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were noted, but debris was trapped by the bracing, and in some instances, the rods were bent by lateral loads imposed by the force of flood waters acting on the trapped debris. Use of knee bracing was also prevalent in elevated wood-frame structures. A common problem observed with knee bracing was that timber piles had been notched, some deeply, to accommodate bearing seats for tie-in purposes. Although the BPAT did not observe any structural failures that could be definitively linked to this problem, notching of piles can undermine their structural integrity and should therefore be avoided. 2.3.8 BREAKAWAY CONSTRUCTION AND ENCLOSURES There were a number of damaged or destroyed enclosures below elevated structures (see Figure 2-11), many ,,~th electrical wiring attached to breakaway walls. The presence of breakaway walls indicates the designer was aware of potential flood impacts. However, the placement or attachment of utilities to breakaway walls below the elevated portions of the structures demonstrates, at a minimum, lack of awareness oflocal, CCCL, and NFIP regulations by owners or contractors, or possibly disregard of those regulations. In some post-FIRM structures with breakaway walls below the lowest habitable floor, the walls broke away as intended but in doing so, damaged exterior sheathing and wall finishes above the lowest floor. The damage above the breakaway wall was usually minor but could have been prevented by better design and construction of this detail (as shown in Figure 2-11). Rolldown garage doors were damaged or destroyed in pre-FIRM and post-FIRM construction alike (see Figure 2-11). 2.3.9 STAIRS, DECKS, AND PORCHES Timber stairs and decks were frequent casualties of the storm. Many were supported by short, small-diameter shallow posts or piles. Some decks were supported by knee braces attached to structural piles supporting the main structure. Decks of this design seemed to better resist Opal's forces. Loss of decks sometimes led to roof damage where roof overhangs were supported by posts attached to the decks. In one instance, a deck located seaward of the State's CCCL and permitted by the State survived the storm, while the landward habitable structure (behind the CCCL and not within the State's jurisdiction) was destroyed. 2.3.10 UTILITIES .' The BPAT noted several problems associated with utilities and utility connections at habitable structures: . Placement of electric meters, panels, boxes, and wiring below a building's lowest habitable floor, rendering that equipment vulnerable to storm surge, wave, debris and overwash damage (see Figure 2-12). . Attachment of,,~ring, conduit, and electrical panels to breakaway walls (see Figure 2-13). . Failure to adequately support and fasten air conditioning compressor units (see Figure 2- 14). Many support platforms were destroyed, leading to compressor damage. Some platforms survived, while unfastened compressor units were blown or washed away. Units not properly supported and attached were also observed to have caused damage to exterior walls of some structures. . Placement of utility lines, septic systems, and mechanical connections and equipment, including air conditioning units, on the sides or seaward of buildings, rather than landward of the building. Loss of air conditioning units and/ or utility/mechanical components sometimes led to damage of the main strucpre. HURRICANE OPAL IN FLORIDA 2-9