Civil Engineering

floating foundation is use at the bes ment at the building.

Plastering sand is find sand screened to suit the plaster coarse i.e. base coat or finish coat. For finish coat very fine sand is used.

Sand for concrete is not sived if pebles are not present. Both sand shall be sweet sand, if from sea it has to be washed before use.

construction joints are leave in RCC Slab one third of span.

From the engineering point of view, there are different aspect and factor to analyse two different structure.

For the answer of your question, first thing is the materials is differently. There are list of differences . pls let me know what is the thing you want to know precisely.

If the concrete sample has been tested in a uniaxial compressive test machine (which would be the normal destructive method of testing a cylindrical sample), then you would use the failure load divided by the cross sectional area of the cylinder to find the strength of the material.

Failure Stress = Uniaxial Compressive Strength = Force / Area

It should also be noted that concrete strength is more normally found by measuring "cube strength", that is where the concrete is pored into cube shaped moulds of 100 mm x 100 mm x 100 mm and is then allowed to cure for a period of time (typically 28 days). The concrete cube is then tested in a uniaxial test rig. The formula for calculating the strength is the same, however the major difference is in the preparation of the sample as described above.

Malcolm Hall

modern houses are new but ot tudor houses

beam transfer loads from the joist to the wall or column where it supports..

2(A+B)+20d-5d

Seven

The beam will deflect or bend with the maximum deflection at the center = (wl^3)/(48EI). For a steel beam with 2 inch diameter 10 feet (120 in.) long

l = 120 inches

E = 30 x 10^6 psi

I = .784 in^4

w = load lbs.

Deflection in inches at the middle = w x .0015

so 500 lbs would be 500 x .0015 = .75 inches

If your looking for max load before yield: for 1018 cold drawn round bar yield stress is 53700 psi which gives a max load of roughly 1430 lbs which will deflect in the center 2.15 inches. I would not recommend loading it with this much weight as you will have no factor of safety.

The Twin Span Bridge is located on Interstate 10 in Louisiana. It begins in Orleans Parish and crosses into St. Tammany Parish while spanning Lake Pontchartrain.

They are reinforced. :)

A graph drawing in which each edge is represented by a polyline, each segment of which is parallel to a coordinate axis.

it is the rebar provided before completion of above columns where in overlaps shall be provided for the extension of columns

(hope this help)

75mm, 100mm or 150mm diameter cores are taken on site using state of the art core cutting machines. Cover meter is used to locate the reinforcement steel before core cutting. This prevents structural damage to the RCC member by avoiding the reinforcement. These cores are dressed in our lab and tested using standard compression testing methods to determine compressive strength and arrive at equivalent cube strength of concrete.

IS Codes applicable: IS : 456 / IS : 516 / IS : 1199

Applications:

Assessment of strength.

Study of aggregates used in the mix design.

Assessing probable causes of failures/problems.

Equipment Used:

Core cutter.

Core compression testing machine.

Test basis:

A core sample is the actual representation of the material used in the structural element. When processed and subjected to load, it fails at a particular load, giving a fair idea of its compressive strength.

Methodology:

Step1: Reinforcement Mapping.

By using a special instrument, based on eddy currents, the reinforcements are mapped in the structural member.

Step 2: Core cutting.

Cores are taken using special diamond cutters of 75 mm, 100 mm or 150 mm diameter. Locations are selected to avoid steel so as to minimize the damage to the structure.

Step 3: Dressing.

The edges of the core are smoothend using grinding and cutting wheels and epoxy mortar is applied on both sides for capping. This ensures that the ends are approximately at 90% to the axis and are within 0.05 mm plane ness.

Step 4: Immersion in water

The core samples are immersed in water for 48 hours. The cores are weighed before and

after immersion.

Step 5: Compression testing.

The cores are then subjected to compression forces on compression testing machine. The breaking point is observed.

Step 6: Reporting.

Based on the lab report, sizes of the core etc. an equivalent cube strength is calculated for the concrete applying necessary correction factors. The density, core strength and equivalent cube strength are reported.

Influencing factors:

Core diameter and length (h / d ratio)

Proper capping and hydration of the cores as per IS code.

Old/new/Mixed (jacketed) concrete.

Understanding results:

The result is normalized for comparison with compressive test results of a standard cube. This is done so that the cube results can be compared with the core results. Standard correction factors as per IS code are used for this purpose. This value may not be the same as the core strength.

Following are the factors which affect the compressive strength of extracted concrete cores:

Size of stone aggregate: If the ratio of diameter of core to maximum size of stone aggregate is less than 3, a reduction in strength is reported. For concrete with 20mm size aggregate, 50mm dia core has been tested to give 10% lower results than with 10mm dia cores.

Presence of transverse reinforcement steel: It is reported that the presence of transverse steel causes a 5 to 15% reduction in compressive strength of core. The effect of embedded steel is higher on stronger concrete and as its location moves away from ends, i.e. towards the middle. However presence of steel parallel to the axis of the core is not desirable.

H/D ratio: This has been already discussed above. However its value should be minimum 0.95 and maximum 2. Higher ratio would cause a reduction in strength.

Age of concrete: No age allowance is recommended by the Concrete Society as some evidence is reported to suggest that in-situ concrete gains little strength after 28 days. Whereas others suggest that under average conditions, the increase over 28 days' strength is 10% after 3 months, 15% after 6 months. Hence it is not easy to deal the effect of age on core strength.

Strength of concrete: The effect in reducing the core strength appears to be higher in stronger concretes and reduction has been reported as 15% for 40 MPa concrete. However a reduction of 5 50 7% is considered reasonable.

Drilling operations: The strength of cores is generally less than that of standard cylinders, partly as a consequence of disturbance due to vibrations during drilling operations. Whatever best precautions are taken during drilling, there is always a risk of slight damage.

Site conditions vis-a-vis standard specimens: Because site curing is invariably inferior to curing prescribed for standard specimens, the in-situ core strength is invariably lower than the standard specimens taken and tested during concreting operations.

Engineer Muhammad Mubashir

Refrences

http://theconstructor.org/concrete/core-sampling-and-testing-of-concrete/2865/

http://www.aaryanengineers.com/core_testing.html

Ruby Bridges was the First African American to go to an all white school. She is still alive and she has written books about her past. She had to have body guards because they didn't trust a African American

The stress reduction factor is a product of the relationship between the Unconfined compressive strength of a rock and the sigma 1, or principal stress field in that area. The higher the value, the more likely the rock is to deform when placed under load.

X-ray is used to see inside concrete and is often used to test for cracks in high stress applications.

1. San Jacinto Memorial (TEXAS) 567.31-foot 172.9 m 2. The Washington Monument (U.S.A) 555 feet 5⅛ inches 169.294 m 3. Great Pyramid of Giza (Egypt) 481 Feet 146.6 meters This is a tough one, the San Jacinto Memorial is made of reinforced concrete - does this count as a 'stone structure'? Does this question then include towers and concrete buildings? - if so the Juche memorial tower in North Korea would come in second, taller than The Washington Monument. The Washington Monument is a genuine stone structure made of bluestone gneiss as well as other commemorative stones, and should be counted as the tallest.

Yes under reamed piles are most suited for the black cotton soils.The upward stress ,when the soil shrinks would be taken care by the reamers.

the top of the arch under goes tension and horizontal thrust

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i hate NovaNET... the answer is true=]

There are a number of ways to build a tunnel. The location of the structure and the material through which the tunnel will pass will dictate the approach used. Sometimes we just blast away rock, like in the side of a mountain. Other times will use a boring machine to cut through materials, and we'll install "pieces" behind the machine that become the sides and overhead of the tunnel. We might dig a big "trench" in the ground, put in supports and an overhead, and then cover the whole thing over. Other tunnels are built in sections, like "tubes" or something similar, and are then placed under water, linked together and sealed, and then pumped out to form the tunnel. There are yet other techniques, and you can begin to learn about them by using the link below.