Experimental Investigation of Composite (Steel-Concrete) Walls under Pure out-of-plane Load

This paper presents a new structural system for retaining walls. In civil works, in general, there is a trend to use the traditional reinforced concrete (RC) retaining walls to resist against the soil pressure. Despite their good resistance, RC retaining walls have some disadvantages such as need for huge temporary formworks, high dense reinforcing, low construction speed, etc. In the present work, composite wall with only one steel plate (steel – concrete) was proposed to cover the disadvantages of the RC walls. In this system, steel plate was utilized not only as tensile reinforcement but also as a permanent formwork for the concrete. In order to evaluate the efficiency of the proposed SC composite system, an experimental program that included six specimens was performed. In this experimental campaign, effects of different parameters such as length of shear connectors, use of compressive steel plate, concrete ultimate strength, distance between shear connectors and compressive steel reinforcement were investigated. The results showed that with proper design, the composite walls have very good and ductile behavior under out-of-plane loads. Furthermore, it was observed that even with large distance between the shear connectors, short length of the shear connectors etc., this system is capable to keep the flexural performance and shows the semi-ductile behavior. Furthermore, the design equations based on ACI code for calculating out-of-plate flexural and shear strength of SC composite walls are presented and compared to experimental database.