Experimental and analytical studies on laced reinforced concrete and laced steel-concrete composite elements

Abstract

Ductility and structural integrity are essentially required for structures subjected to suddenly applied dynamic loads such as shock loads. Reinforced Concrete (RC), the most widely used construction material, possesses considerable mass, excellent fire-resistance characteristics and can also absorb large amount of energy, if provided with proper detailing. However, one of the disadvantages of concrete is the possibility of spalling/scabbing when it is subjected to shock loading, which weakens the core and affects the integrity of the structure. Among the alternative systems of construction, Laced Reinforced Concrete (LRC) and Steel-Concrete Composite (SCC) construction are found to possess properties that are promising for shock resistant structures. The main objective of the present study is the development of a construction-friendly structural system that can resist the shock loads. A new form of Steel-Concrete Composite (SCC) system is proposed, after analyzing the limitations of existing systems. In addition to this, an equivalent material model for the analysis of Laced Composite Systems such as Laced Reinforced Concrete (LRC), Laced Steel-Concrete Composite (LSCC) is proposed. In the first phase of the study, a new approach for modeling RC/LRC/LSCC structural elements primarily under flexure is proposed. In this approach, RC/LRC/LSCC is treated as a homogenous material and conventional beam elements are used to model these beams, thus making the modeling of these beams very simple. Equations for obtaining the equivalent stress and strain characteristics have been derived retaining the moment-curvature characteristics. The proposed approach is able to predict the peak load and ductility factors satisfactorily for LRC beams. The proposed approach is extended for solving a LRC slab subjected to uniform distributed loading. LRC has a proven performance against blast loading. Steel-Concrete Composite (SCC) can be considered as an alternative material in view of complex detailing requirements in LRC