Abstract.Almost all of road damage can be caused by dynamic loads of vehicles that fluctuate
according to the type of vehicle that passes through. This study aims to calculate the vertical
dynamic load of the vehicle actually occurs on road construction by the mechanism of vehicle
wheel suspension. Pneumatic cylinders driven by pressurized air directly load the spring and
shock absorber installed on the wheels of the vehicle. The load fluctuations of the medium
weight categorized vehicles are determined by the regulation of the amount of pressurized air
that enters into the pneumatic cylinder chamber, pushing the piston and connecting rods. The
displacement that occurs during compression on the spring and shock absorber, is substituted
into the equation of vehicle dynamic load while taking into account the spring stiffness
constant, and the fluid or damper gas coefficient. The results show that the magnitude of the
displacement when the compression force works has significant influences to the amount of
vertical dynamic load of the vehicle that overlies the road construction. The presence of
dynamic load of vehicles that fluctuates and repeats, also affects on the reduction of road
ability to receive the load. Experimental results using pneumatic actuators instead of real
dynamic vehicle loads illustrate the characteristics of the relationship between work pressure
and dynamic load. If the working pressure of P2 (bar) is greater, the vertical dynamic load Ft
(N) that overloads the road structure is also greater. The associate graphs show that the shock
absorber has a greater ability to reduce dynamic load vertically that burden the road structure
when compared with the ability of screw spring.
Keywords: Pneumatic Cylinder, Dynamic load, Pressurized air, Suspension, Road