# Ihab Saad – Line of Balance

The efficiency of driving distance and speed for highway activities is estimated to be between 75% and 83%, with a total duration of 12.6 hours. A buffer is formed by a horizontal offset from one activity to its destruction, and the location is formed by a vertical offset from one activity to follow. A control tool is used to update project information and updates daily, including measuring actual performance and updating work schedules, and is designed to be a control tool. The tool is used to update project information and updates work schedules, including updates to project information and actual progress.
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30s of that piece of equipment.

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The formula for the distance in miles, again, this is from the

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construction equipment

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class time is equal to number of passes times distance divided by

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speed times efficiency. So we have the number of passes for each one

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of the activities, whether it's nine passes, six passes, etc, the

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distance is going to be the same for all the activities because

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we're doing it for the same segment of the highway. Speed has

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been obtained from the previous slide, depending on the gear and

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efficiency is, how many productive minutes do you get per hour from

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that piece of equipment? No piece of equipment is going to work

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continuously. 60 minutes an hour. It's going to be probably 50

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minutes an hour, or 45 minutes an hour. So the efficiency is going

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to be probably 75% 83% something like that.

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So distance is going to be in miles, speed in miles per hour.

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Resulting time is going to be in hours.

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The efficiency factor for an average operator during daylight

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hours, we would expect a 50 minute per hour efficiency or a 0.83

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which is 50 divided by 60 efficiency factor.

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So the time to ditch,

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the number of passes is six, distance is four miles, speed is

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2.3 miles per hour efficiency factor point eight three. So by

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applying the equation, we get the duration for this activity is

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going to be 12.6 hours.

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To reshape same distance for miles, number of passes I did

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increase a little bit, and the speed has also increased. So we do

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it in 14 hours. And then for grading, it's going to be done in

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only four point point three hours, because it's a lower number of

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passes and a higher speed.

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So the total duration for this process, if these activities were

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done as finished to start back to back, is going to be 12.6 plus 14

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hours, plus 4.3 hours.

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Now how we know that we don't need to do one activity for all four

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miles in order to be able to start the following activities? In this

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case, they can start as a start to start with some lag. In this case,

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the lag is going to be called our buffer that we talked about. So

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the activity slope does not have to be constant, which means the

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duration, the progress rate, or the production rate, which in this

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case is the speed does not have to be constant.

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So it can vary from one segment to another. You can start very slow,

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and then build up speed and then slow down again towards the end.

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So if we were to produce it graphically through a line of

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balance, it's going to be appear something like this. Of course,

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the lines are not going to be exactly parallel, because the

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production rate, and therefore the speed of the activity, is going to

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vary from one activity to another.

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The curves in the previous example are usually placed by broken

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straight line again, because the speed might not you may slow down

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little bit, you may increase your speed a little bit, and so on.

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So

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if the activity is at one location, which means you're not

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moving, you're spending time without moving. Then in this case,

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you are it's represented by horizontal line, like here, for

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example, again, horizontal line means that there's no there's time

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passing with no progress being done.

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On the other hand, this is another example three activities,

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surveying, underground utilities and foundation. The underground

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utilities can be a little bit slower than surveying and the

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foundation. So if we do it this way, you're going to have an

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interference or a clash, and we cannot accept that. So how are we

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going to deal with that?

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The buffer is going to be the linear schedule. The linear

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schedule uses two types of buffers, the time buffer and the

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location or space buffer. Time buffer is formed by a horizontal

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offset from one activity to its follower, the gap between the

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activities, what we call the lag, or the delay. Location buffer is

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formed by a vertical offset from one activity to is follow.

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So this, for example, here is a buffer that's introduced at the

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end to make sure that the activity is not clash.

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So this is the buffer,

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horizontal buffer, or time buffer,

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and then another example of a time buffer also.

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And then here, this is a vertical buffer.

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It shows the difference in location. So this is going to be

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at a certain location, this is going to be at another location.

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So.

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The example. Don't worry about it, because the example at the end is

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going to explain all of these things. The productivity rate of

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an activity can vary. Therefore the line representing its progress

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can be broken. So it's going to proceed at certain speed, chain

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speed, accelerate it and then slow it down at the end, which is going

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to be represented by a broken line. How are we going to update?

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So this is a planning tool. How are we going to make it a control

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tool as well? How are we going to update our project schedule,

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updates reflecting actual performance information, include

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time of occurrence, when did it actually happen, amount or

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percentage of work completed and changes. In case of changes,

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changes for to future work. An updated schedule is a revised

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schedule reflecting project information at a given data date.

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Same thing, the vertical line, as we did with the Gantt chart, is

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going to represent the data date regarding completed activities, in

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progress, activities and changes in logic, cost and resources

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required and allocated at any activity level.

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So the data date also known, if you remember, from updating, also

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known as cutoff date as of date status date. All of these are

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different names, the date as of which all progress on a project is

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reported. It's not the current date or the time. Now this may be

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two weeks ago when I made the update for my schedule.

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So here, for example, this was the original schedule,

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and then I introduced the data date to measure my actual

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performance. And this green line for earth moving represented the

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planned schedule. The red line, the dark red line, represents the

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actual schedule. So this shows the delay in the activities.

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In fact,

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it shows that the activity the line is milder, therefore the

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progress was slower, therefore we have a delay. We were supposed to

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be here on this date after four days, but we are only here.

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We are at the same point at after five five days, so we are one day

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behind scale.

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Let's look at an example, and this example, hopefully is going to

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make things very clear.

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A project consists of five activities. These

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five activities are excavating a trench, laying a sub base of

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gravel, laying a concrete pipe, back filling after you lay the

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pipe and you connect them, of course, and then compacting to

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flatten and to level the site so we have length of the pipe, which

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is the same, 1000 feet, and then we have production rates that are

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shown in the table. To excavate the trench is going to be done at

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the pace of 100 linear feet per day. So it's going to take

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basically 1000 feet divided by 100 linear feet per day, which is

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going to take 10 days laying a sub base of gravel, is going to be

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again, 125 linear feet per day. So to this whole activity is going to

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take 1000 feet divided by 125

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that's going to give eight days laying a concrete pipe, 75 linear

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feet per day. We can calculate the duration back filling 200 linear

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feet per day much faster. So it's going to take only five days, and

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then compacting

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150 linear feet per day, so it's going to be about maybe six and a

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half days, which can be rounded up to seven days. So from this

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production rate, we can basically calculate the durations,

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just as we said on the previous slide, 1000 divided by 100 which

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is a production date, gives 10 days, eight days, 30.335

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6.67 days.

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So if we were to plot these activities, how are we going to do

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that?

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This is the first one showing the speed. So

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one segment is going to take that long, or one day is going to take

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that amount, and then the following day, and so on. So the

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first activity. Here's the first activity, and then I'm going to

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introduce a two day buffer between activities, because, as you can

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see from the previous from the previous table here,

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this activity is faster. Laying a sub base of gravel takes only

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eight days. So if I were to proceed at the same speed as the

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first activity, we're gonna clash at a certain point. So what I did

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is I waited. I calculated this from the end. I drew the graph

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first, and based on that, I decided, when am I going to be

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able to start the second activity? But I did it from the end. I

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looked when is the last

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excavation part is going to take place? And then I added two days

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from the end, from the back. So if we start on day zero, for example.

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