amardeep s

surface of a massive body, such as a planet. Also known as the acceleration of free fall, its value can be calculated from the formula g = GM / (R + h) 2 whereM is the mass of the gravitating body (such as the Earth), R is the radius of the body, h is the height above the surface, and G is the gravitational constant (= 6.6742 × 10-11 N·m2/kg2). If the falling object is at, or very nearly at, the surface of the gravitating body, then the above equation reduces to g = GM / R 2 In the case of the Earth, g comes out to be approximately 9.8 m/s2(32 ft/s2), though the exact value depends on location because of two main factors: the Earth's rotation and the Earth's equatorial bulge. The earth is not perfectly round, it is slightly egg-shaped, wider at the equator as it spins. The farther you are from the center of the earth the less gravity, the less you weigh. So if you are on a high mountain or at the equator you...

The grading and maximum size of aggregates is important parameters in any concrete mix. They affect relative proportions in mix, workability, economy, porosity and shrinkage of concrete etc. Experience has shown that very fine sands or very coarse sands are objectionable – the former is uneconomical, the latter gives harsh unworkable mixes. Thus the object in this paper is to find the best fineness modulus of sand to get the optimum grading of combined aggregate (all-in-aggregate), which is most suitable, and for economy. In general, the grading of aggregates, which do not have a deficiency or excess of any size of aggregate and give a smooth grading curve, produce the most suitable concrete mix. Further a cohesive mix is also desired for the pumped concrete produced by RMC Plant. In the present investigations, effect of the grading of river sand particles has been investigated for a good Concrete mix. Sand has been sorted in three categories i.e. Fine, Medium, and Coarse. These w...

to find the wt per mtr of steel bar • Take the dia of the bar • Divide the dia by 2 • Square the obtained value • Divide the value by 4 • Mark the point before last digit Example 1 IF THE DIA IS 16 MM DIVIDE BY 2 16/2 = 8 SQUARE THE OBTAINED VALUE 82 = 64 DIVIDE THE VALUE BY 4 64/4 = 16 MARK THE POINT BEFORE LAST DIGIT 1.6 kg/m Example 2 IF THE DIA IS 12 MM DIVIDE BY 2 12/2 = 6 SQUARE THE OBTAINED VALUE 62 = 36 DIVIDE THE VALUE BY 4 36/4 = 9 MARK THE POINT BEFORE LAST DIGIT 0.9 kg/m

Review of Laminated Elastometric Bearing Pad (AASHTO M251 & BS 5400: Part 9) Steel-Reinforced Elastometric Bearings – Method B A. Allowable Delamination compressive Stress: 1. Shear Modulus (G) = 130 ~ 199 psi (Say Use 150 psi = 1.03 MPa) 2. Hardness -- Use 50 Durometer (Between 50 ~ 60 on Shore A scale) 3. Compressive Stress (AASHTO 14.7.5.3.2) In any elastometric bearing layer, the average allowable compressive stress at the service limit state shall satisfy: • For bearing subject to shear deformation: S: Shape factor (8.5 Service DL per bearing: DL = 300 kN (67.443 kips) Service LL per bearing: LL = 500 kN (112.404 kips) Existing L= 600mm W= 200 mm c= (DL+LL) / LW = 800*1000N/ (600x200)mm2 =6.67 MPa = 1 ksi hri: 6.4mm hrc: 6.3mm so, S=600*200/(2*6.4*(600+200))=11.7 (actual) c=6.67 MPa B. Determine Bearing Pad size: 4. n: number of interior layers = 6 Reinforcing steel shims : hs= 2.7mm 8. Bearing pad Thickness check: ...

Specific Gravity Specific gravity is the ratio of density of a substance compared to the density of fresh water at 4°C (39° F). At this temperature the density of water is at its greatest value and equal 1 g/mL. Since specific gravity is a ratio, so it has no units. An object will float in water if its density is less than the density of water and sink if its density is greater that that of water. Similarly, an object with specific gravity less than 1 will float and those with a specific gravity greater than one will sink. Specific gravity values for a few common substances are: Au, 19.3; mercury, 13.6; alcohol, 0.7893; benzene, 0.8786. Note that since water has a density of 1 g/cm3, the specific gravity is the same as the density of the material measured in g/cm3. The Discovery of Specific Gravity The discovery of specific gravity makes for an interesting story. Sometime around 250 B.C., the Greek mathematician Archimedes was given the task of determining whether a craftsman had d...

Drum Rotations of Transit Mixer/ Agitator Another test method is to count the actual rotation of the ready mix truck drum rotations. Once the mix and water are placed in the drum the load should be delivered and discharged before the drum has revolved 300 times. Over-mixing concrete damages the quality of the concrete. Over-mixing may: • Grind the aggregate into smaller pieces, • Increase the temperature of the mix, • Separate the aggregates from the cement paste • Lower the slump, • Decrease air entrainment, and • Decrease the strength of the concrete. Also, over-mixing puts needless wear on the drum and blades of the transit mixer Time An important quality control test for concrete is to identify the length of time from when water is added to the mixture until the mixture is poured. The batch ticket has the elapsed time recorded between the mixture and the placement. Concrete begins to stiffen as soon as the cement and water are mixed. However, the degree of stiffening th...

All reinforcement shall be furnished in full lengths as indicated on the drawing. No splicing of bars, except where shown on the drawing, shall be permitted without approval of the Engineer. Where practicable, overlapping bars shall not touch each other, and shall be kept apart by 25 mm or 1.25 times the maximum size of coarse aggregate, whichever is greater . If this is not feasible, overlapping bars shall be bound with annealed steel binding wire not less than 1 mm diameter and twisted tight in such a manner as to maintain minimum clear cover to the reinforcement from the concrete surface. Lapped splices shall be staggered or located at points, along the span where stresses are low.