Planning & scheduling

Transcription

1 Hashemite University Department of Civil Engineering Construction Planning & scheduling Introduction Dr. Maha alkasasbeh Planning & scheduling Owners want their projects completed within specified time and budget constraints The challenge of delivering a construction project in time, with high quality, within budget, and in a safe environment. Planning can be thought of as determining what is going to be done, how, where, and by whom 1

2 Planning & scheduling Planning is processes of identifying all the activities necessary to successfully complete the project. Scheduling is the process of determining the sequential order of the planned activities,assigning realistic duration, and determine the start and finish dates for each activity. Planning & scheduling There is a significant difference between planning and scheduling Scheduling can never be performed effectively without planning Planning is the first step of project scheduling,as change occur additional planning is required to incorporate the change into schedule. Planning and Scheduling can serve in preventing problems.it can prevent delay in work and prevent low worker morale and decline in productivity 2

3 Planning & scheduling Begin planning before starting work, rather than after starting work. Involve people who will actually do the work. Include all aspect of project :scope,budget, schedule and quality. Build flexibility into plan. Keep the plan simple. Communicate the plan to all parties, any plan is worthless unless it is known Steps in Planning and Scheduling Develop a work break down structure(wbs) that identify work items Prepare a drawing (network diagram) that shows each activity in the order it must be performed to complete the project. Determine the time,cost, resources required to complete each activity. Compute the schedule to determine start, finish,and float time. 3

4 Steps in Planning and Scheduling Analyze cost and resources for the project. Communicate the results of the plan and schedule. display time, cost and schedule for activates Techniques for planning and scheduling The technique used for project scheduling will vary depending upon the projects size, complexity, duration, personal, and owner requirements. The project manager must choose a scheduling technique that is simple to use and is easily interpreted by all project participants. 4

5 Techniques for planning and scheduling Methods that commonly used: -Bar chart (Gantt chart) -Critical path method(cpm or network analysis system ). - The program evaluation review technique (PERT) Bar chart (Gantt chart) Henry Gantt developed a method of relating a list of activities to a timescale in a very effective manner, by drawing bar charts 5

6 Bar chart (Gantt chart) Value of Bar Charts A major strength of bar charts is the ability to clearly and quickly present the status of a project. No extensive training is required to learn how to extract information from them 6

7 Shortcomings of Bar Charts Bar charts begin to fail to provide valuable information when projects become more complex A general criticism of bar charts is that they do not show clear dependencies between activities Changes in the logical sequencing of activities in a bar chart cannot be readily made, especially when many activities are involved Critical Path Method(CPM) The CPM commonly used in engineering and construction industry. CPM identifies chains of activities in the project that control how long the project will take Provide interrelationships of activities and scheduling of costs and resources. 7

8 Critical Path Method(CPM) A traditional CPM technique is the Activity-on- Arrow,(A-on-A), or arrow diagram, Activities are represented as arrows or lines The alternative approach is Activity-on-Node (A-on-N), referred to as the Precedence technique. Require more effort than a bar chart. It is an effective technique for overall project scheduling The program evaluation review technique (PERT) PERT can be thought of as a generalized CPM in which an expected activity duration is computed PERT is used primarily in undertakings where insufficient experience or historical data are available for estimating durations of individual activities in a project CPM is deterministic and PERT is probabilistic 8

9 A Work Breakdown Structure (WBS) A Work Breakdown Structure (WBS) is a systematic way to describe components of a project schedule Developing the WBS begins with the definition of the major systems or components of a project Each system is defined in greater and greater detail, until there exists a discrete or measurable piece of work and a single responsibility work packages Work packages can be viewed as mini projects that are contained within the entire project A Work Breakdown Structure (WBS) Information should be provided by various individuals, Project manager; job superintendent; others WBS divides & subdivides a project into different components area, phase, function, or other means By using the WBS approach, the project will become easier to comprehend The backbone of the project control or tracking system 9

10 A Work Breakdown Structure (WBS) The WBS is an orderly presentation of the tasks that must be performed to complete a particular project On a typical construction project the WBS consists of numerous categories depending on complexity In general terms, the WBS can be viewed as a representation of the physical breakdown of the work to be performed A Work Breakdown Structure (WBS) Work Breakdown Structure for a Storage Facility Project 10

11 Standard classification systems Two standard formats for organizing construction specifications Can use them as a guideline for defining WBS Uniformat: Masterformat: asp Standard classification systems Standard classification systems could be used as a guideline for defining WBS. Major classification systems in North America are MasterFormat, UniFormat and OmniClass,. These classifications are produced by CSI (Construction Specifications Institute) and CSC (Construction Specifications Canada). UniFormat is a standardized classification for organizing preliminary construction information into standard categories or on the basis of systems and assemblies. UniFormat classifies elements that usually perform a given function regardless of the design specification and construction method 11

12 Standard classification systems UniFormat is used for cost estimation during schematic design phase UniFormat framework is a hierarchical system. It comprises eight major groups UniFormat classification system 12

13 UniFormat classification system Standard classification systems MasterFormat is a master list of numbers and titles Since the 1960s most buildings in the United States and Canada have used this standard for managing building information. MasterFormat organizes construction information into procurement and contracting requirements, and technical divisions of activities and work practices. 13

14 Standard classification systems It is mainly used to organize project manuals, organize cost information, and relate drawing notations to specifications MasterFormat is a hierarchical classification system. It is broken down into two groups and seven subgroups. Each subgroup includes divisions,. There are fifty divisions (00-49) with 15 of them reserved for future expansion. MasterFormat classification system (CSI 2004) 14

15 MasterFormat divisions (CSI 2004) Standard classification systems The OmniClass Construction Classification System (OCCS) has been widely used in North America for many years. The purpose of OmniClass is to help in managing project information, sorting and retrieving information, and providing classification for all components and processes within the building life cycle OmniClass uses 15 tables.table 21 (Elements) is based on UniFormat, Table 22 (Work Results) is based on MasterFormat. Table 23 (Products). Each table demonstrates a different facet of building information. In addition, each of them classifies a particular type of information. 15

16 OmniClass tables (CSI 2006) Reasons For Planning & Scheduling Finish the project on time Continuous flow of work(no delay) Reduce amount of rework Minimize confusion and misunderstandings Increased knowledge of statues of project by every one 16

17 Reasons For Planning & Scheduling Meaningful and timely reports to management. You run the project instead the project running you. Know of schedule times of key parts of the project Clear understanding of how. what, when,and how much. Reasons For Planning & Scheduling Many project contract documents expressly require contractors to submit a CPM analysis prior to commencing work In some cases CPM analysis is required with the bid CPM allows the user to examine the trade-off between the time & cost required for a project By accurately monitoring project status, decisions can be made regularly about schedule viability 17