Some crucial factors for perfect reinforcement concrete design
As per opinion of the art, engineering science and technology, the design of a structure refers to the method of picking exact materials and proportioned elements of the structure. To satisfy its objective, the structure should abide by its conditions of safety, usableness, economy and effectiveness.
Strength design method: It is subject to the extreme strength of the structural members suspecting a failure condition, whether caused by the suppression of concrete or the yield of reinforced steel bars. Even though there exist extra strength in the bar once yielding is completed (because of Strain Hardening), this extra strength is not taken into consideration while analyzing or designing the reinforced concrete members.
Under the strength design method, actual loads or working loads are multiplied with load factor to acquire the final design loads. The load factor stands for a high percentage of factor for safeguard necessary in the design. The ACI code features this method of design.
Working stress design: This design concept is undertaken on the basis of elastic theory, supposing a straight line stress distribution along the depth of the concrete. The real loads or working loads functioning on the structure are measured and members are proportioned subject to the specific allowable stresses in concrete and steel. The allowable stresses belong to the divisions of the crushing strength of concrete (fc') and the yield strength (fy).
Limit state design: It is the better version of the strength design method. It denotes the state of the member in which it finishes to fulfill the necessities of service requirements, like, lacking ability to resist external loads or local damage. As per limit state design, reinforced concrete members should be evaluated relating to three limit states:
1. Load carrying capacity (comprises safety, strength and durability)
2. Deformation (deflection, vibrations, and impact)
3. The development of cracks
The motto of this examination is to make sure that no limiting sate will come out in the structural member throughout its service life.
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