A project is about placing reinforcing steel for a cast-in-situ footing. The project manager needs to plan job clock time, labor productivity and labor cost estimate by employing two skilled steel setters. Steel bars are to be purchased to reinforce a single isolated concrete footing of 7 ft wide and 6 ft long. The reinforcing steel is #8 bars (1 inch diameter, 2.67 lb/ft) with a 6-inch bend in both sides in both long and short directions of the footing; additionally, the bars are spaced at maximum 8 inches center to center apart both ways in top and bottom layers. Important to note: the concrete cover is specified as 0.5 ft, which is the gap from the first rebar center line to the concrete edge; this specification applies to the four edges of the footing. Sketch to illustrate the rebar bending at the end of the footing (not in exact scale) Precast concrete blocks, spaced over average 2 ft but not over 3 ft apart each way under the intersection of bars, will be used to support the reinforcing. The bars will be tied at each intersection, by bar ties. The steel will be stored in orderly stock piles, grouped by rebar length, about 100-ft distance away from the center of the footing. The footing will be constructed 2 ft below the ground. The rebar placing crew has two steel-setters; hourly rate (bare) is $63/hr for each individual worker.

a) Quantity Takeoff: 

i. Takeoff the required quantity of reinforcing in total length (ft) and weight (lb) along the long side and the short side of the footing, respectively. In case the number of bars is a float number, you round up to the next integer. 

ii. Takeoff the quantity of intersections of bars that need to be tied. iii. In market the maximum length of #8 bars limited to 20 ft. How many 20 ft bars needs to be purchased? You need to sketch the scheme showing how to cut 20 ft bars so as to fulfill the requirements on this project. You also need to determine the rebar wastage percentage in terms of weight (note: wastage is defined as the quantity of bars purchased but unused on the current footing job). 

b) Given the specific information on method productivity, estimate time requirements in hours for each of the following activities in handling the rebar. On a project a worker will seldom work more than 45 to 50 min/hr, because of necessary delays. Based on a 45-min hour for the current project, estimate the total clock time to handle and place the reinforcing by the crew. Note: Finish-to-Start logical relationships are imposed between Activity B and Activity A; Activity C and Activity B. The quantity takeoff for estimating rebar handling labor cost and productivity only includes all the bars installed in the footing, excluding the wastage.

 Activity A: Carrying bars to the footing site by employing two steel setters who work as a crew: The cycle time required to place the reinforcing includes the time to carry bars to the footing site at speed of 80 ft/min, plus the time for the two workers to walk back to the steel stockpile also at speed of 80 ft/min; plus a total time of 2 min for the two workers to pick up and put down reinforcing. The two workers can carry 30 lb in each trip. Estimate the total time to carry rebar in hr (rounded to two decimal places)  Activity B: Placing the bars on blocks and spacing them: the two workers crew working together can place 20 lb/min. 

 Activity C: Tying the bars at intersections: Each worker can make three ties per min. Based on the above information, estimate (i) productivity in terms of labor-hours per ton, (ii) crew hourly production rate in ton per hr; and (iii) the unit labor cost in dollars per lb. Note 1 ton = 2000 lbs.