40.350.040 Private Bridges

A.    Purpose.

    The purpose of this section is to establish minimum design standards for privately owned bridges to provide a unified approach to assure the safety of emergency responders as well as the public.

(Added: Ord. 2012-05-30)

B.    Applicability.

    This section applies to any private bridge that exists or that is proposed as part of a subdivision, short plat, site plan review application, conditional use permit application, or building permit application.

(Added: Ord. 2012-05-30)

C.    Definitions. For the purposes of this section, the following definitions shall apply:

AASHTO Type 3 truck

The Type 3 truck is defined by AASHTO and is generally a three (3) axle truck carrying fifty thousand (50,000) pounds.

AASHTO Type 3S2 truck

The Type 3S2 truck is defined by AASHTO and is generally a five (5) axle truck carrying seventy-two thousand (72,000) pounds.

AASHTO Type 3-3 truck

The Type 3-3 truck is defined by AASHTO and is generally a six (6) axle truck carrying eighty thousand (80,000) pounds.

AASHTO

“AASHTO” means the American Association of State Highway and Transportation Officials.

LRFD

Load resistance factor design as defined as AASHTO.

Design tandem

A “design tandem” is defined as two (2) twenty-five thousand (25,000) pound loads measured four feet apart as measured longitudinally along bridge deck.

Design lane

A design lane is twelve (12) feet transversely measured across a bridge deck.

HS-20 (also design truck)

An “HS-20” loading configuration is defined as a three (3) axle truck that has eight thousand (8,000) pounds on the first axle, thirty-two thousand (32,000) pounds on the second and third axles with a spacing of a fourteen (14) foot distance between the front and middle axles and between fourteen (14) foot and thirty (30) foot distance between the middle and rear axles. The distances are measured longitudinally along the bridge deck.

HL-93

An “HL-93” loading configuration is defined by three (3) components: the design truck, design tandem and design lane as defined in this section of code.

LFR

“LFR” means load factor rating, which is used to analyze load capacity on bridges constructed prior to October 1, 2010.

LRFR

“LRFR” means load resistance rating factor which is used to analyze load capacity on bridges constructed on or after October 1, 2010.

MUTCD

“MUTCD” means the Manual on Uniform Traffic Control Devices.

WSDOT

“WSDOT” means the Washington State Department of Transportation.

(Added: Ord. 2012-05-30)

D.    Standards and Approval Criteria.

1.    General. Private bridges are not allowed:

a.    When they conflict with the Arterial Atlas, as amended;

b.    When they are needed for public circulation;

c.    When they connect two (2) public roads; or

d.    When they are to serve more than fifty (50) potential residential lots in rural areas or one hundred (100) lots in urban areas, created after April 12, 1994, except within a planned unit development; provided, that where expansion of a public road is not presently feasible, the limitations of this subsection shall not apply if the affected internal and frontage roads are improved to public standards (if otherwise required) and dedicated to the county, with the acceptance of such dedication(s) being deferred until extension of a public road allows connection.

2.    The signature, date and stamp with seal of a licensed professional engineer registered in the state of Washington are required for all bridge plans and specifications, ratings, and evaluations. The stamp and certification shall be deemed in compliance with the requirements of this chapter and constitute acceptance.

3.    Category A Bridges. Category A bridges are new bridges permitted and constructed on or after January 1, 2012. A building permit is required for construction of a Category A bridge.

a.    Definitions. For the purposes of this section, the following definitions apply:

Category A bridge

“Category A bridge” means a new bridge that is constructed privately that will remain privately owned.

•    Category A1: Bridges that provide access on a private road for up to twenty (20) residential lots.

•    Category A2: Bridges that provide access on a private road for more than twenty (20) residential lots.

•    Category A3: Bridges that provide access on a private road to commercial or industrial traffic.

b.    Design. All Category A bridges are new bridges and must comply with the latest adopted editions of the International Building Code (IBC) or AASHTO LRFD Bridge Design Specifications, US Customary Units (AASHTO), except as follows:

(1)    Vehicular loading for a Category A1 or A2 bridge capacity analysis must use a minimum of an HS-20 loading configuration with no other uniform or concentrated loads applied concurrently with that load. Load factors for Category A1 and A2 bridges for strength design shall be in accordance with the IBC. At a minimum, an HL-93 loading configuration shall be used to determine load capacity for Category A3 bridges. Load factors for Category A3 bridges for strength design shall be in accordance with AASHTO. Applied locations of design live loads for all Category A bridges shall be in accordance with AASHTO.

(2)    Load rating of new bridges shall be in accordance with the AASHTO Manual for Bridge Evaluation (MBE), latest edition, and use the load resistance factor rating (LRFR) method with the following:

(a)    All superstructure elements, including decks, shall be analyzed and load rated. Substructure elements need not be load rated.

(b)    Load rating shall analyze load effects from the following vehicles: AASHTO legal vehicles (Type 3, Type 3S2, and Type 3-3). No other vehicles or notional loads need be applied.

(c)    Upon completion of the load rating, the bridge limits shall be posted on a load limit sign, AASHTO Regulatory Sign, R12-5, as defined by the Manual on Uniform Traffic Control Devices (MUTCD).

(d)    Upon submission of an evaluation to the Clark County Fire Marshal, a sticker for the sign shall be issued indicating the year that a new inspection is required.

(3)    A minimum three (3) feet of clearance is required between the one hundred (100) year flood elevation and the bottom of the bridge span, if the bridge is crossing a stream or other body of water, unless a backwater evaluation is submitted, signed, stamped and sealed by a licensed professional engineer registered in the state of Washington.

(4)    A scour evaluation according to Hydraulic Engineering Circular No. 18 (HEC-18) is required for the bridge crossing, and the foundations must remain stable under the maximum scour conditions.

(5)    A geotechnical investigation is required for bridge spans sixty (60) feet or greater in length or for any bridge located in a known hazard area.

c.    Railings and Curbs. Category A bridges shall have a minimum of a twelve (12) inch curb height on both sides of the bridge that shall resist a horizontally applied load at any location along the length of the bridge in compliance with IBC design for vehicle barriers. Vehicle and pedestrian rails other than curbs are not required, but if provided, they must comply with IBC.

d.    Bridge Width. Category A1 and A2 bridges shall be a minimum of twelve (12) feet in clear width between inside face of curbs and signed for a one (1) way bridge. Bridges with clear width greater than eighteen (18) feet can be considered a two (2) way bridge and signage for a one (1) way bridge is not required.

e.    Bridge Construction, Special Inspection, and Structural Observation.

(1)    Special inspections in accordance with the IBC are required for foundations, steel reinforcing, concrete, steel fabrication and erection, welding of metal deck, any other field welding, and as determined by the building official.

(2)    The structural engineer who stamped or sealed the drawings shall observe the bridge construction at a minimum during foundation construction, substructure construction, steel fabrication, superstructure construction and railing installation.

(3)    Before issuance of an occupancy permit for use of the bridge, the licensed professional engineer registered in the state of Washington must submit a final letter of acceptance with copies of all the inspection and testing reports, and certify to the building official that the bridge was constructed in compliance with applicable standards.

f.    Turnouts. New one (1) way bridges shall have turnouts at each end that comply with the requirements of the Standard Details Manual.

4.    Category B Bridges. Category B bridges are existing bridges permitted and constructed before January 1, 2012.

a.    Definitions. For the purposes of this section, the following definitions apply:

Category B bridge

“Category B bridge” means an existing privately owned and maintained bridge permitted and constructed before January 1, 2012.

•    Category B1: Existing bridges that do not provide access to any new dwellings or new lots.

•    Category B2: Existing bridges that provide access to a maximum of twenty (20) residential lots.

•    Category B3: Existing bridges that provide access to more than twenty (20) residential lots or to any property zoned commercial or industrial.

b.    Category B1 bridges are not required to be evaluated or upgraded.

c.    For Category B2 bridges, an applicant for an applicable development must submit a load rating evaluation and recommendation, post the bridge in accordance with Section 40.350.040(D)(5) and choose one (1) of the following options:

(1)    If a repair, upgrade, retrofit or rebuild is required, owners must comply with that recommendation; or

(2)    Install a residential fire sprinkler system conforming to the NFPA Standard 13-D in new residences served by the bridge.

d.    Category B3 bridges shall require evaluation and upgrade according to Section 40.350.040(D)(5) for a land division or building permit for a new dwelling.

e.    Railings and Curbs. AASHTO and IBC rail, barrier, and curb elements are not required on any Category B bridges.

5.    Existing Bridges Requiring Evaluation. All Category A and Category B1 and B2 bridges shall be re-inspected every five (5) years. Inspections must be conducted by an engineer certified as a bridge condition inspector by the Washington Department of Transportation or National Highway Institute. If the evaluating engineer determines that the load capacity requires modification, more frequent inspections, or repair is necessary, compliance shall be required. The inspection and load rating evaluations are to be submitted to the Clark County Fire Marshal.

a.    Load rating evaluations of existing bridges shall be in accordance with the AASHTO Manual for Bridge Evaluation (MBE), latest edition and use the LRFR method with the following:

(1)    All superstructure elements, including decks, shall be analyzed and load rated. Substructure elements need not be load rated although their condition should be considered in the overall bridge capacity results.

(2)    The load factor rating (LFR) method can be used on bridges constructed prior to October 1, 2010. LFR load ratings shall apply operating level load factors for live loads. Inventory level live load factors need not be applied.

(3)    For both the LRFR and LFR load rating methods, analyze load effects from the following vehicles: AASHTO legal vehicles (Type 3, Type 3S2, and Type 3-3). No other vehicles or notional loads need be applied.

(4)    Upon completion of the load rating evaluation, the bridge limits shall be posted on a load limit sign, AASHTO Regulatory Sign, R12-5, as defined by the Manual on Uniform Traffic Control Devices (MUTCD).

(5)    Upon completion of the load rating evaluation to the Clark County Fire Marshal, a sticker for the sign shall be issued indicating the year that a new inspection is required.

b.    If the resulting load rating is below one (1.0), posting of the allowable tonnage as a direct percentage of the HS-20 loading configuration is required. In addition, at the discretion of the Fire Marshal, residences that require the bridge for emergency vehicle access may receive a notice that emergency vehicles may not cross the bridge. Recording of the notice for affected parcels is required until such time as the bridge is upgraded/replaced and the load rating is above one (1.0).

c.    If the bridge is voluntarily upgraded, any modifications or additions shall conform to the requirements listed for Category A bridges in Section 40.350.040(D)(3).

d.    If the bridge is voluntarily removed or replaced, the new construction shall conform to the requirements listed for Category A bridges in Section 40.350.040(D)(3).

(Added: Ord. 2012-05-30)

E.    Private Bridge Agreement.

1.    The county will not maintain private bridges, associated signs or other improvements. The owners of the properties served by private bridges requiring evaluation shall maintain such bridges in compliance with applicable standards. Any Category A private bridge serving more than three (3) lots requires a private maintenance covenant recorded with the County Auditor. Submission of the covenant to the Building Official for approval is required prior to recording. Applicants seeking site plan or building permit approval are required to sign a covenant running with the land promising to sign a maintenance agreement at such time as the other owners using the bridge sign the agreement.

2.    Covenants, which may be in the form set forth in the Standard Details Manual, shall run with the land, and shall include the following:

a.    Minimum annual assessments in an amount adequate to defray costs of ordinary maintenance and procedures for approval of additional needed assessments;

b.    A periodic bridge maintenance schedule; and

c.    A process for assessing maintenance, repair, retrofit, rehabilitate and rebuild costs equitably to property owners served by the private bridge.

3.    The covenants for maintenance must be enforceable by the owner of any property served by the private bridge.

4.    Developer Maintenance Obligation. The developer of a residential plat or short plat shall be responsible to ensure the maintenance of the private bridge for a period of two (2) years from the date of recording of the plat or short plat. Thereafter, the developer’s maintenance responsibility will depend upon the number of lots under the developer’s continuing ownership, as stated in the recorded covenant.

5.    Private Bridge Inspection. Private bridges will be subject to the same inspection schedule as stated in Section 40.350.040(D)(5).

(Added: Ord. 2012-05-30)

F.    Notice. The following statement is required on the face of any site plan, or binding site plan or within the developer covenants to Clark County for any subdivision or short plat containing a private bridge:

Clark County has no responsibility to improve or maintain the private bridges contained within or private roads providing access to the property described in this development. Any private bridge shall remain a private bridge unless it is upgraded to public bridge standards at the expense of the developer or abutting lot owners and is accepted by the county for public ownership and maintenance.

(Added: Ord. 2012-05-30)