## REINFORCEMENT QUANTITY ESTIMATION

**REINFORCEMENT QUANTITY ESTIMATION**

For estimating the cost of the structure, it is necessary for the quantities of the materials, including those of the reinforcement to be known. Accurate quantities of the concrete and brickwork can be calculated from the layout drawings. If working drawings and schedules for the reinforcement are not available it is necessary to provide an estimate of the anticipated quantities. The quantities are normally described in accordance with the requirements of the **Standard method of measurement of building works**.

**In the case of reinforcement quantities the basic requirements are:**

1. Bar reinforcement should be described separately by steel type (e.g. mild or high-yield steel), diameter and weight and divided up according to:

**(a) Element of structure**, e.g. foundations, slabs, walls, columns, etc., and

**(b) Bar ‘shape’**, e.g. straight, bent or hooked; curved; links, stirrups and spacers.

2. Fabric (mesh) reinforcement should be described separately by steel type, fabric type and area, divided up according to 1(a) and 1(b) above.

There are different **methods for estimating the quantities of reinforcement**;, three methods of varying accuracy are:

**Method-1 for Reinforcement Estimation**

The simplest method is based on the type of structure and the volume of the reinforced concrete elements. Typical values are, for example:

• Warehouses and similarly loaded and proportioned structures: 1 tonne of reinforcement per 105m^{3}

• Offices, shops, hotels: 1 tonne per 13.5m^{3}

• Residential, schools: 1 tonne per 15.05m^{3}

However, while this method is a useful check on the total estimated quantity it is the least accurate, and it requires considerable experience to break the tonnage down to Standard Method of Measurement requirements.

**Method-2 for Reinforcement Estimation**

Another method is to use factors that convert the steel areas obtained from the initial design calculations to weights, e.g. kg/M^{2} or kg/m as appropriate to the element.

If the weights are divided into practical bar diameters and shapes, this method give a reasonably accurate assessment. The factors, however, do assume a degree of standardization both of structural form and detailing.

This method is likely to be the most flexible and relatively precise in practice, as it is based on reinforcement requirements indicated by the initial design calculations.

**Method-3 for Reinforcement Estimation:**

For this method sketches are made for the ‘typical’ cases of elements and then weighted.

**This method has the advantages that: **

(a) The sketches are representative of the actual structure

(b) The sketches include the intended form of detailing and distribution of main and secondary reinforcement

(c) An allowance of additional steel for variations and holes may be made by inspection.

This method can also be used to calibrate or check the factors described in method 2 as it takes account of individual detailing methods.

**When preparing the reinforcement estimate, the following items should be considered:**

**(a) Laps and starter bars**

A reasonable allowance for normal laps in both main and distribution bars and for starter bars has shall be considered. It should however be checked if special lapping arrangements are used.

**(b) Architectural features**

The drawings should be looked at and sufficient allowance made for the reinforcement required for such ‘non-structural’ features.

**(c) Contingency**

A contingency of between 10% and 15% should be added to cater for some changes and for possible omissions.

Htwe Htwe Sein

Dec 06, 2012@ 15:26 pmIt's useful.

Shwetha S Rao

Dec 07, 2012@ 06:25 amGood one but more detail will be highly appreciable…

Vijay Kale

Dec 08, 2012@ 01:45 amGood Sirji. Usefull for all Engineers.GM.

Durga Prasad Sharma

Dec 08, 2012@ 06:48 amit is useful for site engineers.

Fakowajo Oyeniyi

Dec 08, 2012@ 13:04 pmthanks

Nabam Budh Hina

Dec 08, 2012@ 16:56 pmsame to shewta.

Manish Shah

Apr 29, 2013@ 12:42 pmSo usefull site this

Vishnu Thekkeattam

Oct 11, 2013@ 14:35 pmIt's useful

Shashi Kant Arya

Oct 11, 2013@ 15:24 pmuseful

Gul Afsar Khan

Oct 11, 2013@ 15:36 pmits batter .

Engr Abdul Rauf Shaikh

Oct 11, 2013@ 17:45 pmexcellent veb site

Karwan Khalid

Oct 11, 2013@ 19:36 pmwell done.

Kumar K Sriraman

Oct 12, 2013@ 01:00 amvery useful

Mohamed Hussain Mohamed Rizwan

Oct 12, 2013@ 02:28 amIn Method-I , reinforcement estimation/% by area also very helpful.

Kallimakala Reddy Prakash

Oct 12, 2013@ 06:14 amExcellent & very useful.

Dawood Mohammed Rabjan

Nov 14, 2013@ 17:32 pmthank u

Varun Bhandari

Nov 26, 2013@ 05:17 amfor ware houses it should be 1 ton/10.5m3 …printing mistake i suppose…

Mohd Ahsan Ali

Dec 24, 2013@ 14:54 pmHow to calculate number of laps in 12 mts column height as per IS Code in various dias

Ismath Janeer

Jan 12, 2014@ 04:18 amgood job

Shakeel Ahmed

Mar 07, 2014@ 06:30 amAre there specific names of Estimation of Reinforcement?

Amanj Othman

Mar 10, 2014@ 18:32 pmaa

Navee Naveen

Sep 19, 2014@ 15:24 pmvery use full thanks