## 6 Blast Performance of Proposed Connection
### Discussion  
The simulation results for through-diaphrag and plate-reinforced large CFT connections are summarized in Tables 3 and 4, respectively. The blast performances of the two connection models based on the evaluation criteria described previously were virtually identical, but the failure modes  
Figure 14: Deflection histories of beam and column for through-diaphrag large CFT connection. (a) Beam; (b) column.  
Figure 15: Deflection histories of beam and column for plate-reinforced large CFT connection. (a) Beam; (b) column.  
were somewhat different. Both connections satisfied the design criteria for \(W=223\) and 454 kg; the end rotations for beam and column did not exceed 2.0\({}^{\circ}\).  
There was no damage to the beam and column for these charge weights, as shown in Figure 13a,b. For \(W=1814\) kg, the end rotation of the beam for both connections exceeded the specified limit but it did not for the column. Significant damages were observed for the beam of the through-diaphrag connection, whereas minor damage was identified at both of the side ends of the reinforcing plate in contact with the column for the plate-reinforced connection, as shown in Figure 13c. For the column, minor damage was observed at the bottom of the through-diaphrag connection and near the bottom of the plate-reinforced connection.  
Both connections for \(W=4536\) and 11,000 kg did not meet the design criteria for beam and column. For \(W=4536\) kg, the beam of the through-diaphrag connection was separated from the column at \(t=20\) ms, as shown in Figure 13d. There was no beam separation for the plate-reinforced connection but serious damage to the beam near the column face was accompanied by the blast loads. The columns for both connections suffered a wide range of damage for this charge weight. For \(W=11,000\) kg, both connections led to similar failure modes, as shown in Figure 13e; the beams were disconnected from the columns, which were significantly damaged.  
Figure 16 enables a comparison of beam and column end rotation between the through-diaphrag and plate-reinforced connections.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \multirow{2}{*}{\(W\) (kg)} & \multicolumn{2}{c}{**Max Deflection (mm)**} & \multicolumn{2}{c}{**End Rotation (Degrees)**} & \multicolumn{2}{c}{**Evaluation**} & \multicolumn{2}{c}{**Failure Mode at \(t=20\) ms**} \\ \cline{2-9}  & **Beam** & **Column** & **Beam** & **Column** & **Beam** & **Column** & **Beam** & **Column** \\ \hline
224 & 26 & 14 & 0.37 & 0.20 & A 1  & A & No damage & No damage \\
454 & 48 & 24 & 0.69 & 0.34 & A & A & No damage & No damage \\  & & & & & & & Minor damage to & Minor damage to \\
1814 & 269 & 93 & 3.85 & 1.33 & NA 1  & A & Minor damage to & & & \\  & & & & & & & & \\  & &It is evident that the plate-reinforced connection subjected to the cargo van and delivery truck explosions, corresponding to \(W=1814\) and 4536 kg, respectively, shows greater blast performance; the end rotations were smaller by factors of 1.56 and 1.5, respectively, as shown in Figure 17.  
The blast loading from the moving van explosion, corresponding to \(W=11\),000 kg, was so large that the end rotations of the beams for both connections were similar. For all charge weights, there were insignificant differences in the end rotation for column.