A Closer Look at Prevailing Civil Engineering Practice - European ...

A Closer Look at Prevailing Civil Engineering Practice, What, Why and How
Vincent T. H. CHU
evaluating a flexible pavement structure because the magnitude and shape
of pavement deflection is a function of traffic, pavement structure,
temperature and moisture affecting the pavement structure. Deflection
measurements can be used in back calculation method to determine the
stiffness of pavement structural layers.
The Benkelman Beam measures the static deflections and it is operated on
the basis of lever arm principle. Measurement is made by placing the tip of
the beam between the dual tires and measuring the pavement surface
rebound as the truck is moved away. The test is of low cost but it is time
consuming and labour intensive in carrying out the test.
In Falling Weight Deflectometer Test, the falling weight deflectometer is
mounted in a vehicle. The sensors are lowered to the pavement surface
and the weight is dropped. The test measures the impact load response of
flexible pavement. It has the potential advantages that it is quick to perform
and the impact load can be readily changed. Moreover, the impact action of
falling weight appears to be more accurately representing the transient
loading of traffic.
6. What is the importance of friction course to expressways and high
speed roads
Friction course, which is known as porous asphalt, is often used as surface
material in high speed roads and expressway. It is porous in nature which
allows for speedy drainage of surface water. Road safety can be improved
because it reduces the chance of hydroplaning/aquaplaning (i.e. there is a
layer of water between the tires of the vehicle and the road surface. It may
lead to the loss of traction and thus prevent the vehicle from responding to
control inputs such as steering, braking or accelerating). It also decreases
the splash and spray from vehicles in wet weather. It serves as a drainage
channel for water to flow beneath the pavement surface.
Friction course has larger texture depth and this enhance improved skid
resistance for vehicles traveling at high speed. It also has other benefits
like the reduction of noise generated by vehicle tyres.
7. For a concrete pavement constructed over a box culvert, why is it
important to match the location of transverse joints with boundary of
box culvert
When a concrete pavement is constructed over a box culvert, it is important
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