Session 9 Guardrail Attachments to Bridge Ends Common

Session 9 Guardrail Attachments to Bridge Ends

Common Deficiencies in Bridge Railings n Inadequate Dynamic Strength n Potential for Snagging n Use of “Safety” Walk n Inadequate Transition 13 -2

Transitions n Guardrail Deflects – Bridge Ends DONOT!! n n n 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 n n n 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 n n n Normal Guardrail Post Spacing is 6’ 3” n 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 Reduced Post Spacing Nested

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 Not Island Curb Rub Rail

Standard Drawing RBC-001 Guardrail 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 & B

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 B Should have Island Curb in Throat of the Inlet n Std Draw RBC-001 Note 5 “Island Curb” Std Draw RBD-280 “Match Adjacent Curb” n

Curb Inlet Type B Should have Island Curb in Throat of the Inlet n n Lt Std Draw RBD-280 Curb Box Inlet Type B (Detail Drawing) “Match Adjacent Curb” Rt Std Draw RDB-281 Curb Box Inlet Type B (Steel Drawing) "Island Curb Detail”

Type B Drainage Box As-Builts vs. Std Draw Construction memo No 5 -11 July 6, 2011 n n n 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: n n Retrofit by extending the double ply rail from 25 linear feet to 50 linear feet Replace the drain box top with the correct one