How is Working Stress Method (ASD) different from Limit state method (LRFD or LFD)? Assumptions, Advantages and Comparisons Limit state method (LRFD or LFD) “A limit state is a condition beyond which a structural system or a structural component ceases to fulfill the function for which it is designed” Various limit states are Strength limit … Read more
What are the advantages of Prestressed Concrete over Conventional Reinforced Concrete. The prestressing of concrete has several advantages as compared to traditional reinforced concrete without prestressing. A fully prestressed concrete member is usually subjected to compression during service life. This rectifies several deficiencies of concrete. Serviceability and Strength Reduces occurrence of cracks . Freezing & … Read more
Resilience and Modulus of Resilience Resilience. Resilience is the total elastic strain energy which can be stored in the given volume of metal and can be released after unloading. it is also equal to area under load deflection curve within elastic limit. Modulus of Resilience is defined as elastic strain energy per unit volume and … Read more
Toughness and Impact Strength of Metals Toughness is the resistance to the impact loading against fracture. If a metals is tough, then it has the ability to store large strain energy before failure, deflection curve up to fracture stage. Modulus of Toughness It is the total strain energy per unit volume upto fracture stage. it … Read more
Proof Stress In some ductile materials such as Aluminium, Copper, Mild Steel, the yield point cannot be clearly defined during tension test, therefore yield stress is Unknown. For such metals design stress called PROOF stress is calculated using offset method. An offset of strain equal to given permissible plastic strain, eg at 0.2% for Al, … Read more
Why Mild Steel is most commonly used metal in Civil Engineering for Reinforced Concrete? Even though there are lots of metals (like Aluminium, Cast iron ) available for reinforcing concrete, Mild Steel is the most widely used reinforcing material in reinforced concrete. Following are the major reasons behind this. It is highly ductile. The Young’s … Read more
Failure Modes in beams There are two common types of failure in slender, non Prestressed flexural elements that carry the load in one direction only are Compression failure of the Compressive Chord “ductile flexural failure”: After yielding of the reinforcement, if no redistribution of forces is possible, the deformations of the beam become important while … Read more
Ribbed (Waffle) Slab System Ribbed floors consisting of equally spaced ribs are usually supported directly by columns.They are either one-way spanning systems known as ribbed slab or a two-way ribbed system known as a waffle slab. This form of construction is not very common because of the formwork costs and the low fire rating. A 120-mm-thick … Read more
Beam and Slab Floor System This system consists of beams framing into columns and supporting slabs spanning between the beams. It is a very traditional system. The relatively deep beams provide a stiff floor capable of long spans, and able to resist lateral loads. However, the complications of beam formwork, co-ordination of services, and overall … Read more