3. CONCRETE COLUMNS Concrete columns are used for carrying loads of a building. They transfer the same to a suitable soil bearing capacity. They carry loads horizontally, vertically and laterally. They can be erected as free standing, used for hanging gates. Alternatively they can be incorporated within the walls of a building structure. Concrete columns are made from steel and concrete cast in a formwork. These are done in circular, rectangular or square shapes. In erecting concrete columns the load to be carried is considered. This determines the size of column and type of reinforcement to use
4. MATERIALS AND MACHINERY 1.Batching plant. 2.Transit mixer 3.Concrete pump 4.Vibrators 5.Chute and C I Pipes .
5. ERECTION OF COLUMN 1.The size of column to be marked and checked 2.Form work consists of plywood board / Wall forms with rigid supports by Jacks/tubes. 3. Reinforcement shall be cut and placed as per the structural drawings and approved bar bending Schedules. Specified cover blocks should be provided at regular spacing and intervals. Cover blocks should be tied with reinforcement by using binding wires for preventing misplacement from its location during concreting
6. Need to have a column For the purpose of wind or earthquake engineering, columns may be designed to resist lateral forces. Other compression members are often termed "columns" because of the similar stress conditions. Columns are frequently used to support beams or arches on which the upper parts of walls or ceilings rest. In architecture "column" refers to such a structural element that also has certain proportional and decorative features. A column might also be a decorative or triumphant feature but need not be supporting any structure e.g. a statue on top .
7. CLASSIFICATION A column may be classified based on different criteria such as: 1. Based on shape Rectangle Square Circular Polygon circular column polygon column 2. Based on slenderness ratio Short column, ? ? 12 Long column, ? > 12
8. 3. Based on type of loading Axially loaded column A column subjected to axial load and unaxial bending A column subjected to axial load and biaxial bending 4. Based on pattern of lateral reinforcement Tied columns Spiral columns Spiral columns Tied columns
9. Minimum eccentricity Emin > l/500 + D/30 >20 Where, l = unsupported length of column in ‘mm’ D = lateral dimensions of column
21. STRUCTURE The building is held by 60 columns of 6.5 meters in height, with a base of only 22 cm which is expanding to reach the roof covering the whole surface. This novel structure caused a lot of mistrust between the authorities, who not only asked for a thorough study of it but in turn requires a test with a real pillar model. Each pillar should be able to support 6 tons in weight, however, due to the skepticism that has generated this structure, the commission approved only if they were capable of withstanding twice. On June 4, 1937 was the date set for the test. Column 6 tons, without problems, then 12, but Wright, offended by the distrust of the authorities ordered further adding weight to the pillar until it finally collapsed after bear 60 tons.
24. CONCLUSION A column in structural engineering is a vertical structural element that transmits, through compression, the weight of the structure above to other structural elements below. A column is an upright pillar or post. Columns may support a roof or a beam, or they may be purely decorative.
![COLUMNS ,[object Object]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)