Important Question And Answer: civil - Civil - Construction Scheduling

1.     What is the object of scheduling?

Scheduling means putting the plan on calendar basis. A project network shows the sequence and

inters dependencies of activities, their time and their earliest and latest completion time, but these needs to be scheduled to determine commencement and termination dates of each activity. Using optimum resources or working within resource constraints, it is a time table of work. A basic distinction exists between resource oriented scheduling techniques. The project is divided into number of operations.

2. List out the advantages of scheduling.

1..  By studying of any work and the many alternative methods of execution, we can choose the best one.

2. It gives a clear idea regarding the required men, materials, and equipments at different stages of

work.

3. Resource utilization is optimized.

4.  Actual progress of the work is monitored with the actual plan. If there is any delay, proper remedial measures can be taken to avoid such delays.

3. What is the purpose of work scheduling?

The bar - chart type work schedule provides a simplified version of the work plan, which can easily be understood by all concerned with planning, co - ordination, execution, and control of the project.

(b) It validates the time objectives:

A work schedule shows the planned sequence of activities, data - wise while putting the work

plan on a calendar basis; it takes into account reduced efficiency of resources to adverse climatic conditions and other factors.

(c) It evaluates the implications of scheduling constraints:

A work schedule brings out the implications of constraints and enables preparation of a plan of work within the frame work of these constraints.

4. What are the steps involved in schedule chart?

(a) Select the EST point of activity layout on the graph, and draw a line sloping equal to its rate of execution i.e., 1 unit per day.

(b) Plot the lowest rate slowing line and mark its intersection with the top to foundation horizontal

line.

(c)  Starting from the point of intersection, move forward horizontally on the top line and identify latest completion point of subsequent activity as indicated by the set back.

5. What are the factors affecting work scheduling?

(a) Time:

Most of the projects carry time constraints in the form of imposed dates, these dates may include constraints on start and completion of activities.

(b) Manpower:

Man power is one of the main in the successful execution of projects. The idle labour time is paid

for and the strikes and breakdown of work are kept in view by manpower.

(c) Materials:

Construction materials are increasingly becoming scarce and their procurement is a time consuming process. The schedule aids in forecasting of materials and their timely supply determines the economics and progress work.

6. What is the purpose of numbering events?

i. It simplifies the identification and description of a n activity in terms of event numbers.

ii.   The activities are coded as i- j where i and j are the event numbers as commencement and termination of an activity.

iii. It helps in developing identification code for computer application.

iv. It systematizes the computations of critical path for each activity as far as possible, the number of the proceeding event it should be less than that of the succeeding event.

7. Define the following terms:

1. Critical path:

The longest path through the network is called critical path and its length determines the minimum durations in which the project can be completed.

2. PERT (Program Evaluation and Review Technique):

PERT is vent oriented. It is parabolistic model i.e., it takes into account uncertainties involved in the estimation time of a job or an activity. It uses three estimates of the activity time, optimistic time and pessimistic time and, most likely time.

3. Dummy activity:

It is superimposed activity, which does not represent any specific operation or process. It has zero duration and consumes no resources, its purpose is

twofold. (a) To provide a logical link to maintain the correct.

(b) To simplify the description of concurrent activities in terms of event numbers. The dummy activity is drawn like any other activity, but with dotted lines.

8. What is the significance of critical path?

(a) It is the longest path in the network; however it is possible for a network to have more than one critical path. The sum of the durations of critical activities along the critical path determines

the duration of the project.

(b). It is the most sensitive path, any change in duration critical activities along the critical path is bound to effect the duration of the entire project.

9. Define the following terms.

1. EST (Earliest Start Time):

This is the earliest time an activity can be started, assuming that all the activities prior to it have taken place as early as possible.

2. LST (Latest Start Time) :

This is the latest time an activity can start consistent, with the completion of the project in the stipulated time. The LST of an activity is determined by subtracting the activity duration from the LFT

3. EFT (Earliest Finish Time):

It is the earliest time by which an activity can be completed assuming that all the activities prior to it begin at their EST.

4. LFT (Latest Finish Time):

It is the latest time by which an activity must be completed to ensure the completion of project within the stipulated time.

10. What are the classifications of networks?

1. Skeleton network

2. Master network

3. Detail network

4. Summary network.

11.Define the following terms: (a) Float:

The difference between the latest start time and earliest start time of an activity is called as float.

Float is a measure of the amount of time by which the start of an activity can be delayed consistent with the completion of the project on time.

(b) Total Float:

Total float of an activity is defined as the difference between the maximum duration of time

available for the completion and duration required to carry out that duration.

12.What is mean by resource leveling and crashing? Resource leveling:

The aim is reduce the peak resource requirements and smooth out period to period assignment within a constraint on the project duration.

Crashing:

Higher amounts of direct activity cost would be associated with smaller activity duration times, while longer duration time would involve comparatively lower direct cost. Such deliberate reduction of activity times by putting in extra effort is called Crashing.

13.      Define the following terms:

1. Normal cost:

Normal cost is the lowest possible direct cost required to complete an activity.

2. Normal time:

Normal time is the maximum time required to complete an activity at normal cost.

3. Crash time:

Crash time is the minimum possible time in which an activity can be completed using additional resources.

4. Crash cost:

Crash cost is the direct cost i.e., anticipated in completing an activity within the crash time.

14.      Define activity cost slope.

Activity cost slope is the rate of increase in the cost of activity per unit with a decrease in time.

The cost slope indicates the additional cost incurred per unit of time saved in reducing the duration of an activity.

Activity Cost slope =  crash cost - Normal cost  .    /  Normal time - Crash time