Rate analysis for brickwork in construction

When we analyse a rate for construction work, we can get different answers according the previous records which have been recorded during construction period. Since the theoretical answer is the same for everyone, it shall be vary due to material quality, wastage, transport and limitation to the work, etc. The other major factor is the labour cost. For an example, the area can be covered for a certain work might be different for one another. It depends on the skill level and the work experiences.

Rate Analysis for Brick Work - 225mm thick (Ground Floor Level)

Required number of brick (Size 215x112.5x65mm) for 9.29m2 = 1090 Nr
Required number of cement bags (50kg) for 9.29m2 = 4 Nr
Required volume of sand for 9.29m2 = 0.3 Cu

As per the previous field records;

1 mason and 1 labour can cover approximately 6.5m2 per day (8 hr). Let's say to cover 9.29m2, it takes 1.43 mason days and 1.43 labour days. Assume mason charge 2500 LKR per day and labour charge 1600 LKR per day.

Total Labour Cost = 5,863.00LKR/9.29m2
Therefore labour cost for  1 m2 = 631.11 LKR


Assume cost of a brick is 13 LKR, Cement bag = 950 LKR and sand cube 13000 LKR.

Total cos of Material = 14170 LKR + 3800 LKR + 3900 LKR
                                   = 21870 LKR

Allow;

Wastage for brick 7.5% = 1062.75 LKR
Wastage for sand 10% =  390 LKR

Acutual cost of material = 233322.75 LKR/ 9.29m2

Hence cost for 1m2 = 2167.50 LKR


Now for the above rate, we need to add and apply the cost of necessary scafoldings, Tools & equipment hiring charges in the market. Usually, we add 3% of labour cost for the above.

Therefore charges for scafoldings, tools & equipment hiring charges for 1m2 would be  = 18.93 LKR

Now we can sum the cost of Labour, Material and Equipment hiring charges to get the actual working cost of 1m2 of 9" thick brick work as follows;

Total cost =  2817.54 LKR/m2 

Please note the above cost is indicated for the direct labour and cost can be vary due to wastage as I mentioned in the beginning of the paragraph. 

Rate Breakdown for Ready-mix Concrete - (Step - 01)

When you are building up a rate for concrete work for a particular tender, it is important to refer the preamble notes prior to the pricing.

examples:-

	All concrete works shall comply to the specifications, filled into formwork and well packed around reinforcement.  Note                     All concrete works shall be Grade 30 ready mix unless otherwise specified in the drawings and specifications.  Note                     All lean concrete works shall be Grade 15 as specified in the drawings and specifications. Note                     Contractor shall not cause any damage direct or consequential to the new structure during carrying out the work detailed in "Concrete Work" trade and he at his own expense, make good any damage caused to them, arising directly and/or indirectly out  of his fault and/ or negligence and/or  failure to take precautionary measures to avoid such damage. Note                     All Reinforcement unless otherwise specified shall be rod reinforcement and free from rust, mill scale, dirt, grease, or any other substance organic and/or giving specified strengths intended by the Engineer.  Note                     Rate for concreting columns, walls shall include for kickers.  Note                     Measurement of Slabs & Walls.                        Slab concrete include that part of beam to a depth of largest adjacent slab thickness. Note                     Concrete work for slabs and walls have been  categorized according to their thickness as followings: Note                     a. not exceeding 150 mm            b. between 150 mm and 300 mm            c. exceeding 300mm                        Measurement of Columns & Beams                        Concrete work for columns have been categorized according to their cross sectional areas as follows:  Note                     a. not exceeding 0.10 m2           b. exceeding 0.10 m2                       Concrete work for beams have been categorized to their cross sectional areas from lowest adjacent soffit of slabs as follows:  Note                     a. not exceeding 0.10 m2           b. exceeding 0.10 m2                       Concrete work related to Ramps has been measured separately and slopes have not been indicated. Slopes shall be as shown in the drawings.   (approximate slope is 1:10 ) Note                     Contractor shall ensure that all contacting surfaces including reinforcement dowels left out for bonding purposes is free from any organic or artificial material which can be a hindrance to achieve specified properties in the Drawings and Specifications.  Note                     Wherever work has been categorized according to the thickness, slope,  cross sectional area, height etc., the upper limit shall be include in the same category. Example walls between 150mm and 300mm thick shall include walls exceeding 150mm in thickness up to and including 300mm in thickness. Walls having 150mm thickness included in walls not exceeding 150mm thick category.  Note                     Rates for lean concrete shall include for preparation of bottom of excavation prior to pouring of lean concrete.  Note                     Contractor shall ensure that the top of the lean concrete layer shall be finished semi rough to receive waterproofing layer where applicable.   Note                     Rates for formwork shall include for control joints,  isolation joints wherever specified and required according  to the drawings and specifications.  Note                     All concrete shall be ready mix unless obtain approval for the Engineer to use site mix in special areas. Mix design of ready mix concrete shall be approved by the Engineer and the Contractor shall submit detail of his ready mix supplier, mix design calculation past tests report, sieve reports and other technical information.  Note                     Rate of concrete for floor slabs shall include for sand trowel finish to slab surface wherever specified to the satisfaction of the Engineer.  Note                     Rates for concrete shall include all necessary tests by an institute/Authority acceptable to the Engineer.  Note                     All concrete shall be ready mix unless allowed by the Engineer.  Note
	All concrete shall be ready mix unless obtain approval for the Engineer to use site mix in special areas. Mix design of ready mix concrete shall be approved by the Engineer and the Contractor shall submit detail of his ready mix supplier, mix design calculation past tests report, sieve reports and other technical information.	Note
	Rate of concrete for floor slabs shall include for sand trowel finish to slab surface wherever specified to the satisfaction of the Engineer.	Note
	Rates for concrete shall include all necessary tests by an institute/Authority acceptable to the Engineer.	Note
	All concrete shall be ready mix unless allowed by the Engineer. Rates for lean concrete shall include for preparation of bottom of excavation prior to pouring of lean concrete.    Contractor shall ensure that the top of the lean concrete layer shall be finished semi rough to receive waterproofing layer where applicable.   The estimator or the quantity surveyor must read all the above and should include necessary expenses for the above requirements.	Note

Role of Contract Administrator

Contract Administration

Contract administration involves managing your contracts to make sure you comply with and fulfill the contract conditions. Good contract administration ensures customer satisfaction and minimizes disputes (masterbuilders 2015).

A contract administrator should have a deep understanding of the contract data and documents of a project. A construction project will have a lot of contract documents and will be complex with the project scale. For an example, a project that goes around four or five years will have a considerable amount price fluctuation of materials, labour, and equipment. It is more likely increases the estimated cost. Appropriate contract documents for such situations are very critical.

All the construction work should be followed fully accordance with the BOQ, drawings & specification given. Completion of the project should be on time as stated in the contract documents. But sometimes extreme weather condition will effect in delaying the construction. In this case, acceptable way of recording these weather conditions is important and should include in the contract documents. Construction projects will have variations such as change of designs, change of specification, etc. so it is necessary to have proper conditions of the contract to deal with these kinds of situations. Hence, contract administration can be explained as the legal management of construction projects.               

The construction contract administration is a very responsible and vital job role for any kind of a construction project. The following responsibilities will be carried out by the contract administrator.

·         Preparing initial contract data and documents

·         Negotiate and make acceptable contract modifications

·         Evaluation and approval of progress payment and the final payment

·         Monitoring the progress and recording them properly

·         Certify contractor compliance with quality assurance requirements

·         Assess and make approvals on contractor appeals for disclaimers and deviations

·         Ensure timely submission of required documents

Academic qualification of a contract administrator is very important. He should have the knowledge of conditions of contracts that are issued by the government and relevant authorities. The academic qualification should be bachelor’s degree in quantity surveying, construction management or business management.   

A contract administrator should have the following proficiencies in order to become good contract administrator.

•          Good negotiation skills
•          Practical knowledge in construction work
•          Sound understanding in use of language of contractual agreements
•          Management and leadership
•          Effective communication skills
•          Excellent reading ability
•          Attentiveness to the detail

Reference

MASTERBUILDERS (2015). Contract administration. [online]. https://www.masterbuilders.asn.au/contracts-and-disputes/contract-administration

Rate Analysis for Tile Work

The rate analysis for tile work is very important because most of the floors finishes of the commercial and residential buildings are done by using tiles. For the tiling work, we need tiles, cement, sand, grout, tile adhesive, and tillers and helpers. The below calculations are based on BSR and field experiences.

Let's take an area of 100 sq.ft. 

Tile size - 2' x 2'

Number of tile required = 100 / 4 = 25 Nos

Add - wastage 10% = 25 x 10% = 2.5 

                                             say = 3 Nos

Total  = 28 Nos

12.5 mm thick Cement mortar bed

Cement = 1.25 bags

Add - wastage 5% = 1.25*5% = 0.08 

Total = 1.33

Sand = 0.07 Cu

Add - wastage 10% = 0.07*10% = 0.007

Total = 0.08

Tile Adhesive - 35Sq.ft / (30kg) bag 

Number of tile adhesive bags 30kg = 100/35 = 2.86 Nos

Tile Grout - 1kg bag can cover 250 Sq.ft 

Number of tile grout 1kg = 100/250 = 0.4 Nos

Total Material Requirement

2' x 2' Tiles = 28 Nos 

Tile Adhesive (30kg bags) = 2.86 Nos

Tile Grout (1kg pct) = 0.4 Nos

Cement (50kg bag) = 1.33 Bags

Sand = 0.08 Cu

Labour Requirement

Assume 1 Tiller and 1 Helper can lay up to 70-100 sq.ft per day

From the above analysis, we can calculate the rate for tiling work by applying the cost of each item such as tile price, adhesive price and labour rates.

 

 

Importance of Work Breakdown Structure (WBS)

What is Work Breakdown Structure (WBS)?

Work Breakdown Structure can be simply explained as the process of dividing a complex project into manageable components. Using a WBS, we can understand the project scope properly, task by task. A WBS is essential for any construction project regardless of the project scale.

The Project manager will be responsible for preparing a realistic and executable WBS. To formulate an appropriate WBS, the project manager should possess a vast knowledge and experience in the construction field. He must be able to distinguish between the activities that can be performed simultaneously and independently.

Importance of Adopting a Suitable WBS for a Project

As previously mentioned, a WBS is essential for any construction project, regardless of its scale, since it simplifies the execution process of a project. A large task can be shown in simple steps using a WBS and it will be easy to handle and complete the task without any complexity.

WBS will be beneficial in many aspects in a construction project as follows;

·         Awareness of the start date and end date of the project

·         Ability to recognize the start date and end date of each task

·         Realization of the project stages and project progress

·         The ability to estimate the project budget easily

·         Assists allocating money and forecasting of the project

·         Provides the client with a vision about the project stages

·         Monitoring the progress become easy

·         Supports early allocation of resources and responsibilities

·         Early decisions can be taken regarding the project

·         Simplifies the project scope

The main purpose of a WBS is to reduce complicated activities into a collection of tasks (Markgraf 2016). The project managers can handle the small tasks more efficiently rather than dealing with the complex ones. It is important for each task to have a limit and indicate a unique activity.

Since the tasks are quantifiable the allocation of resources and money become easy. The project budget can be forecasted easily which helps the project manager and financial manager to decide the amount of capital to be allocated on different stages of the project. WBS assists improving the financial stability of a construction project.

WBS provides accountability because of individuals or groups can be appointed early for a particular task. They must be able to complete the task according to the given schedule and cost. Early preparation for their tasks can be done, consequently the time and the scope of each task is measurable. Hence, the project delays can be minimized and eliminated by using an appropriate WBS.

A major criterion for project success is that it fulfills its intended purpose. The tasks of the WBS each implement a part of the overall function. A task is only completed when it fulfills its partial function (Markgraf 2016).

As the project manager, the aim is to complete the project within the time and the budget. To make it happen, it is vital to establish the most realistic Work Breakdown Structure. The construction should be carried out in line with the schedule. It needs a lot of effort and concentration on the project. It is required to complete the number of components in order to complete a major task of the WBS. 

When there is an appropriate WBS, we can identify the critical activities and the floating activities. Thus, we can give priority on those critical activities and get them done. It is a good practice not to drift the floating activities to their last moment and make them critical activities. The project team taking breaks in between without delaying the project is the strategy. Most of the time project managers follow the critical path as they believe that the project can be completed on time by this practice. 

With all the interpretations above, it proves the importance of a Work Breakdown Structure (WBS) for any construction project. It allows the project manager to focus on the project and make important decisions prematurely and assign responsibilities to employees. The finance managers and purchasing managers can be informed about the financial and material requirements of the project as early as possible. The Confusions and delays due to the material supply or the financial problems can be omitted by this practice. Thus, adopting a suitable Work Breakdown Structure is very important to complete the project successfully.

References

[1] MARKGRAF, Bert (2016). The Importance of a Work Breakdown Structure. [online]. http://smallbusiness.chron.com/importance-work-breakdown-structure-54294.html

[2] MATHIS, Micah (2016). WORK BREAKDOWN STRUCTURE (WBS) PURPOSE, PROCESS AND PITFALLS. [online]. https://www.projectsmart.co.uk/work-breakdown-structure-purpose-process-pitfalls.php

[3] SEAVUS (2016). PROJECT MANAGEMENT TIPS. [online]. http://pmtips.net/blog-new/benefits-work-breakdown-structure

[4] TUTORIALSPOINT (2016). Work Breakdown Structure. [online]. http://www.tutorialspoint.com/management_concepts/work_breakdown_structure.htm

[5] What is a Work Breakdown Structure (WBS) and Why is it Important? (2012). [online]. Last updated 12 9. http://www.pmdocuments.com/2012/09/12/what-is-a-work-breakdown-structure-wbs-and-why-is-it-important/

Taking-off Measurement for the Foundation

Taking-off Measurements

Estimating costs for particular construction work can be divided into categories as follows.

1. Method of construction
2. Detail drawings
3. Measurements
4. Specification of materials
5. Availability of material and market price
6. Quantity (Labour and Material)
7. Transport and operational expenses

Measurements are one of the most important parts in estimating the construction cost.  Estimate the materials, labor, transport, or whatever the expenses are prior to the quantities gathered from the drawings. Therefore, quantities must be very accurate to estimate the construction cost.

Taking-off measurement is called the process of recording dimensions in a standard way which is accepted by construction professionals. It is done in a particular sheet called TDS. Taking-off measurements and estimating the project quantities are time-consuming, but it is required to be done. Because to reduce errors and give a rational elucidation for the estimated quantity whenever necessary. The measurements entered are should be accurate while being clear and readable for others.

In this article, we will discuss how we take measurements for excavation work for the foundation in a building.

Foundation Detail

Foundation Layout

According to the given details in the drawings, we can find the centerline girth of the building.

Horizontal Lengths          = 3 x 20’-0” + 2 x 10’-0”

                                         = 60’=0” + 20’-0”

                                         = 80’-0”

Vertical Lengths              = 3 x 20’-0” + 2 x 12’-0”

                                         = 60’-0” + 24’-0”

                                         = 84’-0”

Centerline Girth            = 80’-0” + 84’-0”

                                        = 164’-0”

Let’s find the excavation volume of the rubble foundation with the following steps;

Excavation for Rubble Foundation            = 164’-0” x 1’-6” x 2’-0”

                                                                   = 492 Cu.ft

Ddt

For Column bases            = 8 x 3’-0” x 3’-0” x 2’-0”

                                         = (144 Cu.ft)

Therefore Total excavation for Rubble Foundation = 492 Cu.ft – 144 Cu.ft

                                                                                                    = 348 Cu.ft

                                                                                                   = 3.48 Cube

                                                                                                   = 9.85 m3

Excavation for Column Bases      = 8 x 3’-0” x 3’-0” x 3’-0”

                                                      = 216 Cu.ft

Total Excavation Work for the foundation of the Building = 348 Cu.ft + 216 Cu.ft

                                                                                                                = 564 Cu.ft

                                                                                                                = 5.64 Cube

                                                                                                                = 15.96 m3

                                      

Material Calculation for Concrete Mixing Designs

Introduction to Concrete

Concrete is an artificial stone which we used in construction. Concrete can be divided into two main categories as follows;

1. Mass Concrete
2. RCC Concrete

The only different between Mass concrete and RCC concrete is reinforcement. The mass concretes are designed without reinforcement while RCC concrete are designed with considerable reinforcement. The mass concrete are not being used as structural concrete. It is only used for leveling & as ground floor slabs and may be as some other architectural designs.

The concrete is basically made with cement, sand, metal and water to mix them together. The metal used for increasing the volume and also to give a considerable strength to the concrete. The sand used to fill the rest of the void which cannot be filled with metal. The cement is used in concrete will make these components attached well together with the jelly kind of thing that they produce in the mixing. Again the cement will make sure to fill other micro small voids which the sand cannot go through. 

Density of Cement  = 1440 kg/m3

Density of Sand      =  1920 kg/m3 

Density of Metal     = 1800 kg/m3

How to Find the cement, sand & metal quantities used in different type of  concrete mixing designs.

Calculations are based on the following assumption;

• Sand includes 15% wastage
• Cement Included 5% wastage
• No wastage includes for metal
• Contribution of the sand 65% per 1m3 of concrete by volume
• Contribution of metal 85%  per 1m3 of concrete by volume
• Contribution of cement 2% per 1m3 of concrete by volume

Nominal Mixing Designs

1. G15 (C:S:M = 1:3:6)
2. G20 (C:S:M = 1:2:4)
3. G25 (C:S:M = 1:1 1/2:3)
4. G30 (C:S:M = 1:1:2)

Contribution of material for 1 m3 of concrete = Sand 65% + Metal 85% + Cement 2%

                                                                          = 152 %

                                                                          = 1.52 m3

This means (1.52m3) to produce a 1m3 of solid concrete requires a 1.52 m3 of the actual quantity of the above material.

Hence, we can find the required material for the different type of concrete.

Required Material for G15 Concrete

1. G15 (C:S:M = 1:3:6)

Cement  = 1/10 = 0.1

Sand      = 3/10 = 0.3

Metal     = 6/10 = 0.6

Number of 50 kg cement bags per 1m3 = 0.1 x 1.52 m3 / Volume of cement bag

                                                             = 0.152 / 0.035

                                                             = 4.343 

                                                             = 4.343 x 1.05 

                                                             = 4.560 Nr

Therefore required number of cement bags per 1Cu = 4.56 x 2.83 Nr

                                                                                   = 12.91 Bags

                                                    Say Nr of Bags      = 13 Nos

 Required amount of Sand = 0.3 x 1.52 Cu 

                                           = 0.456 Cu

                                           = 0.456 x 1.15 Cu

                                           = 0.525 Cu

Say Required Amount of Sand      = 0.53 Cu

 Required amount of Metal = 0.6 x 1.52 Cu 

                                            = 0.912 Cu

Say Required Amount of Metal      = 0.91 Cu

Required material for G20 Concrete

2. G20 (C:S:M = 1:2:4)

Cement  = 1/7 = 0.14

Sand      = 2/7 = 0.29

Metal     = 4/7 = 0.57

Number of 50 kg cement bags per 1m3 = 0.14 x 1.52 m3 / Volume of cement bag

                                                             = 0.21 / 0.035

                                                             = 6.00 

                                                             = 6.00 x 1.05 

                                                             = 6.30 Nr

Therefore required number of cement bags per 1Cu = 6.30 x 2.83 Nr

                                                                                   = 17.83 Bags

                                                    Say Nr of Bags      = 18 Nos

 Required amount of Sand = 0.28 x 1.52 Cu 

                                           = 0.43 Cu

                                           = 0.43 x 1.15 Cu

                                           = 0.50 Cu

Say Required Amount of Sand      = 0.50 Cu

 Required amount of Metal = 0.571 x 1.52 Cu 

                                            = 0.87 Cu

Say Required Amount of Metal      = 0.87 Cu

Required material for G25 Concrete

3. G25 (C:S:M = 1:1.5:3)

Cement  = 1/5.5 = 0.18

Sand      = 1.5/5.5 = 0.27

Metal     = 3/5.5 = 0.55

Number of 50 kg cement bags per 1m3 = 0.18 x 1.52 m3 / Volume of cement bag

                                                             = 0.27 / 0.035

                                                             = 7.71 

                                                             = 7.71 x 1.05 

                                                             = 8.1 Nr

Therefore required number of cement bags per 1Cu = 8.1 x 2.83 Nr

                                                                                   = 22.92 Bags

                                                    Say Nr of Bags      = 23 Nos

 Required amount of Sand = 0.27 x 1.52 Cu 

                                           = 0.41 Cu

                                           = 0.41 x 1.15 Cu

                                           = 0.47 Cu

Say Required Amount of Sand      = 0.47 Cu

 Required amount of Metal = 0.55 x 1.52 Cu 

                                            = 0.836 Cu

Say Required Amount of Metal      = 0.87 Cu

Required material for G30 Concrete

4. G30 (C:S:M = 1:1:2)

Cement  = 1/4 = 0.25

Sand      = 1/4 = 0.25

Metal     = 3/5.5 = 0.50

Number of 50 kg cement bags per 1m3 = 0.25 x 1.52 m3 / Volume of cement bag

                                                             = 0.38 / 0.035

                                                             = 10.86 

                                                             = 10.86 x 1.05 

                                                             = 11.40 Nr

Therefore required number of cement bags per 1Cu = 11.40 x 2.83 Nr

                                                                                   = 32.26 Bags

                                                    Say Nr of Bags      = 31 Nos

 Required amount of Sand = 0.25 x 1.52 Cu 

                                           = 0.38 Cu

                                           = 0.38 x 1.15 Cu

                                           = 0.437 Cu

Say Required Amount of Sand      = 0.44 Cu

 Required amount of Metal = 0.50 x 1.52 Cu 

                                            = 0.76 Cu

Say Required Amount of Metal      = 0.76 Cu

Please go through the below link to survey form.

https://docs.google.com/forms/d/e/1FAIpQLSfEaESLCOB1f1RjUpi0QpBp_bAKKhLTgqcqLlBaFSZm5ITH1A/viewform?c=0&w=1&usp=mail_form_link