Session 9Guardrail Connections to

Bridge Ends

Common Deficiencies in Bridge Railings

Inadequate Dynamic Strength

Potential for Snagging

Use of “Safety” Walk

Inadequate Transition

13-2

Transitions Guardrail Deflects – Bridge Ends DONOT!!

Bridge End Connections are an example of a change in the type of Barrier Deflection Characteristics

Must Reduce the Deflection of the Guardrail before you reach the Bridge End from 3’ to Zero

Must have adequate Structural Connection

Transition Considerations

Adequate structural connection to the bridge railing

Reduced post spacing and nested rail to increase stiffness gradually

Block outs and rub rails used to minimize snagging

How can you REDUCE DEFLECTION of Standard

Strong Post W-Beam Guardrail Normal Guardrail Post Spacing is 6’3”

Reduce Post Spacing to 3’ 1½” and reduce deflection by 50%

Nest the Guardrail (double thickness) and reduce deflection by 50%

Add a Guardrail panel to the back of the Post and reduce deflection by 50%

Add a Rub Rail and reduce deflection by nearly 50% & reduce snagging potential

Combine 2 of the above and reduce deflection by 75%

How can you REDUCE DEFLECTION of Standard

Strong Post W-Beam Guardrail

Nested

ReducedPostSpacing

Gradually Increase Stiffness by Increasing the

number of Post

13-7

Rub Rail Components - Std Draw RBC-001 002 & 003 “Guardrail

Connection to Bridge End Type A and A-1 Components”

Rub Rail

RubRail

Not Island Curb

Standard Drawing RBC-001Guardrail Connector to

Bridge End Type A and A-1

Inadequate Structural Connection or Stiffening of

Approach Rail

Adequate Structural Connection Terminal Sect No

2 Plate A & BStd Draw RBC-002 & 003

Inadequate Reduction in Deflection and Structural

Connection

Transition of Curb and Rub Rail to Bridge’s Safety

Shape

Addition of a Spacer Tube

Combination of all of the Proceeding for a Successful

Transition

Std Draw RBC-001 Guardrail Connection to Bridge End

Type A and A-1

Curb Inlet Type BShould have Island Curb in

Throat of the Inlet Std Draw RBC-

001 Note 5 “Island Curb”

Std Draw RBD-280

“Match Adjacent Curb”

Curb Inlet Type BShould have Island Curb in

Throat of the Inlet

Lt Std Draw old RBD-280 Curb Box Inlet Type B (Detail Drawing) “Match Adjacent Curb”

Rt Std Draw RBD-281 Curb Box Inlet Type B (Steel Drawing) "Island Curb Detail”

Type B Drainage Box As-Builts vs. Std Draw

Construction memo No 5-11July 6, 2011

Have not been getting Island Curb on Type B Inlet therefore a Const Memo was Issued

See Std Draw RBC-001, RBD-280, RBD-281 Previous Slides

Corrective Actions: Retrofit by extending the double ply rail from

25 linear feet to 50 linear feet Replace the drain box top with the correct

one

Std Draw RDB-280 Curb Box Inlet Type B 2012 Design Changed Detail to Show Island Curb instead of Std

Curb

Changed to Island Curb

Normally getting Standard Curb instead of Island Curb

Rub Rail Components - Std Draw RBC-001 002 & 003 “Guardrail

Connection to Bridge End Type A and A-1 Components”

Rub Rail

RubRail

Not Island Curb

What is the Difference in Type A and A-1 Connection to

Bridge EndStd Drawing RBC-001 ???

Std Draw RBC-001 Note 1. c.

Std Draw RBC-001 Note 3. d.

Type A Curb is needed even if

there is not a Drop Box – WHY??

Helps prevent the vehicle’s wheel from coming in contact with the Bridge End.Works in combination with the rub rail in the Transition to Safety Shape on Bridge.

The Curb is not just for drainage. Curb is sometimes left off in error.

What makes this a good Guardrail Connection to Bridge

End? Q & A Time