Civil Engineering Information

Before undertaking a construction project it is necessary to know the expected cost and it is worked out by estimation. It is a computation of the quantities required and expenditure likely to be in the construction of the work.

The following are the different types of estimates:

1. Preliminary or Approximate Estimate:
This estimate is prepared to decide the financial aspects,policy and to give the idea of the cost of the proposal to the competent sanctioning authority.The calculation for approximate estimate is done in many ways. There are three types of approximate estimate
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INTRODUCTION
It consists of various items of work in the form of a statement depicting quantities, description and rate per unit. It is used to define the quality and quantity of works to be carried out by main contractor for completing work. It is made in tabular format and is mainly used for inviting tender and supplied to contractors to fill up the rates. On receipt of tenders the rates are compared and decision is made regarding the work. It is prepared by quantity surveyors and building estimators to be handed over to contractor.

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INTRODUCTION
For earthwork in excavation, foundation which are symmetrical, brickwork in superstructure and plinth and concrete in foundation, two methods are there for estimation. These are-

1. Separate or Individual wall method and
2. Centre Line Method.

With these methods the lengths and widths of various items are mainly found out which helps in calculations.
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CIVIL ENGINEERING ABBREVIATION:
The common abbreviation used in civil engineering are as follows:

A.A.S.H.T.O – American Association of State Highway Transport
A.B – Anchor Bolt Or Asbestos Board
A.C.I – American concrete institute.
A.R.E.A – American Railway Engineering Association.
A.S.C – Allowable stress of concrete.
A.S.T.M – American Society for Testing Materials
AC – Asphalt Concrete
AE – Assistant Engineer
APM – Assistant Project Manager
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By
Sourav Dutta
Manager-Civil

We generally designate stirrups by its external dimensions. For example, a 250mm x 300mm stirrup has the 250mm and 300mm dimensions in perpendicular directions as shown in Fig 1.

Now a stirrup has 2 bends, types of which are shown in Fig 1 and Fig 4. Guideline of minimum bend length is as per Cl.3.8 of BIS2502 (shown in Fig 3).
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By
Er. Vaishnav C R Nair

Introduction
The slabs are made depressed in depth form the general floor level in wet area like toilets, balconies, wash area in kitchen etc. This is to ensure the wet and dry area separations in buildings. Even though the sunken slabs provided the toilet and balcony areas are found with a major quality problem of Dampness. This is due to the continues contact of water with building blocks. Here comes the importance of Kerb Construction.

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By
Sourav Dutta
Manager-Civil

Brand embossing
On rebar pieces, different items are encrypted in the following manner:

Here, X = Dia of rebar in mm, eg, 20
ABCD = Brand of rebar, eg, TATA TISCON / SAIL / JSPL etc
Y = Yield stress of rebar, eg, 500 indicates Fe500 with yield stress=500 Mpa
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By
Sourav Dutta
Manager-Civil

Design and construction:
The design and construction of formwork should take account of safety and of the surface finish required. The formwork should be sufficiently rigid and tight to prevent loss of grout or mortar from the fresh concrete, during its placing and construction.

Formwork and its supports should maintain their correct position and be to correct shape and profile so that the final concrete structure is within the limits of the dimensional tolerances specified. They should be designed to withstand the worst combination of self-weight, reinforcement weight, wet concrete weight, concrete pressure, and construction and wind loads, together with all incidental dynamic effects caused by placing, vibrating and compacting the concrete.

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By
Sourav Dutta
Manager-Civil

Common Hazards/issues normally countered at all construction sites:

Human error in rebar fabrication (manual).

Fig 1 : Incorrect bend

Compromise with safety and quality.

Fig 2 : Safety and Quality issues upon using rebar cutter

Procurement schedule delays affecting site progress, and thereby delaying project completion.

Inventory management. Capital locked in inventory.

Fig 3 : Lack of space at site affects storage/procurement

Rebar pilferage.
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By
Sourav Dutta
Manager-Civil

The first version of BIS 1786 came out in 1985 when in Cl.5.1, the code suggested the nominal sizes as shown below:

Fig 1 (s) : BIS1786-1985 and the relevant clause

The next version of the code BIS 1786 was introduced in 2008, where nominal sizes were rationalized and nominal sizes 7 mm, 18 mm, 22 mm, 45 mm and 50 mm had been removed. In Cl. 6.1, the code had suggested the nominal sizes as shown below:

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