Limit State Box Culvert Design IRC:6-1966



Standard IRC:6-1966

1.0 Design Data
1.1 Dimension Detail
 No of cells
 Clear Span
 Clear Height (at outer edge)
 Clear Height (at median location)
 Width of road at top 
 Width of Box
 Ht of fill (W.C / P.C.C / pavement layers) over the top slab
 Thickness of top slab
 Thickness of bottom slab
 Thickness of external vertical wall
 Size of haunch
 Width of Crash barrier
 Distance of edge of crash barrier from edge of box
 Height of surcharge
 Safe Bearing Capacity of the soil
 Permissible Settlement
1.2 Material Properties
 Density of concrete
 Density of soil
 Density of wearing coat 
 Density of Profile corrective course
 Coefficient of active earth pressure
 Angle of internal friction (in degree)
1.3 Design Parameters
 Grade of Concrete
 Clear Cover for earth face structural component
 Clear Cover for inside face structural component
 Clear Cover for bottom slab
 Permissible direct comp. strength of Concrete (scc)
 Permissible flexural comp. strength of Concrete (scb)
 Permissible tensile strength of Concrete ( sct )
 Permissible tensile strength of  Steel ( sst )
 Design Costants:
 Base Projection
2.0 Load Calculations for the Box Structure    
2.1 Dead Load    
 Self weight of the structure has been calculated directly in STAAD file by the comment 'SELFWEIGHT -1'.    
2.2 Super Imposed Dead Load    
2.2.1 Top Slab    
 Wearing coat thickness    
 Ht of fill (Thickness of W.C / P.C.C / pavement layers)    
 Load (UDL) on top slab =    0.065*22
 Wt of Crash barrier per meter    
     Total UDL load due to S.I Dead Load
 Height of soil on projected portion of base slab    
 Wt of soil on the projected portion of base slab    
2.3 Earth Pressure    
 Thickness of top slab    
 Height of top haunch    
 Clear height between top & bottom slab    
 Height of bottom haunch    
 Thickness of bottom slab    

2.4 Live Load Surcharge    
 Equivalent height     
 Uniform Intensity of loading =   0.5 * 1.2 * 20 
2.5 Braking Load    
 Carriageway Live Load    
 Width of the box    
 Braking Load =  0.2 * 400 / 12  
2.6 Additional pressure on edge 1m strip due to eccentricity of Live Load    
 Live Load    
 Width of culvert (parallel to traffic direction)    
 Width of culvert (perpendicular to traffic direction)    
 Distance of CG of load from outer edge of box culvert    
 Transverse Moment    
 Section Modulus of box in transverse direction    
 Upward UDL on edge 1m strip    
2.2.2 Bottom Slab    
 Thickness of earth fill    
 Load (UDL) on bottom slab =   0.3 * 20 

Calculation Reference
Limit State Design
Box Culvert Design

Limit State Box Culvert Design IRC:6-1966 is a code of practice developed by the Indian Roads Congress (IRC) for the design of box culverts. Box culverts are precast concrete or masonry structures used for the passage of water under roads, railways, and other transportation infrastructures.

The design of box culverts using IRC:6-1966 involves considering the various limit states or failure modes that may occur during the service life of the culvert. These limit states include the ultimate limit state (ULS) and the serviceability limit state (SLS).

The ultimate limit state refers to the maximum load or stress that the culvert can withstand without failure. The design of the culvert involves ensuring that it can withstand the maximum loads that may occur during its service life, such as traffic loads, soil and water pressures, and seismic forces.

The serviceability limit state refers to the acceptable level of deformation or deflection that the culvert can undergo without affecting its function or safety. The design of the culvert involves ensuring that the deflections and deformations do not exceed the acceptable limits, which can affect the hydraulic capacity and structural stability of the culvert.

The IRC:6-1966 provides guidelines and procedures for the design of box culverts, including the determination of the design loads, selection of the appropriate culvert size and shape, calculation of the reinforcement and concrete thickness, and evaluation of the hydraulic and structural performance of the culvert using appropriate analysis methods and criteria.

The design of box culverts using IRC:6-1966 requires expertise in structural engineering, hydraulic engineering, and transportation engineering. The code of practice provides a comprehensive and standardized approach to the design of box culverts, ensuring that they are safe, efficient, and durable for their intended use.

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21 Dec 2017
Last Modified
27 Apr 2023
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Maiwand Khan

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Comments: 2
cvk 1 year ago
JohnDoyle[Admin] 6 years ago
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