Live Loads for Bridge Design as per IRC Code || IRC 6: 2017

Before going to calculate bending moments due to live load, you have to know about live load for Bridge Design. We will calculate bending moments due to live load as per IRC 6 2017.

First of all, you have to know Indian standard loading classes. There are four types of class loading vehicles are present as per Indian Codes IRC 6: 2017. 

1.      1. IRC Class AA Loading Vehicle: 

• Heavy military vehicle
• Structure on NH & SH
• Checked for Class A Loading
• Applicable for special loading cases

A. Tracked Vehicles: 

- Packed load = 70t (equally distributed over two track of 0.8m width)

- Length of vehicle = 7.2m

- Out distance between track = 2.9m

B. Wheeled Vehicle:

- Max load for single axle = 201 - Max wheel load = 6.25t

- Nose to tail spacing between two vehicle < 99m

2. IRC Class A Loading Vehicle: 

• Heavy commercial vehicle
• Permanent road bridges & culverts
• Considered as Standard IL of bridge

A. Footways:

- Accessible only to pedestrians & animals-LL of 4 KNim2

- At crowded town or pilgrimage where fairs are held seasonally = LL of 5 Mini

B. Successive Trains:

- Minimum distance between successive trains = 18.4m.

3. IRC Class 70R Loading Vehicle: 

• It can be used in place of Class AA Loading
• 'R' indicates Revised Classification
• Minimum clear carriage way shall be more than 1.2m+2x2.9m=5.30m).

A. Tracked Vehicle:

- Similar to Class AA Loading - Ground contact length 4.75m

- Length of vehicle - 7.92m - Min spacing between

successive vehicle = 30m

B. Wheeled Vehicle:

- Length of vehicle = 15.22m

- Contain 7 axles with total load of loot

- Additional 40t of bogie loading.

4. IRC Class B Loading Vehicle:

• Design of temporary structures, wooden bridges
• Considered as Light Loading

Picture-1: Live Loads for Bridge Design as per IRC Code || IRC 6: 2017

More Posts: 

1. RCC Slab Bridge Analysis and Design Step-By-Step Manually || Part-1

2. Live Load Bending Moment IRC Class 70R Tracked Vehicle for Slab Bridge Design Manually || Part 2

3. Maximum Shear Force Calculation for IRC Class 70R Tracked Vehicle || Slab Bridge Design Manually || Part 3

4. Bridge Deck Slab Design Example as per IRC || Slab Bridge Design example || LSM Method-Part 4

5. Live Load IRC Class AA Wheeled Vehicle || RCC Slab Bridge Design Part-5

6. Slab-Bridge-Design-In-Midas-Civil-as Per Indian Code IRC 112