how to calculate twisting moment?
Basic differences PCC RCC Plain Cement Concrete R/f Cement Concrete It doesn’t carry ‘Steel’. It carries Steel. PCC is weak in tension loading while strong in compression loading. RCC is strong in both. PCC blasts on excessive loading & in an instant w/t giving any warning. RCC gives you enoughRead more
Basic differences
PCC | RCC |
Plain Cement Concrete | R/f Cement Concrete |
It doesn’t carry ‘Steel’. | It carries Steel. |
PCC is weak in tension loading while strong in compression loading. | RCC is strong in both. |
PCC blasts on excessive loading & in an instant w/t giving any warning. | RCC gives you enough time to vacate the structure before collapse. |
Plain Cement Concrete | R/f Cement Concrete | |
Tension | Steel tendons
High tensile steel bars Included with tension |
Ordinary Mild Steel Deformed Bars
No tension included |
Basic materials used | Min grade of concrete
Post-Tensioning → M30 Pre-Tensioning → M40 to resist high stresses
High strength steel to transfer large prestressing force |
Min grade of concrete → M20
Steel → MS |
Effectiveness of member | Entire section carries load | Does not carries load |
Crack resistance | High
Cracks don’t occur under working loads |
Less |
Wt & suitability | Light
Heavy loads & longer spans |
Heavy
Wt is more desired than steel |
Equiments | Requires many specialized equiments
Pulling jack, Post-tensioning pump, Master wedges, Anchhor head & bearing |
Doesn’t involve specialized equiments. |
Quality of steel reqd | 1/3rd of RCC
More strength & less c/s area |
More |
Deflection | Very less | More |
Load carrying capacity & Durability | More | Less |
Shock resistance | More | Less |
Yield | As high as 2100 N/mm2 | 200 – 300 N/mm2 |
Testing | Testing of steel & concrete can be done while prestressing. | No way of testing the steel & concrete. |
Cost | Economical for span of 10m – 18m.
As length of span gets ↑ Cost % ↑ C/s area of beam ↓ |
Economical for span < 9m. |
nikeetasharma
Torsion is the twisting of a beam under the action of a torque (twisting moment). It is systematically applied to screws, nuts, axles, drive shafts etc, and is also generated more randomly under service conditions in car bodies, boat hulls, aircraft fuselages, bridges, springs and many other structuRead more
Torsion is the twisting of a beam under the action of a torque (twisting moment). It is systematically applied to screws, nuts, axles, drive shafts etc, and is also generated more randomly under service conditions in car bodies, boat hulls, aircraft fuselages, bridges, springs and many other structures and components. A torque, T , has the same units (N m) as a bending moment, M . Both are the product of a force and a distance. In the case of a torque, the force is tangential and the distance is the radial distance between this tangent and the axis of rotation.
All torsion problems can be solved using the following formula:
T/J = shear stress/ r = (G * angle)/ L
where:
T = torque or twisting moment, [N×m, lb×in]
See lessJ = polar moment of inertia or polar second moment of area about shaft axis, [m4, in4]
τ = shear stress at outer fibre, [Pa, psi]
r = radius of the shaft, [m, in]
G = modulus of rigidity (PanGlobal and Reed’s) or shear modulus (everybody else), [Pa, psi]
θ = angle of twist, [rad]
L = length of the shaft, [m, in]