Structures Design Guidelines | Jan 2008
1 - General Requirements |

# 1- General Requirements

## 1.1 General

This Chapter clarifies, supplements, and contains deviations from the information in LRFD Sections [2], [5], and [6]. These combined requirements establish material selection criteria for durability to meet the 75-year design life requirement established by the Department.

### 1.1.1 Design Review

Category 1 structures will be reviewed by the DSDE and Category 2 structures will be reviewed by the SSDE. See the PPM Chapter 26.

### 1.1.2 Substructure and Superstructure Definitions

See the substructure and superstructure definitions in the FDOT Standard Specifications for Road and Bridge Construction, Section 1-3 Definitions, and note the following:

A. Box culverts, retaining wall systems (including MSE walls), and bulkheads are substructures.

B. Approach slabs are superstructure; however, Class II Concrete (Bridge Deck) will be used for all environmental classifications.

### 1.1.3 Clearances (07/06) July 2006 - Per TDB C04-04 regarding 36 feet min vert clearance, added link to PPM manual where vertical clearance is addressed.

A. Vertical Clearances

1.) The vertical clearance of bridges over water is the minimum distance between the underside of the superstructure and the normal high water (NHW) for navigable water crossings or the mean high water (MHW) for coastal crossings. When applicable, vertical clearance is measured at the inside face of the fender system.

2.) The vertical clearance for grade separations over roads or railroads is the minimum distance between the underside of the superstructure and road or railroad.

3.) See SDG 8.1.4
for Movable Bridge clearance requirements.

B. See SDG 8.1.5
for Movable Bridge horizontal clearance requirements.

C. See Plans Preparation Manual 2.10.

### 1.1.4 Bridge Height Classifications

FDOT classifications of bridges over water are based on the following vertical clearances:

A. Low Level - less than 20 feet.

B. Medium Level - 20 feet or greater but less than 45 feet.

C. High Level - 45 feet or greater.

### 1.1.5 Buy America Requirements (07/06) July 2006 Revised Per TDB C05-18

The Code of Federal Regulations, 23 CFR 635.410 requires that steel or iron products (including coatings) used on Federal Aid Projects1 must be manufactured in the United States. "Buy America" requirements are covered in FDOT Specification 6-12.2. and PPM Volume I, Chapter 13.

### 1.1.6 ADA on Bridges (01/07) Jan 2007- Added Section for ADA requirements.

Sidewalks on bridges and approaches must comply with the Americans with Disabilities Act (ADA) and Florida Accessibility Code. Generally the maximum longitudinal slope of bridges along any grade or vertical curve should be limited to 5% and sidewalk cross-slopes must be not exceed 2%. Portions of bridges with grades in excessive of 5% require the use of continuous handrails and landing areas. Preferred Details (Vol. 3) Sheet Nos. S-39 through S-43 provide details for expansion joint treatment and sidewalk grades steeper than 5%. See ADA Accessibility Guidelines for Buildings and Facilities, Section 4.8 (Ramps) and Section 4.26 (Handrails).