10.7 Comparisons with Test Data
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detonation and the subsequent axial compression tests, the current numerical simulation can provide reasonable predictions on the post-blast axial capacity of UHPCCFST column. Therefore, the validations of adopted numerical simulation algorithms,
constitutive models and the corresponding modified parameters are verified.
10.8 Parametric Study
In this section, based on the above verified numerical models, the parametric studies
are carried out to further investigate the factors that may influence the blast resistance
and residual axial capacity of UHPCC-FST column subjected to contact detonation,
including the steel tube wall thickness and strength, core concrete strength and section
diameter, respectively. The scenario of the present column C-2 under 2 kg TNT
contact detonation is adopted as the baseline, and the detailed parameters used in the
numerical model for C-2 column can be referred to Sect. 10.3.
10.8.1 Steel Tube Thickness and Strength
From the above analysis, it is found that the presence of steel tube can prevent the
spalling of core UHPCC, thus the influences of the steel tube thickness and strength
on explosion crater depth, residual axial capacity and damage index of UHPCC-FST
column under contact detonation and the subsequent axial compression tests are
discussed.
10.8.1.1 Thickness
Four different steel tube thicknesses, i.e., 4, 8, 10 and 16 mm, are further selected,
while the other parameters, e.g., steel tube strength, compressive strength of concrete,
and cross-sectional diameter of core concrete remain the same as those for column
C-2.
Figure 10.27a illustrates the crater depth formed on the UHPCC-FST column
with varied steel tube thicknesses under contact detonation. It can be seen that the
crater depth decreases dramatically when the steel tube thickness increases from 4
to 6 mm, while the decreasing slope reduces when the steel tube thickness increases
beyond 6 mm. Figure 10.27b further shows the dependence of residual axial capacity
of the post-blast UHPCC-FST column on the steel tube thicknesses. For comparison
purpose, the corresponding original axial capacity of intact column is also included.
Figure 10.27(a and b) indicate that increasing the steel tube thickness could effectively improve the blast resistance of UHPCC-FST column, and thus enhance the
residual axial load bearing capacity after the contact detonations. This mainly because
that the thicker steel tube can provide prominent confinement to the core UHPCC.
355
detonation and the subsequent axial compression tests, the current numerical simulation can provide reasonable predictions on the post-blast axial capacity of UHPCCFST column. Therefore, the validations of adopted numerical simulation algorithms,
constitutive models and the corresponding modified parameters are verified.
10.8 Parametric Study
In this section, based on the above verified numerical models, the parametric studies
are carried out to further investigate the factors that may influence the blast resistance
and residual axial capacity of UHPCC-FST column subjected to contact detonation,
including the steel tube wall thickness and strength, core concrete strength and section
diameter, respectively. The scenario of the present column C-2 under 2 kg TNT
contact detonation is adopted as the baseline, and the detailed parameters used in the
numerical model for C-2 column can be referred to Sect. 10.3.
10.8.1 Steel Tube Thickness and Strength
From the above analysis, it is found that the presence of steel tube can prevent the
spalling of core UHPCC, thus the influences of the steel tube thickness and strength
on explosion crater depth, residual axial capacity and damage index of UHPCC-FST
column under contact detonation and the subsequent axial compression tests are
discussed.
10.8.1.1 Thickness
Four different steel tube thicknesses, i.e., 4, 8, 10 and 16 mm, are further selected,
while the other parameters, e.g., steel tube strength, compressive strength of concrete,
and cross-sectional diameter of core concrete remain the same as those for column
C-2.
Figure 10.27a illustrates the crater depth formed on the UHPCC-FST column
with varied steel tube thicknesses under contact detonation. It can be seen that the
crater depth decreases dramatically when the steel tube thickness increases from 4
to 6 mm, while the decreasing slope reduces when the steel tube thickness increases
beyond 6 mm. Figure 10.27b further shows the dependence of residual axial capacity
of the post-blast UHPCC-FST column on the steel tube thicknesses. For comparison
purpose, the corresponding original axial capacity of intact column is also included.
Figure 10.27(a and b) indicate that increasing the steel tube thickness could effectively improve the blast resistance of UHPCC-FST column, and thus enhance the
residual axial load bearing capacity after the contact detonations. This mainly because
that the thicker steel tube can provide prominent confinement to the core UHPCC.