Chapter3.13 Rails

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Kansas Department of Transportation Design Manual

Volume III US (LRFD) Bridge Section

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3.13 Railings

Table of Contents

3.13.1 General ................................................................................................................1

3.13.2 Design Requirements ..........................................................................................13.13.3 Curbs ...................................................................................................................2

3.13.4 Railings/ Barriers .................................................................................................2

3.13.5 Fencing ..............................................................................................................24

3.13.6 Sidewalks ..........................................................................................................30

3.13.7 Temporary Barrier .............................................................................................34

3.13.8 Light Standard Support .....................................................................................38

3.13.9 Americans with Disabilities Act Accessibility Guidelines ...............................42

3.13.10 Guard Fence - Bridge Rail Transition .............................................................45

3.13.11 KDOT BRIDGE RAIL POLICY ....................................................................45

List of Figures

Figure 3.13.4-1 Kansas Bridge Summary Sheet (A) ......................................................................5

Figure 3.13.4-1 Kansas Bridge Summary Sheet (B) .......................................................................6

Figure 3.13.4-3 Guidelines for the 32" Kansas Corral Rail (Std. BR182C) ..................................8

Figure 3.13.4-4 Guidelines for the 32" Kansas Corral Rail (Std. BR182E) ..................................9

Figure 3.13.4-5 Guidelines for the 27" Kansas Corral Rail (Std. BR183A) ................................10

Figure 3.13.4-6 Guidelines for the 27" Kansas Corral Rail (Std. BR183D) ................................11

Figure 3.13.4-7 Guidelines for the 27" Kansas Corral Rail (Std. BR183E) ................................12

Figure 3.13.4-8 Guidelines for the F4 Barrier Curb (Std. BR184A) ...........................................13Figure 3.13.4-9 Guidelines for the F4 Barrier Curb (Std. BR184B) ...........................................14

Figure 3.13.4-10 Kansas Corral Rail Quantities (27") .................................................................15

Figure 3.13.4-11 Kansas Corral Rail Quantities (32") .................................................................16

Figure 3.13.4-12 F-Shape Barrier Curb Quantities (32") ............................................................17

Figure 3.13.4-13 F-Shape Barrier Curb Quantities (42"& 51 - Vertical Face) ..........................18

Figure 3.13.4-14 F-Shape Barrier Curb Quantities (42" & 51" Sloping Face) ............................19

Figure 3.13.4-15 Typical 51" F-Shape Barrier Curb Details .......................................................20

Figure 3.13.4-16 Kansas Barrier Summary Sheet (A) .................................................................21

Figure 3.13.4-16 Kansas Barrier Summary Sheet (B) .................................................................22

Figure 3.13.4-17 32 Corral Rail with Expansion Joint ...............................................................23

Figure 3.13.5-1 Railroad Overpass Fencing ................................................................................25

Figure 3.13.5-2 Railroad Overpass Fencing .................................................................................26

Figure 3.13.5-3 Pedestrian Fence Details (Std. BR170) ...............................................................27

Figure 3.13.5-4 Railroad Fence Details (Std. BR171) ..................................................................28

Figure 3.13.5-5 Railroad Pededtrian Protective Fence (UP & BNSF RR) (Std. BR171A) ..........29

Figure 3.13.6-1 5-0 Bridge Sidewalk (Design Speed > 40 mph) ............................................31

Figure 3.13.6-2 5-0 Bridge Sidewalk (Design Speed < 40 mph) ..............................................32

Figure 3.13.6-3 Bicycle Safety Railing .........................................................................................33


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Figure 3.13.7-1 Anchorage of Type F3 Temporary Safety Barrier to Bridge Deck .....................35

Figure 3.13.7-2 Barrier Protection for Repair Projects .................................................................36

Figure 3.13.7-2 Temporary Expansion Barrier ............................................................................37

Figure 3.13.8-1 Lighting Standard Support Without Sidewalk (Preferred) ..................................38

Figure 3.13.8-2 Lighting Standard Support Without Sidewalk (Alternate) .................................39

Figure 3.13.8-3 Lighting Standard Support With Sidewalk (Preferred) ......................................40Figure 3.13.8-4 Lighting Standard Support With Sidewalk (Alternate) ......................................41

Figure 3.13.9-1 Plate Over Expansion Joint .................................................................................43

Figure 3.13.9-2 Americans With Disabilities Act Accessibility Guidelines (ADAAG) ..............44

Figure 3.13.11-1 Details of Thrie Beam Guard Fence Transition (Std. RD613) .........................49

Figure 3.13.11-2 Gutter Detail at Bridge Ends (Std. RD614) ......................................................50

Figure 3.13.11-3 W-Beam with Rubrail Bridge Approach Transition (Std. RD615) ...................51

Figure 3.13.11-4 W-Beam with Rubrail Bridge Approach Transition Details (Std. RD616) ......52

Figure 3.13.11-5 Thrie Beam Bridge Approach Transition (Std. RD612) ...................................53

List of Tables

KDOT Rail Summary .....................................................................................................................4

List of Appendixes

Appendix A Historic Rail ...............................................................................................................1

Appendix B KDOT 3R Standard Bridge Rails ..........................................................................1

Appendix C Non Standard Rails ....................................................................................................1
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Disclaimer:

Disclaimer: This document is provided for use by persons outside of the Kansas Department of

Transportation as information only. The Kansas Department of Transportation, the State of Kansas, its

officers or employees, by making this document available for use by persons outside of KDOT, do notundertake any duties or responsibilities of any such person or entity who chooses to use this document.

This document should not be substituted for the exercise of a persons own UProfessional Engineering

JudgementU. It is the users obligation to make sure that he/she uses the appropriate practices. Any

person using this document agrees that KDOT will not be liable for any commercial loss; inconvenience;

loss of use, time, data, goodwill, revenues, profits, or saving; or any other special, incidental, indirect, or

consequential damages in any way related to or arising from use of this document.

Typographic Conventions:

The typographical convention for this manual is as follows:

Non italic references refer to locations within the KDOT Bridge Design Manuals (either the LRFD or LFD),

or Hyper links shown in red, as examples:

Section 3.2.9.12 Transportation

Table 3.9.21 Deck Protection

Italic references and text refer to locations within the AASHTO LRFD Design Manual, for example:

Article 5.7.3.4

Italic references with a LFD label and text refer to locations within the AASHTO LFD Standard

Specifications, for example:

LFD Article 3.5.1


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3.13 Railings

3.13.1 General

Section 13 of the LRFD Specifications addresses the design of railings. "Railings" are used as a

generic term in the specifications. Railings include outside traffic safety barriers or parapets aswell as medians and bicycle and pedestrian railings.

The design requirements for railings utilized on KDOT bridges have undergone changes in recent

years as the Federal Highway Administration (FHWA) has established crash-testing requirements

and AASHTO Specifications have been revised. Additionally, a desire for more attractive railings

has influenced the style of railings on projects where aesthetics is a consideration. Please discuss

at field check as KDOTs participation will be limited in scope and dollar amount percentage.

Minimal aesthetic enhancement is allowed where it makes sense such as in high visiblity urban

areas. Aesthetic enhancements should be limited to durable items such as form liners and concrete

coloring. High maintenance aesthetics such as surface staining/painting and ornate railings should

be avoided. Aesthetic enhancements, if used, should stay below 5% of the structure cost and be

appropriate for the location. If ornate railings are requested by cities and approved for use in the

project, an agreement will be established limiting the responsibility for maintenance, by the state,

to structural concerns only.

Incidences involving objects thrown from railroad overpasses onto rail traffic below has led to

the adoption of protective screening requirements by the railroad. The rapid increase in bicycle

trails and traffic has increased attention on bicycle railings. This section of the LRFD Bridge

Design Manual details our policies regarding the design of bridge railings for KDOT projects.

3.13.2 Design Requirements

The design of newly constructed bridge railings must conform to the requirements of the latest

edition of the "AASHTO LRFD Bridge Design Specifications" as given in Section 13. This spec-

ification gives geometric and strength requirements and also requires crash testing. FHWA

requires all bridges carrying traffic on the National Highway System (NHS) to be crash tested

regardless of speed, in accordance with NCHRP Report 350 Recommended Procedures for the

Safety Performance Evaluation of Highway Features. There are six levels of service and testing

depending on vehicle size and speed. FHWA maintains a list of crash tested railings.

Crash testing requirements may be waived if an analytical evaluation shows the railing to be crashworthy. This allows minor changes to crash tested railings without having to go through the time

and expense of crash testing. For bridges on the NHS any such evaluation must be approved by

the FHWA.

Crash testing has shown that during impact vehicles slide along the top of the railing and parts of

the vehicle, especially the boxes on trucks, extend beyond the face of the railing a considerable

distance. Attachments to bridge railings, such as architectural metal railings, noise wall panels or


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objects just behind the railing (such as light poles), must address safety concerns presented by this

encroachment including:

1)Snagging on posts - which can result in the attachment (i.e., post) penetrating the

occupant compartment or causing the vehicle (i.e., hood) to penetrate the cab.

2)Spearing - objects, such as a horizontal railing member, penetrating windshields

and injuring occupants.3)Debris falling onto traffic below. (i.e., impacted noise wall panels)

Attachments within the area of encroachment shall be designed to break away before severely

damaging the vehicle, contain any debris from damaging traffic below, and have no members,

such as rail ends, which might spear the occupant compartment. Ends of rails shall be sloped at

45 degrees or flatter to reduce the chance of spearing. Posts shall be setback from the face of rail-

ing to minimize snagging.

Small sections of curb or sidewalk placed in front of railings cause vehicles to vault up onto the

railing. For this reason sidewalks with a projection between 9" and 3'-6" from the face of railing

are not allowed and curb heights are limited to a maximum of 8".

3.13.3 Curbs

Where curb and gutter sections are used on the roadway approach, a closed section of rail on the

bridge should match the road curb, except it may exceed the road curb height on the approach.

Bridge curbs serve mainly the purposes of drainage control and in limited capacity to delineation

of pedestrian walkways. Curbs shall be designed in accordance with Article 13.7. Current KDOT

policy is not to use brush curbs on bridges other than for city streets with speed limits less than or

equal to 40 mph and not designated as a school routes or bike paths.

3.13.4 Railings/ Barriers

The primary purpose of traffic railing or barrier is to contain the average vehicle using the struc-

ture. Consideration should also be given to protection of the occupants of a vehicle in collision

with the railing and protection of other vehicles near the collision or persons and vehicles on road-

ways underneath the structure.

Bridge railings on bridges on Federal-aid projects must be (or have been) crash tested and meet

the acceptance criteria in NCHRP Report 350 Recommended Procedures for the Safety Perfor-

mance Evaluation of Highway Features. This document includes six different Test Levels. Kan-

sas will use a minimum of TL-4 for bridge rails on state routes.

For structures with existing railing the Remain- In-Place (RIP) requirements follow KDOTs 3R

Policies found in Appendix B KDOT 3R Standard Bridge Rails

Current KDOT designs utilize one of two types of railing, either the Corral Railing, or the Bar-

rier Rail type. Refer to 3.13.11 KDOT BRIDGE RAIL POLICYfor type to be used for each sit-

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The corral-type rail may be either an open section or a closed section, depending upon whether or

not bridge drainage at the curb line is a requirement. Most rural bridges using the corral railing

will be of the open type, which allows bridge drainage over the side.

For overpass bridge structures over a railroad, highway, or a local road, no drainage is allowed to

drop on the railroad right-of-way or the shoulder-to-shoulder width of the road underneath. Forlong overpass bridges, openings may be provided for drainage over protected berm slopes; use

details similar to those shown in the Bridge Design Standard BR104d .

The common height of the Kansas Corral Rail is 27 or 32 inches. The common heights of the Bar-

rier Rail is 32, 42, 51 or 54 inches. The preferred railing is the 32 inch Kansas Corral Rail or the

32 inch F4 Barrier Rail. Bridges on curves with a radius of 500 ft. or less should have a rail

height of 42 inches on the extrados as an additional safety precaution. The 51 inch Barrier Rail is

used in the median as a glare barrier and a 54 barrier mounted to the shoulder is use for pier pro-

tection.

For railroad overpass structures the barrier height is a function of the shoulder width. Use a 32"barrier with 6-0 shoulders and use 42" with 4-0 shoulders. Provide the 42" barrier for the 4-

0 shoulders for a distance of 25-0 from centerline of track or access road. (See Figure 3.13.5-1

Railroad Overpass Fencing).

Transitions for different height rails will be 12:1 maximum. Adjacent structures with a median

gap of two feet or less are considered one structure with a closed median. Adjacent structures

more than two feet apart are treated as individual structures.

Sample standard rail details shown in the following graphics are intended for use on either slab

bridges or girder bridges; with or without curbs. They are detailed so they can be inserted directly

into a set of plans.

At locations in the rail were discontinuities occur, such as at bridge expansion joints and at end

sections without an end block, half the reinforement spacing from that shown on the design stan-

dard for the F4 barrier. Provide this extra reinforcement for a length equal to the depth of the

vertical break.

Railing types are ranked by a Testing Level (TL- X) designation to indicate the level of protection

a rail provides. The larger the number in the (X) position the greater the protection.

Table A13.3-1indicate the forces and loading geometry for the given test levels. In the past, thedesignation used for this same reason was Performance Level (PL-X), this designation is no lon-

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KDOT Rail Summary

If the design of the structure includes a sidewalk, a concrete barrier rail will be used between the

traveled way and the sidewalk. For State routes with design speed less than or equal to 40 mph,

the minimum height of the separator railing above the sidewalk shall be 24 inches and the railing

surface shall be smooth to avoid snag points for pedestrians or cyclists, See Figure 3.13.6-2 5-0

Bridge Sidewalk (Design Speed < 40 mph) for additional details. The exception previously noted

is for locally owned structures with speeds less than or equal to 40 mph and not located on a

school walk route for which current Figure 13.7.1.1-1 may be considered for use. For design

speeds over 40 mph or if a high volume of bike traffic is expected and the risk involved if a cyclist

would fall over the separator is great, use a minimum railing height of 42 inches. A height of 42

inches would enable a falling cyclist to grasp the railing. See Figure 3.13.6-1 5-0 Bridge Side-

walk (Design Speed > 40 mph)for additional details.

The height of the railing on the outside edge of the sidewalk shall be a minimum of 42 inches for

pedestrians and a minimum of 54 inches for bicycles.

To obtain the height of 42 inches on the outside of the sidewalk, a metal rail on top of a concrete

riser or a short height of chain link fence may be used Figure 3.13.6-3 Bicycle Safety Railing.

Type Testing Application

27

Corral Rail

PL-1 /TL-2 BoLP

32

Corral Rail

or Barrier

PL-2 /TL-4 State System

Pier Protection

42

(32+10)

Barrier

PL-2 /TL-4 RR/Glare

Pier Protection

42

Barrier

PL-3 /TL-5 Pier Protection /

Curves

51(32 + 19)

Barrier

PL-2 /TL-4 Median/Glare

54

(42+12)

Barrier

PL-3 /TL-5 Pier Protection

Shoulder or

Median


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Figure 3.13.4-1 Kansas Bridge Summary Sheet (A)


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Figure 3.13.4-1 Kansas Bridge Summary Sheet (B)

.


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Figure 3.13.4-2 Guidelines for the 32" Kansas Corral Rail (Std. BR182B)


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Figure 3.13.4-3 Guidelines for the 32" Kansas Corral Rail (Std. BR182C)


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Figure 3.13.4-4 Guidelines for the 32" Kansas Corral Rail (Std. BR182E)


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Figure 3.13.4-5 Guidelines for the 27" Kansas Corral Rail (Std. BR183A)


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Figure 3.13.4-6 Guidelines for the 27" Kansas Corral Rail (Std. BR183D)


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Figure 3.13.4-7 Guidelines for the 27" Kansas Corral Rail (Std. BR183E)


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Figure 3.13.4-8 Guidelines for the F4 Barrier Curb (Std. BR184A)


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Figure 3.13.4-9 Guidelines for the F4 Barrier Curb (Std. BR184B)


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Figure 3.13.4-10 Kansas Corral Rail Quantities (27")


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Figure 3.13.4-12 F-Shape Barrier Curb Quantities (32")


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Figure 3.13.4-14 F-Shape Barrier Curb Quantities (42" & 51" Sloping Face)


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Figure 3.13.4-16 Kansas Barrier Summary Sheet (B)


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Figure 3.13.4-17 32 Corral Rail with Expansion Joint


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3.13.5 Fencing

It is KDOTs practice to provide an economical, functional and durable fencing system for struc-

tures over the railroad track area or with pedestrian sidewalks. Chain link fence on bridges over

the Interstate in urban areas shall be 6-0 high.

Over railroads, provide a straight chain link fence on the barrier to a height of 10-0 on both sidesfor all highway overpass structures. When a sidewalk is involved, provide a 8-0 high chain link

fence with a curved top. Examples of rail and fence are shown onFigure 3.13.5-2 Railroad Over-

pass Fencing.

For handrails to be painted, a duplex system is reccomended. Duplex is a galvanized base coating

which has powder coating as the top surface. For pedestrian and architectural fencing a duplex/

PVC system is reccomended. The woven chain link fence is galvanize, then dip coated in PVC.

The posts and all hardware are galvamized then powder coated. The designer will select either

galvanized or duplex coating. If duplex is choosen, the designer will select either black, green or

dark green as the color.

Use a leveling nut detail to attach all hardware, devices, fencing, plates or rails to concrete mem-

bers using a detail similar to the detail shown in Figure 3.13.6-3 Bicycle Safety Railing.

For grade separation structures over major routes, use either a corral rail with closed panels over

traffic lanes or use a barrier rail to prevent snow, during snow plowing operations, from squeezing

out through the open panels and landing on passing traffic below the bridge. This is especially

important for fly-overs at multi-level interchanges.

See 3.2.11 Bridge Deck Expansion Devicesfor policy on plating expansion gaps in railing and

barriers.

Fencing will be designed to resist, as a minimum,Article 13.8.2loads and conditions.
http://wwwdev.ksdot.org/burDesign/bridge/lrfd/LRFD_3_14_JointsandBearings.pdfhttp://wwwdev.ksdot.org/burDesign/bridge/lrfd/LRFD_3_14_JointsandBearings.pdf


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Figure 3.13.5-1 Railroad Overpass Fencing


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Figure 3.13.5-3 Pedestrian Fence Details (Std. BR170)


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Figure 3.13.5-4 Railroad Fence Details (Std. BR171)


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3.13.6 Sidewalks

Generally, sidewalks are provided on bridges located in urban areas. Where a sidewalk is a

requirement, it shall have a minimum usable clear width of 5-0 to accommodate bicycles and

vehicles for the handicapped. Pedestrian Overpass structures are to comply with the Americans

with Disabilities Act Accessibility Guidelines concerning maximum grades and handrail

requirements (See 3.13.9 Americans with Disabilities Act Accessibility Guidelinesand Figure3.13.9-2 Americans With Disabilities Act Accessibility Guidelines (ADAAG)).Sidewalks on

bridges which have expansion joints will have plates covering the opening. The maximum plate

thickness will be 3/8 and will be attached to one side of the joint with the other side free to move,

see Figure 3.13.9-1 Plate Over Expansion Jointfor example details. Bevel the edges of the plate

with a maximum slope of 3:1 and radius the edge to prevent having an exposed sharp edge. Des-

ignated bikeways, which connect to an existing trail or where there is a trail formally planned,

shall have a minimum 8-0 sidewalk width. As a rule, keep pedestrians and bicyclist separated.

Designated bicycle paths or equestrian paths are special cases and will be discussed at the Field

Check.

Handrail:Handrail will be used on both sides of the sidewalk where the slope exceeds the ADAAG require-

ments given in the KDOT Rail Summary,this may be terminated where the slope does not exceed

the ADAAG requirements.

Include Handrail on both sides of sidewalks on designated school routes or when requested by

KDOT District Offices.

Loads:

Sidewalk floors, stringers and their immediate supports shall be designed for a liveload of 85

pounds per square foot of sidewalk in accordance withArticle 3.6.1.6

Main supporting members and stringer shall have no less carrying capacity than would be

required if no sidewalk existed.

A wheel load is not applied to a sidewalk when the barrier curb is located between the traveled

way and the sidewalk.

Drainage:

Drainage of the sidewalks over streams or unimproved areas may be drained over the side. How-

ever, drainage should not be permitted to fall over the side for overpasses and urban areas where

dripping water or freezing snowmelt could create a nuisance. In this case, the drainage should be

carried along an edge lip to the end of the bridge or dropped on unimproved areas. If the bridge

has a deck drain system then slope the sidewalk toward the roadway and use the bridge drainage

system.

All transverse expansion joint openings in the sidewalk shall be bridged with a steel plate.

See previous Section 3.13.4 Railings/ Barriersfor railings to be used with sidewalks.


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Figure 3.13.6-1 5-0 Bridge Sidewalk (Design Speed > 40 mph)


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Figure 3.13.6-2 5-0 Bridge Sidewalk (Design Speed < 40 mph)


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Figure 3.13.6-3 Bicycle Safety Railing


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Figure 3.13.7-1 Anchorage of Type F3 Temporary Safety Barrier to Bridge Deck

When A is < 2-0:

1) Use Type F3 Barrier (Std. No. RD622).

2) Anchor each 12-6 Barrier unit to the bridge deck by three bolts on the traffic side.

When A is 2-0 < 4-0:


2) Anchor each pin and loop connection to the bridge deck with the strap connector. As

an option, unless otherwise noted on the plans, the contractor may anchor each 12-6

barrier unit to the bridge deck by three bolts on the traffic side.

When A is 4-0:


2) Anchorage to bridge deck is not required, unless otherwise noted in the plans.

Note: For Bridges with greater than of total thermal movement anticipated during construction

use an expansion type barrier system (RD622c) at bridge expansion joint locations. Coordinate

this with Road Design


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Figure 3.13.7-2 Barrier Protection for Repair Projects


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Figure 3.13.7-2 Temporary Expansion Barrier


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3.13.8 Light Standard Support

Refer tofigures belowfor preferred and alternate methods of attaching light standards to barrier

bridge railings.

Figure 3.13.8-1 Lighting Standard Support Without Sidewalk (Preferred)


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Figure 3.13.8-3 Lighting Standard Support With Sidewalk (Preferred)


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B. If other than A or B routes, refer to Section 13 for the AASHTO LRFD Bridge

Design Specifications to determine Testing Level required. If the Test Level Selection

Criteria indicates a TL-2 level is required, use a 27 high corral rail. If a TL-4 level is

required, usea 32 high rail. (If TL-5 railing is required, use a 42 Barrier.)

C. All Structures not covered in Section I.

1. Place curbs in spans over Railroads and Traveled Ways.

2. Omit curbs at other locations unless requested otherwise by District at time of field

check.

III. Retrofit or replacement of Bridge Rails shall be made in accordance with Section I and

Section II on existing structures if other work is being done to the structure with Federal

funds (Overlay, Widen, or Major Repairs).

IV. All widened structures shall meet the requirements of Section I or Section II. If a struc-

ture is widened on one side only, both rails shall match or be replaced. A determination

should be made during field check.

V. If a rail is to be replaced, it shall be as per Section I or Section II.

VI. Retrofit of different rail types should be as follows:

A. The Safety Curb plus metal rail will need no modification if the height above the gutter

line remains 2'-3 or greater. See Appendix A Historic Railfor examples.

B. The 1'-6 Safety Curb plus offset rail shall be modified or replaced as follows:

(See Appendix A Historic Railfor an example.)

1. Replace on all structures under Section I.

2. Replace on all structures with an AADT greater than 4,000** on the structure and the

posted speed limit is greater than 35 mph. For AADT less than 4,000** but greater

than 2,000; the type of retrofit should be determined consistent with existing condi-

tions.

3. Place double nested guard fence or thrie-beam if AADT is less than 2,000** and thedeck in the overhang is in good condition. If there is considerable overhang deck to be

replaced full depth, then the curb should be replaced.

C. The 9" concrete curb plus offset wall and metal rail shall be replaced if AADT is greater

than 4,000** and the posted speed limit is greater than 35 mph. See Appendix A His-

toric Railfor an example. For AADT less than 4,000**, the type of retrofit will be deter-

mined consistent with existing conditions.


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Figure 3.13.11-5 Thrie Beam Bridge Approach Transition (Std. RD612)


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Chapter3.13 Rails

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