Construction Management
Project planning, scheduling, cost estimation, and site management
1. Project Planning Fundamentals
Project Management Triangle
Balancing scope, time, and cost while maintaining quality. Changing one affects the others.
Project Life Cycle
1. Initiation
Feasibility study, project charter, stakeholder identification
2. Planning
WBS, scheduling, budgeting, resource planning
3. Execution
Construction, monitoring, quality control
4. Closeout
Final inspection, handover, documentation
Work Breakdown Structure (WBS)
Hierarchical decomposition of project scope into manageable work packages.
Level 1: Project
Level 2: Phases (Foundation, Superstructure, MEP, Finishes)
Level 3: Deliverables (Footings, Columns, Beams)
Level 4: Work Packages (Excavation, Formwork, Reinforcement)
Project Delivery Methods
| Method | Description | Advantages |
|---|---|---|
| Design-Bid-Build | Sequential: Design → Bid → Build | Clear scope, competitive pricing |
| Design-Build | Single entity for design and construction | Faster, single point of responsibility |
| CM at Risk | CM guarantees maximum price | Early CM input, cost certainty |
| Build-Operate-Transfer | Private builds, operates, then transfers | Infrastructure financing |
2. CPM and PERT Scheduling
Network Scheduling Techniques
CPM (Critical Path Method) and PERT (Program Evaluation and Review Technique) are essential for project scheduling.
Activity Relationships
Finish-to-Start (FS)
Most common. B starts after A finishes.
Start-to-Start (SS)
B starts when A starts (with lag).
Finish-to-Finish (FF)
B finishes when A finishes.
Start-to-Finish (SF)
Rare. B finishes when A starts.
CPM Calculations
Forward Pass (Early Times)
ES = max(EF of predecessors)
EF = ES + Duration
Backward Pass (Late Times)
LF = min(LS of successors)
LS = LF - Duration
Float/Slack Calculations
Total Float (TF)
TF = LS - ES = LF - EF
Time activity can be delayed without delaying project
Free Float (FF)
FF = ES(successor) - EF(current)
Time activity can be delayed without delaying successor
Critical Path
Critical Path = Longest path through network = Total Float of 0
- • Determines minimum project duration
- • Any delay on critical path delays project
- • Focus resources on critical activities
- • May have multiple critical paths
PERT (Probabilistic Approach)
Three-Time Estimate
a
Optimistic
m
Most Likely
b
Pessimistic
te = (a + 4m + b) / 6
Expected time (Beta distribution)
σ = (b - a) / 6
Standard deviation of activity
Project Duration Probability
σproject = √(Σσ²critical)
Sum variances along critical path
Z = (Ts - Te) / σproject
Ts = scheduled time, Te = expected time
3. Bar Charts and Scheduling Tools
Gantt Chart (Bar Chart)
Characteristics:
- • Horizontal bars showing activity duration
- • Time scale on horizontal axis
- • Activities listed on vertical axis
- • Easy to understand and communicate
- • Limited for showing dependencies
S-Curve (Progress Curve)
Types of S-Curves:
- Planned S-Curve: Baseline cumulative progress over time
- Actual S-Curve: Actual cumulative progress to date
- Earned Value S-Curve: Value of work completed
Shape reflects typical project progress: slow start, rapid middle, slow finish
Resource Leveling
Adjusting activity schedules to optimize resource utilization while respecting constraints.
Time-Constrained
Fixed deadline, variable resources
Resource-Constrained
Limited resources, variable duration
Line of Balance (LOB)
Used for repetitive projects (highways, high-rise floors)
- • Shows production rate for each activity
- • Slope of line = rate of progress
- • Parallel lines indicate balanced resources
- • Identifies buffers needed between activities
Schedule Compression
Crashing
Add resources to critical activities
- • Increases direct costs
- • Crash critical path first
- • Use lowest cost slope
Cost Slope = (Crash Cost - Normal Cost)/(Normal Time - Crash Time)
Fast Tracking
Perform activities in parallel
- • No additional cost (typically)
- • Increases risk
- • May require rework
4. Cost Estimation
Types of Estimates
| Type | Accuracy | Purpose |
|---|---|---|
| Order of Magnitude | -30% to +50% | Feasibility, conceptual |
| Preliminary | -15% to +30% | Budgeting, schematic |
| Definitive | -5% to +15% | Bidding, detailed design |
Cost Components
Direct Costs
- • Labor
- • Materials
- • Equipment
- • Subcontractors
Indirect Costs
- • Overhead (office, insurance)
- • Supervision
- • Temporary facilities
- • General conditions
Quantity Takeoff
Common Units:
- • Concrete: cubic meters (m³)
- • Reinforcing steel: kilograms (kg)
- • Formwork: square meters (m²)
- • Excavation: cubic meters (m³)
- • Painting: square meters (m²)
- • Electrical/Plumbing: points or meters
Unit Price Analysis
Unit Price = Labor + Materials + Equipment + Overhead + Profit
Labor: (Crew hours × Wage rate) / Output
Materials: Quantity × Unit cost + Waste allowance
Equipment: Ownership + Operating costs
Markup: Typically 10-20% for overhead, 5-15% for profit
Earned Value Management (EVM)
PV (BCWS)
Planned Value
EV (BCWP)
Earned Value
AC (ACWP)
Actual Cost
Variances:
Schedule Variance (SV) = EV - PV
Cost Variance (CV) = EV - AC
Positive = favorable, Negative = unfavorable
Performance Indices:
Schedule Performance Index (SPI) = EV / PV
Cost Performance Index (CPI) = EV / AC
>1.0 = ahead/under, <1.0 = behind/over
5. Construction Contracts
Contract Types
Lump Sum (Fixed Price)
- • Contractor bears most risk
- • Fixed price for defined scope
- • Best when scope is well-defined
- • Encourages cost efficiency
Unit Price
- • Payment based on quantities
- • Risk shared between parties
- • Good when quantities uncertain
- • Common for infrastructure projects
Cost Plus (Cost Reimbursable)
- • Owner bears most risk
- • Contractor paid actual cost + fee
- • Used when scope uncertain
- • Variations: Cost + Fixed Fee, Cost + Percentage
Guaranteed Maximum Price (GMP)
- • Cost plus with ceiling
- • Owner pays actual cost up to GMP
- • Savings often shared
- • Common with CM at Risk
Contract Documents
Order of Precedence (typical):
- Agreement
- Addenda
- Special Conditions
- General Conditions
- Specifications
- Drawings
Change Orders
Types of Changes:
- Owner-Directed: Scope changes requested by owner
- Differing Site Conditions: Unforeseen subsurface conditions
- Design Errors: Corrections to drawings/specs
- Regulatory Changes: New code requirements
Process: Request → Review → Negotiate → Approve → Execute
Philippine Bidding Law (RA 9184)
Key Provisions:
- • Competitive bidding is default procurement method
- • Single calculated and responsive bid acceptable
- • Ceiling price based on Approved Budget for Contract (ABC)
- • Lowest Calculated Responsive Bid wins
- • Alternative methods: Limited Source, Direct Contracting, Shopping
6. Construction Safety
Safety is Priority
Construction is one of the most hazardous industries. DOLE-OSH standards and DENR regulations apply.
Hierarchy of Controls
- Elimination: Remove the hazard entirely
- Substitution: Replace with less hazardous alternative
- Engineering Controls: Isolate people from hazard
- Administrative Controls: Change work procedures
- PPE: Personal Protective Equipment (last resort)
Common Hazards
Fatal Four (OSHA)
- • Falls (leading cause)
- • Struck by object
- • Electrocution
- • Caught in/between
Other Hazards
- • Excavation collapse
- • Scaffold failures
- • Heavy equipment
- • Hazardous materials
Fall Protection
Required at 6 feet (1.8m) or more in general construction
- • Guardrails: Top rail at 42" (1.07m), mid rail, toe board
- • Safety nets: Within 30 feet of work
- • Personal fall arrest: Anchor, connector, body harness
- • Hole covers: Capable of supporting 2× expected load
Excavation Safety
Protection required at 4 feet (1.2m) or more depth
- Sloping: Cut back trench walls at safe angle (1:1 for Type B soil)
- Benching: Series of horizontal levels
- Shoring: Support systems (timber, hydraulic, aluminum)
- Shielding: Trench boxes to protect workers
Safety Metrics
Incidence Rate = (N × 200,000) / Hours Worked
N = number of injuries/illnesses, 200,000 = 100 full-time workers
Severity Rate = (Lost Days × 200,000) / Hours Worked
Measures impact of injuries
Frequency Rate = (Lost Time Injuries × 1,000,000) / Hours Worked
7. Quality Control and Assurance
QA vs QC
Quality Assurance (QA)
Preventive: Processes to ensure quality
Quality Control (QC)
Corrective: Testing to verify quality
Concrete Quality Control
Common Tests:
- Slump Test: Workability (typical 75-100mm for structural)
- Compressive Test: 150mm cubes or 150×300mm cylinders at 7, 28 days
- Air Content: Pressure method, typically 4-7% for durability
- Temperature: Should not exceed 32°C at placement
Acceptance Criteria (NSCP):
- • Average of 3 tests ≥ f'c
- • No single test < f'c - 3.5 MPa (for f'c ≤ 35 MPa)
Steel Testing
- Tensile Test: Yield strength, ultimate strength, elongation
- Bend Test: Ductility, 180° bend without cracking
- Chemical Analysis: Carbon, manganese, sulfur content
- Mill Certificates: Required for structural steel
Soil Testing (Field)
- Field Density Test: Sand cone, nuclear density gauge
- Plate Load Test: Bearing capacity verification
- SPT (Standard Penetration Test): N-value for soil strength
- DCP (Dynamic Cone Penetrometer): Quick subgrade assessment
Quality Tools
Seven Basic QC Tools
- Check sheets
- Histograms
- Pareto charts
- Cause-and-effect (Fishbone)
- Scatter diagrams
- Control charts
- Flowcharts
Inspection Types
- Pre-pour: Before concrete placement
- In-process: During construction
- Final: Completion inspection
- Third-party: Independent verification
8. Professional Practice and Ethics
Civil Engineering Law (RA 544)
Key Provisions:
- • Only licensed CEs may practice civil engineering
- • Board of Civil Engineering regulates profession
- • Seal required on all CE documents
- • CPD (Continuing Professional Development) required
Code of Ethics
Fundamental Canons:
- Hold paramount the safety, health, and welfare of the public
- Perform services only in areas of competence
- Issue public statements only in objective and truthful manner
- Act as faithful agent or trustee for each employer/client
- Avoid deceptive acts
- Conduct themselves honorably and responsibly
National Building Code (PD 1096)
Key Requirements:
- • Building permit required before construction
- • Occupancy permit required before use
- • Fire safety requirements (RA 9514)
- • Accessibility requirements (BP 344)
- • Zoning compliance
Environmental Compliance
Requirements (DENR):
- ECC: Environmental Compliance Certificate for major projects
- EIS: Environmental Impact Statement
- IEE: Initial Environmental Examination
- CNC: Certificate of Non-Coverage for small projects
Insurance and Bonds
- Bid Bond: 1-5% of bid, ensures serious bidders
- Performance Bond: 100% of contract, ensures completion
- Payment Bond: Ensures payment to subcontractors/suppliers
- Retention: Typically 5-10% held until final acceptance
- CAR Insurance: Contractor's All Risk, covers project damage
- Professional Liability: Errors and omissions coverage
Dispute Resolution
- Negotiation: Direct discussion between parties
- Mediation: Neutral third party facilitates agreement
- Arbitration: Binding decision by arbitrator(s)
- Litigation: Court proceedings (last resort)
CIAC (Construction Industry Arbitration Commission) handles construction disputes in the Philippines
Key Takeaways for CE Board Exam
Must-Know Formulas
- ✓ Total Float: TF = LS - ES = LF - EF
- ✓ PERT Expected Time: te = (a + 4m + b)/6
- ✓ PERT Variance: σ² = [(b-a)/6]²
- ✓ Cost Variance: CV = EV - AC
- ✓ Schedule Variance: SV = EV - PV
- ✓ CPI = EV/AC, SPI = EV/PV
- ✓ Incidence Rate = (N × 200,000)/Hours
Critical Concepts
- ✓ Critical Path = Zero float activities
- ✓ Forward pass (ES, EF) then Backward pass (LS, LF)
- ✓ Contract types and risk allocation
- ✓ Crashing vs Fast Tracking
- ✓ Hierarchy of Safety Controls
- ✓ QA (preventive) vs QC (corrective)
- ✓ RA 544, PD 1096, RA 9184 provisions