EVALUATION OF DEFLECTION PERFORMANCE OF SIZING-OPTIMIZED COLD-FORMED STEEL BEAMS WITH VARIOUS CROSS-SECTIONS

Abstract

Strength-based optimization of cold-formed steel (CFS) sections is a common strategy to enhance material efficiency, but it often results in slender profiles where serviceability performance is a concern. This study investigates the deflection performance of three distinct CFS profiles—a lipped channel, an unlipped channel, and a built-up I-section—after they were sizing-optimized (via parametric scaling) for strength limit states according to AISI S100-16. The final optimized dimensions for both secondary beams and girders were evaluated against the serviceability criteria of the International Building Code. A numerical analysis based on the conjugate beam method was employed, which accurately accounts for the variable effective moment of inertia along the beams’ spans. The results demonstrate that all six optimized sections comfortably satisfy the deflection limits for both live load (L) and total load (D+L) conditions. A comparative analysis revealed that while the lipped channel section was the most materially efficient, it exhibited greater, though still acceptable, deflections compared to the heavier unlipped and I-sections. This study contributes by quantitatively demonstrating that CFS beams optimized solely for AISI S100-16 strength limits can inherently satisfy IBC serviceability criteria, confirming the viability of this optimization approach in practical floor design. The findings confirm that a well-executed strength optimization does not compromise serviceability and that the lipped channel section provides an optimal balance between material economy and structural performance for the floor system studied.

Keywords

• Cold-Formed Steel
• Deflection
• Serviceability Limit State
• Section Optimization
• Effective Moment of Inertia

Çeşitli Enkesitli Boyut Optimizasyonu Yapılmış Soğukta Şekil Verilmiş Çelik Kirişlerin Sehim Performansının Değerlendirilmesi

Abstract

Soğukta şekil verilmiş çelik (SŞVÇ) kesitlerin dayanım esaslı optimizasyonu, malzeme verimliliğini artırmak için yaygın bir stratejidir, ancak bu durum genellikle kullanılabilirlik performansının kritik hale geldiği narin profillerle sonuçlanır. Bu çalışma, AISI S100-16’ya göre dayanım sınır durumları için (parametrik ölçeklendirme yoluyla) boyut optimizasyonu yapıldıktan sonra üç farklı SŞVÇ profilinin— dudaklı C, dudaksız C ve birleşik I-kesit—sehim performansını incelemektedir. Hem tali kirişler hem de ana kirişler için optimizasyon sonucu elde edilen boyutlar, Uluslararası Yapı Yönetmeliği’nin kullanılabilirlik kriterlerine göre değerlendirilmiştir. Kirişlerin açıklıkları boyunca değişken olan etkin atalet momentini hassas bir şekilde hesaba katan, eşlenik kiriş yöntemine dayalı sayısal bir analiz gerçekleştirilmiştir. Sonuçlar, altı optimize edilmiş kesitin tamamının hem hareketli yük (L) hem de toplam yük (D+L) koşulları için sehim sınırlarını rahatlıkla sağladığını göstermektedir. Yapılan karşılaştırmalı analizde, dudaklı C kesitinin malzeme açısından en verimli olmasına rağmen, daha ağır olan dudaksız C ve I-kesitlere kıyasla daha büyük, ancak yine de kabul edilebilir, sehimler oluşturduğu görülmüştür. Bu çalışma, yalnızca AISI S100-16 dayanım sınırlarına göre optimize edilmiş SŞVÇ kirişlerin, IBC kullanılabilirlik kriterlerini kendiliğinden karşılayabildiğini kantitatif olarak göstererek bu optimizasyon yaklaşımının pratik döşeme tasarımındaki uygulanabilirliğini doğrulamaktadır. Bulgular, etkin bir dayanım optimizasyonunun kullanılabilirliği tehlikeye atmadığını ve dudaklı C kesitinin, incelenen döşeme sistemi için malzeme ekonomisi ve yapısal performans arasında en uygun dengeyi sağladığını doğrulamaktadır.

Keywords

• Soğukta Şekil Verilmiş Çelik
• Sehim
• Kullanılabilirlik Sınır Durumu
• Kesit Optimizasyonu
• Etkin Atalet Momenti

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