THE ROLE OF SECONDARY VARIABLES IN PUNCHING STRENGTH OF SLABS

Year 2018, , 606 - 614, 11.12.2018

Ahmet Abdullah Dönmez

https://doi.org/10.21923/jesd.423263

Abstract

Punching shear strength of reinforced
concrete slabs exhibits size effect. Size effect on punching shear of
reinforced concrete slabs has been being discussed since past decades and there
has not been any consensus on the subject yet. Most of the discussions focus on
the nonlinearity of the structures, of which deviates the size effect slope of
the LEFM from -1/2 to milder slopes.
But extrapolation of the practical sizes to very large sizes results in brittle
behavior. Diminishing the secondary influencing parameters, makes linear
elastic fracture mechanics available to apply. In this study it is intended to
demonstrate the structural scaling phenomenon that the large structures behave
more brittle and conical fracture surface of slab punch becomes more smooth.

Keywords

Size effect, Fracture surface, Asymptotic extrapolation, Concrete, Punching

ZIMBALAMA BOYUT ETKİSİNDE İKİNCİL DEĞİŞKENLERİN İŞLEVİ

Abstract

Betonarme döşemelerin zımbalama kırılmalarında boyut etkisi gözlenir. Bu
etkinin matematiksel ifadesi konusunda mühendisler arasında bir fikir birliği
bulunmamaktadır. Tartışmalar yapısal elemanların doğrusal olmayan
davranışlarının betonun kırılma yüzeyinin şeklini değiştirdiği ve böylece boyut
etkisi asimptotik eğiminin -1/2’den
saptığı konusunda yoğunlaşmıştır. Fakat normal boyuttaki betonarme yapıların
asimptotik ekstrapolasyonu bizi lineer elastik kırılma mekaniğinin geçerli
olduğu durumlara yaklaştırır. Bu çalışmada zımbalama etkisindeki elemanların
boyutlarının artması ile lineerliği bozan ikincil parametrelerin etkilerinin azaldığı
gösterilmiştir. Yapı elemanlarının boyutlarının artması ile daha gevrek
davrandığı hipotezi üzerinde durulmuş olup bu durumun sonuçları üzerinde
tartışılmıştır.

Keywords

Boyut etkisi, Kırılma yüzeyi, Asimptotik ekstrapolasyon, Beton, Zımbalama

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