نوع مقاله : پژوهشی
نویسندگان
دانشکده ی مهندسی عمران، دانشگاه فردوسی مشهد
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Punching shear failure is usually the critical failure mechanism for flat slab
reinforced concrete structures. The special brittleness of slab-column
connections is due to the relative ease with which the flexural reinforcement
in the top of the slab can be torn out of the concrete once an inclined failure
surface has formed. If unpredictable loads are applied to the flat slab-column
connections, punching shear failure occurs with almost no warning signs.
According to the brittle manner of this failure, the load carried by the
slab-column connection redistributes to adjacent supports and can cause
overloading to these supports. It is necessary to provide a secondary load
carrying mechanism after punching shear failure. In this Paper, Suggestions for
establishing a supporting mechanism in the flat slab connections after punching
shear failure are proposed. For this purpose, an experimental study was
performed to investigate the post-punching behavior of 11 slab specimens with
various reinforcement layouts. The effects of integrity, compressive, shear and
bent-up reinforcements on the post-punching behavior of slab-column connections
were studied. The results of the experiments show that Integrity reinforcements
significantly increased the post-punching shear strength. These reinforcements
can develop tensile membrane action and through alternative load paths to
transfer the load. These reinforcements did not have much influence on the
punching shear strength. In the \ column \ strip, compressive \ bars (except
integrity reinforcements) \ did not \ have much \ influence on \ the \ punching and
post-punching shear strength. The bent-up \ integrity \ reinforcements
significantly \ increase \ punching \ and post-punching shear strength. The
additional bent-up reinforcements increase punching shear strength but these
reinforcements are not effective to the post punching phase and cannot increase
the post \ punching \ shear strength. The shear reinforcements increase punching
shear strength, but these reinforcements cannot increase post-punching shear
strength. Furthermore, if the shear reinforcements are effectively extended,
the behavior flat slabs will be more ductile.
کلیدواژهها [English]