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# Florida Department of Transportation

CHARLIE CRIST GOVERNOR | 605 Suwannee Street Tallahassee, FL 32399-0450 | STEPHANIE KOPELOUSOS SECRETARY

January 31, 2008

MEMORANDUM

TO: | All Users of the Florida Department of Transportation Structures Manual.
FROM: | Robert Robertson, State Structures Design Engineer
COPIES: | Director Office of Design, Lora Bailey Hollingsworth; FHWA, Jeffery Ger; Assistant State Structures Design Engineers (Thomas Andres, Andre Pavlov, Charles Boyd, and Marc Ansley); State Geotechnical Engineer, Larry Jones; State Structures Maintenance Engineer, Jeff Pouliotte; District Structures Design Engineers (Gerard Moliere, Rod Nelson, Keith Shores, Fred Ochoa, Neil Kenis, Jorge Rodriguez, Scott Arnold, and Agnes Spielmann); District Structures Maintenance Engineers (Pepe Garcia, Keith Campbell, John Locke, John Danielsen , Ron Meade, Frank Guyamier, Aran Lessard)
SUBJECT: | January 2008 Structures Manual (625-020-018).

The Florida Department of Transportation Structures Design Office has officially released the January 2008 Structures Manual. The Structures Manual can be found on the Structures Office website at www.fdot.gov/structures.

The Structures Manual is a web based application and includes hyperlinks, navigation tools, indexes, and advanced search capabilities. PDF's of the Design Guidelines, Detailing Manual, Design examples and FDOT modifications to LRFR and LTS-4 are provided for printing purposes. Standard Drawings and Drawing Examples are available in both MicroStation (dgn) and Adobe Acrobat (pdf) formats.

The Structures Manual, updated every January, is the primary source for FDOT structural design criteria. The design criteria found in the Structures Manual shall be incorporated on all future projects and on those projects currently being developed (i.e., when design and detailing have not already reached final stages). Submit design exceptions or variations in accordance with Chapter 23 of the Plans Preparation Manual.

For questions about the Manual, or its application to a particular project, contact the District Structures Design Office.

To improve or further develop the Manual, submit suggestions to Charles Boyd, Florida Department of Transportation, 605 Suwannee Street, MS 33, Tallahassee, Florida 32399-0450

(e-mail charles.boyd@dot.state.fl.us).

Structures Manual Jan 2008 Revisions
Volume 1 - Design Guidelines
1.3.2 Classification Criteria - Table 1.1 Changed Slightly Aggressive Cl value for steel from "N.A". to "<500".
1.3.3 Chloride Content - Corrected chloride intrusion rate to 0.016 lbs/cy/year.
1.7 Load Rating - Revised to require Load Rating Summary Detail Sheet and Summary Form with the 90% submittal.
2.2 Dead Loads - Added paragraph C.
2.5 Miscellaneous Loads - Rounded loads to nearest 5 lbs. and added Retrofit Traffic Railings, Prestressed Beams, Pedestrian/Bicycle Railings & Fences to Table 2.1
2.6.1 General - Revised paragraph D. to apply when a ground mounted Test Level 5 (TL-5) barrier is required.
2.6.4 Vehicular Collision Force - A. Added "(other than pier protection)."
3.5.8 Minimum Tip Elevation - Moved drilled shaft requirements to SDG 3.6.4
3.5.12 Pile Driving Resistance - Added paragraph E.
3.6.4 Minimum Tip Elevation - Deleted reference to SDG 3.5.8 and added specific criteria for drilled shafts.
3.6.10 Minimum Reinforcement Spacing - changed 6” spacing to clear distance between reinforcing and required State Geotechnical Engineer approval for multi-cage shafts.
3.11 Pier, Column, and Footing Design - Added designations for Normal High Water and Normal Low Water.
4.2.8 Crack Control in Continuous Decks and Superstructures - Deleted "and Superstructures" from title; revised section to expand deck casting requirements and include continuous decks on simple spans including new paragraphs C.; D.; & E.
5.1.Superstructure Steel - B. General - added reference to NSBA Guidelines for Design Details.
5.5 Minimum Steel Dimensions - A. Added "4.)The minimum stiffener thickness is 1/2-inch."
5.8 Transverse Intermediate Stiffeners - Added to A. "If bolted tab plates are used, specify that the bolts are to be installed prior to making welds."
5.11.3 Welded Splices - Added paragraphs D. through G. (notes previously shown in the preferred details.)
5.12.2 Inorganic Topcoat System - A. & B. deleted until further specifications development is completed.
5.12.3 High Performance Topcoat System - A. revised to be applicable to all locations, B. added paragraph.
6.5.1 Design - A. Added live load check for combined compression and rotation and revised standard shear modulus values; B. - Added “Method A” design criteria; C. - Added Index No. 20500 reference; D. - Added paragraph and commentary.
6.5.2. Maintainability Added sentence requiring steel box girders be designed so that jacks are placed directly under diaphragms.
8.1 General - Updated LRFD MHB Design Spec to Second Edition. Deleted "use soft conversions to convert..."
8.1.1 Applicability - Prohibited single leaf bascules except with approval. B. Prohibited hydraulic systems unless approved; D. - added "or reduced counterweight"; Added H. (closed decks).
8.1.2 Redundancy - Commentary: 1) - added "for bridge rehabilitations."
8.1.3 Trunnion Support Systems Changed title. Added C. "Provide concrete trunnion columns: do not use steel trunnion towers."
8.1.7 Definitions and Terms - Added J. Leaf Tail and K. Leaf Tip; Renumbered M. thru O.
8.4 Speed Control for Leaf-driving Motors 8.4.1 Requirements for Mechanical Drive Systems - Revised B. to require that drive meet 20 psf wind load in full open position; 8.4.2 Requirements for Hydraulic Drive Systems - Added A. Use hydraulic drive systems only if approved by the SDO.
8.5.1 Trunnions and Trunnion Bearings - Deleted A.2.) For keys and keyways..." Renumbered sections; Added in A.5.) "...in trunnion alignment and are a three-piece assembly. If not, provide repair recommendations."; Deleted "A.7. If Hopkins frames are used..."; Deleted C.2, renumbered sections; C.6. Changed to "Machine surfaces per LRFD-MHBD 6.7.8."
8.5.2 Racks and Girders - Revised to requirements for parallelism, perpendicularity and dimension tolerances for rack.
8.5.3 Span Balance - Deleted A.3.) "Design hydraulic drive systems..." and added last sentence of B. Rehabilitation Projects.
8.5.4 Speed Reducers - Changed reference from ANSI/AGMA 6010 to 6013
8.5.6 Span Locks - A. General - 1.) Prohibited tail locks and side locks on new designs.
8.5.10 Bearings - Changed C. Bearing Supports. 4.) to "Machine the mounting surface per LRFD-MHBD 6.7.8.
8.5.12 Fasteners - Revised paragraph B. to "Specify fasteners as per the requirements of AASHTO LRFD-MHBD."; Deleted paragraphs D thru H. Changed reference to Unified Coarse Thread Series. Deleted R. Made in USA requirement.
8.6.2 Cylinders - Changed B. Chrome finish spec. from AMS QQ-C-320C to SAE AMS 2406L, Class 2a.
8.7.12 Conductors Added new section, renumbered balance of chapter
8.7.14 Electrical Connections across the Navigable Channel Revised A. Power Cable requirements. Revised D. to allow Schedule 120 PVC if exposed, or Schedule 80 PVC if encased in concrete.
8.7.15 Conduits - Added new section, renumbered balance of chapter.
8.7.17 Navigation Lights - Added "B. Specify the use of LED fixtures."
8.9.10 Service Accessibility - Added "B. Provide a permanent walkway from bascule pier to fender system to allow access to fender mounted components."
9.0 BDR Cost Estimating Updated per Estimates Office.
9.4 Design Aid for Bridge Debris Estimation - Added section as aid in estimating debris removal costs.
10.1 General - Changed as follows: C. Minor timber or aluminum structures associated with boardwalks...; D. Aluminum or Fiber reinforced polymer (FRP) (i.e. plastic, carbon fiber, or fiberglass) pedestrian bridges are not allowed.
10.13 Railings/Enclosures - C.2 Changed "Bicycle railing" to "Special Height Bicycle railing."
Volume 2 - Detailing Manual
4.1 Sheet Numbers - Changed sheet prefix numbers for existing bridges from "B1E" etc to "BX1" etc. 4.1.C. required separate pdf for each existing bridge.
Volume 3 - Examples, Details & Instructions
Instructions for Design Standards - Index 20500, Added "Type C" pads, shear modulus and skew ranges to table; Updated Examples; Revised Maximum Service Loads for Type A & B pads.
Preferred Details - Revised to eliminate duplication of the "NSBA Guidelines for Design Details."
Detailing Manual Examples - EX-1. Added "Bridge Name" note; EX-2. Changed "Redundant" to "Non-Fracture Critical" and "Non-redundant" to "Fracture Critical" in CHARPY V-NOTCH note; Deleted "Inorganic Topcoat System" from PAINTING note. EX-8. Added "Top of Rock Socket Elevation" column to Drilled Shaft Table.
Volume 7 - Design Aids
Added link and pdf for Standard Prestressed Beam Section Properties;
Updated BDRbridgecostestimate.xls spreadsheet.
Volume 8 - FDOT Modifications to LRFR
2.2.17 Rating Records - Moved the requirement for including the LRFR Summary form with the 90% submittal to SDG 1.7.
Table 6-1 - Deleted SL (4 ) from Post-tensioned Concrete (Longitudinal) Design Load (Inventory) Load Factor; Changed footnote (1) to refer to FDOT Table 6-9B.
Table 6-9B Stress Limits for All Prestressed Concrete Bridges - Added separate criteria for Longitudinal Tensile Stress - Nonsegmental Bridges. Changed Longitudinal Tensile Stress (Design Operating) for Segmental Bridges to 3 sq root f'c (agg. env) and 6 sq root f'c (mod. agg. env). Changed the Principal Tensile Stress for segmental bridges from 3.0 (Design Inv.) & 4.0 (Design Op.) to 3.5 sq root f'c.
Volume 9 - FDOT Modifications to LTS-4
5.15 Welded Connections - Deleted "circumferential welds are also permitted"(at the flange plate). Revised to read as follows: "...the exceptions of the base plate socket weld, the flange plate connections on tubular truss members, and the mitered arm-to-upright angle weld on monotubes."