Introduction:
Embarking on a career in bridge engineering or simply interested in understanding the intricate world of bridges? This beginner’s guide will walk you through essential terminologies that form the foundation of bridge engineering. Let’s dive into the terminology pool and unravel the significance of each term for aspiring bridge engineers.
I. Fundamental Bridge Terms
- Abutment:
Definition: A sub-structure component supporting the end of a superstructure and retaining part or the entirety of the bridge approach fills. - Afflux:
Definition: The rise in the flood level of the channel, immediately upstream of a bridge, due to obstruction caused by the bridge’s construction and its approaches. - Approach:
Definition: A part of the road that connects the road to the abutment of the bridge. - Approach Slab:
Definition: A transition slab of reinforced concrete laid on immediate approaches to a bridge, with one end resting on a dirt wall/abutment. - Bearing:
Definition: A vital part of the bridge structure directly bearing all forces from the superstructure above and transmitting them to the supporting substructure. - Bridge:
Definition: A structure exceeding 6 meters in length, designed for carrying traffic or other moving loads across channels, depressions, roads, railway tracks, or any other obstruction. - Camber:
Definition: Transverse inclination given to the cross-section of the carriageway to ensure proper drainage. - Causeway:
Definition: A paved submersible structure with or without openings (vents) allowing flood/water to pass through and/or over it. - Channel:
Definition: A natural or artificial watercourse. - Clearance:
Definition: The shortest distance between the boundaries at specified positions of a bridge/underpass/overpass, ensuring safe passage. - Cofferdam:
Definition: A temporary structure built to exclude water or soil from a working area, permitting construction without the need for excessive pumping. - Crash Barrier:
Definition: A barrier provided at the side of the carriageway designed to reduce the risk of serious accidents by guiding errant vehicles back on the road. - Culvert:
Definition: A structure with a total length of up to 6 meters between outer faces of walls, measured at right angles. Cross drainage structures with pipes are termed as culverts, irrespective of length. - Dirt Wall:
Definition: A vertical wall projecting from an abutment cap to prevent the spill of earth/pavement materials and also to support the approach slab. - Effective Linear Waterway:
Definition: The total width of the waterway of a bridge at the Highest Flood Level (HFL) minus the effective width of obstruction. - Flyover:
Definition: A bridge positioned over another road, allowing uninterrupted traffic flow with approaches on both sides. - Foot Over Bridge (FOB):
Definition: A bridge over a road or other obstructions, exclusively for the use of pedestrians. - Foundation:
Definition: The section of a bridge structure in direct contact with and responsible for transmitting loads to the founding strata. - Free Board:
Definition: The difference between the highest flood level after allowing for afflux, if any, and the formation level of road embankment on the approaches or top level of guide bunds at that point. - Full Supply Level (FSL):
Definition: The water level corresponding to the full supply of a canal. - Grade Separator:
Definition: A bridge facilitating the movement of traffic by segregating ‘at-grade’ conflicting movements to different levels. - High Level Bridge:
Definition: A bridge carrying the roadway above the Highest Flood Level (HFL) of a channel (including afflux) or the high tide level, with appropriate vertical clearance. - Highest Flood Level (HFL):
Definition: The level of the highest flood recorded/observed or calculated from the design discharge, whichever is higher. - Interchange:
Definition: A system of interconnecting roads (ramps and loops) in conjunction with one or more grade separations that provide for the uninterrupted movement of traffic between two or more roads. - Invert:
Definition: The lowest point of a pipe or sewer below the springing line, defining the internal cross-section’s nadir. - Kerb:
Definition: A line of raised concrete section forming an edge between the carriageway and railing/footpath/median. - Kerb Shyness:
Definition: The imaginary distance by which the driver would generally keep his vehicle away from the kerb to avoid brushing with the kerb. - Lateral Clearance:
Definition: The minimum distance between the extreme edge of the carriageway and the face of the nearest obstruction such as abutment, pier, column, etc. - Length of a Bridge:
Definition: The overall length measured along the center line of the bridge between inner faces of dirt walls (or between end deck joints or the outer edge of the deck, where there is no dirt wall). - Low Water Level (LWL):
Definition: The level generally prevailing in the stream/river during dry weather. - Ordinary Flood Level (OFL):
Definition: The level to which the stream/river generally rises during the monsoon period every year.
II. Miscellaneous Terms - Causeway:
Definition: A paved submersible structure with or without openings (vents) allowing flood/water to pass through and/or over it. - Cofferdam:
Definition: A temporary structure built to exclude water or soil from a working area, permitting construction without the need for excessive pumping. - Crash Barrier:
Definition: A barrier provided at the side of the carriageway designed to reduce the risk of serious accidents by guiding errant vehicles back on the road. - Culvert:
Definition: A structure with a total length of up to 6 meters between outer faces of walls, measured at right angles. Cross drainage structures with pipes are termed as culverts, irrespective of length. - Dirt Wall:
Definition: A vertical wall projecting from an abutment cap to prevent the spill of earth/pavement materials and also to support the approach slab. - Full Supply Level (FSL):
Definition: The water level corresponding to the full supply of a canal. - Grade Separator:
Definition: A bridge facilitating the movement of traffic by segregating ‘at-grade’ conflicting movements to different levels. - High Level Bridge:
Definition: A bridge carrying the roadway above the Highest Flood Level (HFL) of a channel (including afflux) or the high tide level, with appropriate vertical clearance. - Highest Flood Level (HFL):
Definition: The level of the highest flood recorded/observed or calculated from the design discharge, whichever is higher. - Interchange:
Definition: A system of interconnecting roads (ramps and loops) in conjunction with one or more grade separations that provide for the uninterrupted movement of traffic between two or more roads. - Invert:
Definition: The lowest point of a pipe or sewer below the springing line, defining the internal cross-section’s nadir. - Kerb:
Definition: A line of raised concrete section forming an edge between the carriageway and railing/footpath/median. - Kerb Shyness:
Definition: The imaginary distance by which the driver would generally keep his vehicle away from the kerb to avoid brushing with the kerb. - Lateral Clearance:
Definition: The minimum distance between the extreme edge of the carriageway and the face of the nearest obstruction such as abutment, pier, column, etc. - Length of a Bridge:
Definition: The overall length measured along the center line of the bridge between inner faces of dirt walls (or between end deck joints or the outer edge of the deck, where there is no dirt wall). - Low Water Level (LWL):
Definition: The level generally prevailing in the stream/river during dry weather. - Ordinary Flood Level (OFL):
Definition: The level to which the stream/river generally rises during the monsoon period every year.
III. Traffic Management and Safety Features - Camber:
Definition: Transverse inclination given to the cross-section of the carriageway to ensure proper drainage. - Causeway:
Definition: A paved submersible structure with or without openings (vents) allowing flood/water to pass through and/or over it. - Crash Barrier:
Definition: A barrier provided at the side of the carriageway designed to reduce the risk of serious accidents by guiding errant vehicles back on the road. - Grade Separator:
Definition: A bridge facilitating the movement of traffic by segregating ‘at-grade’ conflicting movements to different levels.