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Saturday, January 20, 2018

Brief information on Project Cost System

If the design is modified at the design stage of a construction project, the project costs are constantly estimated and evaluated to keep the project costs within the budget of the owners. This working budget is normally known as the engineers or architects estimate. As soon as the design is completed, the field cost-control system is prepared with a final, detailed cost estimate of the total work.

This type of cost estimate is generally created by the construction contractor or another party who will be directly associated with the field operations. The contractor estimate is then abridged to a working construction budget and develop the foundation of the construction cost control system.

While the construction process is going on, cost accounting methods are utilized to recover actual construction expenses from current construction operations. This information is then applied for the purpose of controlling the cost on the current project and for working out the cost of future projects. Besides, the cost system offers significant information related to project financial control.

Preliminary Cost Estimates: Preliminary estimates of future construction expenses, are prepared throughout the project planning and design stages on the basis of approximation because these are accumulated prior to define the project entirely. This type of conceptual estimates differs from ascertaining the final detailed estimate of construction costs.

Basically, all conceptual price estimates are prepared on the basis of some system of gross unit costs which are acquired from earlier construction work. These unit costs are guessed forward in due course to focus on present market conditions, project location as well as the specific character of the job currently being considered. The following methods are followed to make preliminary estimates.

Cost per Function Estimate: This analysis is produced on the basis of the estimated expense per unit of use, like cost per patient, student, seat, or car space.
Construction expense may also be guessed like the average outlay per unit of a plants manufacturing or production capacity. These factors are normally applied as a method of instantly characterizing facilities costs at the setting up of a project when there is only raw marketing information, like the number of patients retained by a planned hospital. This extensive method of producing costs can also provide a powerful control on more detailed estimates as soon as they are created.
Index Number Estimate: This method is applicable for working out the price of a projected structure by upgrading the construction cost of the same type of current facility. It is performed by multiplying the original construction cost of the current structure with a national price index that is modified as per local conditions, like weather, labor expense, materials costs, transportation, and site location. A price index refers to the ratio of current construction cost to the original construction outlay for the type of structure concerned. Various types of price indexes are available in different trade publications.
Unit Area Cost Estimate: Under this type of method an approximate cost is selected with an estimated price for each unit of gross floor area. The method is found extensively in building and residential home construction. It offers a perfect rough calculation of costs for structures which are standardized or contain a large sampling of historical cost information from equivalent structures. This type of estimate is frequently applied in the industry to tally the relative value of different facilities.
To gather more information, go through the following construction article
Brief information on Project Cost System

Published By
Rajib Dey

Friday, January 19, 2018

Use and benefits of self compacting concrete

Self-consolidating concrete alias self-compacting concrete (SCC) is a concrete mixture that can flow into very complex forms with various reinforcing bars (rebar congestion) and leaves no voids.

It can be arranged with its own weight devoid of any mechanical vibration. SCC retains all the conventional mechanical and durability characteristics of concrete.

With extremely fluid nature of SCC, it becomes possible to arrange it in complicated conditions and in sections with congested reinforcement. It can also reduce hearing-related damages on the worksite due to vibration of concrete. In SSC, the required time is curtailed significantly for arranging bigger sections.

In some cases, the superplasticizers and viscosity modifier are provided to the mix to minimize bleeding and segregation.

A well designed SCC mix never segregates because it contains extreme deformability and outstanding stability characteristics.

Self-Compacting Concrete Properties: Self-compacting concrete has good resistance capacity against segregation as it applies mineral fillers or fines as well as special admixtures. Self-consolidating concrete is essential to flow and fill special forms under its own weight. It is flown adequately to travel over extremely reinforced areas, and should have capability to circumvent segregation of aggregate.

Self-compacting concrete contains an equivalent water cement or cement binder ratio that provides normally a slightly higher strength with regards to conventional vibrated concrete and because of non-existence of vibration, a better interface among the aggregate and hardened paste is created.

The concrete mix of SCC should be arranged at a comparatively greater velocity as compared to regular concrete. Self-compacting concrete is placed from heights longer than 5 meters exclusive of aggregate segregation. It is also useful for areas having normal and congested reinforcement, with aggregates as large as 2 inches.

Self-Compacting Concrete Uses - Self-compacting concrete is mostly utilized in bridges and even on pre-cast sections. This type of concrete is suitable for the following:

• Drilled shafts
• Columns
• Earth retaining systems
• Areas with high concentration of rebar and pipes/conduits

To know about the benefits of self consolidating concrete, go through the following link

Use and benefits of self compacting concrete

Published By
Rajib Dey

Thursday, January 18, 2018

Benefits and drawbacks of steel members

Steel is formed by mixing iron, carbon and other components. Due to its extreme tensile strength and low cost, it is considered as a most vital component that is extensively utilized in buildings, infrastructure, tools, ships, automobiles, machines, appliances, and weapons.

The steel provides lots of benefits as follows:

1. The steel members contain high strength. So, the steel members have the ability to withstand extreme loads with relatively light weight and small size of members.
Due to their small size, it becomes easier to deal with and transport steel members.
2. The steel members have strong resistance capacity against gas and water due to their high density power (the unit weight of steel is 7.85kN/m3).
3. The steel members last for prolonged periods due to great and standardized strength and density properties of steel.
4. The steel members are utilized as pre-fabricated members as they can be easily managed, fabricated and constructed.
5. The steel members can be easily disassembled or substituted.
6. The supplementary sections or plates can be added with the existing steel structure and structural components to improve the strength significantly.
7. The steel structures can be examined rapidly and smoothly.

8. It may be reprocessed / recycled in furnaces.
9. This material contains high ductility and it is very effective for earthquake resistance structures.

The drawbacks of steel members are as follows:

1. The steel members are vulnerable to corrosion. To get rid of corrosion, apply painting or other methods.
2. The steel members are expensive.


Benefits and drawbacks of steel members

Published By
Rajib Dey

Wednesday, January 17, 2018

Post Tension Slab and its benefits

Generally, post-tensioned (PT) slabs belong to flat slabs, band beam and slabs or ribbed slabs. PT slabs provide the leaner slab type, as concrete functions to its strengths, mostly being maintained in compression. Longer spans are obtained because of pre-stress, which are also utilized to resist deflections.

Post-tensioned slabs employ high-strength tensioned steel strands to compress the slabs to retain most of the concrete in compression. Reinforcement is arranged to control the compression.

In Post tension slab, the cables/steel tendons are applied to replace the reinforcement. It develops a very well-organized structure to reduce material usages as well as economic span range with regard to reinforced concrete.

Post-tensioning is very useful to defeat the natural weakness of concrete in tension and to optimize its strength in compression. In concrete structures, high-tensile steel tendons/cables are placed in the element prior to casting.

If the concrete attains the preferred strength the special hydraulic jacks are used to drag tendons and retain them in tension with specially designed anchorages fixed at each end of the tendon. It offers compression at the edge of the structural member that enhances the strength of the concrete for withstanding tension stresses.

If tendons are properly curved to a specific profile, they will employ, besides compression at the perimeter, a beneficial upward set of forces (load balancing forces) that will resist applied loads, alleviating the structure from a portion of gravity effects.
In this type of slab, cables are attached in spite of reinforcement. In Steel reinforcement the gapping among bars is 4 inch to 6 inch while in Post tension slab the gapping is over 2m.
• It facilitates slabs and other structural members to be slimmer
• It facilitates us to develop slabs on expansive or soft soils
• The produced Cracks are retained firmly mutually
• Post tension slabs are useful for building up stronger structures economically.
• It minimizes or removes shrinkage cracking. So, no joints, or fewer joints, are essential
• It allows us to design longer spans in elevated members, like floors or beams
• Only experienced professionals can construct post tension slabs.
• If precaution is not undertaken at the time of making it, it can cause future mishaps. In various situations, untaught workers become unable fill the gaps of the tendons and wiring entirely. These gaps lead to decay of the wires which become breakable quickly and unexpected collapsing may occur.
Post Tension Slab and its benefits

Published By
Rajib Dey

Tuesday, January 16, 2018

Some practical issue prior to start foundation design

In foundation design, there may occur different types of issues associated with construction and costs.
Given below, the details of main issues :-
1. The foundations should be retained as shallow as possible, suitable for coping up with climatic effect, and strength of the surface soil; particularly in waterlogged ground. Excavation in severely waterlogged ground is extravagant and time consuming.
2. Expensive and complicated shuttering details should be bypassed specifically in stiffened rafts. Proper care should be taken with buildability.
3. Curtailment in the costs of piling, betterment in ground treatment, improvements in soil mechanics, etc. have significantly impacted the economics of design, and various standard solutions becomes obsolete. So, it is very much important to evaluate construction costs and methods on a regular basis.
4. Designers should have clear ideas on the assumptions which are provided in design. These range from the inconsistencies of ground conditions, the infrequent unsuitability of refined soil analyses and the feasibility of construction.
5. The authenticity of the soil analysis, through vital evaluation.
6. Impact of construction on ground properties that range from vibration from piling, degradation of ground uncovered with excavation in unfavorable weather conditions, exclusion of overburden, seasonal disparity in the water-table, compaction of the ground by construction plant.
7. Impact of changeable shape, length and inflexibility of the foundation, and the requirement for movement and settlement joints.
8. Consequences on finished foundations of sulfate attack on concrete, ground movements because of frost heave, shrinkable clays, and the impacts of trees; also modifications in local environment due to new construction, re-orientations of heavy traffic, setting up of plant in adjacent factories inducing impact and vibration.
9. Rapid but invaluable construction is more cost-effective as compared to low-cost but slow construction to clients to bring quick return on capital investment.
10. Impact of new foundation loading on obtainable adjacent structures.
For more information, go through the following construction article

Some practical issue prior to start foundation design
Published By
Rajib Dey

Friday, January 12, 2018

Simplify the rectangular & continuous footing design with StruCalc

StruCalc’s footing design module is very useful to create the design of square, rectangular and/or continuous footings.

The footing module can be used to meet size and reinforcement requirements for any concrete footing loaded with pure vertical load. Once a footing type is set, StruCalc will then require what is providing the load; it signifies that the type of column is set for the square or rectangular footing, or the stemwall type for the continuous footing.

As soon as the footing type is provided, then the loads on the footing should be entered. The loads originate from two sources: calculations somewhere in the structure that might leads to reactions from beams, columns, walls, etc., or they might originate from the use of the load calculator. The load calculator will produce loads on the footing depending on the user set floor, roof, and wall loads accompanied by indicating tributary widths or areas.

Just fill in the load options of the calculator and it will automatically workout the Live Load and Dead Load.

As soon as the loads are provided, there exist some supplementary footing/environment information like steel yield strength, concrete compressive strength, soil bearing pressure, reinforcement cover, and reinforcement bar size etc. should have been entered.

StruCalc preloads some common values for the properties stated above, but the user will be able to modify any values that seem to be inappropriate.

Besides, adequate information concerning the column should also be entered while going to perform a square or rectangular footing design.

Now, for creating the designing of a square or rectangular footing, StruCalc will need a depth and a trial footing width (and length for rectangular footing) to be entered. Once, these are entered, StruCalc will check their capability provide the necessary reinforcement.

If the dimensions of the footing are not sufficient, a red bar will be visible in the lower right hand corner of the screen and new dimensions should have to enter. It will be at this point though, that StruCalc will have computed a necessary area for the footing. It will facilitate the user to indicate dimensions to fulfill the required area.

While going to design a continuous footing, then the density of the stemwall and height, along with the footing depth should have been entered. Once they are entered, StruCalc will produce a necessary footing width and the continuous reinforcement that is essential.

For more information, go through the following article

Simplify the rectangular & continuous footing design with StruCalc

Published By
Rajib Dey

Thursday, January 11, 2018

Some useful terms and definition used in brick masonry

Brick masonry is applied for developing buildings and other structures by bonding brick stone, stone blocks, brick blocks with various types of masonry.

For temporary sheds mud mortar is suitable but for all permanent buildings lime or cement mortars are utilized.

Different terms and definitions associated with Brick Masonry:

Course: A course refers to a layer of the same unit that runs parallel in a wall.

It is also described as a continuous row of any masonry unit like bricks concrete masonry units (CMU), stone, shingles, tiles, etc.

Bed: It belongs to the surface of stone vertical to the line of pressure. It specifies the lower surface of bricks or stones in every course.

Back: It is the inward surface of a wall that is not uncovered. The material that is used to develop the back is called backing.

Face: The outside of wall uncovered to weather is called face. The material that is utilized in the face of the wall is named as facing.

Hearting: It belongs to the inside part of a wall among n the facing and backing.

Side: It refers to the surface that builds up the boundary of bricks or stones in a transverse direction to the face and bed.

Joint: It is the meeting point of two or more bricks or stones. If the joint is parallel to the bed of bricks or stones in a course then it is termed as bed joint. Alternatively, it is a horizontal layer of mortar on which masonry units are arranged.

The joints which are set perpendicular to the bed joints are called vertical joints or side joints or just joints.

Some useful terms and definition used in brick masonry

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Published By
Rajib Dey