The effects of explosive mass ratio on residual compressive capacity of contact blast damaged composite columns

The risks associated with suitcase bombs are of serious concern because they can be easily handled and placed within close proximity of key structural components of building structures. The most common failure mode of structures subjected to blast loads from satchel and suitcase bombs is progressive collapse. The high-fidelity physics-based computer program, LS-DYNA is utilized in this study to provide numerical simulations of the dynamic response and residual axial capacity of composite columns subjected to blast loads. A field test using contact explosive was conducted on one composite column specimen. The test results were compared with the analytical results to validate the finite element model. An extensive parametric study was conducted to investigate the relationship between residual axial capacity and structural and loading parameters such as material strength, column detail and blast conditions. Two empirical equations were derived through a multivariable regression analysis in terms of the various parameters to predict the residual capacity index based on the explosive mass ratio (ωTNTωTNT).

Research highlights
► Two RC and a composite column were subjected to contact explosives in a field test.
► LS-DYNA is used to simulate the dynamic response and residual axial capacity of columns.
► Analytical model is verified by comparing the analytical results with experimental data.
► An empirical equation predicting the residual axial capacity of a damaged columns is developed.