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OCAK 2016
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SAYI : 117
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Kompozit Önüretimli Beton Boşluklu Döşeme
Elemanlarının Eğilme Davranışı
FLEXURAL BEHAVIOR OF PRECAST
CONCRETE HOLLOW-CORE PANELS
WITH CAST-IN-PLACE CONCRETE
TOPPING
ABSTRACT:
Floor systems made of precast
concrete hollow-core panels and
cast-in-place (CIP) concrete topping
have been widely used globally in
many types of structures, including
buildings, parking structures, and even
bridges. Thecompositeactionbetween
the precast hollow-core panels and
the CIP concrete topping leads to
increased stiffness and strength. The
horizontal shear force capacity at the
interface between hollow-core panels
and topping concrete is crucial in
achieving a composite behavior. The
manufacturing technique commonly
used for production of precast
concrete hollow-core panels do not
allow the use of reinforcing bars
crossing the interface. In this case,
the primary horizontal shear force
transfer mechanism between the
two components is through bond at
the interface. There is an uncertainty,
however, whether the horizontal
shear strength at the interface will be
sufficient to allow a fully composite
behavior under flexural loading
when the concrete topping is placed
over machine finished surface of a
hollow-core unit with no intentional
roughening. American Concrete
Doç. Dr. Eray Baran
, Orta Doğu Teknik Üniversitesi İnşaat Mühendisliği Bölümü
Institute (ACI) specifies a maximum
horizontal shear stress of 0.55 MPa for
composite concrete flexural members
with no reinforcement crossing the
interface, provided that the contact
surface is intentionally roughened. A
horizontal shear strength of 1.65 MPa
is specified in AASHTO LRFD Bridge
Design Specifications for concrete
placed against a surface intentionally
roughened to an amplitude of 6.3 mm,
while the horizontal shear strength is
reduced to 0.52 MPa if the surface is
not intentionally roughened.
An experimental study integrated with
numerical analyses was conducted in
order to identify the extent to which a
CIP concrete topping placed over the
as-cast surface of precast concrete
hollow-core panels improves the
flexural behavior. This document
presents the results obtained from
load testing of four 15 cm deep full-
scale precast prestressed concrete
hollow-core panels. Two of the panels
were tested with a 5 cm thick cast-
in-place concrete topping while the
remaining panels were tested with no
topping.
The experimental results demonstrate
that a major composite action is valid
between the hollow-core unit and
the topping slab under load levels
corresponding to uncracked state of
the cross section. The topping slab
was observed to improve the flexural
behavior of hollow-core panels by
increasing the cracking moment
and initial stiffness. The beneficial
effect of topping slab on the ultimate
moment capacity was observed to be
limited, mainly because of the loss of
composite action prior to reaching the
ultimate moment capacity.
Limited number of push-off tests was
conducted on small-sized topping
slab pieces in an attempt to determine
the horizontal shear strength at the
Doç. Dr. Eray BARAN
Lisans öğrenimini Orta Doğu Tek-
nik Üniversitesi İnşaat Mühen-
disliği Bölümü’nde 1999 yılında
tamamladı. Aynı yıl Amerika Bir-
leşik Devletleri’nde Minnesota
Üniversitesi İnşaat Mühendisliği
Bölümü’nde lisansüstü eğitimine
başlayarak yüksek lisans ve dok-
tora derecelerini sırasıyla 2003 ve
2006 yıllarında aldı. Amerika Birle-
şik Devletleri’nin Nevada eyaletinde
bir süre tasarım mühendisi olarak
çalıştı. Halen Orta Doğu Teknik
Üniversitesi İnşaat Mühendisliği
Bölümü’nde öğretim üyesi olarak
görev yapmaktadır.