FDOT Standard Plans Index 521-001: Concrete Barrier

Design Criteria

Design Criteria FDOT Design Manual (FDM) ; AASHTO Roadside Design Guide , 4th Edition; AASHTO Manual for Assessing Safety Hardware (MASH) , Test Level 2 & 4 Criteria; AASHTO LRFD Bridge Design Specifications , 7th Edition.

Design Assumptions and Limitations

Design Assumptions and Limitations For concrete barrier information including crash test level classification, hazard setback requirements, and general placement information, see FDM 215 . For barrier intended to protect bridge piers that theoretically do not have sufficient strength to resist the LRFD equivalent static impact force, see Index 521-002 (Pier Protection Barrier). A.

General: Index 521-001 defines concrete barrier segments for various conditions that will be used together to design a complete concrete barrier system on a project-specific basis. The design of concrete barrier requires that differing segments and features be shown and labeled correctly in the Plans, where the requirements of the Index are not violated including section dimensions and geometry of barriers. B.

Concrete Barrier Types: 1. Median Barrier (All Design Speeds) – double-faced rigid barrier used in medians to prevent crossover collisions and to shield vehicles from miscellaneous hazards, including sign supports, light supports, and piers. 2.

Shoulder Barrier (All Design Speeds) – single-faced rigid barrier typically used on outside shoulders when minimized barrier deflection (or setback) is required to shield vehicles from miscellaneous hazards, including sign supports, light supports, and piers. 3. Curb & Gutter Barrier (Design Speeds ≤ 45 mph) – single-faced rigid barrier used to shield vehicles from miscellaneous hazards in urban areas, which may be used in conjunction with adjoining raised curb for water conveyance.

4. Wall Shielding Barrier (All Design Speeds) – single-faced rigid barrier used to shield vehicles from continuous retaining walls and adjacent miscellaneous hazards, including sign supports and light supports. Note: Shielding of walls is a project-specific decision based on the relative smoothness and anticipated impact angle of the retaining wall.

The use of concrete barrier can increase crashworthiness as compared to walls that are rough, grooved, or not in compliance with the taper rates shown in Table 2. Index 521 - 001 Concrete Barrier C. Shielding Hazards - Determining Length of Need and Begin/End Barrier Stations: The standard method of determining barrier placement for shielding hazards is based on the Runout Length and the Length of Need (LON) calculation in the AASHTO Roadside Design Guide (RDG) , 4th Edition.

See the FDOT Concrete Barrier Length of Need (LON) Excel program for plan view details and assistance with determining Begin/End LON Stations for shielding various hazard configurations. This program is located in the Design Tools column on the Standard Plans website. On the trailing end, place barrier to shield hazards assuming a 30 degree vehicle departure angle from the roadway.

See Figure 1 , below. Figure 1: Trailing End Barrier Placement Index 521 - 001 Concrete Barrier D. End Treatments: End Treatments are required for all Concrete Barrier ends both not connecting to a different barrier type (Barrier End Connection / Continuation) and under the following conditions of Table 1 , below.

Table 1: Barrier End Treatment Usage Barrier Type: Barrier End Location : Applicable End Treatment Type (s ) : Median Barrier Approach – Inside Clear Zone • Guardrail Approach Terminal (1) • Crash Cushion (2) Approach – Outside Clear Zone • Sloped End Treatment (3) Trailing End • Sloped End Treatment (3) Shoulder Barrier Approach – Inside Clear Zone • Guardrail Approach Terminal (1) • Crash Cushion (2) Trailing End • None Curb & Gutter Barrier Approach – Inside Clear Zone • Guardrail Approach Terminal (1) • Sloped End Treatment (Restricted Use per FDM 215 ) (4) Trailing End • None Wall Shielding Barrier Approach – Inside Clear Zone • Guardrail Approach Terminal (1) • Crash Cushion (2) Trailing End • None Note: If the barrier end is within the Clear Zone of any nearby lane with approaching traffic (e.g. 2-lane, 2-way facility), then “Approach End – Inside the Clear Zone” criteria applies. End Treatment Types: 1.

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Payment

Payment Item number Item Description Unit Measure 521-1-11 Median Concrete Barrier, 38” Height LF 521-1-12 Median Concrete Barrier, 38” Short Grade-Separated LF 521-1-13 Median Concrete Barrier, 38” Tall Grade-Separated LF 521-1-14 Median Concrete Barrier, Variable Section Width for Sign or Pier Shielding LF 521-72-40 Shoulder Concrete Barrier, 38” or 44” Height LF 521-72-41 Shoulder Concrete Barrier, 38” Retaining Section LF 521-72-42 Shoulder Concrete Barrier, 38” Trench Footing Section LF 521-72-43 Shoulder Concrete Barrier, 38” Curb & Gutter Barrier LF 521-72-60 Shoulder Concrete Barrier, 38” Wall Shielding Barrier LF 521-72-61 Shoulder Concrete Barrier, Variable Section Width for Wall or Sign Shielding LF See the BOE and Specification 521 for additional information on payment, pay item use and compensation.