1. Background
This article presents a conceptual viewpoint for the Schedule Architecture of large programs and complex mega-projects.
Programs and mega projects in the infrastructure and construction industry can be characterized by a multitude of stakeholders organized in a complex structure of designers and consultants, contractors and subcontractors, project management companies, owners and other entities. They are also characterized by multiple stages of execution and construction, that are interdependent and integrated into each other. The schedules of such programs and mega projects may include tens of thousands, even hundreds of thousands of tasks and Gantt lines. The proposed architecture is set up in a top-down process, and is updated in a bottom-up process.
At the schedule set up stage, this concept allows to transfer by inheritance, down to lower levels, the project strategy, major milestones and main phases, so that the detailed schedules in the lower levels of the architecture are based on, and comply with, the overall project strategy.
Throughout the design and construction phases, while carrying out schedule monitoring and control, the proposed architecture enables a comprehensive situation awareness and a project-wide picture of the project status, with data at the upper levels being updated based on the progress at the lower levels.
This concept has been successfully implemented in several mega projects such as the "Red Line" project [part of Tel Aviv Mass Transit System]; "Ofek Rahav" project [construction of a large, ultramodern military base to house several old IDF bases]; the expansion project of the railway system and station at Ben-Gurion International Airport; and more.
2. Overview
The architecture is comprised of four tiers:
Tier 4 is the most detailed level; it contains the contractors' detailed execution and construction plans. Climbing up the architecture, the level of detail is gradually reducing, and the schedule is a summary of the level below it.
This architecture, and the tools integrated into it, will be built in such a way that they provide and enable a multitude of advantages and functionalities, such as: planning, monitoring and control of all project components; overall strategic planning, with “Drill down” options to the sub-project levels; ‘What if’ scenario analyses; flexible control with IT tools [MS Project, Primavera]; management of an integrated plan, in an environment coordinating between all sub-projects and work packages in the various phases of the project; management and monitoring of contractors, designers and other stakeholders; and production of reports, plans and status updates to various levels of operations, management and control.
3. Architecture in detail
Tier 1 - Executive Summary - a summary of the entire project work plan, depicting the project schedule objectives and the major milestones of the main sub-projects and work packages; the resolution is such that it contains the project main work packages and deliverables [top level WBS]. The Executive Summary schedule serves as the skeleton for the Strategic Schedule and the Master Schedule.
Tier 2 - Strategic Schedule - a ‘skeletal’ strategic plan that contains all main sub-projects, main work packages and their components [the upper levels of the WBS]; the schedule comprises also pre-planned buffers at the project level. The Strategic Schedule enables performing ‘What-if’ scenario analyses, while examining the impacts on the various sub-projects.
Tier 3 - Master Schedule - the main overall integrative plan. The Master Schedule is derived from the Strategic Schedule [level 2], and comprises all sub-projects in a level of detail that enables logic-linking all sub projects and work packages; this will then enable critical path analyses for the entire project.
Project Baseline Plan - after NTP is received, the Master Schedule is updated and ‘frozen’ to constitute the base schedule plan, the Baseline. The Baseline, after being approved by the Owner, becomes an integral part of the contract and serves as the basis for all subsequent schedules.
Tier 4 - Detailed Work Plans - an aggregation of all schedules of the various sub-projects and work packages, down to the contractor/designer level. This is the plan according to which the Owner/Project Manager works with the contractors during the implementation phase.