Natural structures are those that are not built by people. Their occurrence takes place naturally. On the other hand ‘manufactured structures’ are usually built by people. Many of the manufactured structures are modelled in accordance to some natural structures.
Structures when are classified on the basis of their design, categories like ‘mass structures’, ‘layered’, ‘frame structures’, ‘shell structures’ etc. are found. Mass structures are built by piling up similar materials to reach a specific design or shape. Coral reefs and mountains are some of the examples of natural mass structures. On the other side dams, brick walls and sand castles are mass structures that are built by people. A major advantage of mass structures is that their strengths are little affected if some small parts are lost. Mass structures are often found to be having a ‘layered’ look. For instance, pyramids of Egypt are having a layered structure. There are four major factors that are important in order to avoid failure. First of all the structure has to be heavy enough so that it stays in place. Secondly structure must not be so heavy that it affects the earth unevenly. Thirdly the structure has to be thick enough so that one cannot make out of place and finally it must be anchored tightly.
Another important type of structure is ‘frame structure’. In case of this structure there is a skeleton which is built of strong materials. This skeleton is then filled with other materials that support the overall structure. Some of the examples are partition walls, load-bearing walls. Shell structures, on the other hand are the structures in which the shape of the structure is kept without any frame or even solid materials inside the structure. The strength and rigidity of this type of structure is dependent on a thin outer layer of materials. Thanks to its