FDOT Standard Plans Index 521-405: Guardrail Transitions - Existing Post & Beam Bridge Railings (Wide Curbs)

Design Criteria

Design Criteria NCHRP Report 350 ; FDOT Design Manual ( FDM 114 )

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 bridge mounted structurally continuous Post and Beam Concrete Handrails (traffic railings) as shown on the following and other s imilar obsolete Indexes: Index 3199 Handrail for 20 ft. Span (1954) Index 3274 Concrete Handrail (1954) Index 3276 Handrail - 76 ft. Span (1954) Index 3489 Handrail - 76 ft.

Span (1955) Index 3959 Concrete Handrail (1961) Index 4058 Concrete Handrail (1957) Index 4727 Concrete Handrail (1960 with 1962 Revisions) Index 7678 Concrete Handrail (1963) Index 8572 Concrete Handrail (1964 with 1967 Revisions) Index 521 - 405 is applicable for use with the obsolete railings listed above that are constructed on curbs as shown below on roadways with a Design Speed of 45 mph or less: Standard Plan s Instructions Topic No. 625 - 010 - 003 Index 521 - 405 Guardrail Transitions - Existing Post & Beam Bridge Railings (Wide Curbs) Neither a new load rating nor an evaluation of the structural adequacy of the existing bridge deck, approach slab or wingwalls are required to use this index. Index 521 - 405 depicts five different retrofit schemes for installing the approach or trailing end guardrail transitions.

In each of the retrofit schemes, a section of Vertical Face Retrofit railing is constructed to facilitate connection of the new guardrail transit ion. The applicability of the individual retrofit schemes to different wingwall configurations is shown in the following views. Standard Plan s Instructions Topic No.

625 - 010 - 003 Index 521 - 405 Guardrail Transitions - Existing Post & Beam Bridge Railings (Wide Curbs) Standard Plan s Instructions Topic No. 625 - 010 - 003 Index 521 - 405 Guardrail Transitions - Existing Post & Beam Bridge Railings (Wide Curbs) Standard Plan s Instructions Topic No. 625 - 010 - 003 Index 521 - 405 Guardrail Transitions - Existing Post & Beam Bridge Railings (Wide Curbs) Index 521 - 405 is to be used in conjunction with Index 536 - 0 02.

The appropriate Index 536 - 0 02 approach guardrail transition retrofit and its limiting station must be selected and specified in the plans based on the shapes and designs of the existing post and beam railing, approach slabs and end bent wingwalls. Determine the attachment point for the Thrie - Beam Terminal Connector based on the shape, length and direct means of support of the end most section of the Vertical Face Retrofit, the existing wingwall and/or approach slab as follows: Perpendicular or Angled Wingwalls - Attach the Thrie - Beam Terminal Connector to the Vertical Face Retrofit on the bridge. Parallel Wingwalls - 1.

If the Vertical Face Retrofit is supported by the wingwall, attach the Thrie - Beam Terminal Connector to the Vertical Face Retrofit along the wingwall if the wingwall is a minimum of 5' - 0" long and directly pile supported. If the Vertical Face Retrofit is s upported by the approach slab, attach the Thrie - Beam Terminal Connector along the approach slab section of the retrofit if that section is a minimum of 5' - 0" long. 2.

Attach Thrie - Beam Terminal Connector to the Vertical Face Retrofit on the bridge if the any of the appropriate preceding criteria for parallel wingwalls or approach slabs are not met. Flared Wingwalls with parallel portions - 1. If the Vertical Face Retrofit is supported by the wingwall, attach the Thrie - Beam Terminal Connector to the Vertical Face Retrofit along the parallel portion of the Vertical Face Retrofit if the wingwall is a minimum of 5' - 0" long, directly pile supported, and if the parallel portion of Vertical Face Retrofit is a minimum of 2' - 0" long.

If the Vertical Face Retrofit is supported by the approach slab, attach the Thrie - Beam Terminal Connector along the approach slab section of the retrofit if that section is a minimum of 5' - 0" long and has a parallel portion that is a minimum of 2' - 0" long. 2. …

Payment

Payment for the removal of the prior retrofit, if required, must be evaluated on a case by case basis dependin g 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 , delineators are only included in the cost of new traffic railings/barriers. Payment 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 - 13 Guardrail Approach Transition to Rigid Barriers EA 705 - 11 - A Barrier Delineators EA

What your plans must show

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

• In the Roadway Plans: The Roadway Plans shall include all of the sheets necessary to define and detail the retrofit of the existing guardrail transitions. Generally, this index can be used without any modifications being made to it. If project specific details are required, use this index as a guide for developing typical details & notes to be included in the plans. Examples of
• Standard Plan s Instructions Topic No. 625
• - 405 Guardrail Transitions
• - Pro file sheet is as follows: "Construct Guardrail Approach Transition Retrofit, Index 521