Experimental and numerical investigation of CFS-concrete composite trusses


Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2018

Öğrenci: HAZAL GÜLDÜR

Danışman: ERAY BARAN

Özet:

Cold-formed steel (CFS) structural systems have been intensely studied especially due to the economy and ease of implementation that they provide. A common failure mode of CFS members is the local instability of the section. The aim of this study is to control the local instability in CFS floor trusses by providing concrete infill inside compression chord members. Numerical and experimental studies were conducted in order to investigate the flexural behavior of steel-concrete composite trusses made of CFS sections. Main test parameters were the presence of concrete infill, orientation of top chord CFS member, presence of shear enhancing connectors, and the presence of a concrete slab. The finite element (FE) model of the CFS floor trusses was created and three types of analysis, namely Materially Nonlinear Analysis (MNA), Geometrically and Materially Nonlinear Analysis (GMNA) and Geometrically and Materially Nonlinear Analysis with Imperfections (GMNIA), were conducted. While the FE model was able to simulate the actual strain behavior for the stiffened elements of the compression chord CFS section, the measured and numerically predicted strain values differ significantly for the lip part of the section. Additional analytical studies were conducted in order to predict the behavior of composite trusses without the need of detailed analysis or load tests. The procedure adopted for the analytical approach is based on calculating the chord cross-sectional strain and then determining the initial stiffness, yield and maximum load capacities using this strain information.