What is the use of Benkelman beam?
Benkelman Beam is a simple lever-arm device that measures the deflection of flexible pavements under the action of moving wheel loads. The probe beam, supported by a rigid reference beam, measures deflections using its 2.44m (8ft) probe end and a dial indicator at the end of the fulcrum.
What is Benkelman beam deflection method?
With the Benkelman Beam measurement method, the vertical deflection of the road surface is measured after a defined load of 5 tons has rolled away. It is a quasi-static procedure. The load vehicle moves away and the pavement surface rebound is read from the dial gauge.
Which type of pavement overlay needs to be designed by the Benkelman beam deflection method?
Conventionally in India overlay of Flexible pavement design is carried out as per IRC: 81-1997-Guidelines for Strengthening of Flexible Road Pavement using Benkelman beam deflection (BBD) technique. In the BBD technique overlay design is based on computed characteristic elastic deflection at standard load.
Which method is used for determine the deflection in highway pavement from following?
The Benkelman beam method is thus widely used for evaluation of the structural capacity of existing flexible pavements and also for estimation and design of flexible overlays for the strengthening of any weak pavement for highways.
Is code for Benkelman beam test?
Measurement of pavement surface deflection on the flexible pavement by using the Benkelman Beam Deflection.
How many types of methods are there to design a flexible pavement?
Explanation: There are three types of methods to design a flexible pavement they are empirical, semi empirical and theoretical method.
What is the operating speed of Benkelman beam deflection equipment?
Explanation: the operating speed of Benkelman beam deflection equipment is very slow and it can be considered to be crawling speed. The automatic road analyser is the equipment that moves with operating speed between 30 and 100 km/hr. Instrumented car is the equipment that operates at a speed of 32 km/hr.
What are the corrections to be applied to the surface deflections measured using Benkelman beam?
Explanation: The correction for temperature is to be applied, as in the question the test temperature is 40°C, but the standard is 35°C. So, the correction to be applied is negative and it is taken as 0.01 per degree.
What is overlay in pavement design?
An overlay is any operation that consists of laying either Portland Cement Concrete (PCC) or Hot Mix Asphalt (HMA) over an existing pavement structure. When constructing an overlay, the old surface is typically milled or ground off. Any minor structural deficiencies are then repaired.
What is the operation speed of Benkelman beam deflection equipment?
What is beam deflection?
What is Beam Deflection? The deflection of the beam towards in a particular direction when force is applied to it is known as Beam deflection. The beam can be bent or moved away from its original position. This distance at each point along the member is the representation of the deflection.
What is deflection test?
The primary purpose of deflection testing is to determine the structural adequacy of an existing pavement and to assess its capability of handling future traffic loadings.
What is the Benkelman deflection?
The Benkelman beam is the simplest and the oldest deflection. test device, developed in the United States in the mid-1950s. Its used to measure the structural capacity of a flexible pavement.
When was the Benkelman Beam invented?
BENKELMAN BEAM METHOD A. C. Benkelman devised the simple deflection beam in 1953 for measurement of pavement surface deflection. It is widely used all over the world evaluation of the requirements of strengthening of flexible pavements.
What is NDT Benkelman Beam deflection measurement?
Introduction NDT Benkelman Beam Deflection Measurement Calculation Correction Overlay Non Destructive Testing (NDT) NDT devises are Instruments imposing a load to the pavement surface and measuring the oncoming surface deﬂection; so-called deﬂection measuring devices.
How do you test a Benkelman Beam?
The probe of the Benkelman beam is inserted between the duals and placed on the selected point. The locking pin is removed from the beam and the legs are adjusted so that the plunger of the beam is in contact with the stem of the dial gauge. The beam pivot arms are checked for free movement. 14/25 15.