advantages and disadvantages of. hydrolic bridge which is in london and some more information for speech.
Answers
Advantages
If accurately calibrated, there is no need for computers to control the hydraulic actuators. The hydraulic rams can be in motion only by the loading applied to it. That is to say, if a certain load is applied on the bridge, the hydraulic ram applies an appropriate force upwards to counteract any deflections. This implies that there is very little maintenance concerning automated systems and in situations such as blackouts or malfunctions, the bridge will not be in any immediate concern for failure.
As a result of applying a force upwards that is dependent on the load and displacement of the bridge, the quantity of material required to construct the bridge is reduced. The material alone does not have to handle all imposed loading; the load is distributed onto the hydraulic rams. Consequently, less money can be used in purchasing materials and the project cost is reduced (arguably, the money may be spent on the hydraulic systems).
Certainly, elegant bridges may be constructed with thinner structural members, which can increase its aesthetic and social impact on the community around it. What is more is that if the load becomes to great and causes the mid-span piston to go down, then the support pistons will push inwards resulting in the arch heading upwards; hence they maintain equilibrium.
Reversal of Hydraulic Fluid.jpg[Fig.3: How Reversal of Hydraulic Fluid Still Results in Equilibrium]
Disadvantages
As a consequence of the vertical hydraulic column being required to be located in the centre of the arch, there are intrinsic complications. For example, to install the hydraulic pipe connections would require tunnelling either underground or to lay the pipes over ground; this entails placing construction workers in hostile environments and they have to be specialised workers. This requires extensive training which can affect the building project economically.
Vertical column type hydraulic bridges may never be used in arch bridges required to span gaps which are very high in the context of the altitude of the locale. Without solid ground for the column to rest on, the action of the hydraulic will cause deflection and eventual failure. However, there are methods to overcome this problem.
Possible hydraulic failure at the three main points can be caused by very high forces and pressures due to excessive loading on the main bridge. The high pressure of hydraulic fluid can cause failure at any O-ring and gasket seals rendering it useless.