Overview - Minnesota LTAP · 2018-04-17 · 1 Section 4 Standard Plans for Design Fall, 2017 Ann...

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Section 4

Standard Plans for Design

Fall, 2017

Ann Johnson, PE Services

Brady Rutman, SRF Consulting Group

Design Overview

Overview

• Pedestrian Access Routes– Design Basics

– Recommendations: The Zone System

• Driveway Crossings

• Pedestrian Curb Ramp Standard Plans– Types of Curb Ramps

– Design Details

– Alternate Pedestrian Access Routes

• Accessible Pedestrian Signals– APS Compliance Checklist

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Pedestrian Access Routes

• Public Rights of Way Accessibility Guidelines (PROWAG) – Adopted by MnDOT in 2010

• Minimum 4 foot wide Pedestrian Access Route (PAR) with a maximum cross slope of 2% is required.

• The PAR must be continuous and unobstructed.

• The PAR shall connect accessible elements, spaces and facilities.

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Cross Slope

• Steep cross slopes are inconvenient and hazardous

• Require extra effort by wheelchair users to move forward

• Become slippery when wet, icy or snowy

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FHWA: Designing Sidewalks and Trails for Access (2001)

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Longitudinal Slope• Sidewalks adjacent to an existing roadway may follow, not

exceed the grade of the road.

• When outside the typical roadway section, recommended

maximum grade of 5%

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Longitudinal Slope

• On trails or sidewalks on independent alignments, slopes exceeding 5% must be treated as ramps.

– 8.3% max for a maximum rise of 30 in. with 5- by 5-ft level landings between segments

– At 8.3% grade, 30 in. rise = 30 ft long

– Ramps with a rise greater than 6 in. require handrails. (Does not apply to curb ramps)

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Longitudinal Slope

• Reduce the impacts of steep or long grades:• Decrease cross slope, even to 0%

• Provide signs that indicate:

– Grade and length

– Less steep alternate routes

• Consider providing handrails

• Consider providing a “refuge” or place to rest offline

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Cross Slope Solution:

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• Pick up elevation change outside the pedestrian access route

• Consider bus stops when using this design to be sure standards are still met

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The “Zone” System (Recommended, Not Required)

• Establishing a buffer area between sidewalk and traffic creates a safer and more pleasant place to walk and makes it easier to meet all ADA requirements.

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10

Roadway

Furniture

Zone

Pedestrian

Zone

(contains the PAR)


The “Zone” System

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Roadway

Parking

FurnitureZone

Pedestrian Zone(contains the PAR)



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• Maintain a 5’ wide path when doors of a building are open

• 3’ clearance recommended between building and PAR when doors open toward the PAR

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Protruding Objects

• When obstacles mounted on posts can be approached from the side, they shall not protrude more than 4 inches.

• Pole-mounted objects that can only be approached from the front shall not protrude more than 12 inches into the sidewalk corridor.

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FHWA: Designing Sidewalks and Trails for Access (2001)

Pedestrian Access Routes Pedestrian Access Routes

Surface Requirements

• Sidewalks must:

– Be firm, stable and slip-resistant

– Be smooth – no rough textures, large openings or gaps

– Avoid using surface treatments that limit usability

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Surface Continuity

• Bricks, cobblestones and other textured pavement create:

– Increased rolling resistance

– Tripping hazards

– Painful vibrations to people with brittle bones or spinal cord injuries in wheelchairs

– Potential maintenance issues

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Strongly discouraged by PROWAG


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Surface Continuity

• Tolerances:

– Up to ¼ inch: No Treatment

– ¼ to ½ inch: Bevel Surface (Max grade of 50%)

– Minimizes the amount of exertion from a wheelchair user

– Minimizes tripping hazards for all others

– More than ½“ inch: Replace sidewalk panel

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Gaps and Grates• Grates to have spaces no more than 1/2 inch wide in

direction of travel (ADA Standard)

• “Elongated openings shall be placed so that the long

dimension is perpendicular to the main direction of travel.”

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• PROWAG requires bus boarding and alighting areas to provide a clear length of 8 ft. minimum, measured perpendicular to street, and a clear width of at least 5 ft. Slopes no steeper than 2%.

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Mn/DOT Road Design Manual, Chapter 11

Bus Stops


• Maintenance of facilities, both seasonal and repair-related,

is required to remaining ADA-compliant.

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Maintenance

Driveway Crossings

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6

Driveway Crossings

Perpendicular Driveway• To be used when the driveway PAR is level with or above the

top of curb and sidewalk is separated from the road

• Maintain level passage (continuous PAR profile)

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Driveway Crossings

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Perpendicular Driveway• Sidewalk continues, full width and level, through the driveway

Driveway Crossings

Perpendicular Offset Driveway

• To be used when sidewalk is attached to curb

• Design Option in a Retrofit: Secure additional ROW from

adjacent property in order to improve pedestrian access on

narrow sidewalks

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Driveway Crossings

Perpendicular Offset Driveway

• Sidewalk bends around sloped portion of the driveway

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Driveway Crossings

Parallel Driveway

• To be used with ROW constraints prevent use of a level landing and when sidewalk is attached to curb

• Acceptable Design: Less desirable because it forces users to negotiate two ramps instead of one level surface, also subject to snow and ice collection in the PAR

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Driveway Crossings

Parallel Driveway

• Sidewalk drops down to elevation of street from both sides

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Driveway Crossings

• Driveways built like driveways encourage slower-speed turns.

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Driveway Crossings

• Driveways built like intersections encourage higher-speeds.

• PAR still needs to meet slope and surface requirements

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8

Pedestrian Curb Ramps

• If longitudinal slope exceeds 5 percent, or there is a change in direction, landings must be provided on any pedestrian facility.

• Maximum ramp slope is 8.3 percent.

• Maximum length of initial ramp is 15 feet.

• Slopes and dimensions are absolute. ADA Standards and PROWAG allow no tolerance for exceeding these maximums.

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Standard Plans Legend 2017:

- Ramp Slope Ranges

- Landing Areas

- Curb Heights “X”

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Pedestrian Curb RampsStandard Plans - Sheet 1


• NOTES: Landings shall be located anywhere the

pedestrian access route changes direction, at the top of

ramps that have running slopes greater than 5% , and if

the approaching walk is inverse grade greater than 2%.

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Landing

9






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Landing 5%-8%


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Landing






Curb Ramp Types

• Perpendicular ramp

• Tiered perpendicular ramp

• Parallel ramp

• Fan ramp

• Depressed corner

• Diagonal ramp (not recommended)

• One-way directional ramp

• Combined directional ramp

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Perpendicular

• Ramp is perpendicular to the curb line

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Landing

S

10


Tiered Perpendicular

• Used where the initial curb ramp cannot make up the elevation difference, so a secondary ramp is needed

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Landing

S

F F


Parallel

• Ramp is parallel to the curb line

• Landing occurs at the bottom of the ramp

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LandingS S


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Fan

•Ramp is radial at back of curb, 5% max slope

•Landing at top of ramp

Note 8; 7’ Min top radius grade break required to be constructible.


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24’ min.

Modified Fan

• Similar to Fan; Use when ROW is constrained

• Note 2: 4’ min. depth landing required across top of ramp

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Depressed Corner

• Ramps on approaching walk lead to Landing at bottom

• Fan Ramps preferred over Depressed Corners due to likelihood of ponding at depressed corner

SLanding

S

Landing


Diagonal Ramp

• Shall only be used after all other curb ramp types have been evaluated and deemed impractical

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Pedestrian Curb Ramp

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Diagonal Ramp

4’x4’ clear space required within crosswalk


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Standard One-Way Directional• Detectable Warnings to be placed perpendicular to travel at the closest

location to the curb with full sidewalk/trail width

• Note 7: Max 2% slope in all directions and drain to flow line. SHALL be constructed integral with curb and gutter.


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Directional with Detectable Warnings at Back of Curb

• When placement of warnings in Standard One-Way Directional exceeds 5’ offset from back of curb

• Note 13: Concrete walk shall be formed and constructed perpendicular to the back of curb. Maintain 3” between edge of domes and edge of concrete.


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2% Max.

Directional with Detectable Warnings at Back of Curb

• When placement of warnings in Standard One-Way Directional exceeds 5’ offset from back of curb

• Note 13: Concrete walk shall be formed and constructed perpendicular to the back of curb. Maintain 3” between edge of domes and edge of concrete.


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8%-10% SLOPE

Directional Ramp Walkable Flare

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LandingS

S

Combined Directional

• Landing shared by two separate directional ramps at a two-way crossing


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Combined Directional• Preferred over Fan/Depressed

Corner due to increased clarity of crossing direction

• Note 3: Min 3” Curb Height (4” Preferred) between domes

• Note 4: The “bump” between ramps should not be in direction of pedestrian travel


• Initial curb ramps landings shall be constructed within 15’ from the back of curb, with 6’ from the back of curb being the preferred distance.

• Secondary curb ramp landings are required for every 30” of vertical rise when longitudinal slope is greater than 5%

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Initial Landing Within 15’ BOC

Secondary LandingEvery 30” of Vertical Rise


• Contraction joints shall be constructed along all grade breaks.

• ¼” deep visual joints shall be used at the tops of concrete flares adjacent to walkable surfaces.

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• To ensure initial ramps and initial landings are properly constructed, landings SHALL be cast separately. Follow sidewalk reinforcement details on sheet 6 and the Special Provisions. Prosecution of Work (ADA).

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Curb and Gutter Details

• Any vertical lip at the flow line shall not be greater than ¼”

• Perpendicular and parallel ramps can have a maximum 5% gutter slope because the pedestrian’s path of travel is perpendicular to the gutter flow line.

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Curb and Gutter Details:

• Positive flow line drainage shall be maintained through the PAR at 2% maximum. No ponding shall be present in the PAR

• Curb ramp types where the pedestrian’s travel is not perpendicular to the gutter flow line (i.e. directional, depressed corners and fan ramps) shall have a flattened gutter slope of 2% to 3%.

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• Curb machine Placement

• Optional Sill Curb when sidewalk is at back of curb

• Note 3 Begin Gutter slope transition 10’ outside of all curb ramps.


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• Outflow Gutter 5% Max.


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Side Treatments

• When adjacent to pavement, flares shall be constructed at 8-10% max slope.

• When adjacent to turf, 1:6 graded flare is generally preferred.

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8% - 10 %1:6

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Side Treatments• A walkable surface is defined as a paved surface adjacent to a curb ramp

without raised obstacles that could be mistakenly traversed by a user who is visually impaired.

• A walkable Flare is a concrete flare constructed adjacent to a curb ramp with a slope of 8% - 10%

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1:6

Non- Walkable

SurfaceWalkable Surface

Walkable Flares 8%-10%


Detectable Edge at Quadrant• All constructed curbs must have continuous detectable edge for users

with visual impairments.

• Curb transitions are considered detectable edges when the taper starts

within 3” of the edge of truncated domes.

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3” MINIMUM CURB HEIGHT / 4”

PREFERRED

0”

0”0”

0”

CURB TAPER


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Pedestrian Approach Nose Detail• Note 15: 3’ for both upstream and

downstream side on medians and

splitter islands

3’

2’2’

3’

Best Practice: Match crosswalk width


Detectable Edge Without Curb and Gutter• Detectable warnings shall be place 1’ from edge of bituminous roadwayN

for visual contrast (MnDOT recommendation)

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1’

1’

17


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Rail Crossing• Nearest edge of detectable

warning surface shall be placed 12’ Minimum to 15’ Maximum from the nearest rail.

• For skewed railways in no instance shall the detectable warning be closer than 12’ measured perpendicular to the nearest rail.

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Vertical Face Curb

• V-curb adjacent to building


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V-Curb

• V-curb adjacent to landscape and outside sidewalk limits (preferred)

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V-Curb

• V-curb adjacent to landscape and inside sidewalk limits


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Semi-Directional Ramp with Walkable Flare


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Push Buttons


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Push Button Station

Push Buttons

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Accessible Pedestrian Signals (APS)Standard Plan

Accessible Pedestrian Signals (APS)

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Push Button Location

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10’

1.5’ - 10’

5’ Max



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77

Push buttons are

improperly oriented


Push Button Location• Buttons at outside edge of crosswalks


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Push Button Station• New Breakaway Pedestal


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APS Push Button Station and Location

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Maintenance Access Route (MAR)

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Compliance Checklist

1) Push buttons stations are properly placed and the push button faces are oriented properly.


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2) There must be a 4’ x 4’ landing adjacent to the push button.


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3) Max 5’ distance from crosswalk edge to push button face:


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4) 1.5’ to 10’ Distance from the push buttons to the back of curb (Ideally 4-6’)


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Compliance Checklist:

5) Min 10’ Distance between the push buttons

10 ft. minimum


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6) 42” Push button height

Height of 42” +/- 2”

42”42”


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7) The push button needs an unobstructed side reach of 10” maximum.

Side Reach

10” Maximum


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Overview - Minnesota LTAP · 2018-04-17 · 1 Section 4 Standard Plans for Design Fall, 2017 Ann...

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