1. “See-Through” Bridge Rails
Agenda:
Introduction
Bridge Barriers and Railings
Development of See-Through Rails
Applications
Desired Features
See -Through Alternatives
Cost Comparison
FAQs
Next Steps
Your Questions..
Welcome to our presentation today on see-through bridge rails.
My name is Shannon Post and I am an Office Chief in Structure Design. I am joined today by Greg Kaderabek, who is a Senior Specialist for issues related to barrier railing and sound walls.
Here in California, we have been developing and implementing a program for “see through” bridge rails for nearly ten years. Today, we will be presenting information on this program as part of a series of deployable innovative opportunities sponsored by the Caltrans Division of Research and Innovation (DRI).
On the national level, the Federal Highway Administration has undertaken an innovation initiative called “Every Day Counts”.
This initiative is designed to identify and deploy innovation aimed at:
shortening project delivery,
enhancing safety and
improving environmental sustainability.
Today, we will be sharing information that supports all three of FHWA’s objectives:
Project delivery: we will share designs for bridge rails that are “ready to go” and can be expediently added to your projects.
Safety: we will share information with you regarding our crash test program, with the intent of keeping our motorized and non-motorized travellers safe
Environmental: we will share designs that are not only functional, but support the department’s goals of addressing environmental issues and context sensitivity.
Here’s what we will cover in our presentation today: REVIEW AGENDA
Shannon Post/ Greg Kaderabek
Caltrans
Division of Engineering Services
August, 2011

2. Bridge Rails Classes of Railings
Railing Types
Function
a.) Vehicular Barrier Railings
Retain and redirect errant vehicles
b.) Combination Vehicular Barrier and Pedestrian Railings
Dual function of retaining both vehicles and pedestrians on the bridge. Consist of two parts: concrete parapet, generally with a sidewalk and a metal hand railing or fence-type railing
c.) Pedestrian Railings
Prevent pedestrians from accidentally falling from the structure
d.) Bicycle Railings
Retain bicycles and riders on the structure. May be a combination type consisting of a vehicular railing surmounted by a fence or metal handrail
First, some information about bridge rails….
How significant are bridge rails in California?
Well, if you were to lay the 12, 000 state bridges end to end, they would stretch from the Oregon border to the Mexican border, nearly 800 miles.
Assuming bridge rail on each side of the bridge, we can guestimate that there is about 1600 miles of bridge rail on the state highway system.
(There’s also a significant amount of bridge rail on the local system).
There are basically four different types, as defined by FHWA and AASHTO.
Each performs a different function, which impacts the design and detailing of each railing.
Today, we will be focusing on:
Vehicular railings (vehicle)
Combination Railings (vehicle and pedestrian)
Bicycle Railings: (vehicle and bikes)

3. Bridge Rails Design and Crash Criteria
Specification
Structural Design
AASHTO LRFD Bridge Design Specifications, 4th Edition with California Amendments
Crash Testing
NCHRP Report 350 (six test levels)
NEW! AASHTO Manual for Assessing Safety Hardware (MASH)
a.) Test Level 2
(TL-2)
Local and collector roads with favorable site conditions
Roadways with speeds up to 45 mph
Crash test with a small car and pickup truck at 45 mph
b.) Test Level 4
(TL-4)
High speed highways, freeways, expressways and Interstate
Roadways with vehicle speeds greater than 45 mph
Crash test with small car/pickup at 62 mph, medium size truck at 50 mph
After determining the type of rail and its function, we then must address the structural requirements and the crash test requirements.
Structural :
AASHTO LRFD Bridge Design Specifications.
Here in CA, we are using the 4th Edition, with California Amendments
Section 3: Loads
Section 13: Railings
Structure Design is responsible for designing the rails to meet the structural requirements
Crash Testing:
All rails that we will share with you today have been tested using the requirements in NCHRP 350.
AASHTO has adopted the Manual for Assessing Safety Hardware (MASH).
Caltrans is in the process of adopting MASH, too.
Existing rails are “grandfathered in” but new rails will need to meet MASH.
Caltrans Roadside Safety Research Group is the lead for the crash test program.
There are six different test levels.
Today, we will be referring only to Test Level 2 (up to 45 mph) and Test Level 4 (greater than 45 mph)

4. Bridge Rails “See-Through” Alternatives
Applications:
California Coastal Commission/ Local Coastal Program
Context Sensitive Solutions (CSS)
Bridge or Roadside
So, we’ve talked briefly about function (the what) and design/crash criteria (the how), but now we will discuss “form”.
Recognizing that bridge rails do more than just retain motorized and non-motorized traffic the Department began working closely with the California Coastal Commission about 10 years ago on bridge rail issues.
The CCC is the state agency responsible for protecting California’s coastline and coastal zone.
The California Coastal Act of 1976 established responsibilities for the California Coastal Commission including the protection of scenic landscapes and views of the sea.
Projects in the coastal zone require review and approval from the CCC and/or from the Local Coastal Program.
Caltrans has also adopted a policy on Context Sensitive Solutions with some guiding principles:
Integrate the transportation system with the community that it serves
Provide harmony with community goals and the local environment
With these applications in mind, Caltrans has developed a “see-through” bridge rail program.
While these rails were developed for bridges in coastal areas, many of these rails can be adopted for context sensitive applications or roadway applications.

5. Bridge Rails “See-Through” Alternatives
Desired Features:
Visibility: minimize impairment of views from the bridge; aesthetically pleasing view of the bridge from public areas
Rail Height: consistent with minimum required height for anticipated users (vehicle, bicycle and/or pedestrians)
Aesthetics: enhance visual appeal by applying color, texture and other treatments
In developing bridge rails, there are a number of important considerations:
Function
Structural design/crash worthiness (as previously discussed)
Vehicular design speed
Railing height and width
Structural materials (generally either concrete or steel)
Constructability
Ease of maintenance
Initial and life cycle costs
When developing “see-through” alternatives, the designer must also consider key desired features:
Visibility
Rail Height
Aesthetics

6. Bridge Rails “See-Through” Alternatives
Metal Bridge Rails
Concrete Barriers
TL-4
California ST-10
Concrete Barrier Type 80
California ST-20S
Concrete Barrier Type 90
California ST-30
California ST-70
TL-2
California ST-40
Concrete Barrier Type 80SW
Here’s an at-a-glance summary of the bridge rails developed by CA that have incorporated these desirable features.
(We have many more “solid” railings that we won’t be talking about today.)
I’ve divided them into two groups by primary structural material (concrete or steel) and then further listed them by test level.
TL-4 (greater than 45 mph)
TL-2 (up to 45 mph)
Now, I would like to share with you some of the key characteristics of each railing.

7. California ST 10 Bridge Rail
Description: See through 2-bar curb-mounted steel bridge rail
Test Level: TL-4
Standard Plans: B11-68, B11-69, B11-70
Height: 33” above bridge deck (27” steel rail plus 6” curb)
Comments: Requires additional rail for use as a pedestrian/bicycle rail to increase height to a minimum of 42”.
Successfully used on past projects in the Coastal Zone.
This first railing is the California ST-10 Bridge Rail.
It is our most commonly used aesthetic steel rail. It was modeled after the Wyoming rail, but modified for California usage.
It can be used for pedestrian/bicycle applications by adding a handrail to achieve a minimum height of 42”, offset 15” from the face and modifying the clear opening. There are some situations where the designer may wish to go higher than the 42”, more discussion on this later in the presentation.
Here in CA, we have successfully used this rail on the Mad River Bridge, Ten Mile River and the Noyo River Bridge, to name a few.

8. California ST 10 Bridge Rail
Here’s an example of how to modify this railing. Note that the handrail must be offset 15” from the front face of the rail. We have verified this dimension through dynamic modeling using the LSDYNA program.
California ST-10 Bridge Rail with Bicycle Rail offset 15” from rail face
California ST-10 Bridge Rail separated from the Pedestrian Handrail by a Walkway.

9. California ST 10 Bridge Rail
Here’s another view showing the versatility of this rail type.

10. California ST-20S Bridge Rail
Description: See through 5-bar curb-mounted steel bridge rail
Test Level: TL-4
Bridge Standard Detail Sheets: see website
Height: 54” above bridge deck (48” steel rail plus 6” curb)
Comments: The rail is 12” higher than the minimum required Bicycle Rail or Pedestrian Rail height of 42”.
The California ST-20 is similar to the ST-10, but has five bars including the handrail. Because it is already 54” in height, it does not need to be modified for use in non-motorized applications.
This bridge rail has been used at the Van Duzen River Bridge in Humboldt county in northern California

11. California ST-20S Bridge Rail
Van Duzen River Bridge
Humboldt County

12. California ST-30 Bridge Rail
Description: See through 2-bar curb-mounted steel bridge rail
Test Level: TL-4
Standard Plans: Standard Plan B11-65
Height: 32” above bridge deck (25” steel rail plus 7” curb)
Comments: Requires additional rail for use as a pedestrian/bicycle rail to increase height to a minimum of 42”.
The California ST-30 is also similar to the ST-10 but has a different detail at the post. The ST-30 is very similar to the Alaska railing used in other states.

13. California ST-30 Bridge Rail
This railing has been constructed at the South Fork Dibble Creek bridge in Tehama County.
South Fork Dibble Creek, Tehama County

14. California ST-70 Bridge Rail
Description: See through 4-bar curb-mounted steel bridge rail
Test Level: TL-4
Bridge Standard Detail Sheets: see website
Height: ” above bridge deck (40.5” steel rail plus 6” curb)
Comments: Rail is similar to California ST-20S Bridge rail except that the top 7.5” high handrail has been removed. This rail is 4.5” higher than the minimum required Bicycle Rail or Pedestrian Rail height of 42”.
The California ST-70 has now been approved for use in California, although we have not constructed any of these rails yet.

15. California ST 40 Bridge Rail
Description: See through 4-bar sidewalk mounted steel bridge rail.
Test Level: TL-2
Standard Plans: Standard Plans B11-66, B11-67
Height: 42”above sidewalk. 8” high sidewalk/curb next to traffic (9” at edge of deck).
Constraints: Cannot be used on bridge decks with vehicular traffic signed for greater than 45 mph.
The California ST-40 has been approved at Test Level 2 and should not be used at locations where the speed limit is greater than 45 mph.
This railing is mounted on a sidewalk and is appropriate for locations with pedestrians.

16. California ST 40 Bridge Rail
Renderings of California ST-40
Here’s some renderings showing the CA ST-40

17. Concrete Barrier Type 80 Description: See through concrete barrier.
Test Level: TL-4
Standard Plans: Standard Plans B11-60, B11-61, XS Sheet website
Height: 32” above bridge deck.
Comments: Requires addition of steel rail on top to increase height to a minimum of 42” as well as modification of the clear opening for use as a pedestrian/bicycle rail.
Successfully used on past projects in the Coastal Zone.
Moving on to the concrete barriers…..
The Concrete Barrier Type 80 is our most commonly used concrete aesthetic or see-through barrier in California, in part because it is easy to construct and easy to modify for use in pedestrian and/or bicycle applications.

18. Concrete Barrier Type 80
This view shows how the Type 80 was modified for height and for clear openings (ADA compliance)
Photo of Concrete Barrier Type 80 - Modified with Architectural Treatment and with Bicycle Rail Offset 15” from Rail Face.

19. Concrete Barrier Type 80 Sheffield Drive Bridge Santa Barbara County
Here’s an example of the Concrete Barrier Type 80 in a vehicular application in Santa Barbara county.

20. Concrete Barrier Type 90
Description: Concrete barrier with see through steel rail on top.
Test Level 4: TL-4
Bridge Standard Detail Sheets: See website.
Height: 32” above bridge deck.
Comments: In order to also be used as a pedestrian/bicycle rail, requires additional steel rail mounted at least 15” behind the rail face to increase height to a minimum of 42” as well as modification to reduce the clear openings.
The Concrete Barrier Type 90 has now been approved for use in California, although we have not constructed any of these rails on the state highway system to date. This is a concrete barrier with a steel rail on the top. It can be modified for pedestrian or bicycle applications by adding a steel rail behind the vehicular railing and modifying the clear openings.

21. Concrete Barrier Type 80SW
Description: See through concrete barrier with a raised sidewalk.
Test Level: TL-2
Standard Plans: Standard Plans B11-62, B11-63, B11-64
Height: 42” above sidewalk (32” See-through concrete barrier plus 10” of handrail). 8” high sidewalk/curb next to traffic (9” at edge of deck).
Comments: Cannot be used on bridge decks with high speed vehicular traffic (greater than 45 mph).
This version of the Type 80 has been tested for TL-2 and should not be used in locations where the speed limit exceeds 45 mph.

22. Concrete Barrier Type 80SW
Canal Street Bridge
El Dorado County
Here’s an example where this railing was built at the Canal Street Bridge in El Dorado county. The designer provided a context sensitive solutions

23. See-Through Bridge Rails Cost Comparison
Estimated
Cost/LF
Cost/Cost 732
Concrete Barrier Type 732
$88/LF
1.00
California ST-10
$204/LF
2.32
California ST-20S
$297/LF
3.37
California ST-30
----
California ST-70
California ST-40
Concrete Barrier Type 80
$264/LF
3.00
Concrete Barrier Type 90
Concrete Barrier Type 80SW
$313/LF
3.55
This chart shows a comparison of the linear foot cost for some see-through rails and compares those costs to our most typical solid railing, the Concrete Barrier Type 732.
Our cost data in California is fairly limited. While it’s true that the cost of an aesthetic rail is more than a traditional solid railing, we estimate that the cost of the bridge railing is only about 1% or less than the cost of the entire bridge project. We hope that designers won’t be scared off by the extra cost, since the see-through rails can significantly enhance the beauty of the structure.
Based on the AASHTO LRFD Design code, we design our structures for a service life of 75 years. The increase in cost during construction for an aesthetic railing is a good investment in the long run.

24. “See-Through” Bridge Rails Summary
Metal Bridge Rails
Concrete Barriers
TL-4
California ST-10 (H=33”) +, ^
Conc Barrier Type 80 (H= 32”) +, ^,#
California ST-20S (H= 54”) ++
Conc Barrier Type 90 (H= 32”) ++,^, #
California ST-30 (H=32”) +,^
California ST-70 (H= 46.5”) ++
TL-2
California ST-40 (H=42”) +
Conc Barrier Type 80SW (H=42”) +, #
Now I would like to turn the presentation over to my colleague, Greg Kaderabek, to share some FAQs and to answer any specific questions that you might have.
Notes:
+Standard Plans ++ Bridge Standard Detail Sheet
^ Requires additional rail for use as a pedestrian/bike rail to increase height to 42”
# Can apply architectural treatment

25. “See-Through” Bridge Rails
Frequently Asked Questions….
1. What is the recommended minimum rail height for bridge bicycle rails? AASHTO says 42” but the Highway Design Manual says 54”.
AASHTO lowered the minimum required rail height for bicyclists from 54” to 42” at their 2006 annual meeting.
The Caltrans initiated a bicycle rail height study that concluded that a 42” minimum bicycle rail offset 15” from the face of the vehicular rail is sufficient for most situations.
The Department issued a memorandum on November 26, 2008 lowering the height from 54” to 42” for most applications.
Caltrans recommends a minimum height of 48” where a combination of high bicycle speeds and high crash impact angles are anticipated. See AASHTO Bridge Design Specifications for more details

26. “See-Through” Bridge Rails
Frequently Asked Questions….
2. What is the Type Selection process for an aesthetic bridge rail?
The Project Development Team (PDT) shall evaluate the need for a CSS rail early in the project.
A Conceptual Bridge Rail Plan needs to be reviewed/approved by the PDT and used in the environmental process.
During the Design phase, need to ensure that the aesthetic bridge rail meets all project requirements as well as structural/crash test requirements.
Projects in the coastal zone may require special consideration.

27. “See-Through” Bridge Rails
Frequently Asked Questions….
3. Are there any special considerations where barriers are placed on a structure with a high super-elevation?
All bridge barriers are to remain vertical regardless of the super-elevation.
If the super-elevation is 6% or greater, a higher bridge rail is required on the outside of the curve. Issues regarding super-elevation should be discussed as early in the design process as possible.

28. “See-Through” Bridge Rails
Frequently Asked Questions….
4. Can see-through rails developed for bridges be used in other applications?
The see-through rails were developed for bridge applications, but can be modified for other uses by special design.
For example, a see-through rail can be used on the roadside by mounting the rail on a reinforced concrete trench footing or on a trench footing on CIDH piles.
See-through rails can also be used with earth retaining systems, however the design of the earth retaining system needs to consider vehicular impact loads.

29. “See-Through” Bridge Rails
Frequently Asked Questions….
5. Are there any limitations on the type of aesthetic treatment that can be applied to these bridge rails?
Any color can be added as architectural treatment.
There are limitations on the architectural texture that can be applied to the surface of rails. Drawings and reports detailing the texture relief limits on rail can be found at the Caltrans Landscape Architecture website:

30. “See-Through” Bridge Rails
Frequently Asked Questions….
6. Can these rails be used to support other roadway appendages, such as sign structures or lighting standards?
In high speed locations (posted speeds over 45 mph), rails can support roadway appendages without any further crash testing, if the appendage is offset 15” behind the front face of the rail. This applies to bicycle rail, sign posts, sign structures, light standards, etc.
In low speed locations (posted speed of 45 mph or less) rails without a sidewalk may have roadway appendages if the appendage is offset 8” behind the front face of rail. Rails with a sidewalk in low speed locations do not require an offset for appendages, but special attachment details may apply depending on the rail type.
Contact Caltrans/DES when there is a need for any roadway appendage to be attached to top or backside of rail.

31. “See-Through” Bridge Rails
Bridge Standard Detail Sheets (aka XS Sheets) website:

32. “See-Through” Bridge Rails Next Steps
Guidance
DRAFT Design Information Bulletin (DIB), Bridge Rail Development, Design and Selection Guidelines
Update Highway Design Manual
Bridge Rails and Barriers: A Reference Guide for Transportation Projects in the Coastal Zone
Crash Testing/ Development of additional alternatives
Shannon Post/ Greg Kaderabek
Division of Engineering Services
August, 2011

33. “See-Through” Bridge Rails
Questions????
Shannon Post/ Greg Kaderabek
Division of Engineering Services
August, 2011