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10 Residual Axial Capacity of UHPCC-FST Column Under …
Due to the high cost and extensive resources are needed for the field blast test, it
is more economic to perform the numerical simulation. Zhang et al. (2015b) established a finite element model of CFST column subjected to blast loadings with the
scaled distance of 0.55 and 0.4 m/kg
1/3 , and the CONWEP code in LS-DYNA (LSTC
2007) was employed to simulate the blast load. The numerical results showed that the
infilled core concrete can significantly reduce the local deformation of steel tube, and
the CFST column has better blast resistance compared to the RC column. Zhang et al.
(2015c, 2017) further adopted the CONWEP code to perform numerical studies on the
dynamic response of CFDST columns infilled with normal strength concrete (NSC)
and UHPC under close-in range detonation (0.35 ≤ Z ≤ 0.55 m/kg
1/3 ), and the parametric influences indicate that increasing the compressive strength of core concrete
significantly reduces the residual deflection of column, increasing the outer steel tube
thickness reduces the mid-span deflection more significantly than increasing the inner
steel tube thickness, and the blast resistance of CFDST column is mainly dominated
by the shape of outer steel tube However, the shape of inner steel tube has a slight
effect. Considering that the blast loadings generated by the CONWEP code deviate
obviously for the close-in range explosions, Remennikov and Uy (2014) proposed a
simplified engineering-level model for the very close-in range blast induced impulse
to predict the dynamic response of CFST columns, and good agreement with the
field blast test data is derived in terms of damage pattern and level of specimens.
Furthermore, based on Arbitrary-Lagrangian–Eulerian (ALE) numerical algorithm
to reproduce the interaction between the blast wave and the structures, Ngo et al.
(2015) and Li et al. (2018) analyzed the dynamic response of CFST column specimens
subjected to close-in range explosion and contact detonation, respectively.
Generally, the existing works still have the following limitations: (i) UHPCC
has the prominent blast and impact resistance compared with NSC, but the studies
on the blast resistance of CFST column, especially for the UHPCC-FST column,
are relatively insufficient; (ii) considering the easy public accessibility of bridge
structure, it is supposed that the terrorist explosive (suitcase or vehicle bombs) can be
placed as near as possible to the bridge columns, i.e., the contact explosion. However,
the existing studies mainly concentrates in the close-in (0.05 ≤ Z ≤ 0.15 m/kg
1/3 )
or near range (0.2 ≤ Z ≤ 0.5 m/kg
1/3 ) blast events, and the relevant studies on the
contact explosion scenario is scarce; (iii) the residual axial load bearing capacity
is vital to evaluate the stability and workability of the whole bridge superstructure,
and the relationship between the damage level of column and the explosive charge
weight is vital for the practical anti-blast design of bridge piers. However, the related
studies are limited.
10.3 UHPCC-FST Columns
Aiming to investigate the failure mode and residual axial capacity of the UHPCC-FST
bridge columns under contact detonation, considering the prototype of the UHPCCFST columns with the diameter of 800 mm under the suitcase or vehicle bombs
10 Residual Axial Capacity of UHPCC-FST Column Under …
Due to the high cost and extensive resources are needed for the field blast test, it
is more economic to perform the numerical simulation. Zhang et al. (2015b) established a finite element model of CFST column subjected to blast loadings with the
scaled distance of 0.55 and 0.4 m/kg
1/3 , and the CONWEP code in LS-DYNA (LSTC
2007) was employed to simulate the blast load. The numerical results showed that the
infilled core concrete can significantly reduce the local deformation of steel tube, and
the CFST column has better blast resistance compared to the RC column. Zhang et al.
(2015c, 2017) further adopted the CONWEP code to perform numerical studies on the
dynamic response of CFDST columns infilled with normal strength concrete (NSC)
and UHPC under close-in range detonation (0.35 ≤ Z ≤ 0.55 m/kg
1/3 ), and the parametric influences indicate that increasing the compressive strength of core concrete
significantly reduces the residual deflection of column, increasing the outer steel tube
thickness reduces the mid-span deflection more significantly than increasing the inner
steel tube thickness, and the blast resistance of CFDST column is mainly dominated
by the shape of outer steel tube However, the shape of inner steel tube has a slight
effect. Considering that the blast loadings generated by the CONWEP code deviate
obviously for the close-in range explosions, Remennikov and Uy (2014) proposed a
simplified engineering-level model for the very close-in range blast induced impulse
to predict the dynamic response of CFST columns, and good agreement with the
field blast test data is derived in terms of damage pattern and level of specimens.
Furthermore, based on Arbitrary-Lagrangian–Eulerian (ALE) numerical algorithm
to reproduce the interaction between the blast wave and the structures, Ngo et al.
(2015) and Li et al. (2018) analyzed the dynamic response of CFST column specimens
subjected to close-in range explosion and contact detonation, respectively.
Generally, the existing works still have the following limitations: (i) UHPCC
has the prominent blast and impact resistance compared with NSC, but the studies
on the blast resistance of CFST column, especially for the UHPCC-FST column,
are relatively insufficient; (ii) considering the easy public accessibility of bridge
structure, it is supposed that the terrorist explosive (suitcase or vehicle bombs) can be
placed as near as possible to the bridge columns, i.e., the contact explosion. However,
the existing studies mainly concentrates in the close-in (0.05 ≤ Z ≤ 0.15 m/kg
1/3 )
or near range (0.2 ≤ Z ≤ 0.5 m/kg
1/3 ) blast events, and the relevant studies on the
contact explosion scenario is scarce; (iii) the residual axial load bearing capacity
is vital to evaluate the stability and workability of the whole bridge superstructure,
and the relationship between the damage level of column and the explosive charge
weight is vital for the practical anti-blast design of bridge piers. However, the related
studies are limited.
10.3 UHPCC-FST Columns
Aiming to investigate the failure mode and residual axial capacity of the UHPCC-FST
bridge columns under contact detonation, considering the prototype of the UHPCCFST columns with the diameter of 800 mm under the suitcase or vehicle bombs