Question

(b) Describe the corrosion problem encountered in Figure Q3(b) and discuss its impact on the economy. [20 marks] Figure Q3(b) Corrosion on a Bridge Foot

Answer 1

Solution:

           Corrosion on a bridge foot mainly due to the atmospheric conditions, dust and water. When the steel is reacted with the moisture or water or any dust particles it undergoes chemical reactions. In steels the iron content is more therefore, this iron will reacts with the atmospheric gases or water molecules then the Iron oxides are formed. These oxides are known as rust. Due to the gradual increase in the rust throughout the foot of the bridge, it leads to failure. During corrosion of bridge foot, some pits may formed due to the chemical reaction in a particluar place. These pits lead to form as a crack on the bridge. The effects of corrosion on bridge foot are the reduction of the strength of structural elements, increase in fatigue, decrease in the bond strength between the particles and diminished in ductility. The corrosion preventive measures are by applying epoxy coatings, alternating the steel composition to increase the corrosion resistance, frequent inspection methods, by repairing cracks and pits as soon as they appear and by using permeable concrete for the construction.

Generally, to construct a bridge it takes a huge investment for all the construction elements, equipment and engineers etc. After the construction, more expensive inspection techniques are required. If the bridge is failing due to corrosion then it become a huge loss for all the investment. By this away the corrosion on bridge foot impact on the economy.