FDOT Standard Plans Index 521-480: Series Traffic Railing - (Vertical Face Retrofit)

Design Criteria

Design Criteria NCHRP Report 350 , Test Level 4; AASHTO LRFD Bridge Design Specifications ; Structures Design Guidelines ( SDG )

Design Assumptions and Limitations

Design Assumptions and Limitations Index 521 - 480 is the lead standard for the Traffic Railing (Vertical Face Retrofit) standard series which includes Indexes 521 - 480 through 521 - 484. Use this standard with Indexes 536 - 0 02, 52 1 - 0 01 , 521 - 481, 521 - 482, 521 - 483 and 521 - 484. The Traffic Railing (Vertical Face Retrofit), Indexes 521 - 480 through 521 - 483, are applicable for retrofitting specific types of existing bridge mounted traffic railings (a.k.a.

concrete handrails) that are not based on crash tested designs. Index 521 - 484 should only be used when space is limited, which precludes the use of a guardrail end treatment or crash cushion. Determine the Length of Advancement for the Tapered End Transition using the criteria shown on Index 521 - 484, Sheet 1.

Indexes 521 - 480 through 521 - 484 are not acceptable as alternatives for new construction. These Standards are to be used in conjunction with Indexes 536 - 0 02 and 52 1 - 0 01 . The appropriate Index 536 - 0 02 approach transition retrofit for Index 521 - 480 S eries B ridge R ailing R etrofits or Index 521 - 484 Tapered End Transition must be selected and specified in the plans based on the shapes and designs of the existing bridge traffic railings, approach slabs and end bent wing walls.

See the Instructions for Index 536 - 0 02 and SDG 6.7 for more information. The applicability of the Vertical Face Retrofit to a particular bridge shall be determined based on a review of the Load Rating of the existing bridge, a comparison of the existing bridge geometry to that shown for the Vertical Face Retrofit and an evaluat ion of the structural adequacy of the existing bridge deck and wing walls in accordance with the requirements of the SDG . See SDG 2.2 for average weight per linear foot of the retrofit.

The Traffic Railing (Vertical Face Retrofit) has been structurally evaluated to be equivalent or greater in strength to a design which has been successfully crash tested previously and approved for a NCHRP Report 350 Test Level 4 rating. The Standards all utilize a cast in place, vertical face, reinforced concrete block that is installed adjacent to the face of the existing curb and in front of, or in place of, all or part of the existing traffic railing. The Standard s work with existing traffic railings th at incorporate either solid concrete parapet type or concrete post and beam type railings with or without top mounted metal railings.

These existing traffic railings are typically mounted on top of concrete curbs of varying widths and heights. The individu al Standards address both narrow and wide curbs (a.k.a. "safety curbs"), and skewed and non - skewed bridges with parallel, perpendicular, angled or flared end bent wing walls.

Each Standard includes several schemes that address the given wing wall configura tions. Standard Plan s Instructions Topic No. 625 - 010 - 003 Index 521 - 480 Series Traffic Railing - (Vertical Face Retrofit) Examples depicting existing curb and end bent wing wall configurations are shown in the Existing Curb Schematic and the Partial Plan Views of Existing Bridges herein.

Generally, the Roadway Plans shall include all of the sheets necessary to define and detail the retrofit of the existing traffic railings. Index 521 - 480, Traffic Railing (Vertical Face Retrofit) Typical Details & Notes , shall be referenced in the Roadway Plans or a similar project specific drawing depicting general notes and details , shall be included in the Roadway Plans. In addition, one or more of the appropriate Indexes 521 - 481 through 521 - 484, that most closely matches the configuration of the existing traffic railing and curb is to be referenced in the Roadway Plans for each bridge as required.

Generally, these Standards can be used without any modifications being made to them. …

Payment

Payment for the removal of all or part of the existing traffic railing shall be included in Removal of Existing Structures, Pay Item 110 - 3. As part of the overall retrofit concept for a bridge, the existing traffic railing may be removed, even though it is not specifically required to be, in order to reduce t he dead load carried by the bridge. In these cases, the potential drop off hazard for pedestrians that will be created behind the retrofit shall be addressed in the Plans.

The treatment of the approach end of the retrofit shall consist of Index 536 - 0 02, 521 - 484 or another appropriate site specific treatment. The appropriate treatment of the trailing end of the retrofit shall be determined by the Roadway Engineer. On approach ends, a Transition Block or Curb is required if the existing Approach Slab does not h ave a curb.

A Transition Block is not required on trailing ends with no opposing traffic, however, a Curb may be required due to drainage needs. An Index 520 - 00 1 , Type D Concrete Curb is generally suitable for this application. The appropriate site specific approach and trailing end treatments shall be shown in the Plans.

If an Index 536 - 0 02 Roadway Guardrail Transition is used, the defining station of the end of the transition must be shown in the Plans. The attachment point for the Thrie - Beam Terminal Connector shall be determined based on the shape, length, structural adequacy and direct means of support of the end most section of the Vertical Face Retrofit, the existing wing wall and/or approach slab as follows: Standard Plan s Instructions Topic No. 625 - 010 - 003 Index 521 - 480 Series Traffic Railing - (Vertical Face Retrofit) Wing Wall Geometry Location of the Thrie - Beam Terminal Connector to the Vertical Face Retrofit Requirements Perpendicular or Angled On Bridge None Parallel Case 1: On Wing Wall Wing wall requirements: 1.

minimum of 5' - 0" long, 2. pile supported, and Case 2: On Approach Slab 1. approach slab is a minimum of 5' - 0" long Case 3: On Bridge (when not meeting Case 1 or 2) None Flared with parallel portions Case 1: On Wing Wall Wing wall requirements: 1.

minimum of 5' - 0" long, 2. pile supported, and Vertical Face Retrofit Requirements 1. parallel portion is a minimum of 2' - 0" long Case 2: On Approach Slab 1.

approach slab is a minimum of 5' - 0" long 2. parallel portion of Vertical Face Retrofit is a minimum of 2' - 0" long Case 3: On Bridge (when not meeting Case 1 or 2) None Flared without parallel portions On Bridge None Indexes 536 - 0 02 and 521 - 480 through 521 - 484 shall be supplemented as required with project specific details that may be deemed necessary to complete the installation of the retrofit railing. These details may include locations and details of any existing utilities, conduits, drainage structures, sign structures and luminaire supports, or designs and details of traffic railing sliding plate assemblies for large expansion joints and any other needed information not included in these Standards.

In the event that the details and indexes presented in these Standards do not closely match the existing conditions, the Structures and/or Roadway Engineer(s) shall prepare a customized project specific retrofit design using the crash tested bridge railing and guardrail transition designs presented in Indexes 536 - 0 02 and 521 - 480 through 521 - 484 as guides. Contact the Structures Design Office and Roadway Design Office for guidance in this event. Standard Plan s Instructions Topic No.

625 - 010 - 003 Index 521 - 480 Series Traffic Railing - (Vertical Face Retrofit) The Utility Adjustment Plans, if required, shall contain all necessary utility adjustment information required for the retrofit of the existing traffic railings. Utilities and/or conduits may exist in or adjacent to the existing traffic railings and will v ary in size, number and location. …

What your plans must show

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

• The appropriate Standard Plan s Index number and Scheme number shall be shown in the Roadway Plans for each bridge along with the limiting stations of the retrofit. Examples of notes containing the required information as they would appear on a Plan or Plan
• - Profile sheet are as follows: "Construct Traffic Railing (Vertical Face Retrofit), Index 521
• - 48X, Scheme X, from Sta. XX+XX.XX (at or near Begin Bridge) to Sta. XX+XX.XX (at or near End Bridge)." "Construct Traffic Railing (Vertical Face Retrofit) Spread Footing Approach, Index 521
• - 484, Scheme X, from Sta. XX+XX.XX (at beginning of Length of Advancement, or at or near End Bridge) to Sta. XX+XX.XX (at or near Begin Bridge, or end of Length of Advancement)." For projects with multiple bridges, a tabular format may be used to convey the necessary information. A separate Plan and Elevation sheet of the type used in Structures Plans is generally not required. Payment Item number Item Description Unit Measure 521
• - 8 Concrete Traffic Railing, Bridge, Retrofit
• - 6 Removal of Existing Structures LF * As required per the Design Assumptions and Limitations.