Construction project management - Guidelines, Part 2: Time Management
2013 Edition

IS 15883 Part 2 advocates employing the Precedence Diagram Method (PDM), also known as Activity on Node (AON), as outlined in IS 14580 (Part 2). It emphasizes defining various dependency types such as Finish to Start (FS), FS with lag, Start to Start (SS) with lag, Finish to Finish (FF) with lag, Start to Finish (SF) with lag, and FS with lead. The scheduling process involves constructing a network diagram, performing forward and backward pass calculations to determine early and late start/finish dates, total and free floats, identifying critical activities and paths, and establishing the overall project duration. Deliverables include network diagrams and Gantt charts for sub-projects, integrated into a master schedule. For repetitive or linear projects, the Line of Balance (LOB) technique is recommended. The method promotes continual schedule updates and coordination among disciplines, facilitated by construction management software.

The standard directs that the Work Breakdown Structure (WBS) should segment the project into manageable hierarchical units tailored to project complexity and timeline. Preparation can be organized by project phases such as pre-construction, construction, and commissioning; by functional disciplines like civil, electrical, plumbing; by organizational frameworks; or by physical locations such as floors or zones. The WBS hierarchy typically includes total project, sub-projects, work packages, and detailed activities. It advocates using tree or outline formats with standardized alpha-numeric codes for clarity and traceability. Activities at the lowest level serve as the basis for scheduling, enabling precise milestone tracking.

IS 15883 Part 2 recommends utilizing the Siemens Approximation Method (SAM) for managing time-cost tradeoffs, aiming to shorten project duration with minimal direct cost escalation. This involves calculating the cost slope—which represents the cost per unit time saved—using the difference between crash and normal costs divided by the difference in respective durations. The method entails identifying all project critical paths, calculating effective cost slopes for activities involved, and selectively crashing activities with the lowest cost slope until the desired project duration is achieved. Additional acceleration strategies include employing advanced construction technologies and equipment-intensive methods while considering resource availability, quality, safety, and project constraints.

Effective project progress monitoring per IS 15883 Part 2 involves dividing the project into defined performance periods, ensuring all stakeholders are aware of scheduled activities and milestones at each period's start, and submitting performance reports comparing actual progress against planned targets at period end. The process includes investigating and addressing time deviations, focusing on critical and near-critical path activities, and revising targets as necessary while keeping all parties informed. Progress is tracked using metrics such as earned value or manhours allocated up to relevant WBS levels, with cumulative data plotted against time to visualize deviations. Reports include tabular and graphical summaries of planned versus actual achievements, critical activity status, and forward-looking program updates.

Resource scheduling and levelling are crucial in ensuring the efficient and balanced allocation of manpower, materials, and equipment throughout the project duration. This process involves estimating daily resource requirements per activity, superimposing resource data onto the schedule, and adjusting allocations to reconcile demand with availability. Levelling optimizes resource usage to prevent peaks and troughs, aligns expenditure with cash flow, and facilitates meeting target completion dates without compromising quality or costs. By smoothing workloads and avoiding resource bottlenecks or idle periods, resource scheduling and levelling contribute significantly to maintaining controlled timelines and supporting successful project delivery.