Wall

=Wall =



===A wall is a usually solid structure that defines and sometimes protects an area. Most commonly, a wall delineates a building and supports its superstructure, separates space in buildings into rooms, or protects or delineates a space in the open air. ===

=== The load-bearing wall of masonry is thickened in proportion to the forces it has to resist: its own load, the load of floors, roofs, persons, etc., and the lateral forces of arches, vaults, wind, etc., that may cause it to crack or buckle. === === Its thickness can often be reduced at the top, because loads accumulate towards the base; in high buildings this is done by interior and exterior setbacks at the floor level of upper stories. Walls that must resist lateral forces are thickened either along the whole length or at particular points where the force is concentrated. The latter method is called buttressing. ===



=== Excluding the independent garden variety, the non-bearing wall appears only where loads are carried by other members, as in heavy timberand other skeletal structures. Modern steel and reinforced-concrete frames === === require exterior walls only for shelter and sometimes dispense with them on the ground floor to permit easier access. Since the wall rests or hangs upon members of the frame, it becomes a curtain screen; and admits treatment in any durable, weather-resisting material. Traditional materials are often used, but light walls of === === glass, plastic, metal alloys, wood products, etc., can be equally efficient. This freedom of choice extends also the form of walls and offers greatly expanded opportunities for creative expression. ===



//__Great Wall of China __//
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