Building codes Standards

When there are significant differences in the height, loads, and structural design of adjacent parts of a building, and the foundation is weak, uneven settlement may occur, causing cracks in some vulnerable areas. To this end, settlement joints should be provided at appropriate locations such as at complex planar or volumetric transitions, areas with changes in elevation, and where the loads, compressibility of the foundation, and foundation treatment methods differ significantly. The difference between a settlement joint and a expansion joint is that in addition to the roof, floor slabs, and walls being separated, the foundation as well must be separated, so that the adjacent sections can settle freely without interfering with each other. The width of the settlement joint should be determined based on the number of floors of the building; it should not be less than 120 mm for buildings with five floors or more. Settlement joints should extend not only through the superstructure but also through the foundation itself. Settlement joints should take into account the effects of uneven settlement and tilting of the structures on both sides of the joint, as well as differences in ground level. Seismic joints and expansion joints need not be provided below the ground level; the connections at these points should be reinforced. However, the foundations of the walls on both sides of the settlement joint must be separated. A expansion joint is also known as a temperature joint. The approach involves leaving gaps at regular intervals along the length of the building; all components of the building above the ground level, such as the roof, walls, and floors, are separated from each other. Since the foundation is less affected by temperature changes, it does not need to be separated. The width of expansion joints is generally 20–30 mm, and insulation material should be filled within the joints; the spacing between such joints is specified in the structural codes. Expansion joints are continuously installed in the areas of buildings and structures where stress is relatively high; they divide such buildings and structures into two or several separate units, and are vertical or horizontal joints that allow for free expansion and contraction between these units. The expansion joints of buildings allow the structures below ground level to remain continuous. The width of the expansion joint should meet the requirements for the maximum possible structural expansion and contraction, as well as other requirements. The maximum spacing for expansion joints is specified in Article 9.1.1 of the \"Code for Design of Concrete Structures\" (GB 50010-2002), Article 6.3.1 of the \"Code for Design of Masonry Structures\" (GB 50003-2001), Article 8.1.5 of the \"Code for Design of Steel Structures\" (GB 50017-2003), Article 4.3.1 of the \"Technical Specifications for Light Steel Structures of Portal Frame Buildings\" (CECS 102:2002), and other relevant standards.