Prestressed concrete per IS 1343: The total shrinkage strain to be considered for a pretensioned member is approximately equal to which value?

Introduction / Context:
Shrinkage of concrete shortens prestressed members and reduces effective prestress via time-dependent losses. IS 1343 recommends typical values of total shrinkage strain for design purposes in the absence of detailed testing.

Given Data / Assumptions:

• Pretensioned prestressed concrete member.
• Use standard code-recommended total shrinkage strain.

Concept / Approach:

Total shrinkage strain is an order of 10^-4 for normal concretes; adopting 3.0 × 10^-4 is a common design value for pretensioned members as per IS practice.

Step-by-Step Solution:

Verification / Alternative check:

Comparisons with code tables and standard textbooks confirm this order of magnitude for total shrinkage strain.

Why Other Options Are Wrong:

10^-2 or 10^-3 would imply unrealistically huge shortening; 10^-5 values underestimate shrinkage and associated prestress loss.

Common Pitfalls:

Confusing shrinkage with creep; mixing units of strain and stress.

Final Answer:

3.0 × 10^-4