Probabilistic models for blast parameters and fragility estimates of steel columns subject to blast loads

Abstract

This thesis proposes a probabilistic framework to predict the failure probabilities of steel columns subject to blast loads. The framework considers the uncertainties in the blast phenomenon, the demands imposed on the column, and the capacities of the column for the limit states of flexure, local buckling and global buckling. As part of the work, we propose four probabilistic blast load models. For different types of explosives and atmospheric conditions, two models predict the incident and reflected peak pressure generated by the explosion and two models predict the incident and reflected positive time duration of the blast wave. The models are probabilistic to capture the associated uncertainties, including variations in the atmospheric conditions, the inherent variability in the blast load data even for identical experimental conditions, and model error. The blast load models are used to predict the structural demands (maximum internal moment and deflection) imposed by the blast on a column. The demand models are combined with strain-rate dependent capacity models for flexure and global buckling to estimate the conditional probability of failure (or fragility) of a steel column for given scaled distance. As an example, fragility estimates for different columns representative of typical columns in steel frames are developed. The results highlight the effect of column dimensions and axial load on the failure probabilities.

Reliability Assessment Methodology of Blast Protective Steel Moment Resisting Frame Using NiTi SMA-based Connection

“…They strengthened the steel beam with externally bonded carbon fiber-reinforced polymer (CFRP) composites. Another probabilistic framework of steel columns is proposed by Singh et al [23] to estimate the failure probability. Two limit states are considered, namely limit state function of flexure and global buckling, to parametrize the column's blast loading profile.…”

The Use of Fragility Curves in the Life-Cycle Assessment of Deteriorating Bridge Structures

“…Dunn et al [22] used fragility curves to investigate the resilience of a public electricity transmission network in the event of failures due to windstorm hazards. Singha et al [23] proposed an assessment method for the fragility curves of steel columns subjected to blast loads.…”

“…The paper wishes to enlighten the use of fragility curves in the life-cycle assessment of the deteriorating bridge structures and the errors that are made in basing such curves on a few experimental data. Therefore, to test the proposed methodology, the authors use a method of simulation of deterioration over time, already validated in the literature [14][15][16][17][18][19][20][21][22][23][24][25][26]: the so-called fragility curves for the "statistical truth".…”

Physics-based probabilistic demand model and reliability analysis for reinforced concrete beams under blast loads

“…The performance prediction of structural systems subject to explosive blast loading has also received much attention. Among the initial contributions is the generalized single-degree-of-freedom (SDOF) representation of structural systems [13][14][15][16][17][18][19][20], a computationally convenient model with a simplified physics. The current approaches in blast design guidelines (e.g., [21]) widely use the generalized SDOF approximation.…”