10.2 Review of the Existing Works
321
10.2 Review of the Existing Works
As for the CFST members subjected to the explosive loadings, Fujikura et al. (2008)
experimentally examined the blast resistance of 1/4 scaled CFST bridge columns, in
which the compressive strength of concrete was 42 MPa, the column height was 1.5 m,
the column diameters were ranged within 102–152 mm, and the steel tube thickness
was 3.2 mm. It was found that the CFST columns exhibit a ductile behavior under
close-in range blast loadings without sectional breaching (punching through the full
concrete thickness) or spalling of the core concrete. However, it should be noted that
the detailed charge weight and corresponding standoff distance were not given due
to the confidential issue. Fouché and Bruneau (2015) experimentally assessed the
performance of concrete-filled double-skin steel tube (CFDST) columns subjected
to the close-in range detonation, in which the standoff distance of explosion and
detailed charge weight were also not disclosed. The compressive strength of core
concrete was 37 MPa, and the outer-diameters of steel tubes were selected as 152.4,
168.3 and 203.2 mm with the corresponding inner-diameters ranging from 50.8 to
101.6 mm. Three typical failure modes were observed, i.e., local indentation, global
deformation and outer steel tube failure, and it was found that the inner steel tube
can effectively prevent the direct shear failure of the CFDST column. Li et al. (2018)
further experimentally investigated the damage mechanism of CFDST columns filled
with normal strength concrete of 40 MPa subjected to the contact detonation (0.6 and
1.0 kg TNT) with different outer steel tube thickness (6, 7, and 8.5 mm). It showed that
the damage mode of CFDST column under contact explosion exhibited a localized
pattern, including cratering around the detonation point, fracture or rupture failure
of the outer steel tube, and breaching failure of the front sandwich wall. It was also
derived that the blast resistance of CFDST columns was enhanced with the increase
of the outer steel tube thickness.
Zhang et al. (2016) conducted the field blast tests on the ultra-high performance
concrete (UHPC) infilled double-skin steel tube columns with circular and square
cross-sections under close-in range detonation. The compressive and flexural tensile
strength of core concrete were 170 MPa and 33.8 MPa, respectively. It was found
that, subjected to 35 and 50 kg TNT detonated at 1.5 m distance (scaled distances Z
= R/W
1/3 were 0.41 and 0.46, R is the standoff distance from the explosive center
to the column surface, W is the TNT charge weight), there was no visible buckling
on the CFDST columns, and only minor cracks occurred in the core concrete. The
integrity of the column was maintained and both two typical CFDST columns exhibited excellent blast resistance. Furthermore, Zhang et al. (2015a) further conducted
the residual axial compression tests on the post-blast CFDST columns. It was derived
that, the outer steel tubes always sufferred local buckling failure at mid-span and/or
column ends for the square CFDST columns, while for the circular CFDST columns,
the steel tube ruptured and local buckling failure were more likely to occur under
high and low damage level, respectively.
321
10.2 Review of the Existing Works
As for the CFST members subjected to the explosive loadings, Fujikura et al. (2008)
experimentally examined the blast resistance of 1/4 scaled CFST bridge columns, in
which the compressive strength of concrete was 42 MPa, the column height was 1.5 m,
the column diameters were ranged within 102–152 mm, and the steel tube thickness
was 3.2 mm. It was found that the CFST columns exhibit a ductile behavior under
close-in range blast loadings without sectional breaching (punching through the full
concrete thickness) or spalling of the core concrete. However, it should be noted that
the detailed charge weight and corresponding standoff distance were not given due
to the confidential issue. Fouché and Bruneau (2015) experimentally assessed the
performance of concrete-filled double-skin steel tube (CFDST) columns subjected
to the close-in range detonation, in which the standoff distance of explosion and
detailed charge weight were also not disclosed. The compressive strength of core
concrete was 37 MPa, and the outer-diameters of steel tubes were selected as 152.4,
168.3 and 203.2 mm with the corresponding inner-diameters ranging from 50.8 to
101.6 mm. Three typical failure modes were observed, i.e., local indentation, global
deformation and outer steel tube failure, and it was found that the inner steel tube
can effectively prevent the direct shear failure of the CFDST column. Li et al. (2018)
further experimentally investigated the damage mechanism of CFDST columns filled
with normal strength concrete of 40 MPa subjected to the contact detonation (0.6 and
1.0 kg TNT) with different outer steel tube thickness (6, 7, and 8.5 mm). It showed that
the damage mode of CFDST column under contact explosion exhibited a localized
pattern, including cratering around the detonation point, fracture or rupture failure
of the outer steel tube, and breaching failure of the front sandwich wall. It was also
derived that the blast resistance of CFDST columns was enhanced with the increase
of the outer steel tube thickness.
Zhang et al. (2016) conducted the field blast tests on the ultra-high performance
concrete (UHPC) infilled double-skin steel tube columns with circular and square
cross-sections under close-in range detonation. The compressive and flexural tensile
strength of core concrete were 170 MPa and 33.8 MPa, respectively. It was found
that, subjected to 35 and 50 kg TNT detonated at 1.5 m distance (scaled distances Z
= R/W
1/3 were 0.41 and 0.46, R is the standoff distance from the explosive center
to the column surface, W is the TNT charge weight), there was no visible buckling
on the CFDST columns, and only minor cracks occurred in the core concrete. The
integrity of the column was maintained and both two typical CFDST columns exhibited excellent blast resistance. Furthermore, Zhang et al. (2015a) further conducted
the residual axial compression tests on the post-blast CFDST columns. It was derived
that, the outer steel tubes always sufferred local buckling failure at mid-span and/or
column ends for the square CFDST columns, while for the circular CFDST columns,
the steel tube ruptured and local buckling failure were more likely to occur under
high and low damage level, respectively.