FDOT Standard Plans Index 521-404: Guardrail Transitions - Existing Post & Beam Bridge Railings (Narrow & Recessed Curbs)

Design Criteria

Design Criteria NCHRP Report 350 ; FDOT Design Manual ( FDM )

Design Assumptions and Limitations

Design Assumptions and Limitations This index is applicable for retrofitting existing approach and trailing end guardrail treatments that are adjacent to existing structurally continuous Post and Beam Concrete Handrails (traffic railings) as shown on the following and other similar obsolete Design Standard Indexes: Index 7936 Handrail for Sidewalk Type B (1963 with 1967 Revisions) Index 10257 - MOD Concrete Handrail (1970 with 1971 and 1973 Revisions) Index 10266 Concrete Handrail (1969 with 1973, 1974 and 1975 Revisions) Index 10276 Concrete Handrail and Light Standard Pilaster Details (1969 with 1973 Revisions) For the purposes of Index 521 - 404, the railings shown on these obsolete indexes are identified as having narrow or recessed curbs as follows: Neither a new load rating nor an evaluation of the structural adequacy of the existing bridge deck or wingwalls are required to use this index. Standard Plan s Instructions Topic No. 625 - 010 - 003 Index 521 - 404 Guardrail Transitions - Existing Post & Beam Bridge Railings (Narrow & Recessed Curbs) Index 521 - 404 depicts six different schemes for installing the approach or trailing end guardrail transitions.

The applicability of the individual schemes to different curb configurations and approach or trailing ends is described as follows: Scheme 1 - Applicable for approach ends of existing bridges with beam or girder type superstructures and narrow curb post and beam railings (obsolete Indexes 10257, 10276 or similar). A section of the existing post and beam railing along the wingwall must be removed and replaced with a new vertical face railing to facilitate connection of the new Thrie Beam Guardrail Approach Transition. Scheme 2 - Applicable for approach ends of existing bridges with flat slab type superstructures and narrow curb post and beam railings (obsolete Indexes 10257, 10276 or similar).

Also applicable for approach ends of existing bridges with beam or girder type superstr uctures, narrow curb post and beam railings and curved wingwalls. A section of the existing post and beam railing at the end of the bridge must be removed and replaced with a new vertical face railing to facilitate connection of the new Thrie Bea m Guardrail Approach Transition. Scheme 3 - Applicable for approach ends of existing bridges with beam or girder type superstructures and recessed curb post and beam railings (obsolete Index 10266 or similar).

A section of the existing post and beam railing along the wingwall must be removed and re placed with a new vertical face railing to facilitate connection of the new Thrie Beam Guardrail Approach Transition. Scheme 4 - Applicable for approach ends of existing bridges with flat slab type superstructures, recessed curb post and beam railings and parallel wingwalls (obsolete Index 10266 or similar). Also applicable for approach ends of existing bridges with beam or girder type superstructures, recessed curb post and beam railings and curved wingwalls (obsolete Index 7936 or similar).

A section of the existing post and beam railing at the end of the bridge must be removed and replaced with a new vertical face raili ng to facilitate connection of the new Thrie Beam Guardrail Approach Transition. Scheme 5 - Applicable for approach ends of existing bridges with beam, girder or flat slab type superstructures and either narrow or recessed curb post and beam railings that have solid sections (i.e. no openings) of railing along the wingwalls a minimum of 5' - 0" lo ng (obsolete Indexes 10257, 10266, 10276 or similar).

No new section of concrete railing is necessary, the new Thrie Beam Guardrail Approach Transition is bolted to the end of the existing solid section of railing along the wingwall. …

Payment

Payment for the removal of Standard Plan s Instructions Topic No. 625 - 010 - 003 Index 521 - 404 Guardrail Transitions - Existing Post & Beam Bridge Railings (Narrow & Recessed Curbs) the prior retrofit, if required, must be evaluated on a case by case basis depending on the type of retrofit that is present. In the event that the details presented in this index do not closely match the existing conditions, the Structures and/or Roadway Engineer(s) shall prepare a customized project specific retrofit design using this index as a guide.

Contact the Structures De sign Office and Roadway Design Office for guidance in this event.

Commentary

Commentary: In the past barrier delineators for the entire bridge were included in the cost of the retrofit; due to changes in Specification S ection 705 , they are only included in the cost of new traffic railings/barriers. Payment Schemes 1 thru 4 only: Standard Plan s Instructions Topic No. 625 - 010 - 003 Index 521 - 404 Guardrail Transitions - Existing Post & Beam Bridge Railings (Narrow & Recessed Curbs) Item number Item Description Unit Measure 521 - 5 - XX Request project specific number from Estimates Concrete Traffic Railing , Bridge, Retrofit - Post & Beam Railing EA 536 - 8 - 1 2 or 536 - 8 - 1 3 Guar drail Approach Transition to Rigid Barrier EA 705 - 11 - A Barrier Delineators EA Schemes 5 and 6 only: Item number Item Description Unit Measure 536 - 8 - 1 2 or 536 - 8 - 1 3 Guardrail Approach Transition to Rigid Barrier EA 705 - 11 - A Barrier Delineators EA

What your plans must show

Plan Content Requirements for this index — the SPI's checklist for designers.

• - Profile sheet is as follows: "Construct Guardrail Approach Transition Retrofit, Index 521