Bridges and Crossings
Modern construction materials include adaptation to new circumstances of all the traditional materials, particularly steel and concrete, plus:
• metal alloys of ever greater strength or specially suited for particular or variable loading conditions;
• built-in properties or sensors that cause structural members to take their own protective measures in response to changes in loads or ambient conditions;
• protective or decorative coatings; and • plastics (such as fibre-reinforced polymers
(FRP)) which may have structural and visual similarities with natural materials but their scientifically controlled production can provide properties not found in nature.