★The  Scheduling Process

The planning and scheduling process, which begins in the preconstruction stage, can be divided into seven steps: 

1. Establish objective（目标建立）

Scheduling begins with a plan. the first step is to establish an objective that can be defined as a specific, measurable project goal.

2. Identify project activities（活动定义） 

The second step is to break down the project into definable work activities that, when completed, reach the objective. An activity should be action oriented, visible, and measurable. Activities should be sortable by area, discipline, and phase.

3. Determine activity sequence（活动排序）

The next step is to sequence the project activities. construction managers must determine in what order activities occur. The best way is to examine each activity independently and ask the following questions:

• What activity must precede（先于 紧前于） this activity?

• What activity must succeed（接任，紧后于） this activity?

4. Determine activity durations（活动时间计算）

At this point the duration of each activity must be determined. If an estimate has already been prepared, each activity should be examined in light of what duration assumptions were made at the time of the estimate. At this stage it is best to calculate the normal duration for each activity: that is, the duration that will complete this activity in the most effective manner.

5. Perform schedule calculations（工期计算）

Once the activity durations are determined, it is possible to add up the durations of the different activity sequences or paths. the longest path through the network is called the critical path and determines the duration for the project. paths that have a shorter duration have extra time, also called float or slack.

6. Revise and adjust（工期优化和调整）

Scheduling is an iterative process（迭代的过程）; the result of Step 5 is only the beginning. However, it may show overcommitted resources（过度投入的资源） or an unacceptable completion date. If this is the case, the scheduler has many tools to work with. He or she can defer（推迟、延缓） work, increase crew（团队、人员） sizes, or plan overtime work to meet project goals. As adjustments are made and the project’s duration shortened, direct costs increase;but because the job is shortened, indirect costs go down

7. Monitor and control. （监督和控制）

The optimum schedule is the baseline or target schedule for the project and defines when the work begins. As the work proceeds, changes may occur due to scope revisions（调整）, unforeseen conditions, or mistakes. the project manager’s goal is to make the appropriate adjustments to keep the forecasted completion date.

▓ In other words（进度计划的另一种表述）

• Activity Definition(活动定义）

• Network Diagram（绘制网络图）

• Activity Duration（活动时间估算）

• Calculations（工期计算）

• Refining（优化）

• Monitoring（监控）