FDOT Standard Plans Index 425-001: Manhole Covers, Frames, Tops, and Supplementary Inlet Details

Design Criteria

Design Criteria and Guidance FDOT Design Manual (FDM) ; Drainage Manual (DM) ; Drainage Design Guide (DDG)

Design Assumptions and Limitations

Design Assumptions and Limitations Manholes: • Specify Manhole top Type 8 in the Plans when depths shown in the Manhole Tops details can be maintained. • Verify the minimum thickness (h) above the pipe opening is met with the Type 8 Manhole. If the minimum thickness (h) cannot be met, specify a Type 7 Inlet.

See Index 425-001 sheet 6 of 8 • Consider using the 2-piece cover where depths exceed 5’ and manual entry may be required for cleaning. Clearly note the requirement for a 2-piece cover on the Drainage Structure sheets in the Plans. • 2-piece covers are required when sump depths exceed 2’.

Structure Bottoms: • Sump bottoms may be used with all manhole and inlet types. • Only use Rectangular Riser Segments with Pipe Opening at Corner when round structures are not practical. Obtain Engineer of Record Approval for these segments.

Shop Drawings are required for rectangular segments with Pipe Opening at Corner. Replace Manhole Top: • Use the standard cover for all frames Types I, II, III, two-piece covers, and as a replacement cover for all previous frames with 1 ½” deep seats (traffic type). • Use the 185 lb.

(non-traffic) cover from the 1984 Roadway and Traffic Design Standards, Index 201, as the replacement cover for existing frames with ½” deep seats only. Installation of new frames with ½” seat is not permitted.

Payment

Payment For pay item purposes, the height used to determine if a drainage structure is greater than 10 feet shall be computed using: A. The elevation of the top of the manhole lid, B. The grate elevation or the theoretical gutter grade elevation of an inlet, or C.

The outside top elevation of a junction box less the flow line elevation of the lowest pipe or to top of sump floor. Item number Item Description Unit Measure 425-1-AAB Inlet – Drainage EA 425-2-AAB Manhole – Drainage EA 425-3-AAB Junction Boxes – Drainage EA 425-4 Adjust Inlet EA 425-5-A Adjust Manholes EA 425-7 Replace Manhole Cover EA 425-8 Adjust Miscellaneous Drainage Structure EA 425-11 Modify Existing Drainage Structure EA 425-12-A Retractable Inlet Screen EA 425-13-AA Drainage Structure Pipe Connection Screen EA 425-14-A Grate for Existing Drainage Structure SF See the BOE and Specification 425 for additional information on payment, pay item use and compensation.

What your plans must show

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

• Summarize the Drainage Structures in the Plans in accordance with the requirements of the Basis of Estimates Manual ( BOE ) . Specify 2-piece manhole cover when required for maintenance access. Reference 1984 Design Standard Index 201 for replacement of manhole covers with ½” seat. Index 425
• - 001 Manhole Covers, Frames, Tops, and Supplementary Inlet Details