CWICR Work Breakdown
Business Case
Problem Statement
Work items in CWICR contain aggregated resources:
- What materials make up a concrete work item?
- What labor categories are needed?
- What equipment is involved?
- How to generate detailed resource bills?
Solution
Decompose CWICR work items into their constituent resources (labor, materials, equipment) with quantities and costs.
Business Value
- Transparency - See inside aggregated items
- Procurement - Generate material lists
- Scheduling - Identify resource needs
- Cost control - Track resource consumption
Technical Implementation
import pandas as pd
import numpy as np
from typing import Dict, Any, List, Optional, Tuple
from dataclasses import dataclass, field
from datetime import datetime
from enum import Enum
from collections import defaultdict
class ResourceType(Enum):
"""Types of resources in work items."""
LABOR = "labor"
MATERIAL = "material"
EQUIPMENT = "equipment"
OVERHEAD = "overhead"
@dataclass
class ResourceComponent:
"""Single resource component of a work item."""
resource_code: str
resource_type: ResourceType
description: str
unit: str
quantity_per_unit: float # Per unit of work item
unit_rate: float
cost_per_unit: float # Per unit of work item
@dataclass
class WorkItemBreakdown:
"""Complete breakdown of a work item."""
work_item_code: str
work_item_description: str
work_item_unit: str
components: List[ResourceComponent]
labor_cost_per_unit: float
material_cost_per_unit: float
equipment_cost_per_unit: float
total_cost_per_unit: float
@dataclass
class BillOfResources:
"""Bill of resources for multiple work items."""
project_name: str
total_labor_cost: float
total_material_cost: float
total_equipment_cost: float
total_cost: float
labor_resources: List[Dict[str, Any]]
material_resources: List[Dict[str, Any]]
equipment_resources: List[Dict[str, Any]]
class CWICRWorkBreakdown:
"""Break down work items into resources."""
def __init__(self, cwicr_data: pd.DataFrame,
resources_data: pd.DataFrame = None):
self.work_items = cwicr_data
self.resources = resources_data
self._index_data()
def _index_data(self):
"""Index data for fast lookup."""
if 'work_item_code' in self.work_items.columns:
self._work_index = self.work_items.set_index('work_item_code')
else:
self._work_index = None
if self.resources is not None and 'resource_code' in self.resources.columns:
self._resource_index = self.resources.set_index('resource_code')
else:
self._resource_index = None
def breakdown_work_item(self, work_item_code: str) -> Optional[WorkItemBreakdown]:
"""Break down single work item into components."""
if self._work_index is None or work_item_code not in self._work_index.index:
return None
item = self._work_index.loc[work_item_code]
components = []
# Extract labor component
labor_norm = float(item.get('labor_norm', 0) or 0)
labor_rate = float(item.get('labor_rate', 35) or 35)
labor_cost = float(item.get('labor_cost', labor_norm * labor_rate) or labor_norm * labor_rate)
if labor_norm > 0:
components.append(ResourceComponent(
resource_code=f"{work_item_code}-LABOR",
resource_type=ResourceType.LABOR,
description=f"Labor for {item.get('description', '')}",
unit="hr",
quantity_per_unit=labor_norm,
unit_rate=labor_rate,
cost_per_unit=labor_cost
))
# Extract material component
material_norm = float(item.get('material_norm', 1) or 1)
material_cost = float(item.get('material_cost', 0) or 0)
if material_cost > 0:
components.append(ResourceComponent(
resource_code=f"{work_item_code}-MAT",
resource_type=ResourceType.MATERIAL,
description=str(item.get('material_description', 'Materials')),
unit=str(item.get('material_unit', item.get('unit', 'ea'))),
quantity_per_unit=material_norm,
unit_rate=material_cost / material_norm if material_norm > 0 else material_cost,
cost_per_unit=material_cost
))
# Extract equipment component
equipment_norm = float(item.get('equipment_norm', 0) or 0)
equipment_rate = float(item.get('equipment_rate', 0) or 0)
equipment_cost = float(item.get('equipment_cost', equipment_norm * equipment_rate) or 0)
if equipment_norm > 0 or equipment_cost > 0:
components.append(ResourceComponent(
resource_code=f"{work_item_code}-EQUIP",
resource_type=ResourceType.EQUIPMENT,
description=str(item.get('equipment_description', 'Equipment')),
unit="hr",
quantity_per_unit=equipment_norm,
unit_rate=equipment_rate,
cost_per_unit=equipment_cost
))
return WorkItemBreakdown(
work_item_code=work_item_code,
work_item_description=str(item.get('description', '')),
work_item_unit=str(item.get('unit', '')),
components=components,
labor_cost_per_unit=labor_cost,
material_cost_per_unit=material_cost,
equipment_cost_per_unit=equipment_cost,
total_cost_per_unit=labor_cost + material_cost + equipment_cost
)
def generate_bill_of_resources(self,
items: List[Dict[str, Any]],
project_name: str = "Project") -> BillOfResources:
"""Generate bill of resources from work items."""
labor_agg = defaultdict(lambda: {'hours': 0, 'cost': 0, 'work_items': []})
material_agg = defaultdict(lambda: {'quantity': 0, 'cost': 0, 'unit': '', 'work_items': []})
equipment_agg = defaultdict(lambda: {'hours': 0, 'cost': 0, 'work_items': []})
for item in items:
code = item.get('work_item_code', item.get('code'))
qty = item.get('quantity', 0)
breakdown = self.breakdown_work_item(code)
if not breakdown:
continue
for component in breakdown.components:
scaled_qty = component.quantity_per_unit * qty
scaled_cost = component.cost_per_unit * qty
if component.resource_type == ResourceType.LABOR:
key = 'General Labor' # Could be more specific with skill data
labor_agg[key]['hours'] += scaled_qty
labor_agg[key]['cost'] += scaled_cost
labor_agg[key]['work_items'].append(code)
elif component.resource_type == ResourceType.MATERIAL:
key = component.description
material_agg[key]['quantity'] += scaled_qty
material_agg[key]['cost'] += scaled_cost
material_agg[key]['unit'] = component.unit
material_agg[key]['work_items'].append(code)
elif component.resource_type == ResourceType.EQUIPMENT:
key = component.description
equipment_agg[key]['hours'] += scaled_qty
equipment_agg[key]['cost'] += scaled_cost
equipment_agg[key]['work_items'].append(code)
# Convert to lists
labor_resources = [
{
'resource': name,
'hours': round(data['hours'], 1),
'cost': round(data['cost'], 2),
'work_items': len(set(data['work_items']))
}
for name, data in labor_agg.items()
]
material_resources = [
{
'resource': name,
'quantity': round(data['quantity'], 2),
'unit': data['unit'],
'cost': round(data['cost'], 2),
'work_items': len(set(data['work_items']))
}
for name, data in material_agg.items()
]
equipment_resources = [
{
'resource': name,
'hours': round(data['hours'], 1),
'cost': round(data['cost'], 2),
'work_items': len(set(data['work_items']))
}
for name, data in equipment_agg.items()
]
total_labor = sum(r['cost'] for r in labor_resources)
total_material = sum(r['cost'] for r in material_resources)
total_equipment = sum(r['cost'] for r in equipment_resources)
return BillOfResources(
project_name=project_name,
total_labor_cost=round(total_labor, 2),
total_material_cost=round(total_material, 2),
total_equipment_cost=round(total_equipment, 2),
total_cost=round(total_labor + total_material + total_equipment, 2),
labor_resources=labor_resources,
material_resources=material_resources,
equipment_resources=equipment_resources
)
def get_resource_composition(self, work_item_code: str) -> Dict[str, float]:
"""Get percentage composition of work item by resource type."""
breakdown = self.breakdown_work_item(work_item_code)
if not breakdown or breakdown.total_cost_per_unit == 0:
return {'labor': 0, 'material': 0, 'equipment': 0}
total = breakdown.total_cost_per_unit
return {
'labor': round(breakdown.labor_cost_per_unit / total * 100, 1),
'material': round(breakdown.material_cost_per_unit / total * 100, 1),
'equipment': round(breakdown.equipment_cost_per_unit / total * 100, 1)
}
def analyze_labor_intensity(self,
work_items: List[str]) -> pd.DataFrame:
"""Analyze labor intensity of work items."""
data = []
for code in work_items:
breakdown = self.breakdown_work_item(code)
if breakdown:
composition = self.get_resource_composition(code)
labor_components = [c for c in breakdown.components if c.resource_type == ResourceType.LABOR]
labor_hours = sum(c.quantity_per_unit for c in labor_components)
data.append({
'work_item_code': code,
'description': breakdown.work_item_description,
'labor_hours_per_unit': labor_hours,
'labor_cost_pct': composition['labor'],
'material_cost_pct': composition['material'],
'equipment_cost_pct': composition['equipment'],
'labor_intensive': composition['labor'] > 50
})
return pd.DataFrame(data).sort_values('labor_cost_pct', ascending=False)
def export_breakdown(self,
breakdown: WorkItemBreakdown,
output_path: str) -> str:
"""Export single work item breakdown."""
df = pd.DataFrame([
{
'Resource Code': c.resource_code,
'Type': c.resource_type.value,
'Description': c.description,
'Unit': c.unit,
'Quantity/Unit': c.quantity_per_unit,
'Rate': c.unit_rate,
'Cost/Unit': c.cost_per_unit
}
for c in breakdown.components
])
df.to_excel(output_path, index=False)
return output_path
def export_bill_of_resources(self,
bill: BillOfResources,
output_path: str) -> str:
"""Export bill of resources to Excel."""
with pd.ExcelWriter(output_path, engine='openpyxl') as writer:
# Summary
summary_df = pd.DataFrame([{
'Project': bill.project_name,
'Total Labor Cost': bill.total_labor_cost,
'Total Material Cost': bill.total_material_cost,
'Total Equipment Cost': bill.total_equipment_cost,
'Grand Total': bill.total_cost
}])
summary_df.to_excel(writer, sheet_name='Summary', index=False)
# Labor
labor_df = pd.DataFrame(bill.labor_resources)
labor_df.to_excel(writer, sheet_name='Labor', index=False)
# Materials
material_df = pd.DataFrame(bill.material_resources)
material_df.to_excel(writer, sheet_name='Materials', index=False)
# Equipment
equipment_df = pd.DataFrame(bill.equipment_resources)
equipment_df.to_excel(writer, sheet_name='Equipment', index=False)
return output_path
class ResourceAggregator:
"""Aggregate resources across work items."""
def __init__(self, breakdown_tool: CWICRWorkBreakdown):
self.breakdown = breakdown_tool
def aggregate_by_trade(self,
items: List[Dict[str, Any]]) -> Dict[str, Dict[str, float]]:
"""Aggregate resources by trade/category."""
by_trade = defaultdict(lambda: {'labor_hours': 0, 'labor_cost': 0, 'items': 0})
for item in items:
code = item.get('work_item_code', item.get('code'))
qty = item.get('quantity', 0)
# Extract trade from code prefix
trade = code.split('-')[0] if '-' in code else 'General'
breakdown = self.breakdown.breakdown_work_item(code)
if breakdown:
by_trade[trade]['labor_hours'] += breakdown.labor_cost_per_unit / 35 * qty # Estimate hours
by_trade[trade]['labor_cost'] += breakdown.labor_cost_per_unit * qty
by_trade[trade]['items'] += 1
return dict(by_trade)
def identify_critical_resources(self,
bill: BillOfResources,
threshold_pct: float = 10) -> Dict[str, List[Dict]]:
"""Identify resources that contribute significantly to cost."""
critical = {
'labor': [],
'material': [],
'equipment': []
}
# Labor
for r in bill.labor_resources:
if bill.total_labor_cost > 0:
pct = r['cost'] / bill.total_labor_cost * 100
if pct >= threshold_pct:
critical['labor'].append({**r, 'percentage': round(pct, 1)})
# Materials
for r in bill.material_resources:
if bill.total_material_cost > 0:
pct = r['cost'] / bill.total_material_cost * 100
if pct >= threshold_pct:
critical['material'].append({**r, 'percentage': round(pct, 1)})
# Equipment
for r in bill.equipment_resources:
if bill.total_equipment_cost > 0:
pct = r['cost'] / bill.total_equipment_cost * 100
if pct >= threshold_pct:
critical['equipment'].append({**r, 'percentage': round(pct, 1)})
return criticalQuick Start
# Load CWICR data
cwicr = pd.read_parquet("ddc_cwicr_en.parquet")
# Initialize breakdown tool
breakdown = CWICRWorkBreakdown(cwicr)
# Break down single item
item_breakdown = breakdown.breakdown_work_item("CONC-001")
print(f"Work Item: {item_breakdown.work_item_description}")
print(f"Labor: ${item_breakdown.labor_cost_per_unit}")
print(f"Material: ${item_breakdown.material_cost_per_unit}")
print(f"Equipment: ${item_breakdown.equipment_cost_per_unit}")
for comp in item_breakdown.components:
print(f" - {comp.resource_type.value}: {comp.description}")Common Use Cases
1. Bill of Resources
items = [
{'work_item_code': 'CONC-001', 'quantity': 150},
{'work_item_code': 'REBAR-002', 'quantity': 5000},
{'work_item_code': 'FORM-003', 'quantity': 300}
]
bill = breakdown.generate_bill_of_resources(items, "Building A")
print(f"Total Labor: ${bill.total_labor_cost:,.2f}")
print(f"Total Material: ${bill.total_material_cost:,.2f}")2. Resource Composition
composition = breakdown.get_resource_composition("CONC-001")
print(f"Labor: {composition['labor']}%")
print(f"Material: {composition['material']}%")3. Labor Intensity Analysis
analysis = breakdown.analyze_labor_intensity(['CONC-001', 'EXCV-002', 'REBAR-003'])
print(analysis)4. Export Report
breakdown.export_bill_of_resources(bill, "bill_of_resources.xlsx")Resources
- GitHub: OpenConstructionEstimate-DDC-CWICR
- DDC Book: Chapter 3.1 - Resource-Based Estimating