Suspension This structure is mostly associated with bridges. Developed in 19th century. Weight of the structure is suspended from steel cables that are attached to vertical pylons driven into the ground.
Reinforced Concrete Concrete: mixture of cement gravel and water, dating back to Roman Times. Concrete: Brittle and low tensile strength. Often seen in sidewalks and patios.
This problem was fixed in the 19th century when a method was developed for reinforcing the concrete by putting metal rods in the concrete.