Bond · Reinforced Cement Concrete · GATE CE

The development length of a deformed reinforcement bar can be expressed as $$\left( {1/k} \right)\left( {\phi {\sigma _s}/{\tau _{bd}}} \right).$$

From the $$IS:$$ $$456$$-$$2000,$$ the value of $$k$$ can be calculated as _________________.

As per $$IS$$ $$456:2000$$ for $$M20$$ grade concrete and plain barsin tension the design bond stress $${\tau _{bd}} = 1.2\,\,MPa.$$ Further, $$IS$$ $$456:2000$$ permits this design bond stress value to be increased by $$60\% $$ for $$HYSD$$ bars. The stress in the $$HYSD$$ reinforcing steel bars in tension $${\sigma _s} = 360\,MPa.$$ Find the required development length, $${L_d},$$ for $$HYSD$$ bars in terms of the bar diameter, $$\phi $$ ______________.

In the design of a reinforced concrete bean the requirement for bond is not getting satisfied. The economical option to satisfy the requirement for bond is by

As per $$IS:$$ $$456$$-$$2000,$$ consider the following statements:

$$1.$$ The modular ratio considered in the working stress method depends on the type of steel used.
$$2.$$ There is an upper limit on the nominal shear stress in beams (even with shear reinforcement) due to the possibility of crushing of concrete in diagonal compression.
$$3.$$ A rectangular slab whose length is equal to its width may not be a two-way slab for some support conditions.

The TRUE statements are

If $$\phi \, = \,$$ nominal diameter of reinforcing bar, $${f_s}\, = $$ compressive stress in the bar and $${f_{bd}}\, = $$ design bond stress of concrete, the anchorage length, $${L_a}$$ of straight bar in compression is equal to

Consider a bar of diameter $$'D'$$ embedded in a large concrete block as shown in the adjoining figure, with a pull out force $$P$$ being applied. Let $${\sigma _b}$$ and $${\sigma _{st}},$$ be the bond strength (between the bar and concrete) and the tensile strength of the bar, respectively. If the block is held in position and it is assumed that the material of the block does not fail, which of the following options represents the maximum value of $$P?$$

Consider the following two statements related to reinforced concrete design, and identify whether they are TRUE/FALSE:

$${\rm I}.$$ Curtailment of bars in the flexural tension zone in beams reduces the shear strength at the cut-off locations
$${\rm II}.$$ When a rectangular column section is subject to biaxially eccentric compression, the neutral axis will be parallel to the resultant axis of bending.

A continuous beam $$250\,mm \times 450\,mm$$ carries $$6$$ numbers of $$12$$ $$mm$$ diameter longitudinal bars as shown. The factored shear force at the point of inflection is $$200$$ $$kN.$$ Check if the beam is safe in bond. Assume $$M15$$ mix with $${\sigma _{ck}} = 15\,\,N/m{m^2}$$ and mild steel with $${\sigma _y} = 250\,N/m{m^2}.$$ A clear cover of $$25$$ $$mm$$ can be assumed. The design bond stress for mild steel bars in $$M15$$ concrete is specified to be $$1.0\,N/m{m^2}.$$