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# Florida Department of Transportation

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

July 31, 2007

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, Larry Sessions, Lex Collins, 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: | July 2007 Structures Manual (625-020-018).

The Florida Department of Transportation Structures Design Office has officially released the July 2007 Structures Manual. Copies of the Structures Manual can be downloaded from the Structures Office website at www.dot.state.fl.us/structures.

The Structures Manual is a virtual document; a web based collection of html files 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 included for printing purposes. Standard Drawings and Drawing Examples are available in both MicroStation format (dgn files) and PDF format.

The Structures Manual is updated twice a year (January and July) and serves as the single source for FDOT design criteria for structural designs prepared by the Department and consultant designers. All users of the Manual are encouraged to submit suggestions to improve and further develop the contents thereby providing maximum assistance to the structural engineering community. Submit any suggestions to Andre Pavlov, Florida Department of Transportation, 605Suwannee Street, MS 33, Tallahassee, Florida32399-0450, or e-mailed to andre.pavlov@dot.state.fl.us.

The design criteria 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). Where incorporation is not feasible, a variance must be requested. For specific questions about the Manual, or its application to a particular project, contact the appropriate District Structures Design Office.

Volume 1 - Structures Design Guidelines – Revisions
I.6 Introduction- Added requirement for use in Paragraph A. and renumbered the following sections. Per TDB C07-06, revised B.6.- LRFD reference to 4th edition, deleted B.9 - reference to Curved Steel Girder Guide Specification and Commentary. Revised D.1- reference to AISC Steel Construction Manual.
1.2 Deflection and Span-to-Depth Ratios – Revised to a llow criteria for deflection in lieu of Span-to-Depth Ratios.
1.3 Environmental Classifications - Revised section to differentiate classification process for marine and non-marine environments which eliminates testing for most marine environments. Deleted 6,000 ppm -12,000 ppm chloride range for superstructures, and sulfate criteria for steel substructures. Revised pH criteria for slightly aggressive environments, sulfate criteria for concrete substructures in soil, resistivity thresholds for steel substructures, and flow chart. Added new Table 1.1.
1.4. Concrete and Environment, 1.4.1 General- Requires Designer to assume use of Florida limerock coarse aggregate with 0.9 correction factor. 1.4.2 Concrete Cover- Revised Table 1.2 Concrete Cover. Added line for Spun Cast Cylinder Piling and 2-inch cover. Added note 5.
1.6 Adhesive Anchors - 1.6.2 Notation - Added commentary suggesting check per ACI 318 Appendix D. when using HSHV Adhesive Anchors with less than 12d spacing.
1.7 Load Rating – Per TDB C07-01. Requires LRFR analysis when load rating.
2.1.2 Live Loads – Added paragraph B and commentary. Req's satisfying SDG 1.7.
2.13 Pedestrian Bridges - Deleted section since loads are clearly shown in LRFD 3.6.1.6.
2.4.3 Wind Loads During Construction – Removed requirements and added reference to SDG 6.8 Erection Scheme and Beam/Girder Stability.
3.5.3 Steel Piles and Wall Anchor Bars- Revised coating requirements. 3.5.3.B. (Table) - Revised Sacrificial thickness. (Commentary) – Added corrosion rates for completely buried piles and 75-year Design Life. 3.5.3.C. Added requirement to include sacrificial thickness in Section Properties on plans and expanded commentary.
3.5.17- Concrete Piling Spliced with Steel Devices. Added new section.
3.6 Drilled Shafts – Minimum Reinforcement Spacing – Added LRFD references.
3.10 Crack Control – Per TDB C07-04, revised A. to add construction loading and Service III loading. Added commentary.
3.11 Pier, Column and Footing Design - Revised paragraph "D" to allow PT bars below 12' above MHW, deleted limitations for PT in structures over land and deleted commentary. E- added "mild reinforcing." F- Revised to differentiate for external and internal PT, H- Added commentary. I- Deleted "precast”.
3.13 Retaining Wall Design – 3.13.2- Renumbered sections B. through L. Revised I- Apparent Coefficient of Friction, changed E. and H. from "H1 = mechanical wall height" to "H = height of wall". Added H.5- reference to External Stability Analysis software.
Figures 3-16 and 3-17 - Removed the Factor of Safety Equations which are not appropriate for LRFD design and other redundant load information that is already covered in LRFD. Changed “H1 = Mechanical Height” to “H = height of wall".
4.1.5 - Minimum Reinforcing Requirements. Added new section per TDB C07-03. Clarifies the minimum reinforcement checks in LRFD 5.7.3.3.2 near the ends of simple span bridge girders.
4.2.8 Crack Control in Continuous Superstructure. A.- Changed 80’ construction joint spacing to points of contraflexure and added continuous flat slab bridges ; C.- Added commentary.
4.3 Pretensioned Beams - 4.3.1 General - Revised D.5 to “pretensioned” members for the use of transformed section properties and clarified when to use the “Approximate Estimate of Time-Dependent Losses. “
4.5 Post-Tensioning, General - 4.5.1.C - Added 15-0.6" strand anchorage size to 4.5.1.C.
4.5.5 Ducts, Tendons and Anchorages – A- Changed requirement for referencing tendon duct radius and dimensions to duct PI points. Change the requirement for offset dimensions to “parabolically curved ducts" only. E - Edited for commentary. I. – Deleted the requirement for shear connectors on steel ducts in diaphragms.
4.5.6 Minimum Dimensions Table 4.5 - Revised Min. Thickness of Segment Pier Diaphragms containing external post-tensioning from 6 feet to 4 feet. Deleted "or 3 times outer duct diameter whichever is greater." from webs of C.I.P. boxes with internal tendons.
4.5.7 Corrosion Protection - Added E - regarding post-tensioning bars used in erection.
4.5.11 Principal Tensile Stresses – Deleted Paragraphs A, B and C, (See LRFD 5.8.5) and added commentary.
4.6.4 Design Requirements for Cantilever Bridges with Fixed Pier Tables - Clarified A for precast superstructures. Revised commentary to exclude C.I.P. construction with travelers.
4.6.7 Construction Data Elevation and Camber Curve for Box Girders- Added to C. "For segmental box girders, the Specialty Engineer shall provide the camber curves, and the EOR shall check them. For other bridge types, the EOR shall provide and check the camber curves."
4.6.9 Span-by-Span Segmental Diaphragm Details – A - Revised to “Design external tendons so that the highest point of alignment is below the bottom mat of the top slab reinforcing in the diaphragm segment.” B - Removed prohibition on arched tendons in diaphragm segments. C. – Removed prohibition on split pier segments in extremely aggressive environments.
5.1 Superstructure Steel - General. Per TDB C07-06, A.- revised to reflect adoption of LRFD 4th edition for both straight and curved bridges. Deleted B and C.
5.12 Corrosion Protection. B.- Revised the finish color to white only for the interior of box girders and added reference the "Painting" note in the Detailing Manual Example SDMEx-2.
6.1 General - Erection schemes and beam/girder stability requirements added.
6.8 Erection Scheme and Beam/Girder Stability - New section added to replace previous SDG 2.4.3.
7.1.1 Load Rating – Revised per TBD C07-01. Clarifies requirements for performing load ratings and Design Variations.
7.7 Deck Grooving - Paragraph A - Added directions for existing grooved decks in good condition.
8.1 Movable Bridges- 8.1.1 Applicability - Changed D - Added counterweight design requirements. Added F – Design requirements to account for future weight changes to the bascule leaf. Revised G. to require gutters and seals.
8.5 Machinery Systems- 8.5.3 Span Balance - Added A.7 – prohibiting lead counterweight blocks. 8.5.7 Brakes - Added AISE-NEMA Rating requirement for brake torque.
9.2.1 BDR Cost Estimating – substructure. Added embedded data collector costs.
Volume 2 - Structures Detailing Manual - Revisions
3.2 Drawing Revisions – Revised to be consistent with the terminology in the PPM and the Preparation and Documentation Manual.
13.3.13 Reinforcing Bar Lists – B; Added “Identical components should be grouped together.”

Volume 3 - Examples, Details & Instructions – Revisions
SDMEx-1 – Deleted “GENERAL SPECIFICATIONS” note. Added “VERTICAL DATUM” note. Revised “CONSTRUCTION OVER TRAFFIC” note.
SDMEx-2 - Revised last paragraph of "PAINTING" note for the interior of steel box girders.
Preferred Details - Sheet S-2 – Revised last paragraph of "PAINTING" note for the interior of steel box girders.

Volume 8 - FDOT Modifications to LRFR – Revisions
Figure 6-1 Flowchart for Load Rating – Changed “Was Bridge Built Before January 2005” to “Was Bridge Designed Before January 2005?”
6.4.2 General Load Rating Equation- Reworded section to clarify the use of transformed section properties before and after losses.
6.5.7 Minimum Reinforcement – Revised per TDB C07-03. Added "Add the following: See SDG 4.1.5 for clarification of the appropriate application of minimum reinforcing at the ends of simply supported bridge girders."
6.6.1 Limit States – Per TDB C07-06 Removed section.
D.6.6 Nominal Capacity – D.6.6.3.3 Prestressed Concrete – Revised per TDB C07-03. Added "Add the following: See SDG 4.1.5 for clarification of the appropriate application of minimum reinforcing at the ends of simply supported bridge girders."
G.6 Load Rating Summary Form – Added drop down menus to Bridge Load Rating Summary Form spreadsheet.

Volume 9 – FDOT Modifications to LTS-4 - Revisions
LTS-4, 13.6 Foundation Design – Drilled Shafts; Added "For drilled shafts, ensure a minimum reinforcement spacing of six inches to allow for proper concrete consolidation.”