CHAPTER 7 VEHICLES... 2

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1 Table of Contents CHAPTER 7 VEHICLES... 2 SECTION 7.1 LEGAL LOADS... 2 SECTION 7.2 STANDARD AASHTO VEHICLES... 3 SECTION 7.3 SPECIAL ROUTE VEHICLES... 7 SECTION 7.4 SCHOOL BUSES Table of Figures Figure 3:7-1: AASHTO H-20 and HS-20 Loads... 4 Figure 3:7-2: AASHTO HS-25 and Alternate Military Loads... 5 Figure 3:7-3: AASHTO Fatigue and HL-93 Loads... 6 Figure 3:7-4: Toll Road Truck Loads... 8 Figure 3:7-5: Michigan Train Truck Loads... 9 Figure 3:7-6: Indiana Extra-Heavy-Duty Highway System Figure 3:7-7: 11-, 13-, and 14-Axel Superload Vehicles Figure 3:7-8: 19-Axel Superload Vehicles Figure 3:7-9: School Buses June 2010 Page 3-7-1

2 Legal Loads CHAPTER 7 VEHICLES With the Federal Highway Administration s (FHWA s) adoption of the American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design Specifications, the FHWA has issued a clarification of policy regarding the appropriate methodology and loads to be used in reporting operating and inventory rating data. It is necessary to accommodate and support Load and Resistance Factor Rating (LRFR), while continuing to accept Allowable Stress (AS) and Load Factor (LF) for the large inventory of in-service bridges that have been designed by a method other than Load and Resistance Factor Design (LRFD). It is not the intent of FHWA to mandate re-rating existing, valid bridge load ratings by LRFR. Load ratings are to be reported to the National Bridge Inventory (NBI) annually. For bridges designed using LRFD using HL-93 loading, load ratings are to be computed and reported in tons and must indicate the rating method used. Ratings shall be based on LRFR methods using HL-93 vehicular live load consisting of the design truck or design tandem and the design lane load. For bridges designed using Allowable Stress Design (ASD) or Load Factor Design (LFD), load ratings are to be computed and reported in tons and must indicate the rating method used. Rating factors shall be based on LRFR methods using HL-93 loading or LFR methods based on the HS-20 vehicle. Bridges designed using LFD, and being rehabilitated, should be load-rated for the AASHTO LFD design vehicles. Load ratings and respective locations should be entered into the Central Database for the following vehicles: H-20 Inventory (Truck and Lane); HS-20 Inventory & Operating (Truck and Lane); HS-25 Operating; Fatigue Truck Operating; and HL-93 Operating. SECTION 7.1 LEGAL LOADS Load limits restrict how much weight can be carried on an axle, a single tire, a pair of tires, and on the vehicle or vehicle combination in total. Load limits are necessary for protecting bridges from structural weakening or fatigue, preventing unsafe conditions, and the early replacement of bridges. Vehicles meeting Indiana Code Article 20, Size and Weight Restrictions, are considered legal loads and should be able to use any highway or bridge within the state (see Appendix A). Some routes, and many bridges, must be posted to protect them from possible damage. A posted bridge may restrict a legal load from use. At this time, a bridge with a load capacity of H-20 is considered to best represent the state's load limit for the evaluation of the need for load posting. June 2010 Page 3-7-2

3 Standard AASHTO Vehicles SECTION 7.2 STANDARD AASHTO VEHICLES The following standard AASHTO vehicles are used in load rating structures: H20-44 Truck/Lane HS20-44 Truck/Lane HS25 Truck/Lane Fatigue Truck HL-93 Design Truck HL-93 Design Tandem HL-93 Design Truck Pair June 2010 Page 3-7-3

4 Standard AASHTO Vehicles Figure 3:7-1: AASHTO H-20 and HS-20 Loads June 2010 Page 3-7-4

5 Standard AASHTO Vehicles Figure 3:7-2: AASHTO HS-25 and Alternate Military Loads June 2010 Page 3-7-5

6 Standard AASHTO Vehicles Figure 3:7-3: AASHTO Fatigue and HL-93 Loads June 2010 Page 3-7-6

7 Special Route Vehicles SECTION 7.3 SPECIAL ROUTE VEHICLES Special Route Vehicles are identified in the Indiana Code and can change annually depending on state legislature. The Alternate Military Loading should be applied for any route falling on the National Highway System (NHS) ( with a design date prior to December 31, In addition to the legal loads, the Indiana Toll Road live load (Heavy Duty Highway) should apply to each state highway bridge located within 15 miles of an Indiana Toll Road entrance or exit. A single truck with the design lane load should be used in each design lane. Factors for multiple presence and dynamic load allowance should be the same as those used for regular design trucks. In addition to the legal loads, the Michigan Truck Train live load (Extra-Heavy-Duty Highway) should apply to each bridge located on the Indiana Extra Heavy Duty Highway system. A single truck with design lane load should be limited to one design lane located to cause extreme force effects, while the other design lanes are occupied by regular design loads. Factors for multiple presence and dynamic load allowance should be the same as those used for regular design trucks. June 2010 Page 3-7-7

8 Special Route Vehicles Figure 3:7-4: Toll Road Truck Loads June 2010 Page 3-7-8

9 Special Route Vehicles Figure 3:7-5: Michigan Train Truck Loads June 2010 Page 3-7-9

10 Special Route Vehicles Figure 3:7-6: Indiana Extra-Heavy-Duty Highway System June 2010 Page

11 Special Route Vehicles Figure 3:7-7: 11-, 13-, and 14-Axel Superload Vehicles June 2010 Page

12 Special Route Vehicles Figure 3:7-8: 19-Axel Superload Vehicles June 2010 Page

13 School Buses SECTION 7.4 SCHOOL BUSES It is recommended that a notice be sent by the county to the school districts advising them of the location of all bridges with a 12-ton or less weight limit. This notice should be sent annually, or whenever a bridge s posting status changes. Figure 3:7-9: School Buses June 2010 Page