The strength of a structure is the ability to resist stress and strength put on the structure. Bending, compression, tension, vibration and turbulence are some of the stresses that structures must withstand. Factors that affect the strength of a structure include the types of materials used, its length, the cross sectional area or shape, how the structure is placed, weathering environment such as high or low temperature, humidity and others.
Wood, brick, stone, iron, steel and aluminium are examples of some of the materials available for building structures, We can combine materials in order to use their best properties for examples fiberglass or glass reinforced plastic. So does reinforced concrete which enables concrete beams to withstand tension.
The use of concrete in construction dates back to Roman era, but the modern practice of using reinforced concrete in construction is new to this century. Using steel embedded within a concrete beam, column or slab utilizes the strength of the steel in conjunction with the compressed strength of the concrete to make a stronger and safer structure called reinforced concrete. An example is in the move towards more and more reinforced concrete in the construction of long span bridges.
|Long Span Bridge|
Wood is quite strong in compression. This is one of the reasons why people build houses from wood. Wood is not easy to break because it is strong when pulled in the direction of its fibres. It is three times easier to break a block of wood if it is stretched from top to bottom, across the direction of its fibres.
Just as important as the type of materials used in building a structure, the way in which the structure is placed is also important. Architects and engineers need to be aware of the loads and stresses on structures. Arches for instance, have been used in stable constructions, such as the main support structure most often found in bridges.