Introduction

Reinforced Cement Concrete (RCC) work involves the use of concrete reinforced with steel bars, mesh, or fibers to enhance its tensile strength. The Central Public Works Department (CPWD) provides detailed specifications for the measurement and execution of RCC works. These specifications ensure consistency, accuracy, and quality in construction practices.

Components of RCC Work

RCC work typically involves the following components:

1. Form Work (Centering and Shuttering): Temporary or permanent molds used to shape and support the concrete until it gains sufficient strength.
2. Reinforcement: Steel bars, mesh, or fibers used to reinforce the concrete.
3. Concreting: The process of mixing, placing, and curing concrete. It can be:

• Cast-in-situ: Concrete cast at the construction site.
• Precast: Concrete cast in a controlled environment and transported to the site.

Steel for Reinforcement

The steel used for reinforcement must conform to specific standards:

1. Mild Steel and Medium Tensile Bars: Conforming to IS 432 (Part I).
2. High Strength Deformed Steel Bars: Conforming to IS 1786.
3. Hard Drawn Steel Wire Fabric: Conforming to IS 1566.
4. Structural Steel: Conforming to Grade A of IS 2062.
5. Thermo-Mechanically Treated (TMT) Bars.

Measurement of Form Work (Centering & Shuttering)

Form work includes all temporary or permanent molds required to shape the concrete. The measurement of form work is crucial for accurate billing and cost estimation.

1. General Inclusions in Form Work:

• Splayed edges, notching, overlaps, and angle passing.
• Supports, struts, braces, and other arrangements for stability.
• Bolts, wire, ties, clamps, spreaders, and nails.
• Working scaffolds, ladders, and gangways.
• Chamfered edges for beams, columns, and similar structures.
• Temporary openings for concrete pouring and vibrators.
• Oil dressing to prevent adhesion.
• Raking or circular cutting as required.

1. Classification of Measurements:

• Measurements are taken for the area of shuttering in contact with the concrete surface.
• Dimensions are measured to the nearest centimeter.
• Separate measurements are taken for different structural components like foundations, walls, suspended floors, lintels, beams, columns, stairs, arches, chimneys, etc.

1. Special Cases:

• Centering and shuttering for structures above 3.5 meters in height are measured and paid separately.
• Form work costs are included in RCC item rates unless specified otherwise.
• No deductions are made for openings or obstructions up to 0.4 sqm.

Measurement of Reinforcement

Reinforcement is measured by length, recorded to the nearest centimeter. The weight of the reinforcement is calculated by multiplying the length by the unit weight of the bar, according to its diameter.

1. Standard vs. Actual Weight:

• If the actual weight is within permissible variation, payment is based on the actual weight.
• If the actual weight exceeds the standard weight, payment is based on the standard weight.
• No payment is made for wastage or unauthorized overlaps.
• Binding wire and welding costs are included in the reinforcement cost.

1. Inclusions in Reinforcement Rate:

• Labor and material costs for cleaning, straightening, cutting, bending, binding, and placing the bars.

Measurement of Concreting

Concreting measurements are based on the volume of concrete, calculated to the nearest 0.01 cubic meter. The classification includes various structural components such as foundations, walls, floors, beams, columns, stairs, arches, chimneys, etc.

1. Separate Measurements for Different Levels:

• Measurements are classified based on the plinth level, floor levels, and above roof level.

1. Exclusions:

• No deductions for voids or openings up to 0.1 sqm.
• No deductions for reinforcement volume.
• No deductions for small cavities or holes.

1. Special Cases:

• Slabs and beams are measured face-to-face.
• Columns are measured as whole entities.
• Chajjas and cantilevers are measured separately.

Form Work Specifics

1. General Inclusions:

• Splayed edges, notching, overlaps.
• Supports, struts, braces.
• Bolts, wire, ties, clamps.
• Scaffolds, ladders.
• Chamfered edges.
• Temporary openings.
• Oil dressing.

1. Measurement Details:

• Area of shuttering in contact with concrete.
• Separate measurements for various structural elements.

1. Special Considerations:

• Heights above 3.5 meters.
• Inclusions in RCC rates.
• Deductions for small openings.

Reinforcement Specifics

1. Measurement:

• Length to the nearest centimeter.
• Calculated weight.

1. Standard vs. Actual Weight:

• Permissible variations.
• Payment based on standard weight if actual exceeds.

1. Cost Inclusions:

• Labor, material, cleaning, bending, binding.

Concreting Specifics

1. Volume Calculation:

• Nearest 0.01 cubic meter.

1. Classifications:

• Foundations, walls, floors, beams, columns, etc.

1. Exclusions:

• Small voids, reinforcement volume, small cavities.

1. Special Cases:

• Face-to-face measurements for slabs and beams.
• Whole entity measurements for columns.
• Separate measurements for chajjas and cantilevers.

Conclusion

The CPWD specifications provide detailed guidelines for the measurement of RCC work, ensuring accuracy and consistency. By following these specifications, construction projects can achieve high quality and efficiency in their execution.