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Tuesday, June 19, 2018

Some useful tips for reinforcement detailing

Given below, some useful tips for reinforcement detailing :-

Create drawings perfectly. Try to mark every bar and demonstrate its shape for transparency.

Cross section of retaining wall that falls quickly as soon as soil backfill is arranged since ¼” dia is used instead of 1 ¼” dia. Errors happen as exact rebar dia is covered with a dimension line.

If required, generate bar bending schedule.

Denote perfect clear cover, nominal cover or effective cover to reinforcement.

Settle detailed location of opening/hole and provide sufficient information for reinforcement around the openings.

Utilize the size of bars and spirals which are easily accessible. For a single structural member, there should limited numbers of various sizes of bars.

The grade of the steel should be mentioned properly in the drawing. Deformed bars should not contain hooks at their ends.

The enlarge details at corner, intersections of walls, beams and column joint should be demonstrated at identical situations. There should not be congestion of bars at points where members overlap and ensure that all reinforcements are placed perfectly.

For bundled bars, lapped splice of bundled bars should be formed by connecting one bar at once; such separate splices inside the bundle should be staggered.

Ensure that the hooked and bent up bars are arranged and there is sufficient protection for concrete.

Specify all expansion, construction and contraction joints on plans and provide details for such joints.

The position of construction joints should be at the point of minimum shear roughly at mid or adjacent to the mid points. It should be created vertically instead of a sloped manner.

Article Source: onlinecivilforum.com

Some useful tips for reinforcement detailing

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Published By
Rajib Dey
www.constructioncost.co
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Monday, June 18, 2018

Definition, causes and remedies of efflorescence in masonry & other building surfaces

Efflorescence stands for a fine, white or greyish, powdery deposit of water-soluble salts that is present on brick, concrete, stone, stucco or other building surfaces when the water vaporizes. Besides, efflorescence also exists on floors and walls and requires special attention. It is often mentioned as "whiskers”.

These efflorescent salt deposits is found at the worst times, normally about a month as soon as the building is developed, and sometimes as long as a year after finishing of structure.

Efflorescence is found in both indoors and exterior, and it can differ in frequency and intensity because of the existence of moisture and temperature.

The efflorescence happens for the following three factors :-

• Existence of water-soluble
• Salts are converted into a soluble solution because of moisture content.
• The transmission of salts through a material to its surface that leads to vaporization of the moisture and cause the salts to crystallize and thus efflorescence is formed.


Moisture is mainly formed due to water, rain and snow and may affect the extent of efflorescence. Condensation, groundwater tapering and interior activities also may influence the extent of moisture formation.

In several cases it is found that efflorescence may happen throughout home construction. If masonry units are left behind all through the night during construction, they can consume moisture from damp soil and rain. It is recommended that masonry units should be wrapped and left in pallets to reduce the risk of efflorescence during a construction project.

The following installation issues associated with building surface result in creating efflorescence

• Improper application of through-wall flashing
• Utilization of masonry devoid of adequate ventilation
• Utilization of masonry in areas where a perfect moisture barrier does not exist
• Joint material failure
• Imperfect ground storage


How to get rid of efflorescence - The following measures should be taken to avoid efflorescence:

1) Hydrophobic Sealant: Use a saturating hydrophobic sealant to a building material surface to resist the immersion of water. The sealant also will resist water from passing through a building material.

2) Capillary Breaks: Set up capillary breaks like polyethylene sheeting among a building material and soil to reduce the risk of salt penetrating the material.

3) Standard Masonry Construction: Apply overhanging copings, eaves and flashings will help in reducing the risk of entering water into a wall.

4) Better Emphasis on Landscaping and Sprinklers: Give concentration to landscaping and sprinklers will guarantee to avoid water from reaching permeable building materials.

5) Set up Grout with Mechanical Vibration: Compile grout with mechanical vibration will control the occurring of voids in the grout.

6) Apply Dense Tooled Mortar Joints: Provide dense tooled mortar joints to minimize the permeable nature of a wall, making it strong for salts to pass through it.

7) Utilizing Grout Admixtures: Various grout admixtures like chemical additives should be used since they can make flow of a grout mix better and minimize its water content all together to lessen voids in grout.

8) Preserve Masonry Materials Properly: Retain masonry materials off the ground and wrap them with water-resistance materials to safeguard these materials from groundwater and precipitation.

Article Source: www.nitterhousemasonry.com

Definition, causes and remedies of efflorescence in masonry & other building surfaces


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Published By
Rajib Dey
www.constructioncost.co
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Saturday, June 16, 2018

Some vital methods for concrete curing

METHODS OF CURING :- Based on the type of construction work, the curing of concrete is done with the use of the following processes :-
1) COVERING: Under this method, wet gunny bags or hessian are utilized to wrap the newly developed concrete surface. This process is very effective for horizontal and vertical surface.
2) PONDING: Under this process, the entire surface is segregated into rectangular or square cages with the development of tiny clay bunds and these cages are filled with water occasionally building small ponds. This process is ideal for curing horizontal surfaces like floor, pavements etc.
3) SUBMERGING IN WATER: Pre-cast concrete members are over and over again cured by submerging them under water.
4) STEAM CURING: With this process, steam under pressure is sprinkled over the concrete surface. This process is very useful for pre-cast members.
5) SPRINKLING: Under this process, the water is sprinkled repeatedly over the concrete surface to keep the surface wet.
6) CURING WITH CHEMICAL: Under this process, water is sprayed over the surface as soon as specific amount of hygroscopic salt like NaCI, CaCletc are added. It helps to engross moisture from the atmosphere.
(7) MEMBRANE CURING: Under this process, concrete surface is wrapped with water proof membrane like wax emulsion, bitumen emulsion etc. The membrane stops the vaporization of water from concrete surface.
Article Sourcewww.civilnoteppt.com
Some vital methods for concrete curing


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Published By
Rajib Dey
www.constructioncost.co
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Friday, June 15, 2018

RCC Column Design – An exclusive mobile based app for civil and structural engineers

RCC Column Design is an exclusive app for civil and structural engineers. This app is available in google play store. It can only work in windows platform.


The app is very user-friendly. There are several fields in the app which range from Factored Axial Load (kN), Length (mm), Width (mm), Concrete Strength (M15, M20 and M25), Steel Strength (HYSD 415, HYSD 500).
Just enter the values in these fields and click on calculate button to get the desired values.
This app is designed on the basis of the Limit State Method with adherence to Indian standard code IS 456:2000. This app takes into account the axial load on a column to recommend a secure design depending on input of column size, concrete strength and steel strength. The app is also very useful for Uniaxial and biaxial bendings.
This app can design a rectangular slender RCC column that contains standard height. It works out necessary reinforcement for a specified axial load for the assumed inputs.
This app is developed for educational purposes only. The answers should be double checked manually.
To download the app, click on the following link play.google.com
RCC Column Design รข€“ An exclusive mobile based app for civil and structural engineers


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Published By
Rajib Dey
www.constructioncost.co
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Thursday, June 14, 2018

How to select perfect scaffolding material towers in construction project

Prior to start any construction project, the most important task is to obtain clear ideas on various types of scaffolding material towers. Improper selection of scaffolding material towers may lead to severe injury to the workers as well as loss of life.

Given below, the detailed lists of commonly used towers in construction site :-

MS Scaffolding Tower

This tower is mostly recognized in the industry due to its well-built design, stability, flexibility & rust resistance. It is built up with the superior quality raw material & cutting technology with regard to established industry standards. The size of the tower can also be customized according to the requirements of the clients. It is normally utilized throughout the formation of the building.

Some useful features of the tower

Perfectly designed, Rugged, Strong resistance capacity against decay

MS Scaffolding Movable Tower: MS Scaffolding Movable Tower is just an extension to MS Scaffolding tower that contains wheels. It is very flexible and can be easily shifted from one place to another without difficulty and huge man power. It also has good longevity & lock system. It is built up with approved hinges and castor wheels with adherence to industry standards.

Features: Strong load bearing capacity, Hassle free movement, Rust proof finish

H Frame Scaffolding Tower: H Frame scaffolding manufactured with superior quality steel having sound tensile strength. Its height is modifiable. There are scissor braces in the tower which are attached through gravity locks to avoid any breakage or mishap. By applying the combination of changing sizes of H Frame, towers can be structured to proper heights.

H Frame Structure: H Frame structure is a part and parcel of H Frame scaffolding. Different types of H Frame structures are combined to form a scaffolding tower. Due to its powerful locking skill, the tower can stand as tall as necessary.

Scaffolding Staircase: There are different types of scaffolding staircases. The size of the staircase can be easily customized as per requirement. Usually, the engineers visit the location of the construction site and offer solutions and build up custom structure as per requirement.

How to select perfect scaffolding material towers in construction project

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Published By
Rajib Dey
www.constructioncost.co
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Wednesday, June 13, 2018

Types and properties of bricks

Bricks is produced from well clay molding, that is dried and then burnt. The size of the brick varies from 90 mm × 90 mm × 90 mm and 190 mm × 90 mm × 40 mm. With mortar joints, the size of brick varies from 200 mm × 100 mm × 100 mm and 200 mm × 100 mm × 50 mm.

Types of Bricks: Bricks are categorized as -
(i) Building bricks, (ii) Paving bricks, (iii) Fire bricks, (iv) Special bricks.
Properties of Bricks: The standard quality bricks should contain the following properties -
(i) Colour: The color should have been identical and clear.
(ii) Shape: Shape of the bricks should have been sharp and genuine rectangular angles.
(iii) Size: There should be standard dimensions for bricks with adherence to codes.
(iv) Texture: A standard brick should contain a fine, solid and consistent texture. They should be free from fissures, cavities, loose grit and unburned lime.
(v) Virtue: If the brick is hit with another brick, there should be a metal sound.
(vi) Hardness: If scratches are made with finger on a brick, there should not be any mark on the brick.
(vii) Strength: The breaking strength of brick should not be under 3.5 N / mm2. A field test is conducted to check the strength by dropping the brick from a height of 0.9 m to 1.0 mm on a hard surface. If the brick has good strength, the stone should not be broken into pieces.
(viii) Water absorption: Once the brick is drowned in water for 24 hours, the water absorption rate should not exceed 20 percent by weight. For class I bricks, this limit remains 15 percent.
(ix) Efficiency: There should not be any white patches in bricks when they are drenched in water for 24 hours and then allowed to dry in the shade. White stains may appear because of the existence of sulfate of calcium, magnesium and potassium. They retain masonry in wet and humid conditions.
(x) Thermal conductivity: Bricks should contain low thermal conductivity, so the buildings developed with bricks should have cold temperature in summer and warm temperature in winter.
(xi) Sound insulation: Bigger bricks have poor sound insulators whereas light and hollow bricks have superior sound insulation.
(xii) (xii) Fire resistance: Normally, the fire resistance capacity of brick is good. Actually, bricks are utilized to trap steel columns to safeguard them from fire.
Types and properties of bricks

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Published By
Rajib Dey
www.constructioncost.co
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Tuesday, June 12, 2018

How to start marking for foundation

This construction video provides detailed guidelines on foundation marking. In the video, the plan of building is given for living room and kitchen room. The center line marking is also provided with 6 numbers of columns. Initially, you have to set the base point as it is very crucial for marking. After that, a base line is arranged from that base point with a thread for fixing the second point.


The centre line of the wall perpendicular to the long wall, is marked by making a proper angle. Right angle is arranged by creating triangles with sides 3,4 and 5units long. If we set the two sides of the right angles triangle to be 3 m, and 4 m, then the third side i.e. the hypotenuse is assumed at 5 m. A steel tape should be used to fix all the dimensions.
The formula is used here as √(L2+B2).

The right angle can be fixed by applying a theodolite. This instrument is very useful in fixing acute or obtuse angles. Small right-angled Projections are generally laid out with mason’s square.

Proper marking of the foundations is specifically important for new walls to make sure that the foundations contain the exact size and are in the perfect position to bear the load of the wall. Good foundations are essential to make sure that no movement can occur because any movement can lead to cracks and problems in the building that is supported with the foundation.

To get the complete instructions, watch the following video.

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Published By
Rajib Dey
www.constructioncost.co
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