Module 1 Recap of Formwork Basics
1. Types of Formwork
Formwork is a temporary mold into which fresh concrete is poured to achieve the desired shape and structural strength. The choice of material depends on cost, project scale, and reusability.
Timber Formwork:
Traditional and cost-effective for small projects.
Made from plywood or lumber; easy to cut and assemble on-site.
Limited reusability due to moisture damage and warping.
Steel Formwork:
Durable, reusable, and provides a smooth concrete finish.
Heavy and expensive but ideal for large, repetitive structures (e.g., bridges, high-rises).
Requires cranes for handling due to weight.
Aluminum Formwork:
Lightweight, corrosion-resistant, and highly reusable.
Faster assembly than steel but less robust for heavy loads.
Common in modular construction (e.g., residential buildings).
Engineered Formwork Systems:
Prefabricated modular systems (e.g., PERI, Doka, Mivan).
Designed for rapid assembly, high precision, and reusability.
Includes table forms, slip forms, and climbing forms for specialized applications.
2. Load Calculations
Formwork must withstand the weight and pressure of wet concrete, workers, and equipment. Key calculations include:
Dead Loads:
Weight of the formwork itself plus the fresh concrete.
Concrete density (~24 kN/m³) is a critical factor.
Live Loads:
Dynamic forces from workers, tools, and machinery (typically 2.4–4.8 kN/m² as per OSHA/ACI standards).
Concrete Pressure:
Hydrostatic pressure depends on pour rate, height, and setting time.
ACI 347 formulas estimate lateral pressure (e.g., for walls: *P = 150 + (9000 × R/T)*, where R = pour rate in m/hr, T = concrete temperature in °C).
Failure to account for pressure can cause blowouts or formwork collapse.
3. Safety Refresher
Formwork failures can lead to catastrophic accidents, making safety protocols critical.
OSHA/ISO Standards:
OSHA 1926.700-706 outlines formwork safety requirements.
ISO 9001/45001 ensures quality and occupational health compliance.
Fall Protection:
Guardrails, harnesses, and safety nets for elevated work.
Secure platforms for workers handling vertical formwork.
Hazard Identification:
Inspect for unstable foundations, overloading, or damaged components.
Monitor weather (wind, rain) that may weaken formwork stability.
Ensure proper bracing and alignment before pouring concrete.
This recap ensures that Level 2 learners reinforce foundational knowledge before advancing to complex formwork techniques.
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