PSI - Issue 60

Anupoju Rajeev et al. / Procedia Structural Integrity 60 (2024) 222–232 Author name / StructuralIntegrity Procedia 00 (2019) 000–000

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Modified peak compressive strength of concrete Dynamic compressive strength of concrete

Dynamic tensile strength of concrete

Depth of column

Yield strength of steel

Static elastic modulus of concrete Dynamic elastic modulus of concrete

Secant modulus of concrete

Breadth of column

Vertical Spacing of ties

Clear vertical spacing of ties Effectiveness coefficient

Elastic stiffness of column section Plastic stiffness of column section

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Load-Mass factor in elastic Load-mass factor in plastic Ultimate moment capacity Yield moment capacity

Yield curvature

Load at ultimate state Load at yield state

Deflection at ultimate state

Elastic deflection

Resistance at ultimate Resistance at yield

Plastic deflection

2. Numerical Investigation The Single Degree of Freedom (SDOF) approximation presumes that a structure will fail in its initial mode. In practice, structural collapse can involve multiple modes, causing deviations between the equivalent SDOF results and actual responses. Therefore, it is often more advantageous and practical to perform finite element analysis using commercially available software packages. Concrete exhibits distinct behaviors in both tension and compression, requiring a realistic material model capable of accurately representing both phases. In this section, we explore the dynamic response of an RC column exposed to shock loading using the commercial finite element software “Abaqus-Explicit”. Experimental investigations are currently in progress, employing a shock-tube apparatus to generate shock pressure. The column's deflection along its height is measured with LVDT sensors and is subsequently utilized to validate both the theoretical and numerical models.

2.1. Material model

The Abaqus material library encompasses material models suitable for analyzing concrete and similar brittle materials. Abaqus offers the Concrete Damage Plasticity (CDP) model, which can evaluate concrete structures under dynamic loads. This model incorporates two scalar damage variables, denoted as d c for compression and d t for tension. These variables are dependent on inelastic strain and signify the degree of damage sustained by the concrete material. The CDP model necessitates stress-strain curves for both tension and compression, as well as degradation