The process of concrete by weight and volume

atching is defined as the method for computing & combining the various components (cement, fine aggregate, coarse aggregate and water) for the formation of concrete prior to mixing following the mix design.

If this calculation is accomplished based on the volume, it is known as volume batching. Batching is categorized as follow :-

1) Volume batching
2) Weigh batching

Volume batching: In volume batching, the mass of each component is not calculated before batching, rather than there are some fabricated boxes(generally wooden) which are calculated in volume to retain the concrete components.

• This method is normally suitable for small jobs.
• Gauge boxes are applied for estimating the fine and coarse aggregate.
• The volume of gauge box has the similarity with the volume of one bag of cement.
• Gauge bow are also titled as FARMAS.
• They are formed with timbers or steel.
• Normally, they are created as deep and narrow.
• Normally, bottomless gauge boxes are not recommended for application.
• At the time of filling the gauge boxes the material should be filled loosely, no compaction is permissible.

Weigh batching: Weigh batching is the proper and most recognized method of estimating concrete ingredients. Weigh batching is performed in very vital modern concrete batching and mixing plants.

• Batching by weight is better than volume batching in terms of perfectness. Besides, it offers more consistent proportioning. It is always recommended professionally.

• It does not contain uncertainties related to bulking.
• Its equipment’s are divided into 3 general categories.
• Manual
• Semi-automatic
• Fully automatic.
• If batching is done by hand all weighing and batching of concrete are performed by hand. It is suitably for small jobs.

• For semi-automatic batching the aggregate bin gates are opened by operating switches with hand and gates are closed automatically when the material is delivered. This system also comprises of interlock that resists charging and discharging.

The process of concrete by weight and volume

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A position is vacant for Quantity Surveyor / Estimator

Introduction: A leading medium size business situated in Benoni and engaged with the manufacturing, and installation of Prefabricated Modular Buildings, together with structures and related services, like basic reticulation and civils, is inviting application for a young +- 30 years old Quantity Surveyor who possesses a degree of BSc or BTech (QS).

The candidate should contain at least 5 years experience and onsite experience with contracts with regard to residential housing / Offices / Warehouse construction.

Objective of the job:

• The candidate has to price all the submitted tenders which should contain the following:
• Rate all project costs along with P&Gs, project cash flows, project programmes.
• The candidate should also take responsibility to monitor to commercial prospects of alloted projects and carry out closeout reports.

Duties and liabilities:

• Costings and budgets formation for the allotted projects.
• Tender and contract documents formation together with the bills of materials for procurement.
• Advocating on the procurement policy.
• Accomplishing monthly valuations of work progress, along with forecasting of final costs.
• Estimate, value, submit and negotiate contract variations.
• Control and generate perfect formal reports with reference to the project timelines.
• Recognizing, analysing and developing responses to commercial risks.
• Providing support to general manager with a range of other duties as essential from time to time.

Skill Requirements:

• Technical qualification with a degree in B.Sc (QS) University Degree or B-Tech Degree.
• At least 5 years experience with quantity surveying in South Africa.
• Should contain sound practical organisation skills, planning of resources and programme scheduling.
• Should be capable of providing both summarised and detailed reports on current activities.
• Good knowledge in computer and have the capability to apply Microsoft Office and Microsoft Projects.

• Comprehensible experience in arranging tenders respecting construction.
• Personal Attributes:
• Motivated and determined individual.
• Good speaking power in English.
• Eagerness to travel.
• Good team player and effective communicator.

Salary:
• Negotiable based on experience

To apply online, go through the following link www.infomine.com

A position is vacant for Quantity Surveyor / Estimator

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SSC Junior Engineer (Civil, Mechanical, Electrical and Quantity Surveying & Contract) Recruitment 2017

Staff Selection Commission is going to arrange an open competitive Computer Based Examination for appointing Junior Engineers Group-„B‟ (Non-Gazetted) posts, in Level-6 (Rs.35400-112400/-) of pay matrix of 7th CPC w.e.f. 5th January 2018 to 08th January 2018.

The last date of submitting application is 17-11-2017.

The written examination through computer will be held on 05-01-2018 to 08-01-2018.

Detail of Posts: Only the male candidates are allowed to apply for the posts of Junior Engineers in Director General. Border

Roads Organisation (BRO), Ministry of Defence.

Reservation: Reservation for SC/ ST/ OBC/ ExS/ PH etc. categories is available as stated by extant Govt. Orders and as announced by the departments reporting vacancies.

The posts are recognized as appropriate for the persons who are suffering from disabilities of forty percent 40%) and above of One Arm (OA), One Leg (OL), Hearing Handicapped (HH) as stated by the Ministry of Social Justice and Empowerment.

To get more information on the vacancies, go through the following link Apply Now

SSC Junior Engineer (Civil, Mechanical, Electrical and Quantity Surveying & Contract) Recruitment 2017

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Rajib Dey
http://www.constructioncost.co
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Brief discussion on lap length of bars

Development length and lap length are two vital parts of reinforcement. But there are some basic differences among development length and lap length.

While going to arrange the steel in RC structure, if the necessary length of a bar is unavailable to produce a design length then lapping is essential. Lapping occurs because of overlapping of two bars alongside to attain desired design length.

As for instance, if it is required to construct a 100 feet tall column, but 100 ft long bar will not be available in practical and caging can’t be done in this situation. So, it is necessary to cut the bars frequently to transmit the tension forces from one bar to the other at the position of suspension of bar. So, it is essential to arrange the second bar adjacent to the first bar that is suspended and overlapping should be performed. The amount of overlapping among two bars is called lap length.

For the RCC structure, if the length of reinforcement bars has to be expanded, splicing is conducted to attach two reinforcement bars for transmitting the forces to the joined bar.

LAP LENGTH FORMULA:
LAP LENGTH IN TENSION:

The lap length along with anchorage value of hooks should have been as follow :-

1. For flexural tension – Ld or 30d either is larger.
2. For direct tension – 2Ld or 30d either is larger.

The straight length of lapping should not be under 15d or 20 cm.

LAP LENGTH IN COMPRESSION: The lap length in compression should have similarity with the development length in compression calculated but not below 24d.

FOR DIFFERENT DIAMETER BARS: In case of bars with dissimilar diameter should have been spliced, the lap length is computed based on the smaller diameter bar.

LAP SPLICES: Lap splices should not be employed for the bars with greater dia than 36 mm. In this situation, welding is needed. But, in case, welding is not possible then lapping is allowed for the bars greater than 36 mm dia. supplementary spirals should have been around the lapped bars.

For more information, click on the following link dailycivil.com

Brief discussion on lap length of bars

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Various types of cofferdam

Coffer belongs to a trunk, casket or chest in which temporary structure is constructed to surround and cover an area that is prepared for excavating of the foundation of the construction. Cofferdams are applicable for structural foundation in Open Water & Open Land like bridge piers, docks, locks, dams and high ground water table.

A cofferdam is a wall with water resistance capacity that is constructed around the boundary of the projected excavation to resist the water flow into the excavation to keep the basement in dry condition.

Given below the lists of common types of coffer dams :

1) Earth Coffer Dams 2) Rockfill Coffer Dams 3) Single-Sheet Pile Coffer Dams 4) Double-wall sheet piling coffer dams 5) Braced Coffer Dams 6) cellular Coffer dams

Categories of cofferdam:

1) Earth Coffer Dams: Earth Coffer Dams are mainly built up in an area where the velocity of the current and depth of the water remains at 13 to 18 in and it is lifted 1 m over the water level. It is built up with a by amalgamating clay and sand. The Side Slopes of the bank on the water side should have been sloped with rubble Boulder to get rid of embankment from scouring. Once the coffer dam is finished, the water is pumped to wipe the interior surface. Sand bag can be utilized in an urgency.

2) Rockfill Coffer Dams: Rockfill coffer dams are constructed with rockfill. The site is often surrounded with dewatered. To safeguard against wave action, the crest and the upper portion of the impermeable membrane are supplied with rip rap. The slopes of rockfill cofferdam is built as steep as 1 horizontal to 1.5 vertical.

3) Single-Sheet Pile Coffer Dams: Single Sheet Coffer Dam is built in a very small area and it’s depth of water surpasses.5 to 6m. Initially First Guide Piles alias Timber Piles are inserted into the firm Ground that is underneath water bed. On the basis of the velocity of the Current in water, the Longitudinal runners spacing fluctuates and it is called as wales which are bolts to a timber piles at a requisite space.

Steel or Wooden Sheet is placed into the River Bed together with wales which are fastened to the wales through bolts. To make the walls stronger against the water pressure, the sheets on the two faces arc bolstered with trussed arrangement of struts and Half-filled bags of sand piled on the internal and the external faces of the sheets. Once the cofferdam is built up, the water in the surrounded area is poured out and the construction work starts.

Various types of cofferdam

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How to find out the required amount of concrete for construction work

To find out the exact quantities of concrete for a construction project is very crucial. Given below, some useful tips for computing the quantities of concrete mix for any construction project.

How to work out the amount of concrete necessary for Slabs(along with odd shapes)

Rule of thumb: Include 1/4″ to the density of your slab for your slab concrete budget. It supposes that the job is uniformly graded to the exact depth, and the grade is properly compacted.

While examining your grade, if it is found that one spot is 4″ and other spots are 4.5″ to 5″ then it is recommended ion to settle the grade for both the job quality and your concrete budget.

Odd shapes: Convert odd shapes into rectangles and odd shapes can be located easily.

Build driveway 14′ x 20′ and your estimate will be perfect. It will be done in this way – The driveway is 16′ at the top and 12′ at the bottom. Throughout the center the width averages 14′.

Working out the Amount of Concrete Essential For Footings

Footings will seldom pursue the drawing accurately. In the soil where there are lots of gravels, the footings may fall down if big rocks are excavated.

It is assumed as a 12″*12″ footing, but check how the left side of the footing has fallen down. Compute the exact width.

The digging is too deep by the excavator, or there may be raining and the digging for footings should be deeper to get to solid soil. Therefore, it is vatal to examine different types of spots on your footing and obtain an average size. Then with the help of a calculator, works out the required amount of concrete.

House slabs on grade that are 8″ out of grade containing a 4″ slab also arranged some of the footing over the grade too.

This 12″ x 12″ footing should be computed as 12″ x 16″ so the footing is built to go over grade to attain the 4″ slab thickness.

To make calculation online, click on the following link www.concretenetwork.com

How to find out the required amount of concrete for construction work

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How to choose pile foundation on the basis of cost versus other foundations for construction project

Get detailed information on how to choose the pile foundations on the basis of cost vs. other foundations for construction projects and factors which impact the cost of pile foundation.

Sometimes, it becomes difficult for structural designer to take stable decision to select types of foundations like pile foundation or ordinary strip or mat foundation to be used for the structure.

The problem becomes acute while going to choose among pile foundation and traditional mat or strip foundation developed in a deeper level to fit a soil layer having desirable bearing strength.

There should be an indicator for all construction conditions under which the use of pile foundation is considered as inexpensive with reference to traditional strip and mat foundations.

This article will focus on the variations through which the decision for choosing of pile foundation over other foundation types can be taken without difficulty. This condition line is formed on the reasonably detailed cost appraisal of the foundation. The foundation cost is impacted by the following factors :-

Factors impacting the cost of Pile Foundation

Evidently, final decision for employing the type of foundation, cannot be taken on the basis of the calculation of excavation volume and concrete quantity of deep mat or strip foundation with regard to cost of piles that support the same load.

A cap is needed for Pile foundation. The density of the cap should be approx 45cm for two piles and 60cm to 120cm for two pair of piles. Plan dimensions of piling cap should be up to 2100mm2 for pile having diameter of 550mm.

With tie beams provided over one direction, the Pile caps are joined together using tie beams in more than one direction.

It is found that, the excavation cost of pile cap along with capping beams and tie beams is two times the cost of machine excavation in moderately large column bases. With the advancement of construction, the perfect structural design as well as stringent supervision is required for pile foundation.

To get more details, click on the following link theconstructor.org

How to choose pile foundation on the basis of cost versus other foundations for construction project

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Curtain Wall Design Tips For Water Penetration & Condensation

Designing curtain walls to water penetration brings huge benefits for maintaining the security, thermal performance and comfort of the structure and residents.

The rain caused by wind and condensation create huge issue and it becomes complicated to handle when curtain wall is designed together with gravity, kinetic energy, capillary action and surface tension and the chances are enhanced for water ingression.

Get the detailed information on the design of curtain wall against the infiltration of water and condensation.

Design of Curtain wall for Water Infiltration and Condensation

  • Wind driven rain and the possibility of water ingression
    • Design of curtain wall to control water penetration
    • Design of curtain walls to control condensation

Wind driven rain and possibility of water ingression

There are five different types of forces such as that contribute either partially or as a whole to the ingression of water may occur due to existence of five various types of forces like gravity, kinetic energy, capillary action, surface tension and air pressure difference.

The curtain wall is capable of resisting forces that enhances the chance of water penetration. It is dependent on glazing details, drainage details, frame construction, weather stripping and frame gaskets, perimeter flashings and sealings and interior sealants.

Wind loads create differentials pressure that may cause windblown rain. It exceeds gravity force and as a result forces water to stir ascending.

Surface tension properties and capillary effect of curtain wall elements are significantly impacted with thermal expansion of various building materials.

As for example, expansion or contraction of materials because of temperatures may tight expansion joints extremely and ultimately raise capillary action among different components of the curtain wall.

The surface tension properties of curtain wall may fluctuate because of contraction and expansion and bring about unwanted results. So, it is necessary to design movable joints, seals and gaskets to accommodate differential movements among various members.

To learn how to make design of curtain walls to manage water penetration, click on the following link theconstructor.org

curtain-wall-construction

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Calculation of Cement and Sand Quantity for Plastering

The ratio and all calculations given below are according to the requirement of 12mm thick plastering.

Plastering, as we all know, removes imperfection of external walls along with maintaining the line level and the alignment. Generally, plastering is defined as a protective surface for walls. It can be many a type depending on the materials it uses such as cement plaster, gypsum plaster and lime plaster. These are the common types of plastering that are required for home construction.

Cement plaster has two main materials in its core – cement and sand. The right proportion is required to get the best outcome you expected. This plaster removes imperfections from both inner and outer walls of the construction. Knowing the right proportion is an important factor in the making the paste or mortar perfect for the walls.

The list below contains the ratio between cement and sand that you need to maintain as per the application.

  • Cement mortar ratio 1:3 – this mortar mix is not used in general applications. It can be used as a repair mortar when they are combined with a waterproofing or bonding agent.
    • 1:4 – for ceiling and external plaster.
    • 1:5 – the ratio proved to be good as brickwork mortar. It is also good for internal plaster.
    • 1:6 – this ratio can be maintained for internal plaster.

 

Calculate Cement and Sand Requirement for Cement Plastering:

Calculating the quantities of cement, sand and water depends on a few parameters. These bring out the logic why you need to maintain the ratio.

  • Volume of plaster requirement: the volume of plaster can be calculated by multiplying the area of the plaster and the thickness of the plastering (in this case – 12mm)
    • Mix Ratio of plaster: deciding the Mix Ratio of plastering contains complex calculation. It indicated the ratio of the volume of cement to sand. Mix ratio of plaster 1:4 means that the mixture has one part cement and 4 parts sand.

For calculating quantity, generally two methods have been applied –DLDB method and Empirical method. These two processes include steps required for a logical distribution of the materials. The calculations and measurements used in this methods based on the quantity of the materials.

For further discussion, read www.onlinecivilforum.com

wall-plaster-calculator

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EMMA calculator for measuring electrical quantities

A generic ‘EMMA’ for work with bulk electrical quantities.

A multi-use EMMA should be applied for any ‘mass’ activity, that entails a physically quantifiable unit of construction work scope measured in tens, hundreds or thousands. As for instance, electrical cable tray or racking or cable laying/pulling are perfect individual subjects for this EMMA.

The EMMA contains 3 ‘pages’, called ‘INPUT’ (Basic data that should be entered to make EMMA functional), ‘TABLES’ (Spreadsheets used for entering target & actual progress percentages, man hours etc), and ‘CHARTS’ (Here accessed spreadsheets should be demonstrates as curves & histograms). The EMMA is applied for different purposes which are described below:

  1. To arrange target rate of progress (S-curve);
    2. To make an estimate regarding man-hours, converted to manpower requirements (histogram);
    3. To register units computed as complete every month;
    4. To register man-hours used each month, in that way automatically matching the actual rate of development and genuine handling of manpower, with premeditated rates.
    5. Besides, unacceptable trends can thus be recognized and work re-scheduled, together with automatic adjustments to manpower requirements, that will lead achievement of target completion.

Primary needs for inputting are:

  1. The projected total quantity;
    b. Meaning of the unit (eg m3);
    c. A valuation of man-hours necessary for each unit;
    d. The average number of hours to be conducted each day;
    e. The average number of days to be conducted on every week.

Subsequently, inputting should be compliant with notes provided.
Application of an EMMA will help in creating specific interest to anyone for taking liability to finish a work scope package before schedule.
6.11.B. Earthing tape, cable racks & trays, cables, terminations

The calculator demonstrated below can be employed for calculating man hours required for any one, or all, concerning the activities related to cabling which are incorporated. Besides, entering quantities, the user will be able to modify the unit manhour rates provided, for rates more in keeping with that User’s environment.

To obtain a hypothetical example, click Real-time Sync, provide secret key ‘electrified’ and click connect.

To start calculation, click on the following link farrell-and-co.com

EMMA calculator for measuring electrical quantities

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