As a consultant, you are given a project to reinforced a tunnel that is subjected to sea-water flooding. The design requirements that you must fulfill are; the beam that will be used to reinforce the tunnel can withstand point load 150 kN in the middle without yielding and shouldn’t deflect more than 10 mm, the length of the beam is set at 5 m, and the beam’s thickness and breadth shouldn’t be more than 30 cm and 10 cm respectively. The beam must not fracture in a brittle manner; therefore, the fracture toughness should be at least 25 MPa.m1/2. For the shape of the beam, you should consider using the rectangle, hollow rectangle and I beam.

 Recommend 3 types of materials for this application and rank them according to suitability and performance (i.e material properties, cost, corrosion resistance, etc). Every decision in materials ranking and selection that you make should have justification. 

Discuss corrosion prevention method(s).