FDOT Standard Plans Index 649-030: Standard Mast Arm Assemblies

Design Criteria

Design Criteria AASHTO LRFD Specifications for Structural Supports for Highway Signs, Luminaires and Traffic Signals (LRFDLTS-1) ; Structures Manual (SM) , Volume 3, FDOT Modifications to LRFDLTS-1; Structures Manual (SM) Introduction, I.6

Design Assumptions and Limitations

Design Assumptions and Limitations See FDM 232 , FDM 261 , and Structures Manual (SM) , Volume 3 for additional design criteria. FDOT Signal Support Programs website provides mast arm design programs to support both “Standard” and “Special” (Custom) designs Design all mast arm assemblies with backplates in accordance with FDM 232 . Knowing galvanizing thickness may vary, mast arm assemblies are designed for a 3 foot splice.

If actual galvanizing thicknesses are as specified, the splice length will be 3 feet and the arm length will be the design length. However, if actual galvanizing thicknesses are significantly larger than specified (not uncommon), the arm may be a foot or so longer than designed, while the splice length will still comply with AASHTO requirements. Standard Mast Arm Assemblies : The maximum span length of Standard Mast Arm Assemblies is 78 feet.

Mast arms with an arm length greater than 78 feet require a Variation in accordance with FDM 261 . Standard Mast Arm Assemblies comply with the minimum requirements and details shown on Index 649-031 . Standard Mast Arm Assemblies may be single arm, single arm with luminaire, double arms, or double arms with luminaire.

Standard double arms are limited to arm orientations of 90° or 270° only. The mast arm design Excel program, located on the Structures Design Programs Library website, will provide design loads and arm, pole and foundation capacities which the designer can use to choose arm type(s), pole type and foundation type for Standard designs. Additionally, the mast arm Mathcad program is also provided for detailed design evaluations/validations of Standard Mast Arm Assemblies.

Available arm(s) and pole combinations are shown on Index 649-030 . Dimension UB (height to the arm from the bottom of baseplate) must be between 18-22 feet. Pole types P2 and larger require a minimum 4.5 foot diameter drilled shaft.

Pole types P5 and larger require a minimum 5.0 foot diameter drilled shaft. Indexes 649-030 Standard Mast Arm Assemblies and 649-031 Mast Arm Assemblies Standard foundation (Drilled Shaft) capacities are based on the following soil criteria: Classification: Cohesionless (Fine Sand) Friction Angle: 30 Degrees Unit Weight: 50 pcf (assumed submerged) Average N-blowcount: >=15 When the designer considers soil types at the specific site location to be of lesser strength properties than shown above, an analysis is required. Auger borings, SPT borings, or CPT soundings may be used as needed to verify the assumed soil properties, and at sites confirmed to be uniform, a single boring or sounding may cover several foundations.

Borings in the area that were performed for other purposes may be used to confirm the assumed soil properties. The Geotechnical Engineer must justify the differing soil criteria to the District Structures Design Engineer during the design phase of the project. If Index 649-031 is used, shop drawings are not required.

Mast Arms with Luminaires Mount luminaires on mast arms only where project constraints do not allow for placement of independent light poles. Prior to use, contact applicable construction and maintaining agencies, verify responsible parties, and include a written summary with the project documents. Special (Custom) Mast Arm Assemblies : Special mast arms are those with unique loadings, soil conditions, and/or geometric constraints that contain any component (arm, pole, or drill shaft) that is outside the range of those available on Index 649-030 .

The mast arm Mathcad program, located on the Structures Design Programs Library website, will provide the necessary variables to be shown in the " Special Mast Arm Assemblies Data Table " cell from the FDOT CADD Menu.

Payment

Payment Item number Item Description Unit Measure 649-2A-BB Steel Mast Arm Assembly EA 715-5-AB Luminaire & Bracket Arm EA See the BOE and Specification 649 & 715 for additional information on payment, pay item use and compensation. Note: Project Specific Pay Items are required for Special Mast Arm Assemblies with arm lengths greater than 78 feet. Examples EXAMPLE 1 1.

Select Arm and Pole Combination. Select A40/S - P2/S from the Mast Arm Combinations Tables. Specify shorter arm, enter 36 under FAA.

Leave Second Arm, UF and LL blank as there is no second arm or luminaire. 2. Determine Arm Mounting Height.

UB + 10' = 12.5' + 17.5'min. + 2' UB = 22' min. Use 22' 3.

Select Drilled Shaft ID. Select DS/12/4.5. 4.

Use the FDOT Signal Support Programs to verify adequacy of the arm, pole, and foundation. EXAMPLE 2 1. Select Arms and Pole Combination.

Select A60/D - A40/D - P4/D from the Mast Arm Combinations Tables. Specify shorter arms, enter 27.5 under FAA for First Arm. FAA = FA - (60' - 52') = 35.5' - 8' = 27.5' 2.

Enter angle between arms. Angle UF is measured counter-clockwise from the First Arm and must be either 90° or 270°. 3.

Specify shorter Pole. Enter 23.5 under UAA. 4.

Determine Arm Mounting Height. Indexes 649-030 Standard Mast Arm Assemblies and 649-031 Mast Arm Assemblies UB + 10' = 9.5' + 17.5' min. + 2' UB = 19' min.

Use 20' 5. Select Drilled Shaft ID. Select DS/16/4.5 6.

Use the FDOT Signal Support Programs to verify adequacy of the arm, pole, and foundation. Indexes 649-030 Standard Mast Arm Assemblies and 649-031 Mast Arm Assemblies Indexes 649-030 Standard Mast Arm Assemblies and 649-031 Mast Arm Assemblies Mast Arm Tabulation Sheet Example: DATE DESCRIPTION REVISIONS DATE DESCRIPTION NO. SHEET STATE OF FLORIDA DEPARTMENT OF TRANSPORTATION ROAD NO.

FINANCIAL PROJECT ID COUNTY PROFESSIONAL TYPE STANDARD MAST ARM TABULATION Indexes 649-030 Standard Mast Arm Assemblies and 649-031 Mast Arm Assemblies

Design Aids

Design Aids 30 Foot Mast Arm Combinations Arm 1 Length Arm 2 Length Regular or Heavy Duty Luminaire? Designation 30' N/A Reg No A30/S P1/S Yes A30/S P1/S/L HD No A30/S/H P1/S Yes A30/S/H P1/S/L 30' Reg/Reg No A30/D A30/D P2/D Yes A30/D A30/D P2/D/L Reg/HD No A30/D A30/D/H P2/D Yes A30/D A30/D/H P2/D/L HD/Reg No A30/D/H A30/D P2/D Yes A30/D/H A30/D P2/D/L HD/HD No A30/D/H A30/D/H P2/D Yes A30/D/H A30/D/H P2/D/L 30 foot Mast Arm Total = 12 Indexes 649-030 Standard Mast Arm Assemblies and 649-031 Mast Arm Assemblies Foot Mast Arm Combinations Arm 1 Length Arm 2 Length Regular or Heavy Duty Luminaire? Designation 40' N/A Reg No A40/S P2/S Yes A40/S P2/S/L HD No A40/S/H P2/S Yes A40/S/H P2/S/L 30' Reg/Reg No A40/D A30/D P2/D Yes A40/D A30/D P2/D/L Reg/HD No A40/D A30/D/H P2/D Yes A40/D A30/D/H P2/D/L HD/Reg No A40/D/H A30/D P2/D Yes A40/D/H A30/D P2/D/L HD/HD No A40/D/H A30/D/H P2/D Yes A40/D/H A30/D/H P2/D/L 40' Reg/Reg No A40/D A40/D P2/D Yes A40/D A40/D P2/D/L Reg/HD No A40/D A40/D/H P2/D Yes A40/D A40/D/H P2/D/L HD/Reg No A40/D/H A40/D P2/D Yes A40/D/H A40/D P2/D/L HD/HD No A40/D/H A40/D/H P2/D Yes A40/D/H A40/D/H P2/D/L 40 foot Mast Arm Total = 20 Indexes 649-030 Standard Mast Arm Assemblies and 649-031 Mast Arm Assemblies Foot Mast Arm Combinations Arm 1 Length Arm 2 Length Regular or Heavy Duty Luminaire? Designation 50' N/A Reg No A50/S P3/S Yes A50/S P3/S/L HD No A50/S/H P3/S Yes A50/S/H P3/S/L 30' Reg/Reg No A50/D A30/D P3/D Yes A50/D A30/D P3/D/L Reg/HD No A50/D A30/D/H P3/D Yes A50/D A30/D/H P3/D/L HD/Reg No A50/D/H A30/D P3/D Yes A50/D/H A30/D P3/D/L HD/HD No A50/D/H A30/D/H P3/D Yes A50/D/H A30/D/H P3/D/L 40' Reg/Reg No A50/D A40/D P3/D Yes A50/D A40/D P3/D/L Reg/HD No A50/D A40/D/H P3/D Yes A50/D A40/D/H P3/D/L HD/Reg No A50/D/H A40/D P3/D Yes A50/D/H A40/D P3/D/L HD/HD No A50/D/H A40/D/H P3/D Yes A50/D/H A40/D/H P3/D/L 50' Reg/Reg No A50/D A50/D P4/D Yes A50/D A50/D P4/D/L Reg/HD No A50/D A50/D/H P4/D Yes A50/D A50/D/H P4/D/L HD/Reg No A50/D/H A50/D P4/D Yes A50/D/H A50/D P4/D/L HD/HD No A50/D/H A50/D/H P4/D Yes A50/D/H A50/D/H P4/D/L 50 foot Mast Arm Total = 28 Indexes 649-030 Standard Mast Arm Assemblies and 649-031 Mast Arm Assemblies Foot Mast Arm Combinations Arm 1 Length Arm 2 Length Regular or Heavy Duty Luminaire? Designation 60' N/A Reg No A60/S P4/S Yes A60/S P4/S/L HD No A60/S/H P4/S Yes A60/S/H P4/S/L 30' Reg/Reg No A60/D A30/D P4/D Yes A60/D A30/D P4/D/L Reg/HD No A60/D A30/D/H P4/D Yes A60/D A30/D/H P4/D/L HD/Reg No A60/D/H A30/D P4/D Yes A60/D/H A30/D P4/D/L HD/HD No A60/D/H A30/D/H P4/D Yes A60/D/H A30/D/H P4/D/L 40' Reg/Reg No A60/D A40/D P4/D Yes A60/D A40/D P4/D/L Reg/HD No A60/D A40/D/H P4/D Yes A60/D A40/D/H P4/D/L HD/Reg No A60/D/H A40/D P4/D Yes A60/D/H A40/D P4/D/L HD/HD No A60/D/H A40/D/H P4/D Yes A60/D/H A40/D/H P4/D/L 50' Reg/Reg No A60/D A50/D P4/D Yes A60/D A50/D P4/D/L Reg/HD No A60/D A50/D/H P4/D Yes A60/D A50/D/H P4/D/L HD/Reg No A60/D/H A50/D P4/D Yes A60/D/H A50/D P4/D/L HD/HD No A60/D/H A50/D/H P4/D Yes A60/D/H A50/D/H P4/D/L 60' Reg/Reg No A60/D A60/D P5/D Yes A60/D A60/D P5/D/L Reg/HD No A60/D A60/D/H P5/D Yes A60/D A60/D/H P5/D/L HD/Reg No A60/D/H A60/D P5/D Yes A60/D/H A60/D P5/D/L HD/HD No A60/D/H A60/D/H P5/D Yes A60/D/H A60/D/H P5/D/L 60 foot Mast Arm Total = 36 Indexes 649-030 Standard Mast Arm Assemblies and 649-031 Mast Arm Assemblies Foot Mast Arm Combinations Arm 1 Length Arm 2 Length Regular or Heavy Duty Luminaire? Designation 70' N/A Reg No A70/S P5/S Yes A70/S P5/S/L HD No A70/S/H P5/S Yes A70/S/H P5/S/L 30' Reg/Reg No A70/D A30/D P5/D Yes A70/D A30/D P5/D/L Reg/HD No A70/D A30/D/H P5/D Yes A70/D A30/D/H P5/D/L HD/Reg No A70/D/H A30/D P5/D Yes A70/D/H A30/D P5/D/L HD/HD No A70/D/H A30/D/H P5/D Yes A70/D/H A30/D/H P5/D/L 40' Reg/Reg No A70/D A40/D P5/D Yes A70/D A40/D P5/D/L Reg/HD No A70/D A40/D/H P5/D Yes A70/D A40/D/H P5/D/L HD/Reg No A70/D/H A40/D P5/D Yes A70/D/H A40/D P5/D/L HD/HD No A70/D/H A40/D/H P5/D Yes A70/D/H A40/D/H P5/D/L 50' Reg/Reg No A70/D A50/D P5/ …

What your plans must show

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

• The signal designer completes the “ Mast Arm Tabulation Sheets ”, and the structures designer completes the “ Standard Mast Arm Assemblies Data Table” or " Special Mast Arm Assemblies Data Table ", as appropriate. See samples of these sheets below. These are the only plan sheets required for mast arm assemblies. The structures data table may be placed on a signal plan sheet, if space permits. The following instructions are for use with the “ Mast Arm Tabulation Sheets ”:
• 1. Each mast arm assembly is identified by a unique ID number. Indexes 649-030 Standard Mast Arm Assemblies and 649-031 Mast Arm Assemblies . Dimensions 1-5 are for signals and dimensions A-E are for signs. Record the horizontal distance from the face of arm baseplate to the center of the signal or sign (similar to arm length measurement, see Index 649-031).
• 3. Signals may be mounted vertically or horizontally. Indicate the mounting in the appropriate column in the table.
• 4. The entire line for arm #2 and the space for the angle between dual arms are left blank for single arm assemblies.
• 5. All arms and poles will be galvanized. If a color is required, indicate the color in the table, otherwise leave blank.
• 6. Starting at the pole, select the signals and/or signs that match the configuration you are tabulating. The spaces representing the signs or signals not used will be blank. Example 1: If no sign is located between the pole and signal 1, the spaces for Sign A would be blank. Example 2: A configuration for three signals and one sign between signal 1 and signal 2
• - Only the spaces for signals 1, 2, 3 and sign B would be completed; the others will be blank.
• 7. Record the number of sections in each signal head in the space following the distance to that head.
• 8. Record the height and width of each sign in the space following the distance to the sign.
• 9. When double arm poles are used for a skewed intersection, the standard design should be used whenever possible. The standard orientation for arm #2 is 90 or 270 degrees measured in a counter clockwise direction from arm #1. The normal orientation of the mast arm is perpendicular to the roadway. Adjustments in mounting hardware can compensate for a skew angle of approximately 15 degrees or more from the normal, depending upon the attachment method. The designer should verify the mounting hardware capability before specifying an arm with a skew greater than 15 degrees.
• 11. The standard handhole location is 90 degrees from arm #1 facing away from traffic. Other handhole locations must be noted in the Special Instructions. Indexes 649-030 Standard Mast Arm Assemblies and 649-031 Mast Arm Assemblies . A free swinging internally illuminated street name sign may be attached to the pole by an independent bracket arm if the sign area does not exceed 18 square feet and weigh more than 144 pounds. The Structures Design Engineer must review other signs attached to the pole or any size sign of this type attached to the signal mast arm.
• 13. The "Special Instructions" Table is used to tabulate pedestrian buttons and pedestrian signal locations and handhole locations when the handholes are not in the standard location. Tabulate the ID No. and the orientation of the pedestrian buttons and signals in degrees measured counter clockwise from arm #1. The handhole location should be left blank if the handhole is in the standard location (see note 11).
• 14. Arm #1 is the arm for a single arm assembly or the longer arm for a double arm assembly. If the arms are equal length, arm #1 is over the project roadway.