concrete connections have
been done in research centers around the world. In general,
studies include the development of connections which provide
high rigidity and easiness of implementation. In the research of
Shariatmadar and Beydokhti [2] was tested a connection be-
tween precast beam and column preformed without the use of
corbel. The region which joins the elements was cast in situ.
The improvement of the bending moment transfer to the col-
umn by the use of prestressed reinforcement was another way
found by the researchers to improve the connections behav-
ior. Hawileh et al. [3] performed a numerical and experimental
study of connections involving prestressed reinforcement. The
authors compared both results and they concluded that com-
puter simulation is an economical option to analyze the behavior
of connections. Following this line of study, Kaya and Arslan
[4] also analyzed beam-column connections with prestressed
reinforcement. They noted that for different levels of prestress-
ing applied, the connections presented satisfactory behavior. In
the literature review was found that the use of prestressed re-
inforcement in precast concrete connections has been studied
for a long time. The search of Saqan [5] is one of these stud-
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IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 6
M. N. KATAOKA
| M. A. FERREIRA
| A. L. H. C. EL DEBS
Figure 1 – Indication the local of load application and the node of a porch structure analyzed