Ordinance No. 25-86-17 v 4111/1 ORDINANCE NO. 25-86- 17
AN ORDINANCE AMENDING THE ORDINANCE CODE
OF THE CITY OF ATLANTIC BEACH, FLORIDA;
AMENDING CHAPTER 6, ARTICLE II, TO ADD
SECTIONS 6-18 THROUGH 6-28, PROVIDING
RULES AND REGULATIONS FOR THE CITY'S
COASTAL CONSTRUCTION CODE; PROVIDING AN
EFFECTIVE DATE
BE IT ORDAINED by the City Commission of the City of Atlantic
Beach, Florida:
Section 1. Chapter 6, Article II is hereby amended to add
sections 6-18 through 6-28 which said sections shall read as follows:
CHAPTER 6
BUILDINGS AND BUILDING REGULATIONS
ARTICLE II BUILDING CODE
Section 6-18 TITLE - COASTAL CONSTRUCTION CODE
The provisions contained herein shall constitute the Coastal
Construction Code for construction within the coastal building zone in
Atlantic Beach, Florida, and shall be referred to as the "Coastal Code".
Section 6-19 PURPOSE - GENERAL
The purpose of the Coastal Code is to provide minimum standards for
the design and construction of buildings and structures to reduce the
harmful effects of hurricanes and other natural disasters occurring
along the coastal areas of Atlantic Beach which front on the Atlantic
Ocean. These standards are intended to specifically address design
features which affect the structural stability of the beach, dunes and
topography of adjacent properties. The Coastal Code is site specific to
the coastal building zone as defined herein, and is not applicable to
other locations. In the event of a conflict between these sections and
other chapters of this code, the requirements resulting in more
restrictive design shall apply. No provisions in these sections shall
be construed to permit any construction in any area prohibited by any
other Atlantic Beach regulation.
Section 6-20. SCOPE - APPLICABILITY
The requirements of this Coastal Code shall apply to the following
types of construction in the coastal building zone in Atlantic Beach.
(a) The new construction of, or improvement to major structures,
4110 nonhabitable major structures, and minor structures as defined
herein.
4111/0 (b) Construction which would change or alter the character of the
shoreline (e.g. excavation, grading, paving) . The Coastal
Code does not apply to minor work in the nature of normal
beach cleaning or debris removal.
(1) - Existing Structures
The requirements of this section shall not apply to
existing structures, structures under construction, or
structures for which a valid and unexpired municipal or
county building permit was issued prior to the adoption
of the Coastal Code.
(2) - Multi-Zone Structures
For structures located partially in the coastal building
zone, the requirements of the Coastal Code shall apply to
the entire structure.
(3) - Construction Seaward of Mean High Water
Structures or construction extending seaward of the mean
high water line which are regulated by Section 161.041 ,
Florida Statutes, (e.g. groins, jetties, moles,
breakwaters, seawalls, revetments, beach nourishment,
41/111 inlet dredging, etc.) , are specifically exempt from the
provisions of these sections. In addition, the Coastal
Code does not apply to piers, pipelines, or outfalls
which are regulated pursuant to the provisions of Section
161.053, Florida Statutes.
(4) - Applications for Permits
Applications for building permits for all construction in
the coastal building zone; if-net-ef-fcermal-eF-esctal
design-es-determined-by- he-Buiidiag-effieal; shall be
certified by an architect or professional engineer
registered in the State of Florida. Such certification
shall state that the design plans and specifications for
the construction are in compliance with the criteria
established by this Coastal Code.
Section 6-21. DEFINITIONS
The following terms are defined for general use in the Coastal
Code:
(a) "Beach" means the zone of unconsolidated material that extends
landward from the mean low water line to the place where there
is marked change in material or physiographic form, or to the
line of permanent vegetation, usually the effective limit of
• storm waves. "Beach" is alternatively termed "shore".
(b) "Breakaway wall" or " frangible wall" means a partition
411111 independent of supporting structural members that will
withstand design wind forces, but will fail under hydrostatic
wave, and runup forces associated with the design storm surge.
Under such conditions, the wall shall fail in a manner such
that it breaks up into components that will minimize the
potential for damage to life or adjacent property.
(c) "Building Support Structure" means any structure which
supports floor, wall or column loads, and transmits them to
the foundation. The term shall include beams, grade beams, or
joists, and includes the lowest horizontal structural member
exclusive of piles, columns, or footings.
(d) "Coastal Barrier Islands" means geological features which are
completely surrounded by marine waters that front upon the
open waters of the Gulf of Mexico, Atlantic Ocean, Florida
Bay, or Strait of Florida, and are composed of quartz sands,
clays, limestone, oolites, rock, coral, coquina, sediment, or
other material, including soil disposal, which features lie
above the line of mean high water. Mainland areas which were
separated from the mainland by artificial channelization for
the purpose of assisting marine commerce shall not be
considered coastal barrier islands.
41/111 (e) "Coastal Building Zone" means the land area 1500 feet landward
of the coastal construction control line established pursuant
to Section 161.053, Florida Statutes. Fer-these-eeastal
eities-and-enemies-fef-whieh-ae-eeastal-eenstruetien-eentfel
Ilne-has-been-establshed;-the-'-'eeastal-buildng-gene'-'-Is
delied-as-that-lead-area-3888-fee -landward-€nem-the-mean
high-water-line.---An-eeastal-barfIe -Islands;-the-'-'eeastal
building-$nae"is-de€road-as-the-afea-;88A-€net-IaadwaEd-€rem
the-eeastal-eeastfuetien-annual-line-ef-the-entre-island
whiehevef-is-less---An-bathe -islands-€er-whleh-ae-eeastal
eenstuetien-annual-line-has-been-esablished- he-'-''eeastal
buildng-sane'l-is-the-area-;BAA-Feet-Ian4wriEd-€rem-the-mean
high-water-Ine-er-the-entire-island;-whiehever-is-Iess-
(f) "Column Action" means the potential elastic instability in
piles or columns resulting in axial or lateral bending of the
member due to compressive stress.
(g) "Construction" means the carrying out of any building,
clearing, filling, or excavation or the making of any material
change in the size or use of any structure or the appearance
of any land. When appropriate to the context, "construction"
refers to the act of construction or the result of
construction.
(h) "Dune" means a mound or ridge of loose sediments, usually
dill sand-sized, lying landward of the beach, and deposited by
natural or artificial means.
a (i) "Major Structure" includes but is not limited to residential
buildings including mobile homes, commercial, institutional,
industrial, and other construction having the potential for
substantial impact on coastal zones.
(j) "Mean High Water Line" means the intersection of the tidal
plane of mean high water with the shore. Mean high water is
the average height of high waters over a 19-year period (See
Section 177.27 (15) , Florida Statutes) .
(k) "Minor Structure" includes but is not limited to pile-
supported, elevated dune and beach walkover structures;
beach access ramps and walkways; stairways; pile-supported
elevated viewing platforms, gazebos, and boardwalks; lifeguard
support stands; public and private bathhouses; sidewalks,
driveways, parking areas, shuffleboard courts, tennis courts,
handball courts, racquetball courts, and other uncovered paved
areas; earth retaining walls; sand fences, privacy fences,
ornamental walls, ornamental garden structures, aviaries, and
other ornamental construction. It shall be a characteristic
of minor structures that they are considered to be expendable
under design wind, wave, and storm forces.
(1) "Nonhabitable Major Structure" includes but is not limited to
swimming pools; parking garages; pipelines; piers; canals,
All lakes, ditches, drainage structures, and other water retention
structures; water and sewage treatment plants; electrical
power plants, transmission and distribution lines, transformer
pads, vaults, and substations; roads, bridges, streets, and
highways; underground storage tanks; communications buildings
and towers; flagpoles and signs over 15 feet in height.
(m) "NGVD" means National Geodetic Vertical Datum - a geodetic
datum established by the National Ocean Service and frequently
referred to as the 1929 Mean Sea Level Datum.
Section 6-22 COASTAL CONSTRUCTION REQUIREMENTS - GENERAL
Construction within the coastal building zone aad-en-eeastal
baf e -lsleads shall meet the requirements of these sections. All
structures shall be designed so as to minimize damage to life, property,
and the natural environment. Assistance in determining the design
parameters to minimize such damage may be found in the referenced
documents listed in Section 6-28 herein.
Section 6-23 STRUCTURAL REQUIREMENTS FOR MAJOR STRUCTURES
(a) Foundations
All major structures shall be anchored to their foundations in such
a manner as to prevent flotation, collapse, or lateral displacement.
•
Foundation design and construction shall consider all anticipated
loads resulting from design storm conditions, including wave,
hydrodynamic, hydrostatic, and wind loads acting simultaneously with
dead loads. Erosion computations for foundation design shall account
for all vertical and lateral erosion and scour-producing forces,
including localized scour due to the presence of structural components.
1. Pile Foundations - shall be required for buildings located in
Federal Emergency Management Agency Flood
Insurance Rate Map "V" (velocity) zones or
where impacted by wave action.
(A) Pile dimensions, spacing and embedment shall be designed
consistent with the requirements of the site, taking into
account all vertical, lateral, erosion and
scour-producing forces.
(B) Piles shall be driven to a penetration which achieves
adequate bearing capacity taking into consideration the
anticipated loss of soil above the design grade.
(C) In addition to the normal foundation analysis, the pile
foundation analysis shall consider piles in column
action, where appropriate, from the bottom of the support
structure to the design grade.
01/111 (D) Consideration shall also be given to the degree of
exposure to wave attack and the resulting impact loads on
lateral or diagonal bracing between piles.
2. Monolithic Foundations - may be permitted in Federal Emergency
Management Agency Flood Insurance Rate Map
"A" or "B" zones or in locations not
impacted by wave action.
(A) Monolithic foundations may be used if soil conditions
permit and if located at an elevation which minimizes
their effect on the beach and adjacent properties. Due
consideration shall be given to their vulnerability to
erosion under design storm conditions.
(B) In the event that a monolithic foundation is used, the
maximum elevation of the top of the slab is to be below
the design scour depth (see Chapter 5.28, Shore
Protection Manual, U.S. Army Corps of Engineers, 4th
edition, 1984) unless positive methods are provided to
prevent scour.
(C) Other types of spread footings such as running footers or
pads may be permitted when positive methods are provided
to prevent scour.
4110
(b) Understructures
41111/1
No substantial walls or partitions shall be constructed below the
level of the first finished floor. This does not preclude the
construction of:
1. Stairways;
2. Shearwalls essentially perpendicular to breaking waves;
3. Shearwalls essentially parallel to breaking waves which do not
exceed a maximum of 20% of the building length;
4. Wind or sand screens constructed of fabric or wire mesh;
5. Light open lattice partitions with individual wooden lattice
strips no greater than 3/4" thick or 3" wide;
6. Elevator shafts;
7. Breakaway or frangible walls; or
8. Substantial walls constructed above the wave action and storm
surge expected under design storm conditions.
41/111 (c) Building and Floor Elevations
The minimum elevation for the underside of the building support
(excluding foundation) shall be above the elevation of the design
breaking wave crests or wave uprush superimposed on the storm surge with
dynamic wave setup expected under design storm conditions. The
elevation of the storm surge with dynamic wave setup shall be wither the
elevation established by the Florida Department of Natural Resources
Coastal Construction Control Line Study or the base flood elevation for
the specific area established by the Federal Emergency Management Agency
as determined by the design engineer.
(d) Erosion and Design Grade
The elevation of the soil surface to be used in the design of
foundations, calculation of pile reactions and bearing capacities shall
not be greater than that which would result from the erosion reasonable
anticipated as a result of design storm conditions. Calculation of the
design grade shall take into account localized scour due to the presence
of structural components. Erosion computations for foundation design
shall consider all vertical and lateral erosion and scour-producing
forces.
(e) Wave Force Design
1. Calculations for wave forces resulting from design storm
4110 conditions on building foundations and superstructures may be
based upon the minimun criteria and methods prescribed in the
Naval Facilities Engineering Command Design Manual, NAVFAC
DM-26, U.S. Department of Navy; Shore Protection Manual, U.S.
Department of the Army Corps of Engineers; U.S. Department of
the Army Coastal Engineering Research Center Technical Papers
and Reports; the Technical and Design Memoranda of the
Division of Beaches and Shores, Florida Department of Natural
Resources; or other professionally recognized methodologies
which produce equivalent design criteria.
2. Breaking, broken, and nonbreaking waves shall be considered as
applicable. Design wave loading analysis shall consider
vertical uplift pressures and all lateral pressures to include
impact as well as dynamic loading and the harmonic
intensification resulting from repetitive waves.
(f) Hydrostatic Loads
Calculations for hydrostatic loads shall consider the maximum water
pressure resulting from a fully peaked, breaking wave superimposed upon
the design storm surge with dynamic wave setup. Both free and
hydrostatic loads shall be considered. Hydrostatic loads which are
confined shall be determined using the maximum elevation to which the
confined water would freely rise if unconfined. Vertical hydrostatic
loads shall be considered both vertically downward and upward on
horizontal or inclined surfaces of major structures (e.g. floors, slabs,
roofs, walls) . Lateral hydrostatic loads shall be considered as forces
acting horizontally above and below grade on vertical or inclined
surfaces. Hydrostatic loads on irregular or curved geometric surfaces
shall be determined by considering the separate vertical and horizontal
components acting simultaneously under the distribution of the
hydrostatic pressures.
(g) Hydrodynamic Loads
Hydrodynamic loads shall consider the maximum water pressures
resulting from the motion of the water mass associated with the design
storm. Full intensity loading shall be applied on all structural
surfaces above the design grade which would affect the flow velocities.
(h) Design Conditions - General
1. Foundations for all major structures shall be designed for the
horizontal and vertical pressures generated by wave forces
between the elevation of the design breaking wave crests or
wave uprush superimposed upon the storm surge and the stable
soil elevation of the site.
2. All major structures, except mobile homes, shall be designed
to withstand 140 mph windspeeds. Horizontal wind velocity
pressures shall not be less than the values given below:
•
BASIC WIND VELOCITY DESIGN PRESSURE
(Pounds per Square Foot)
Standard Building Code Beeth-F1erlde-Buiidlag-6ede
Height Pressure Height Pessee
(ft) (psf) {€ } {39€)
0- 30 41 9----; 39
31- 50 54 5---15 34
51- 100 65 15---25 45
101- 200 79 25---35 59
201- 300 92 35---55 56
301- 400 101 55---45 63
401- 500 109 45--199 68
501- 800 121 199--159 45
801-1000 133 159--259 83
over 1000 137 259--359 94
359--559 199
559--459 121
459-1999 132
eve -1999 134
* The above table is based upon the formula
1111 P=.00256 x V2 x (H/30)2/7, where: P = pressure in pounds/square foot
V = 140 mph
H = height above grade in feet
3. Appropriate shape factors shall be applied for resistance
against overturning and uplift as required elsewhere in this
code. Internal pressures on internal walls, ceilings and
floors resulting from damaged windows or doors shall also be
considered in the design unless the specified windows and
doors have been tested by an approved testing agency and have
been shown to be capable of withstanding the design pressures
required herein.
4. Mobile homes shall conform to the Federal Mobile Home
Construction and Safety Standards of the Uniform Standards
Code ANSI book A-119.1 , pursuant to Section 320.823, Florida
Statutes, in addition to the other requirements contained in
this chapter.
Section 6-24 STRUCTURAL REQUIREMENTS FOR NONHABITABLE MAJOR
STRUCTURES
Nonhabitable major structures need not meet the specific structural
requirements of Section 6-23, except that they shall be designed to
produce the minimum adverse impact on the beach and dune system and
shall comply with the applicable standards of construction found
• elsewhere in this code. All sewage treatment and public water supply
4110 systems shall be flood-proofed to prevent infiltration of surface water
anticipated under design storm conditions. Underground utilities,
excluding pad transformers and vaults, shall be flood proofed to prevent
infiltration of surface water expected under design storm conditions or
shall otherwise be designed to function when submerged under such storm
conditions.
Section 6-25 STRUCTURAL REQUIREMENTS FOR MINOR STRUCTURES
Minor structures need not meet the specific structural requirements
of Section 6-23 except they shall be designed to produce the minimum
adverse impact on the beach and dune system and shall comply with the
applicable standards of construction found elsewhere in this code.
Section 6-26 LOCATION OF CONSTRUCTION
Construction, except for elevated walkways, lifeguard support
stands, piers, beach access ramps, gazebos, and coastal or shore
protection structures, shall be located a sufficient distance landward
of the beach to permit natural shoreline fluctuations and to preserve
dune stability. Construction, including excavation, may occur to the
extent that the natural storm buffering and protection capability of the
dune is not diminished.
Section 6-27 PUBLIC ACCESS
• Where the public has established an accessway through private lands
to lands seaward of mean high tide or water line by prescription,
prescriptive easement, or any other legal means, development or
construction shall not interfere with such right of access unless a
comparable alternative accessway is provided. The developer shall have
the right to improve, consolidate, or relocate such public accessways so
long as they are:
(a) Of substantially similar quality and convenience to the
public;
(b) Approved by the local government; and
(c) Consistent with the coastal management element of the local
comprehensive plan adopted pursuant to Section 163.3178,
Florida Statutes.
Section 6-28 REFERENCES
Assistance in determining the design parameters and methodologies
necessary to comply with the requirements of this chapter may be
obtained from:
Shore Protection Manual, U.S. Army Corps of Engineers, 4th edition,
1984.
•
U.S. Department of the Army, Coastal Engineering Research Center's
Technical Papers and Reports.
Florida Department of Natural Resources, Division of Beaches and
Shores Technical and Design Memoranda.
Naval Facilities Engineering Command Design Manual, NAVFAC DM-26,
U.S. Department of the Navy.
Section 2. This Ordinance shall become effective March 1 , 1986.
* * * * * * * * * * * * *
Passed by the City Commission on First Reading February 10, 1986.
Passed by the City Commission on Second & Final Reading February 24, 1986.
4111
William S. Howell, Mayor, Presiding Officer
Approved as to Form and Correctness:
ArAdrkeau•e L. Mullis, City 'ttor
(SEAL)
Adelaide R. Tucker, City Clerk