Caltrans See Thru Rail Webinar 24aug2011

7/30/2019 Caltrans See Thru Rail Webinar 24aug2011

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See-Through Bridge Rai ls

Shannon Post / Greg Kaderabek

Caltrans

Divis ion of Engineer ing Services

Augus t, 2011

Agenda:

1. Introduction

Bridge Barriers and Railings

2. Development of See-Through Rails

Applications

Desired Features

3. See -Through Alternatives

4. Cost Comparison

5. FAQs

6. Next Steps

7. Your Questions..


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Bridge Rai ls

Classes of RailingsRailing Types Function

a.) Vehicular Barrier Railings Retain and redirect errant vehicles

b.) Combination Vehicular Barrierand Pedestrian Railings

Dual function of retaining both vehicles and

pedestrians on the bridge. Consist of twoparts: concrete parapet, generally with asidewalk and a metal hand railing or fence-type railing

c.) Pedestrian RailingsPrevent pedestrians from accidentallyfalling from the structure

d.) Bicycle Railings

Retain bicycles and riders on the structure.May be a combination type consisting of avehicular railing surmounted by a fence ormetal handrail


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Bridge Rai ls

Design and Crash CriteriaCriteria SpecificationStructural

DesignAASHTO LRFD Bridge Design Specifications, 4thEdition with California Amendments

Crash Testing

NCHRP Report 350 (six test levels)

NEW!AASHTO Manual for Assessing SafetyHardware (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 at50 mph


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Bridge Rai ls

See-Through AlternativesAppl icat ions:California Coastal Commission/ Local Coastal Program

Context Sensitive Solutions (CSS)

Bridge or Roadside


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Bridge Rai ls

See-Through AlternativesDesired 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, textureand other treatments


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Bridge Rai ls

See-Through AlternativesMetal Bridge Rails Concrete Barriers

TL-4 TL-4

California ST-10 Concrete Barrier Type 80California ST-20S Concrete Barrier Type 90

California ST-30

California ST-70

TL-2 TL-2California ST-40 Concrete Barrier Type 80SW


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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 railto increase height to a minimum of 42.

Successfully used on past projects in the Coastal Zone.


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California ST-10 Bridge Rail with Bicycle Rail offset 15 from railface

California ST-10 Bridge Rail separated from the Pedestrian Handrailby a Walkway.


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California ST-20S 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 requiredBicycle Rail or Pedestrian Rail height of 42.


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California ST-20S Bridge Rail

Van Duzen River Bridge

Humboldt County


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CaliforniaST-30BridgeRail


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/bicyclerail to increase height to a minimum of 42.


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South Fork Dibble Creek, Tehama County


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Description: See through 4-bar curb-mounted steel bridge rail Test Level: TL-4 Bridge Standard Detail Sheets: see website Height: 46.5 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 thanthe minimum required Bicycle Rail or Pedestrian Rail height of 42.


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Description: See through 4-bar sidewalk mounted steel bridge rail.

Test Level: TL-2 Standard Plans: Standard Plans B11-66, B11-67 Height: 42above 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.


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Renderings of California ST-40


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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 aminimum of 42 as well as modification of the clear opening for use as apedestrian/bicycle rail.

Successfully used on past projects in the Coastal Zone.


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Photo of Concrete Barrier Type 80 - Modified withArchitectural Treatment and with Bicycle Rail Offset 15from Rail Face.


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Sheffield Drive Bridge

Santa Barbara County


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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 toincrease height to a minimum of 42 as well as modification to reducethe clear openings.


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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 ofdeck).

Comments: Cannot be used on bridge decks with high speedvehicular traffic (greater than 45 mph).


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Concrete Barrier Type 80SW

Canal Street Bridge

El Dorado County


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See-Through B ridge Rails

Cost ComparisonBridg e Rai l Estimated

Cost/LF

Cos t/Cos t 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


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See-Through Bridge Rails

Summary

Metal Bridge Rails Concrete Barriers

TL-4 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 TL-2California ST-40 (H=42) + Conc Barrier Type 80SW (H=42) +, #

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


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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 bicyclistsfrom 54 to 42 at their 2006 annual meeting.

The Caltrans initiated a bicycle rail height study that concluded thata 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, 2008lowering 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


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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 bythe PDT and used in the environmental process.

During the Design phase, need to ensure that the aesthetic bridgerail meets all project requirements as well as structural/crash test

requirements.

Projects in the coastal zone may require special consideration.


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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 isrequired on the outside of the curve. Issues regarding super-elevation should be discussed as early in the design process as

possible.


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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, butcan be modified for other uses by special design.

a) For example, a see-through rail can be used on the roadsideby mounting the rail on a reinforced concrete trench footing oron a trench footing on CIDH piles.

b) See-through rails can also be used with earth retainingsystems, however the design of the earth retaining systemneeds to consider vehicular impact loads.


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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 appliedto the surface of rails. Drawings and reports detailing the texturerelief limits on rail can be found at the Caltrans LandscapeArchitecture website:

http://www.dot.ca.gov/hq/LandArch/barrier_aesthetics/index.htm
http://www.dot.ca.gov/hq/LandArch/barrier_aesthetics/index.htmhttp://www.dot.ca.gov/hq/LandArch/barrier_aesthetics/index.htm


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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 isoffset 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 asidewalk may have roadway appendages if the appendage is offset 8

behind the front face of rail. Rails with a sidewalk in low speed locations donot require an offset for appendages, but special attachment details mayapply depending on the rail type.

Contact Caltrans/DES when there is a need for any roadway appendage tobe attached to top or backside of rail.


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Bridge Standard Detail Sheets (aka XSSheets) website:

http://www.dot.ca.gov/hq/esc/techpubs/manual/bridgemanuals/bridge-standard-detail-sheets/
http://www.dot.ca.gov/hq/esc/techpubs/manual/bridgemanuals/bridge-standard-detail-sheets/http://www.dot.ca.gov/hq/esc/techpubs/manual/bridgemanuals/bridge-standard-detail-sheets/http://www.dot.ca.gov/hq/esc/techpubs/manual/bridgemanuals/bridge-standard-detail-sheets/http://www.dot.ca.gov/hq/esc/techpubs/manual/bridgemanuals/bridge-standard-detail-sheets/http://www.dot.ca.gov/hq/esc/techpubs/manual/bridgemanuals/bridge-standard-detail-sheets/http://www.dot.ca.gov/hq/esc/techpubs/manual/bridgemanuals/bridge-standard-detail-sheets/http://www.dot.ca.gov/hq/esc/techpubs/manual/bridgemanuals/bridge-standard-detail-sheets/http://www.dot.ca.gov/hq/esc/techpubs/manual/bridgemanuals/bridge-standard-detail-sheets/http://www.dot.ca.gov/hq/esc/techpubs/manual/bridgemanuals/bridge-standard-detail-sheets/http://www.dot.ca.gov/hq/esc/techpubs/manual/bridgemanuals/bridge-standard-detail-sheets/http://www.dot.ca.gov/hq/esc/techpubs/manual/bridgemanuals/bridge-standard-detail-sheets/


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See-Through Bridge Rails

Next Steps

Shanno n Post/ Greg Kaderabek


Aug ust, 2011

Guidance

DRAFT Desig n Inform ation Bul let in (DIB),

Br idge Rai l Development, Design and Select ion

Guidelines

Update Highway Design Manual

Bridg e Rails and Barr iers: A Reference Guide

for Transpo rtat ion Projects in the Coastal Zone

Crash Test ing/ Development of

addit io nal alternatives


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Shanno n Post/ Greg Kaderabek


Aug ust, 2011

Caltrans See Thru Rail Webinar 24aug2011

Documents

Transcript of Caltrans See Thru Rail Webinar 24aug2011