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t ,. ~"7 . / " "-,,,1' (.",,""'~If . (r""- \,/r' "f' .Io.\\, , :#>~ Figure 2-4 Battering 'f'''''',''' ',c ~~>h';c~' Figure 2-5 Pulsating ~ Figure 2-6 Translation .', 2-4 Bat/ering The battering of rushing water, waves, or objects floating in the water can create extensive danger. See Figure 2-4. Battering waves can destroy masonry or concrete structures which have limited laterai strength. Reinforcing steel, properly added during construction, can greatly improve resistance to the impact of waves. Coastal buildings are sometimes built with breakway wall panels on the ground floor. These panels are sacrificed to the wave action while the piles or piers continue to support upper floors of the house and present relatively little surface to impact of the waves. Pulsating Water Pulsating action is most pronounced inside the house. Water rushing in is stopped by an opposite wall and returned toward its place of entry. See Figure 2-5. These oscillations can approach a natural frequency of pulsation, which sustains and amplifies the motion. Floating contents and debris, caught up in the oscillating motion, can act as battering rams. Furnishings and structural elements may be seriously damaged by these pulsating waters. Translation Houses may be pushed off their foundations by moving water; such lateral movement of the structure is called translation. See Figure 2-6. If forces from water occur unevenly around the building, it may rofafe. An effective sill anchoring system as described in Figure 5-8 on page 5-5 can be a major protective factor in preventing translation or lifting of the building. The buoyant force, by reducing effective dead weight of the structure, can make a house more vulnerable to translation.