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

IRC:6-1966

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.