Welded wire mesh in pavements – longitudinal wire spacing In welded wire mesh commonly used for slab/pavement reinforcement, the longitudinal wires are typically placed at what centre-to-centre spacing?

Introduction / Context:
Welded wire mesh (WWM) is used in concrete slabs and pavements as temperature-shrinkage reinforcement and to control crack widths. Standard wire spacings simplify fabrication, placement, and lap calculations.

Given Data / Assumptions:

• Use of WWM for slab reinforcement (temperature/shrinkage control).
• Typical mesh series produced with regular wire spacings.

Concept / Approach:
Common practice adopts 150 mm (15 cm) centres for one direction and sometimes 150–300 mm for the other, depending on slab thickness and crack control requirements. A 15 cm longitudinal spacing provides a good balance of steel distribution and constructability for typical highway slabs.

Step-by-Step Solution:
Identify the longitudinal reinforcement direction in WWM.Select the standard, readily available spacing suitable for slab crack control.Adopt 15 cm centres as the typical answer.

Verification / Alternative check:
Standard WWM catalogs list 150 mm module meshes widely stocked for pavement and slab applications.

Why Other Options Are Wrong:
10 cm provides tighter spacing but is less common for general pavement work; 20–30 cm are looser meshes and may not provide uniform crack control for thinner slabs unless wire sizes are increased.

Common Pitfalls:
Choosing mesh spacing without checking cover, lap, and placement tolerances; ignoring traffic-induced temperature gradients.

Final Answer:
15 cm centres