Construction Management Notes.

Organization

It is a group of people together to get things in systematic ways.

needs:-

  1. to prompt decision.
  2. co-ordinate action for th eachivement of goals.
  3. to faciliates in meeting management’s objectives.
  4. to arrange right people at right position at right time etc.

Types of organization

a. Line or Military Organization:- under such structure all managers have direct authority over their respective sub-ordinates through a chain of command. Authority flows downwards and responsibility flows upward throughout the organization. It is the simple and earliest one.

Advantages:-

i. easy to understand and follow.

ii. facilitates easy supervision.

iii. economical, as no specialists are needed and a limited number of executives are employed.

iv. responsibility is fixed that facilitates fixation of accountability etc.

Disadvantages:-

i. lack of specialization.

ii. lack of co-ordinates among different departments.

iii. no participation of lower officer in decision making etc.

b. Line and Staff Organization:- it is a modification of line organization to execute such large and complicated work superiors staff and specialists are appointed.

c. Functional Organization:- it is introduced by F.W Taylor. Functional organization design involves the grouping of similar jobs under function and major functions as separate departments. Every functional unit has a different set of duties.

Network Analysis

The diagrammatic representation of the activity of the entire project is called Network Analysis Diagram.

Various techniques for Network Analysis are:-

i. Bar Chart (Gnatt Chart).

ii. Milestone Chart.

iii. CPM (Critical Path Method).

iv. PERT (Program Evaluation and Review Technique).

v. Earn Value Analysis etc.

a. Bar Chart:- also known as Gnatt Chart, developed by Henry Gnatt in 1900 AD used in planning. In planning on Bar Chart, a horizontal bar represent different activities. The length of each bar indicates the or time taken for the completion of that activity.

Each bar is divided into two portions, the top portion indicates the progress or completion of the activity whereas the bottom portion indicates the time duration of an activity.

Limitation:-

  • suitable only for minor project.
  • interdependencies of activities.
  • project progress.
  • uncertainities.
  • lack of degree of details.

b. Milestone Chart:- is a modification of bar chart where important events are identified. It was developed in 1940 AD. The events are in chronological but not in a logical sequence.

The main activity of the project is divided into sub-activities. The beginning and end of these sub-divided activities are called Milestones.

c. CPM (Critical Path Method):- is a graphical network based on a scheduling technique developed by Margon R. walker in 1957 AD. It is an activity-oriented diagram and deals with the deterministic network.

Need:-

  • best to reduce time required to perform production, maintainance and construction.
  • to minimize the direct and indirect cost of project.

Main character:-

  • CPM is activity orinted.
  • CPM time are related to cost.
  • CPM does not take into account the uncertainities involved in the estimation of time for excution work.
Notes1:
a. Activity:- is a well-defined job or task that consumes time and resources. The activities are denoted by arrow.
b. Event:- is the instant of time. The beginning or end of an activity, denoted by geometrical figures such as circles, triangles, rectangles, etc.
c. Tail/Head Event:- the beginning of an activity is called a tail event whereas the end of an activity is called a head event.
d. Dual role event:- an event which is ahead event for some activities and at the same time tail event for some other activities called a dual role event.
e. Parallel activity:- the activities which can be performed simultaneously and independently to each other are called parallel activities.
f. Serial activity:- the activities which can be performed one after another in succession are called serial activity.
g. Non-critical activity:- activities that are not on the critical path are called non-critical activities.
h. Predecessor activity:- is that to be necessarily completed before another activity commences.
i. Successor activity:- is that activity that can be performed after the completion of other activities.
j. Dummy activity:- it is that activity, which does not consume any resources like time, cost, manpower, equipment, etc. It is used to maintain the logic of the network. It is represented by a dashed line. Also known as redundant activity.
k. Looping and dangling:- two errors in logic may occur while drawing a network called dangling (if the path of activities back into itself) and dangling (caused due to not emerging of activity).
l. Merge/Burst Node:- an event into which a number of activity enter and from which one or several activities leaves is called Merge Node similarly, an event which has one or several entering activities generating a number of emerging activities called Burst Node.

Notes2:
a. Critical Path:- this is the longest path of activities and determines the total project duration. It does not allow any delay, also known as a chain path.
The critical path always begins with the first event and terminates at the last event. Total floats along the critical path are 0.
b. Total project time:- is the sum of the duration of all activities falling within the critical path.
c. Earliest time & Latest time:-
Earliest Start Time (EST):- of an activity is the earliest time by which it can be commenced.
Earliest Finish Time (EFT):- is the earliest occurrence time for the event from which the activity arrow originates plus the duration of an activity.
Latest Start Time (LST):- for an activity is the latest time by which an activity can be completed of the project.
Latest Finish Time (LFT):- is the latest occurrence time for the node at which the activity arrow terminates.
Calculation,
Forward pass, EFT = EST + Duration.
Backward pass, LST = LFT – Duration.
d. Floats:- that means the available free time for an activity which is useful for the manager to manage the limited resources. In other words, it indicates the range within which an activity’s start time or its finish time may fluctuate without affecting the completion of the project.
Total Floats:- it is the totally free time for an activity. In other words, it is defined as the difference between the maximum time available and the actual time required to complete the activity.
Total floats may be positive, zero, and negative which represents sub-critical activity, critical activity, and super-critical activity.
T.F = LST – EST or LFT – EFT.
Free Floats:- is the spare time allowable for an activity so that the start time of the succeeding activity is not affected. It affects preceding activity.
Numerically, it is the difference between total floats and slack of the head event.
F.F = EST of succeeding activity – EFT of that activity.
Independent Float:- it is the maximum time available if the preceding activity ends as soon as possible and the succeeding activity starts as early as possible. It may be negative but should be taken as zero. It affects particular activity.
Numerically, it is the difference of total floats and slack of head event.
I.F of an activity = EST of SUCCsing activity – LFT of that activity.
Interfering Floats:- is the difference between total floats and free floats. It is nothing but slack of head event.
Int. F = T.F – F.F

d. PERT (Program Evaluation and Review Technique):

It is used in project management for non-repetitive jobs (research and development work). I follow the β-distribution curve. Four times:-

(a) The Optimistic time (to):- is the shortest possible time in which an activity can be completed under ideal conditions.

(b) The Pessimistic time (tp):- is the maximum possible time, it could be required to accomplish the job.

(c) The Most like time (tm):- is lies between the optimistic and pessimistic time estimates. It has a higher probability of occurrence so-called most like time.

(d) The Expected or average time (te):- is an average time taken by activity if it is repeated a large number of times.

te = ( to + 4 tm + tp ) / 6

* standard deviation (SD) = ( tp – to ) / 6 and SD = √variance.

CPM PERT Similarities:- both tools lead to the same end, a critical path and critical activities with a slack time equal to zero.

Difference between CPM/PERT:

CPM (Critical Path Method)PERT (Program Evaluation and Review Technique)
a. it is a deterministic tool, with a single estimate duration.
b. activity-oriented diagram.
c. times are related to cost, generally accurate and realistic.
d. used for repetitive projects.
a. it is a probabilistic tool, with three estimates of time.
b. event-oriented diagram.
c. times are not related to cost outcomes may not be exact.
d. used for research and development projects.

Notes3:
a. Scheduling:- is the advance preparation of a list of times and places, when and where the things planned, are to be accomplished.
b. Planning:- is the determination and formulation of steps and processes for doing any particular things.
c. Updating:- is the progress of incorporating changes and rescheduling.
d. Slack time:- is the difference between the latest event time and earliest event time. Slack may be positive, zero, and negative which represents the time of completion ahead of schedule, on schedule, and behind the schedule.
e. D.R Fulkerson derived a rule of numbering the event.
f. Tail of the activity represents the start of the activity whereas the head of the activity represents the finish of an activity.
g. Arrow representing activity in CPM network is drawn without any scale.
h. CPM follows a normal distribution curve.
i. A maximum number of head and tail events in CPM is one.
j. The number of redundant activities in CPM maybe 0,1,2,3,……
k. The probability of completion of any activity within its expected time is 50%.
l. Event does not consume any time and resources.

e. Earn Value Analysis (EVA):

It is the way to measure the amount of work actually performed on a project (i.e to measure its progress) and to forecast a project’s cost and date of completion. also known as BCWP. It is the latest method of network analysis.

Monitoring parameter:

a. BCWS = Budgeted Cost for Work Scheduled.

b. BCWP = Budgeted Cost for Work Performed.

c. ACWP = Actual Cost for Work Performed.

Cost and Time:-

  • project is a sum of direct cost and indirect cost.
  • direct cost is a cost for material, manpower and equipment.
  • indirect cost is a cost that canot be alloted clearly to the individual activities. eg, revenue,loss of profit, penalty etc.
  • Normal time:- the time usually allowed for an activity by the estimate (Tn).
  • Normal time:- the direct cost required to complete the activity in the normal time (Cn).
  • Crash time:- the minimum possible time in which an activity can be completed by developming extra resources (Tc).
  • Crash cost:- the direct cost crossponding to the crash time of completing an activity.
  • Optimum time:- total cost of project on optimum time is minimum known as optimum cost.
  • total cost slope is like U.
  • Cost slope = (crash cost – normal cost) / (normal time – crash time).

Responsibilities of civil Sub-Engineer:

  1. filling of Measurement Book.
  2. to plan the execution of the work.
  3. to teach sub ordinates
  4. to divide the work among the workers and to direct assets them in doing it.
  5. to improve work method and procedures.
  6. to maintain daily records etc.

Tool Box Talk:- to assist supervisory staff, to prevent accidents and injuries at work.

Contract:- by M. Chakraborti, it is an agreement enforceable by law. Law regarding, contract 2023 of Nepal, an agreement between two or more than two parties to do or not to do any business.

Day Work:- used to denote a procedure of costing an item work on the basis of actual labors and material required.

Tender:- is a written document offer presented before the owner or department in order to perform the specified work within a specified time under the agreed obligations.

Tender notices:- means of the expression thought which contractors know where they have to bid a tender. It contains:

  1. date, time and place of tender.
  2. name of authority inviting tenders.
  3. nature of work and its location.
  4. time of complection.
  5. validity of tender.
  6. amount of earniest money.
  7. estimated cost etc.

Earnest money (Bid Security):- it provides a guarantee of the party’s willingness of carrying out the work if he is awarded. It is taken (2-3%) of the estimated amount and deposited at the time of bidding the tenders.

the amount is returned to unsuccessful bidders. if a successful bidder fails to carry out the contract, this amount is forfeited.

Security Money (Performance Bond):- on acceptance of the tender, the contractor has to be deposit 5% of the bidding amount (with VAT) as security money with the department which is inclusive of the earnest money already deposited known as a performance bond.

An additional 8% is also right to demand if the quoted rate is unreliable.

Condition of Contract:- (a) General condition of contract (b) Special condition of contract:- some condition flow country law, nature of work, etc.

Contract Document:- it includes

  • name of work.
  • agreement content.
  • letter of intention to award the contract.
  • letter of acceptance.
  • contractor’s bid form.
  • condition cof contract.
  • technical speciafication
  • BOQ & Drawing.
  • working schedule.
  • additional document ,etc.

Administrative Approval:- an approval of project made by the concerned department studying the preliminarily report based on design, drawing, and estimates submitted by the concerned technical division known as administrative approval.

Technical Sanction:- project design, drawing, estimate from technical division and all prepared work are needed to be sanctioned by higher technical authority and sanction made is called a technical sanction.

Site Order Book:- it is a register duly certified by the client, including the name of the work, name of the contractor, reference of contract, work order, etc.

Measurement Book (MB):- is a type of document filled by the site in charge in the site as per the progress of work to pay the contractor. It includes,

  • name of the project.
  • name of contract and contractor.
  • date of contract, aggrement, completed, measuremet ,etc.
  • running bill nos. ,etc.

Muster Roll:- is the register commonly used in the department to make payment to the labor engaged in daily wages. it includes,

  • name of employee.
  • age, sex.
  • date of joining.
  • employee number.
  • rate of payment.
  • attendance ,etc.

Completion Report:- is a statement prepared by the contractor after the completion of the work and the final settlement of the account.

Construction schedule:- it shows clear data of a construction project with the quantities to be executed as well as the time required.

Equipment Schedule:- to show a list of equipment required to complete the project.

Material Schedule:- to show the actual quantity of material required for the project at different times.

Mobilization:- the amount of money paid to the contractor after the agreement and before the execution of work. The maximum amount of mobilization should be 20% of the contract amount.

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