§ 252-19. Coastal high-hazard area and Coastal A Zone.

Coastal high-hazard areas (V or VE Zones) and Coastal A Zones are located within the areas of special flood hazard established in § 252-3. These areas have special flood hazards associated with high velocity waters from tidal surges and hurricane wave wash; therefore, the following provisions shall apply:

A. 

Location of structures.

(1) 

All buildings or structures shall be located landward of the reach of the mean high tide.

(2) 

The placement of manufactured homes shall be prohibited, except in an existing manufactured home park or subdivision.

B. 

Construction methods.

(1) 

Elevation. All new construction and substantial improvements shall be elevated on piling or columns so that:

(a) 

The bottom of the lowest horizontal structural member of the lowest floor (excluding the piling or columns) is elevated to or above the base flood elevation plus two feet or as required by ASCE/SEI 24-14, Table 4-1, whichever is more restrictive;

(b) 

All electrical, heating, ventilating, air-conditioning, mechanical equipment and other equipment servicing the building is elevated two feet above the base flood elevation; and

(c) 

With all space below the lowest floor's supporting member open so as not to impede the flow of water, except for breakaway walls as provided or in Subsection B(4) below.

(2) 

Structural support.

(a) 

All new construction and substantial improvements shall be securely anchored on piling or columns.

(b) 

The pile or column foundation and structure attached thereto shall be anchored to resist flotation, collapse or lateral movement due to the effects of wind and water loading values, each of which shall have a one-percent chance of being equaled or exceeded in any given year one-hundred-year-mean-recurrence interval).

(c) 

Prohibit the use of fill for structural support of buildings within Zones V1-30, VE, V and Coastal A on the City's FIRM.

(3) 

Certification. A registered professional engineer or architect shall develop or review the structural design specifications and plans for the construction and shall certify that the design and methods of construction to be used are in accordance with accepted standards of practice for compliance with the provisions of Subsection B(1) above and Subsection B(2)(a) and (b) above.

(4) 

Space below the lowest floor.

(a) 

Any alteration, repair, reconstruction or improvement to a structure started after the enactment of this chapter shall not enclose the space below the lowest floor unless breakaway walls, open-wood lattice-work or insect screening are used as provided for in this section.

(b) 

Breakaway walls, open-wood lattice-work or insect screening shall be allowed below the base flood elevation provided that they are intended to collapse under wind and water loads without causing collapse, displacement or other structural damage to the elevated portion of the building or supporting foundation system. Breakaway walls shall be designed for a safe loading resistance of not less than 10 and no more than 20 pounds per square foot. Use of breakaway walls which exceed a design safe loading of 20 pounds per square foot (either by design or when so required by local or state codes) may be permitted only if a registered professional engineer or architect certifies that the designs proposed meet the following conditions:

[1] 

Breakaway wall collapse shall result from a water load less than that which would occur during the base flood; and

[2] 

The elevated portion of the building and supporting foundation system shall not be subject to collapse, displacement or other structural damage due to the effects of wind and water load acting simultaneously on all building components (structural and nonstructural). Water loading values used shall be those associated with the base flood. Wind loading values used shall be those required by applicable state or local building standards.

(c) 

If breakaway walls are utilized, such enclosed space shall be used solely for parking of vehicles, building access, or storage and not for human habitation.

(d) 

Prior to construction, plans for any breakaway wall must be submitted to the Construction Code Official or Building Subcode Official for approval.

C. 

Sand dunes. Prohibit man-made alteration of sand dunes within Coastal A Zones, VE and V Zones on the community's FIRM which would increase potential flood damage.