Methodology for Analyzing Structural Response to Blast-Type Rapid Dynamic Loading Using SOFiSTiK

Sammanfattning

This thesis investigates the structural response of reinforced concrete elements subjected to blast-type loading using advanced finite element modelling. In engineering practice, blast-resistant design is often performed using simplified equivalent static methods, which may not fully capture the transient behaviour of structures subjected to short-duration loads.The objective of this work is to evaluate the differences between equivalent static approaches and nonlinear dynamic time-history analyses for reinforced concrete structures. A numerical modelling framework was developed in the SOFiSTiK finite element environment. Blast pressure-time histories were generated using empirical relations from the Kingery–Bulmash and UFC 3-340-02 formulations and implemented as time-dependent surface loads.The modelling approach was first verified through comparison with published numerical and experimental studies involving reinforced concrete beams and slabs subjected to blast loading. The methodology was then applied to two engineering case studies: the blast response of an anaerobic digester structure and the accidental drop of a heavy container on a reinforced concrete slab.The results show that nonlinear dynamic analyses capture the transient interaction between load evolution and structural deformation more realistically than simplified static approaches. While dynamic simulations often predict larger displacements, they generally lead to lower internal forces due to energy dissipation mechanisms. This behaviour highlights the limitations of equivalent static methods and demonstrates the potential of nonlinear dynamic analysis to provide more realistic and less conservative structural assessments.The study provides a practical framework for implementing blast loading in SOFiSTiK and illustrates the benefits of dynamic modelling for engineering design applications.