Betonarme Kirişlerin Moment-Eğrilik ve Etkin Kesit Rijitlkleri

Öz

Ulusal ve uluslararası deprem yönetmeliklerinde betonarme yapıların sismik performansının belirlenmesinde, tasarım aşamasında betonarme yapı elemanlarında çatlamış kesite ait etkin kesit rijitliğinin kullanılması istenmektedir. Çatlamış kesitin etkin kesit rijitliği sabit olmamakla birlikte beton dayanımı ve donatı oranı gibi parametrelere bağlıdır. Bu çalışmada, doğrusal olmayan moment-eğrilik ilişkileri ve etkin rijitlik katsayılarını araştırmak için farklı beton dayanımı, çekme ve basınç donatı oranlarına sahip betonarme kiriş modelleri tasarlanmıştır. Analitik olarak incelenen parametreler TBEC (2018), ACI318 (2014), ASCE/SEI41 (2017), Eurocode2 (2004) ve Eurocode8 (2004, 2005) yönetmeliklerinden ve moment-eğrilik ilişkilerinden hesaplanmıştır. Sonunda elde edilen etkin rijitlik katsayısı, farklı yönetmeliklerde betonarme elemanlar için öngörülen rijitlik katsayısı ile karşılaştırılmıştır. Elde edilen sonuçlar farklı parametre ve modellere göre karşılaştırılarak incelenmiştir. Betonarme kirişlerde sabit çekme donatı oranı ve beton dayanımı için, basınç donatı oranının artması ile etkin rijitlik katsayısı değerleri artar. Sabit çekme ve basınç donatı oranına sahip betonarme kirişlerde beton dayanımı arttıkça etkin rijitlik katsayı değerleri de artmaktadır. Basınç donatı oranının betonarme kirişlerin maksimum moment taşıma kapasitesi, etkin eğilme rijitliği ve etkin rijitlik katsayısı ve kesitlerin sünekliği üzerinde etkili olduğu kanıtlanmıştır.

Anahtar Kelimeler

• Sismik performans
• etkin rijitlik
• moment-eğrilik
• yapı elemanları
• betonarme kiriş

Moment-Curvature and Effective Section Stiffness of Reinforced Concrete Beams

Öz

In determining the seismic performance of reinforced concrete (RC) structures in national and international earthquake regulations, it is desired to use effective section stiffness of the cracked section in RC structural elements during the design phase. Although the effective section stiffness of the cracked section is not constant, it depends on parameters such as the concrete strength and reinforcement ratio. In this study, RC beam models with different concrete strength, tensile and compression reinforcement ratios were designed to investigate nonlinear moment-curvature relationships and effective stiffness coefficients. Analytically investigated parameters were calculated from TBEC (2018), ACI318 (2014), ASCE/SEI41 (2017), Eurocode2 (2004) and Eurocode8 (2004, 2005) regulations and moment-curvature relationships. The effective section stiffness coefficient obtained from the analyses were compared with the effective section stiffness coefficient given for RC members in different regulations. The results obtained at the end were examined by comparing them according to different parameters and models. For constant concrete strength and tensile reinforcement ratio in RC beams, with increasing compression reinforcement ratio, effective stiffness coefficient values increase. In RC beams with constant compression and tensile strength ratio, effective stiffness coefficient values increase with increasing concrete strength. The compression reinforcement ratio has been proved to be effective on the maximum moment bearing capacity of the RC beams, effective flexural stiffness and effective stiffness coefficient and ductility of the sections.

Anahtar Kelimeler

• Seismic performance
• effective stiffness
• moment-curvature
• structural elements
• reinforced concrete beam

Kaynakça

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