· INTRODUCTION:-
As transportation ventures become more intricate to structure and manufacture, it is imperative to exploit suitable inventive advancements for lessening venture process duration. Laser checking is one such innovation that has possible advantages over standard studying procedures, for example, absolute station or flying photogrammetry for giving precise as-fabricated drawings. Laser[LIGHT AMPLIFICATION BY STIMULATED EMMISSION OF RADIATION] filtering is an earthbound laser-imaging framework that rapidly makes an exceptionally precise three-dimensional (3D) picture of an article for use in computer-aided drafting (CAD) programming bundles.
In this era of technology, the use of lasers has a very vast application in highway engineering. It is used for various purposes such as road profiling, pavement surface deflection, bridge deflection, speed checkers, deflection of concrete sheet and others. Lasers have rather broad use of highway infrastructure in this age of development.
These techniques have been implemented to overcome the human efforts by making it simple and easy to use. If compared to older methods that were cumbersome, the laser techniques have higher accuracy as it is automated and quicker in obtaining results, which is computed by a computer and needs very less human power.
These strategies have made human work simple to utilize and in the event that we contrast them and the more seasoned procedures which are very little effective and great.
· UTILIZATION OF LASERS IN HIGHWAY ENGINEERING:-
The following are the utilization of lasers in highway engineering are listed below:-
1- Road profiling
2- Pavement surface deflection
3- Bridge deflection
4- Speed checkers
1- ROAD PROFILING:-
Road profiling is defined as the profile of a path is calculated around some inexistent line or point that is permanent. In addition to rutting and other issues, the profile of a path taken along a lateral line shows the over altitude and crown of the route outline. The longitudinal profile displays the ruggedness, hardness, and grade of the material.
üTo track the status of a pavement management system road network (PMS) network.
üTo determines the existence of freshly built or reparated environments.
üTo evaluate the condition of a specific position and agree on effective therapies and,
üTo examines the status of a single test location. On the other side, an inspection method can provide unceasing projections of destinations that are just a few hundred feet wide, in order to distinguish unobtrusive forms of decline at the onset.
Fig-1 Road profiling on highways
Fig-2 Laser scanning for 3-d road profiling
1- PAVEMENT SURFACE DEFLECTION:-
The pavement surface deflection is measured by using a Rolling wheel deflectometer. let me explain briefly about a rolling wheel deflectometer.
Ø ROLLING WHEEL DEFLECTOMETER:-
The rolling wheel deflectometer as per the “Applied Research Associates” (ARA), Inc. created the rolling wheel deflectometer to measure pavement surface diversions at traffic speeds and to represent the heap conveying maximum of in-administration pavements. This device consists of a 53 ft long semitrailer that adds a regular 18,000-lb load to the pavement system by way of compact double tire crossing the single back pivot together.
Ø Working Spatially-Coincident Method:
The RWD tests wheel diversions on the pavement surface by method for a spatially accidental procedure, which investigates the surface profiles in both undeflected and avoided situations. When the RWD passes on top of the ground, lasers for triangulation installed on a 25.5-ft aluminum shaft and positioned at interim 8-ft are used to assess surface avoidance.
To identify the empty area, three spot lasers are positioned before the stacked wheel and one spot laser is specifically placed on top of the double-stacked tire to get together to gauge the diverting object. The laser sensors are placed to collect a reading at all truck speeds at a negotiated intermediate of 0.6 in.
Fig -3 Rolling wheel deflectometer.
1- BRIDGE DEFLECTION:-
Bridge twisting is instigated by shifts in land conditions, including long haul stacking including over-burdening. Estimating the disfigurement is important to know the extension's security, to guarantee its solid use. In bridge deflections, the Bridge deformation is induced by shifts in geological environments, including long-term loading including overloading.
Measuring the deformation is necessary to know the bridge’s safety, to ensure its healthy usage. To quantify deformation, with the advancement of computing technology, sensor technology, and network technologies, modern methods of deformation measurement such as extended cable, tilt-meter, GPS, optical fiber, laser signal.
These approaches may realize online real-time and automated bridge deflection calculation, which is small in cost of repair and high accuracy. The laser beam will provide long-term reliability, anti-interference, and high precision of positioning to guarantee the spot center’s precise positioning.
Fig -4 bridge deflection measured by using the deflectometer and U-Doppler
2- SPEED CHECKERS:-
The speed checkers is used for the measurement of vehicle speed is important for enforcing the rule on speed restriction and it also shows traffic situation. The vehicle’s speed is more dangerous than the specified limit which creates the chance of accidents.
The ITS (Intelligent Transportation System) is a modern solution to traffic vehicle management. Because of their benefits including saving a life, energy, and time these systems are becoming more important.
Lasers have been used to monitor the vehicle’s speed to minimize dangerous road accidents The road speed checker is useful for the traffic police, especially against speed limit violators as it offers a digital monitor as well as buzzing sound or warning to identify the vehicle speed if the vehicle reaches the speed limit required.
Fig -5 speed checker for highways
Fig -6 speed checker to detect rash drivin On highways
· MERITS OF USING LASERS IN HIGHWAY ENGINEERING:-
The following are the merits of using lasers in highway engineering are listed below:-
1- The laser-based system can be used for measuring the road profile and deflection accurately while traveling at the normal speed.
2- The laser-based system also results in the rapid measurement and quick collection of the data.
3- It is used for measuring the multiple locations from the single instrument position.
4- It does not require any setup or breaks down.
3- It is the system that can be fitted on any vehicle required by the user.
4- The laser-based system can operate at a speed of 105 km/hr.
5- It is the system that collects data in real-time as it traverses the pavement’s surface.
6- It eliminates the need for lane closure or traffic control while testing.
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BABA AFRID .S
CMTI Campus Ambassador
4th YEAR, Mother Theresa Institute Of Engineering And Technology -MTIET
PALAMNER CHITTOR DISTRICT