Construction sequence for a raft foundation: arrange the following activities in correct order — (1) ramming foundation bed, (2) excavation to required depth, (3) laying reinforcement, (4) curing the concrete, (5) pouring concrete over reinforcement.

Introduction / Context:Correct sequencing in raft construction ensures dimensional control, reinforcement integrity, and concrete quality. Misordered steps can compromise bearing and durability.

Given Data / Assumptions:

• (1) Ramming/compacting bed, (2) Excavation, (3) Reinforcement placement, (4) Curing, (5) Concreting.
• Conventional in-situ raft with blinding as needed.

Concept / Approach:First excavate to formation level; prepare the founding bed by ramming/compaction (and blinding if specified). Then fix reinforcement, followed by placing concrete. Finally, curing is done to ensure hydration and durability.

Step-by-Step Solution:Start with (2) Excavation to required depth.Then (1) Ram/prepare the foundation bed (and blinding).Next (3) Lay reinforcement as per bar schedule.Proceed to (5) Pour concrete over reinforcement.Finish with (4) Curing of the concrete.

Verification / Alternative check:Method statements for raft pours follow this order; any deviation (e.g., reinforcing before bed preparation) is impractical.

Why Other Options Are Wrong:

• They either place reinforcement or concrete before bed preparation or omit curing until the end.

Common Pitfalls:

• Neglecting blinding or surface preparation before fixing rebar, leading to contamination or cover issues.

Final Answer:2, 1, 3, 5, 4