Erecting columns and beams forms a critical phase in building superstructure works, serving as the skeletal framework that supports floors, walls, and roofs. In Kenya's construction industry, the precision and quality of these structural elements directly affect the durability and safety of buildings. Professionals in building technology must understand the tools, equipment, and materials essential for erecting columns and beams to ensure compliance with design specifications and structural integrity. This chapter explores the key instruments and materials used in this process, equipping learners with the knowledge to execute superstructure works effectively.

1.1 Structural Elements Tools and Equipment

The successful erection of columns and beams depends heavily on the appropriate use of specialized tools and equipment. These instruments not only facilitate accurate measurements and alignments but also ensure safety and efficiency on construction sites. In Kenya, where building projects range from urban commercial complexes to rural housing developments, selecting the right tools influences both the speed and quality of work.

1.1.1 Tools for Measuring and Marking

Accurate measurement and marking are foundational to erecting columns and beams according to design drawings. Tools in this category enable precise determination of positions, levels, and dimensions on site.

Tools and Their Functions

• Measuring Tape: A flexible steel tape calibrated in millimeters and centimeters, used for measuring distances and lengths of formwork, reinforcement bars, and column footprints.

A measuring tape with metric and imperial units (Source: Wikimedia Commons)

• Spirit Level: Contains a bubble vial to check horizontal and vertical alignments ensuring columns and beams are plumb and level.

• Plumb Bob: A weighted object suspended from a string, used to establish a vertical reference line critical for setting column positions.

Traditional plumb bob used in building technology (Source: Wikimedia Commons)

• Chalk Line: A string coated with chalk powder used to mark straight lines on large surfaces such as concrete slabs or formwork.

• Marking Gauge: Used to scribe lines parallel to an edge, particularly useful in timber formwork for beams.

Usage and Maintenance

• Measuring tapes should be retracted slowly to avoid damage and kept clean to maintain accuracy.
• Spirit levels must be checked periodically for calibration by comparing against a known straight edge.
• Plumb bobs require rust prevention and should be stored in protective cases to retain their weight and shape.
• Chalk lines need regular refilling with chalk powder and string replacement to maintain sharp marking.
• Marking gauges should have sharp points and adjustable arms, which must be checked before every use to ensure consistent markings.

1.1.2 Equipment for Handling and Positioning

Erecting heavy columns and beams demands equipment that can safely lift, hold, and position structural elements during installation.

Key Equipment

Operational Guidelines

• Tower cranes require certified operators and must be inspected daily for mechanical integrity and load limits.
• Scaffolding should be erected on firm ground with secure fixings and inspected regularly to prevent accidents.
• Chain pulleys must be lubricated and tested for load-bearing capacity before use.
• Adjustable props are used to provide temporary support; they must be locked firmly and checked for slippage.

1.1.3 Hand Tools for Fixing and Adjusting

Precise fixing and minor adjustments during column and beam erection rely on durable hand tools that enable secure connections and alignments.

Essential Hand Tools

• Hammer: Used for driving nails and adjusting formwork.

• Wrenches: For tightening bolts and nuts on steel beams and column connections.

• Chisels: Employed to remove excess concrete or timber during fitting.

• Spirit Level: Ensures precise alignment after fixing.

• Measuring Tape: Used repeatedly for verification during fixing.

Care and Handling

• Hammers should have firmly attached heads and comfortable grips to prevent injuries.
• Wrenches must fit bolt sizes precisely to avoid rounding off bolt heads.
• Chisels require sharpening and protective covers to maintain effectiveness and safety.
• Spirit levels and measuring tapes should be stored in toolboxes to avoid damage.

1.1.4 Safety Equipment During Erection

Ensuring worker safety while erecting columns and beams is paramount, given the risks of falls and heavy lifting.

Safety Gear

• Hard Hats: Protect against falling objects on site.

Green hard hat worn by worker (Source: Wikipedia (Hard hat))

• Safety Harnesses: Used when working at heights on scaffolding or beams.

• High Visibility Vests: Improve worker visibility to machine operators.

• Gloves: Protect hands from sharp edges and rough surfaces.

Pair of yellow work gloves used in carpentry (Source: Wikimedia Commons)

• Safety Boots: Provide protection against heavy falling materials and punctures.

A single safety boot for industrial use (Source: Wikimedia Commons)

Usage Considerations

• Safety gear must be worn at all times on site and replaced if damaged.
• Harnesses require correct fitting and anchorage to approved points.
• Contractors should conduct regular safety briefings to reinforce proper equipment use.

Chapter Summary

This chapter provides a comprehensive overview of erecting columns and beams, beginning with the essential tools and equipment required for handling structural elements effectively. It then explores the materials used in constructing these elements, emphasizing their suitability and quality. The process of fixing reinforcement bars is detailed, highlighting the importance of correct placement for structural integrity. The chapter further examines the erection of formwork, covering the materials chosen, various methods employed, and the critical procedures for dismantling. Different types of formwork are described alongside the key requirements for good formwork to ensure durability and safety. Common formwork failures are analyzed to understand their causes and prevention. Finally, the chapter addresses the placing of concrete, outlining the correct procedures, the necessity of proper compaction to eliminate voids, and the curing process to achieve the desired strength and durability of the concrete structure.