MIL-HDBK-1013/14

APPENDIX B (Continued)

B.4.2

Example 2. Referring to Figure B-1, the target buildings in this case are 796 and 798.

Perimeter Road "B" has a 60-foot (18-m) offset (distance from the barrier to the restricting opposite

curb). Using Table 1 in Section 6, a vehicle traveling at 50 mph (80 kph) can safely turn on a

maximum 167-foot (51 m) radius curve without skidding. At this speed and angle of approach to

the barrier, the vehicle will strike the barrier at an angle. Because the amount of speed directed at

the barrier is related to the angle of impact (Table 1), the speed directed at the barrier is 76.6 percent

of the 50-mph (80-kph) speed, or 38 mph (61 m). Using Table 2 in Section 6 and rounding up to

the next highest speed [40 mph (64 kph)], the kinetic energy transferred to the barrier will be

214,000 ft-lbf (29 kgf-m), if the threat is a 4,000-pound (1,818-kg) vehicle, and 802,000 ft-lbf (111

kgf-m), if the threat is a 15,000-pound (6,818-kg) vehicle.

Once the kinetic energy has been calculated, refer to Appendix E for a listing of passive

barriers and penetration distances that can be used to select the most effective barrier. Anchored

Jersey Barriers could be used for the low-level threat of a 4,000-pound (1,818-kg) vehicle, and a

bollard system or concrete planter would be the only passive barriers that would be capable of

stopping a 15,000-pound (6,818-kg) vehicle. For the larger threat, it would be appropriate to install

concrete blocks, as shown in Figure 32 in Section 8, and space them in accordance with the

information from Table 14 to reduce the vehicle speed to 30 mph (48 kph) or less.

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