Concrete Planning and Cost Estimation in Construction

INTRODUCTION Concrete often accounts for a large percentage of the total cost of a project. Many times, it represents 15–20% of the total cost, depending on the building materials and methods of construction chosen. If you plan to order concrete, it is essential to order the correct amount. If you order too little, problems will arise as you take measures to quickly acquire more. If you order too much, you have wasted money and resources and will have to dispose of the excess concrete. With proper planning and preparation, the pouring of concrete usually signals an exciting beginning of a construction project. ESSENTIAL QUESTION Why is it important for an architect to communicate the materials used to build residential buildings? OBJECTIVE KS8.1.2 Read and interpret drawings related to the design and construction of a building project STANDARD 2.F.02.11 Create a cost estimate for a construction project. VOCABULARY Concrete A solid, hard material produced by combining Portland cement, aggregates, sand, water and sometimes additional mixtures. Rebar Steel bar used to reinforce concrete. RESOURCES PDF: Existing Utility Shed Construction Drawing Google Slides: Estimating Costs - Concrete Pad Google Sheets: concrete calculator PROCEDURE Cost for the Shed Concrete Pad In this activity, you will calculate the cost of pouring the utility shed concrete floor slab as shown on A1 Example Utility Shed Drawing. The slab contains concrete and reinforcing rods (rebar). Construction costs must also include the cost of a small amount of material to create the concrete forms. 1. Use the diagram of the shed floor to calculate the number of cubic feet of concrete required to construct the pad. The slab is 4-in. thick. Convert cubic feet to cubic yards and record the amount in the quantity column of the table. 2. Use a local concrete vendor to find a current price/yard3 of concrete of bags to opened and mixed on site. Record the final cost of concrete to be poured for the utility shed. 3. Calculate the number and cost of the rebar needed to construct the pad. Determine the cost of rebar using local pricing. Rebar should be spaced 24 inches apart to form a grid pattern in the pad. Rebar comes in 10-foot sections. When more than one bar is needed to extend over 10 feet, adjacent bars are overlapped (end to end) 6 inches and wired together. Plan to provide a 3-inch edge distance; that is, terminate the rebar 3 inches short of the edge of the concrete. amount 10’ #4 rebar cost per total cost Draw pattern of rebar above. 4. Record the number of 12-ft long 2x6s and the number of 16-ft long 2x6s needed to build the forms. Assume that you need no other material for the forms. Determine the cost of the boards using local pricing found in advertisements, phone contact, or the internet. Screenshot the item. 5. Square or Rectangle Concrete Slab: Notes: ● Pre-mix concrete comes in bags that are 60 lbs. and 80 lbs. ● A 60 lb. bag provides 0.45 cubic feet of cured concrete. ● A 80 lb. bag provides 0.6 cubic feet of cured concrete. Material Concrete Concrete Rebar (Steel) Forms Size/Description 106 80 lbs bag 1 60 lbs bag 10’ ½” 12-ft long 2x6s Quantity 2.37 cubic yards 2.37 cubic yards 1 2 Forms 16-ft long 2x6s 2 Unit Cost $4.78 $3.48 $5.68 Cost Total Cost Unit cost sources for example Rebar #4 9/16” X 10’ can you find it for less at a local store in the Worcester area. Repeat the process for each item and include a screenshot of the item on that site. CONCLUSION 1. Describe the problems that would result from ordering too much concrete. 2. Describe the problems that would result from ordering too little concrete. 3. What percentage of the total cost of the pad does the steel rebar account for? 4. Why is it important to estimate the cost of construction for a building project? 5. Place all information from this sheet into your engineering notebook. Place a picture below.