Working Stress And Limit State Method Practice Questions

The structural design method that DOES NOT take into account the safety factors on the design load is

Creep of concrete under compression is defined as the

Consider the singly reinforced section of a cantilever concrete beam under bending, as shown in the figure (M25 grade concrete, Fe415 grade steel). The stress block parameters for the section at ultimate limit state, as per IS 456: 2000 notations, are given. The ultimate moment of resistance for the section by the Limit State Method is ____ kN.m (round off to one decimal place). [Note: Here, As is the total area of tension steel bars, $b$ is the width of the section, $d$ is the effective depth of the bars, $f_{c k}$ is the characteristic compressive cube strength of concrete, $f_{y}$ is the yield stress of steel, and $\mathrm{xu}$ is the depth of neutral axis.]

Two plates are connected by fillet welds of size 10 $\mathrm{mm}$ and subjected to tension, as shown in the figure. The thickness of each plate is $12 \mathrm{~mm}$ . The yield stress and the ultimate stress of steel under tension are $250 \mathrm{MPa}$ and $410 \mathrm{MPa}$ , respectively. The welding is done in the workshop (partial safety factor, $\gamma_{\mathrm{mw}}=1.25$ ). As per the Limit State Method of IS 800: 2007, what is the minimum length (in $\mathrm{mm}$ , rounded off to the nearest higher multiple of $5 \mathrm{~mm}$ ) required of each weld to transmit a factored force $P$ equal to $275 \mathrm{kN}$ ?

In the context of elastic theory of reinforced concrete, the modular ratio is defined as the ratio of

The maximum applied load on a cylindrical concrete specimen of diameter 150 mm and length 300 mm tested as per the split tensile strength test guidelines of IS 5816 : 1999 is 157 kN. The split tensile strength (in MPa, round off to one decimal place) of the specimen is _______.

During the process of hydration of cement, due to increase in Dicalcium Silicate ( $C_2S$ ) content in cement clinker, the heat of hydration

As per IS 456:2000, the pH value of water for concrete mix shall NOT be less than

In the reinforced beam section shown in the figure, the nominal cover provided at the bottom of the beam as per IS 456-2000, is

When aspecimen of M25 concrete is loaded to a stress level of 12.5 MPa, a strain of $500 \times 10^{-6}$ is recorded. If this load is allowed to stand for a long time, the strain increasesto $1000 \times 10^{-6}$ . In accordance with the provisions of IS:456-2000, considering the long-term effects, the effective modulus of elasticity of the concrete (in MPa) is________

In the context of provisions relating to durability of concrete, consider the following assertions: Assertion (1): As per IS 456-2000, air entrainment to the extent of 3% to 6% is required for concrete exposed to marine environment. Assertion (2): The equivalent alkali content (in terms of $Na_2O$ equivalent) for a cement containing 1% and 0.6% of $Na_2O$ and $K_2O$ , respectively, is approximately 1.4% (rounded to 1 decimal place). Which one of the following statements is CORRECT?

The characteristic compressive strength of concrete required in a project is 25MPa and the standard deviation in the observed compressive strength expected at site is 4MPa. The average compressive strength of cubes tested at different water-cement (w/c) ratios using the same material as is used for the project is given in the table. The water-cement ratio (in percent, round off to the lower integer) to be used in the mix is _____

As per IS 456 : 2000, the minimum percentage of tension reinforcement (up to two decimal places) required in reinforced-concrete beams of rectangular cross-section (considering effective depth in the calculation of area) using Fe500 grade steel is ______

The deformation in concrete due to sustained loading is

The frequency distribution of the compressive strength of 20 concrete cube specimens is given in the table. If $\mu$ is the mean strength of the specimens and $\sigma$ is the standard deviation, the number of specimens (out of 20) with compressive strength less than $\mu -3\sigma$ is ______

Let the characteristic strength be defined as that value, below which not more than 50% of the results are expected to fall. Assuming a standard deviation of 4 MPa, the target mean strength (in MPa) to be considered in the mix design of a M25 concrete would be

According to IS 456-2000, which one of the following statements about the depth of neutral axis $\chi _{u,bal}$ for a balanced reinforced concrete section is correct?

For M25 concrete with creep coefficient of 1.5, the long-term static modulus of elasticity (expressed in MPa) as per the provisions of IS:456-2000 is __________.

Consider the following statements for air-entrained concrete. (i) Air-entrainment reduces the water demand for a given level of workability (ii) Use of air-entrained concrete is required in environments where cyclic freezing and thawing is expected Which of the following is TRUE?