CHAPTER 7 PROJECT PLANNING

FIGURE 7.1 Cost-time-scope triangle 7.1 Introduction Cost, time, and scope are the essential elements constantly juggled by each participant in any project. 공사비, 공기, 공사 범위 This chapter discusses tools for planning and managing a project. 프로젝트 계획 및 관리 FIGURE 7.1 Cost-time-scope triangle

7.2 Work Breakdown Structure The bid package consisting of the plans and specifications establishes the scope of work to be performed. 입찰 서류에 공사의 범위 명시 To be properly managed, the scope of work must be broken into components that define work elements or building blocks (sub-elements). 관리를 위해 전체 공사를 작은 과업 단위로 분해 The sub-elements are often referred to as work packages. 과업(Task) The summation of the work packages can be shown in a hierarchical format called a work breakdown structure (WBS). 작업 분류 체계

7.2 Work Breakdown Structure 전체 공사 공사 부위 공사 종류 필요 자재 Reinforced 과업 FIGURE 7.2 Work breakdown structure (WBS) example for a small building

7.2 Work Breakdown Structure Planning can be thought of as the definition and sequencing of the work packages within a given project. 계획(과업의 정의 및 작업 순서 결정) : 작업 분해 & 순서 결정 Planning = Work Breakdown + Work Sequencing Plan  Do  Check  Action: PDCA Cycle 일반적 관리 절차 : 계획  실행  검토  조치 계획 실행 조치 검토 검토 FIGURE 7.3 Deming cycle

7.3 Developing the Work Breakdown Structure In establishing the WBS, the following guidelines need to be considered: 1. Work packages must be clearly distinguishable from other work packages. 하나의 과업은 다른 과업과 명확하게 구분되어야 함 2. Each work package must have a unique starting and ending date. 각 과업은 고유한 시작시간과 종료시간을 가져야 함 3. Each work package should have its own unique budget. 각 과업은 자신만의 고유한 예산을 가져야 함 4. Work packages should be small enough that precise measurement of work progress is possible. 각 과업은 작업 진도를 측정할 수 있을 정도로 충분히 작아야 함

7.4 A Work Breakdown Example In construction, the various aspects of the work that contribute to breakdown of the project into packages relate to: 작업 분해의 기준이 될 수 있는 특성 1. Methods used to place the work. 공법 2. Skills needed for the work. 필요 기술 3. Craft workers involved. 숙련공 4. Critical resources (e.g., cranes, crews, etc.) 핵심 자원

7.4 A Work Breakdown Example Small gas station project example For this example, the following four categories (유일성을 유지하기 위해 범주화) have been defined: 1. Location or area within the project (e.g., foundation–pile cap). 공사 내의 위치(공사 부위) 2. Material type (e.g., concrete, reinforcing steel, etc.). 필요 원자재 3. Method of installation (e.g., excavation). 공사 종류 4. Types of resources required (e.g., labor and equipment needed). 필요 인력 또는 장비

7.5 Work Packages for the Gas Station Project 1단계: Location 범주만 고려 1. Parking and service area 2. Foundation 3. Building walls/structural panels 4. Building roof 5. Interior floors/slabs 6. Interior finishes 7. Exterior finishes 8. Electrical systems 9. Mechanical systems 2단계: Material 범주 추가 토공 아스팔트 콘크리트

7.5 Work Packages for the Gas Station Project 3단계: Method and Resource 범주 추가 1. Excavation of waste water system. 2. Drainage tile installation–waste water. 3. Septic tank installation. 오수 정화조 4. Fresh water lines (piping). 5. Sinks, basins, and toilets installation. 6. Hot water system installation. 7. Pneumatic air system installation.

7.6 Determining Sequence of Work Packages Having broken the work into work packages, activities that facilitate time management and control can be defined and logically placed in sequence. 작업 분해  작업에 대한 관리 시작 : 작업 순서 결정 The word activity is generally used when discussing time control or scheduling. WBS : 과업  공정 관리 : 액티비티 In arranging the work package sequence for time control, the criteria of (a) location, (b) material, (c) method, and (d) required resources must be reconsidered. 작업 순서 결정 요인 : 위치(부위), 자재, 공법, 자원(인력, 장비) Physical constraints or physical logic are common and characteristic of construction operations (e.g., the floor must be completed before installing the floor covering, etc.). 물리적 제약으로 인한 작업 선후행 관계 발생 : 바닥 작업 완료 후 바닥 마감재 작업 가능 Management decision (e.g., the fixture subcontractor is available first and is instructed to proceed) and the sequence is driven by management logic. 관리적 목적으로 인한 작업 선후행 관계 발생 : 붙박이 가구 시공자가 일정이 맞아서 먼저 작업을 진행하도록 함

7.6 Determining Sequence of Work Packages 외부 마감공사 내부 마감공사 착공 현장정리 기초공사 골조공사 지붕공사 내부공사 준공 전기/기계 시스템 공사 FIGURE 7.5 Preliminary project breakdown

7.7 Estimate Development and Cost Control Related to the Work Breakdown Structure A good WBS facilitates cost control during the life of the project. 작업 분류 체계를 원가 관리를 위해 사용 Work packages are defined so that they have their own unique budgets. 과업은 자신만의 고유한 예산을 가짐 When referring to work packages in the context of cost control, the terminology cost accounts or control accounts is often used. 원가(비용) 관리 계정 To provide consistency and structure to the management of large cost control systems, a code of accounts is used as a template or guide in defining and cataloging the cost centers within a project. Several cost coding systems are presented in Chapter 17. 원가(비용) 계정 코드  원가 관리 시스템

FIGURE 7.6 Cost control cycle (PDCA Cycle) 7.7 Estimate Development and Cost Control Related to the Work Breakdown Structure 투찰가 결정 낙찰? 예산 수립 실적 집계 예산 조정 공사 종료? 예산 대비 실적 검토 조치 계획 수립 FIGURE 7.6 Cost control cycle (PDCA Cycle)

7.8 Role of Code of Accounts A typical cost code might define 원가 (비용) 계정 코드는 다음 코드들의 결합으로 정의됨 (a) the project designator 프로젝트 코드 (b) area of work 위치 코드 (c) work discipline (e.g., civil, mechanical, electrical, etc.) 공사 종류 코드 (d) the trade specialty (세부 공정 전문 영역) required. 세부 공사 종류 코드

7.8 Role of Code of Accounts Actual Budget FIGURE 7.7 Work package control account sheet (CII Cost/Schedule Task Force, 1988)

7.9 Summary In order to manage, one should be able to control. In order to control, one should be able to measure. In order to measure, one should be able to define. In order to define, one should be able to quantify (정량화). 정량화  지표 정의  측정  통제  관리 The following is a partial list of other plans that must be developed: Procurement plan, Safety plan, Subcontracting plan, Quality plan, Communication plan, Organizational plan, Completion and start-up plan