Betonarme kolonların eşdeğer akma eğriliği için önerilen pratik bağıntıların irdelenmesi

Abstract

Bu çalışmada, yapı sistemlerinin şekildeğiştirme esaslı tasarımı ve değerlendirilmesi çerçevesinde, eşdeğer akma eğrilikleri için literatürde önerilen pratik yaklaşımların geçerliliği kare enkesitli betonarme kolonlar üzerinde teorik olarak incelenmiştir. Çalışma kapsamında, donatı akma dayanımı sabit tutularak enkesit boyutu, normal kuvvet düzeyi, boyuna donatı oranı ve beton basınç dayanımının parametrik olarak değiştirildiği 1500’ün üzerindeki hesap modeli için moment – eğrilik analizleri gerçekleştirilmiştir. Bu analiz sonuçları referans alınarak, ilgili bağıntıların hangi oranda doğru sonuç verdiği geniş bir çerçevede değerlendirilmiştir. İncelenen kolon enkesitlerine ait eşdeğer akma eğriliklerinin belirlenmesinde normal kuvvetin düzeyine bağlı olarak, P/Agfc' < 0.3 için donatı çeliğinin akması, P/Agfc' = 0.3 için donatı çeliğinin akması ve/veya betonun ezilmesi, P/Agfc' > 0.3 için ise betonun ezilmesi hakim olmuştur. Pratik bağıntılardan elde edilen akma eğrilikleri için boyuna donatı oranı ve beton basınç dayanımının bağımsız etkileri sınırlı iken, normal kuvvet düzeyi ile birlikte olan birleşik etkileri bu parametreleri önemli hale getirmiştir.

Keywords

• Eşdeğer akma eğriliği,betonarme kolon,moment – eğrilik analizi,normal kuvvet düzeyi,boyuna donatı oranı,beton basınç dayanımı

Investigation of practical equations for equivalent yield curvature of reinforcement concrete columns

Abstract

In this study, the usability of practical approaches proposed for equivalent yield curvature on reinforcement concrete columns with the square cross-section was numerically investigated in the framework of deformation based design and assessment of structural systems. In this context, the moment – curvature analyses on the column models more than 1500, in which the axial load level, cross-section dimension, longitudinal reinforcement ratio and concrete compression strength were modified parametrically, were conducted for the constant yield strength. Based on the analysis results, in what proportion the related equations give results was discussed comprehensively. Depending on the axial load levels of P/Agfc' < 0.3, P/Agfc' = 0.3 and P/Agfc' > 0.3 for the considered columns, the yielding of reinforcement, yielding of reinforcement and/or concrete crushing, concrete crushing governed the formation of yield curvatures, respectively. It can be deduced that while the independent effects with regard to the longitudinal reinforcement ratio and concrete compressive strength for the equivalent yield curvatures calculated by the practical approaches remained in minimal levels, the combined effects of them with the axial load level make these parameters become important these parameters.

Keywords

• Equivalent yield curvature,reinforced concrete column,moment – curvature analysis,axial load level,reinforcement ratio,concrete compression strength

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