Quantity Surveying

1. Quantity Surveying

2. Estimate Estimate, An estimate is an educated guess. We are all familiar with estimates. We have obtained estimates*for work on our car, *for getting our house painted*for closing costs on a mortgage. The main difference between these simple estimating activities and the estimates used to price construction is complexity and what's at stake.

3. Example: Simple estimate • You have decided to repaint your living room. You want to go buy the paint but you must first figure out how much you need. What types of information will be required to make this determination? Based on that information, how many kilograms will you need and how much will It cost? • How much area one kilogram of paint covers • The cost of each kilogram of paint • The dimensions of the room • The dimensions of the windows and doors

4. Example • How much area one kilogram of paint covers – 12m2 • The cost of each kilogram of paint – 27 TL • The dimensions of the room – 4x5x3 • The dimensions of the windows and doors – 2 windows 1x2 and one door 2x1.5 The area of ceiling= 4*5= 20 m2 The area of wall = (4+5)*2*3 = 54m2 Total area= 74 m2 Total area of windows and door = 1*2*2+2*1.5=7 Total painting area = 74-7 = 67 m2 Total kilograms of paint Total cost 67/16= 5.58 Must purchase 6 * 27 = 162 TL

5. Cost estimate • Cost estimating is an attempt to forecast the actual cost of a project. • If the estimate is determined less than the actual cost instead of a profit the contractor may have a loss. • If the estimate is determined more than the actual cost the contractor may not receive the bid due to high bid price.

6. Characteristics of Good Estimator • Reads contract documents well • Is knowledgeable about construction techniques • Is familiar with typical job conditions • Is familiar with construction products • Has good visualization skills • Follows instructions explicitly • Is creative, yet practical • Is detail-oriented and thorough • Can meet deadlines and work under pressure

7. Characteristics of Good Estimator • Is familiar with purchasing • Is familiar with computer applications • Works well with numbers and statistics • Is a perfectionist at the task level • Has very good organization skills

8. Factors affecting the project cost • Project Size • Complexity of the project • Shape of facility • Height of facility • Unique materials or applications • Site location • Time of construction • Quality of work • Market conditions • Management Factors

9. Types of estimate • Conceptual estimate • Preliminary estimate • Detailed estimates

10. The estimating process • How many(quantities) • How much (pricing) • How long (productivity) • Estimating requires • Detailed study of the bidding documents including construction drawings and specifications.

11. Quantity surveying; is measuring the items which form a construction one by one and quantifying these items.In calculations,distances, meters, volumes and weights are measured by usingmeters, meter square, meter cubic and tonnes, respectively. There is a direct relationship between the accuracy of the costs of the construction calculated based on quantity surveying and accuracy of quantity surveying. Therefore, it is required to know how to prepare quantity surveys properly. Inappropriate quantity survey>>> Inappropriate estimation of costs of construction Quantity Surveying

12. Warnings while preparing quantity surveying The quantity surveying does not require complex mathematical calculations.However, mistakes inwriting the units of dimensions taken off dimensions simple calculationcan lead to conflicts between the parties involved in construction.

13. Warnings while preparing quantity surveying The parts of the construction which are quantified should be stated at the plan.  The similar height, width, area and volumes should be multiplied with the number of similarity.  The dimensions should be recorded and calculated by using meters.  The mathematical calculations should be performed very carefully.  Firstly, the calculations are made by including voids, then the voids are subtracted from total area.

14. Warnings while preparing quantity surveying The quantity documents should be used to avoid mistakes.The width and lengths should be obtained from plans, and the height should be determined from section plans. Firstly, which dimension units should be used in measuring structures.

15. Filling the quantity documents  Following the calculations in controlling the quantity survey should be easy. In other words, the controller can understand easily how the dimensions are determined.  The plans should be identified appropriately. Therefore, the controller can easily follow the calculations. In addition, eliminating the serious mistakes, the subtotal of each work items should be provided. Example; In the quantity survey of concrete, the survey should be performed for floor, foundation, beton metrajı yapılırken temel, kolon, döşeme ve kiriş betonları metraj cetveli üzerinde ayrı ayrı görülebilmelidir.

16. Quantity abstract The total quantity survey consists of many pages, therefore instead of presenting all calculations related to the quantity survey, a table shows the abstract of all quantity survey which provides total quantity of each construction structure. This table is called quantity abstract table.

17. Example: Finding the number of steel bars Number of steel barsIn the plans, the diameter of steel bars and space between these bars are stated as Ø8/30. These spaces are shown from one straight steel bar to the adjacent straight steel bar and for bent bars from one bent steel bar to the adjacent bent steel bar. This means that the distance between one straight steel bar and adjacent bent bar is equal to the half of the space between bars.

18. Example Number of steel bars:

19. Example Number of steel bars:There are three conditions:a) No residual: If the obtained quotient is an integer, the quotient is equal to the number of steel bar. In floors, firstly the straight steel is montaged, and lastly again the straight steel is montaged. This means that the number of bent bar is one less than the number of straight steel. Floor width Space number Distance between steels Straight bar Number Bent bar Number One less than straight steel bar

20. Example Number of steel bars:b) There is residualWhen there is residual, the residual is divided into two. If the residual is smaller than the half space distance. One more straight steel is inserted into the calculation. Therefore, firstly the straight steel is montaged, and lastly again the straight steel is montaged. This means that the number of bent bar is one less than the number of straight steel. Floor width Space number Distance bar Space number Straight bar Number Bent bar Number One less than straight steel bar

21. Example The number of steel bars:c) There is residual:When there is residual, the residual is divided into two. If the residual is larger than the half space distance, the number of steel is determined as the quotient of the division. Therefore, firstly the straight steel is montaged, and lastly again the bent steel is montaged. This means that the number of bent bar equals to the number of straight steel. Floor width Space number Distance bar Space number Straight bar Number Equals to straight steel bar Bent bar Number

22. Some of the works

23. Minha: Yapılması gereken bir iş için hesaplanan miktardan eksi kısımların düşülmesi. Duvar metrajı yaparken pencere ve kapıların hesaptan düşülmesi gibi.