Influence of Charge Locations on Close-in Air-blast Response of Pre-tensioned Concrete U-girder

Evaluation of critical damage location of contact blast on conventionally reinforced one-way square concrete slab applying CEL-FEM blast modeling technique

“…As the expansion of the hot air goes on, cooling occurs, and movement of the compressed air develops vacuum, that is, pressure drops below the atmospheric pressure, and it is called the negative phase of the blast wave (ASCE/SEI 59-11, 2011; IS 4991, 1968; TM 5-1300, 1990; UFC 3-340-02, 2008). However, the negative blast wave effect is usually not incorporated in the blast analysis of the structures (Anas and Alam, 2021a, 2021b, 2022a, 2022b; Anas et al, 2020a, 2020b, 2020c, 2021a, 2021b, 2021c, 2021d, 2021e, 2021f, 2022a, 2022b, 2022c, 2022d, 2022e; Kyei and Braimah, 2017; TM 5-1300, 1990; UFC 3-340-02, 2008).…”

“…The categories are small (W TNT ≤ 5.0), medium (5.0 < W TNT ≤ 20.0), large (20.0 < W TNT ≤ 100.0), and very large (W TNT > > 100.0), where W TNT is the weight of explosive in “kg-TNT” (Anas et al, 2021b, 2021d). The structural response/damage caused by blast-induced impulsive load takes place for a quite shorter period of time, generally micro- to milli-seconds, and has a very high magnitude as compared to other quasi-static and lower intensity dynamic loads, that can be instigated by pressures of wind, wave, or earthquake (Anas et al, 2021f). Additionally, the responses received from a structure and its materials under such extreme loadings do not certainly lead to the reliable prediction of the structural response/damage.…”

“…Additionally, the responses received from a structure and its materials under such extreme loadings do not certainly lead to the reliable prediction of the structural response/damage. Rather, they are overtly non-linear with complex stress states and are time-dependent delivering available design practices in the current design standards/manuals (Anas and Alam, 2021a, 2021b, 2022a; Anas et al, 2020a, 2020b, 2020c, 2021a, 2021b, 2021c, 2021d, 2021e, 2021f; DOE/TIC-11268, 1992; TM 5-1300, 1990; UFC 3-340-02, 2008). Under blast engineering, which is considered to be a specialized field of structural engineering, the majority of the structural engineers have little to no awareness of the concept of blasts, loadings induced out of it, and dynamic response of the protective or target structures under such extreme short-duration/high-magnitude loading (Anas et al, 2021b).…”

“…The models that are most frequently used for concrete materials include the Concrete Damage Plasticity (CDP) model (ABAQUS/CAE, 2020; Hafezolghorani et al, 2017; Tao and Chen, 2015), smeared crack model (ABAQUS/CAE, 2020), discrete crack model (ABAQUS/CAE, 2020), and Holmquist–Johnson–Cook (HJC) model (ABAQUS/CAE, 2020). With the Concrete Damage Plasticity (CDP) model giving much more promising and favorable results (Anas and Alam, 2021a, 2021b, 2022abib_Anas_et_al_2020abib_Anas_et_al_2020bbib_Anas_et_al_2020c; Anas et al, 2020a, 2020b, 2020c, 2021a, 2021b, 2021c, 2021d, 2021e, 2021f; Kyei and Braimah, 2017; Kumar et al, 2020; Lee and Fenves, 1998; Lubliner et al, 1989; Pereira et al, 2014), it has been deployed for modeling of normal strength concrete (C30) in the present research work. This model assumes that the concrete material damage is generated by activation and growth of flaws and cracks due to compression and tension.…”

Performance of (1) concrete-filled double-skin steel tube with and without core concrete, and (2) concrete-filled steel tubular axially loaded composite columns under close-in blast

“…Over the past 20 years, accidental and man-made explosion incidents have revealed the vulnerability of civilian structures to extreme loadings such as those caused by close-in or contact detonations (Anas, Alam, et al, 2020, 2021, Anas, Ansari, et al, 2020, 2021; Anas et al, 2020a; Anas and Alam, 2021¸ 2021c; Anas et al, 2021c, 2021d., 2021e, 2021f; Byfield et al, 2004; Remennikov and Rose, 2007). Such incidents generate impulsive loading, characterized by their high intensity and very short duration (microsecond to the millisecond), develop blast pressure on structures that can be modeled as an exponential function of time (Hyde, 1992).…”