Reinforced Concrete Design / module 17
Checking, review and design assurance
The only module whose subject is judgement rather than calculation: how to find out whether a design is right, and how to say honestly what it still does not know.
What you will understand
- Explain why repeating a calculation is not checking it
- Use an order-of-magnitude check to find the errors that actually matter
- Use equilibrium as an independent audit of the whole load path
- Judge what each level of checking can and cannot find
- Classify a finding by its consequence rather than its size
- Keep a register of what a design has taken on trust, and say what may be issued
Lessons
Checking is not repeating
A second pass down the same road finds arithmetic slips and nothing else. What finds the errors that matter is a different road.
Assurance, and what a design does not know
Every level of checking has a blind spot it cannot remove. And every design relies on things nobody has verified — which is only dangerous when it is not written down.
Module summary
- Checking is not repeating — a second pass by the same route shares the first one's assumptions
- The big errors matter and the small ones do not: hunt factors, not percentages
- Equilibrium is the free check, and no wrong idealisation can fool it
- Sanity bands prompt a question; a value outside one is unusual, not wrong
- Every level of checking has a blind spot, and it comes from what it SHARES with the design
- Severity is about consequence — a 3% change on a member at 0.99 is significant
- A design that cannot list what it has taken on trust does not know what it is relying on
- This course's own register ran 17 of 17 unverified, then 8, and is now empty — without this page being edited
Teaching basis and review status
These are educational models and exercises. Check their assumptions before using the results. The full technical content and every diagram have not yet been independently verified.
Concrete and steel calculations retain their stated first-generation Eurocode teaching basis. Use the standards and amendments specified for your project; do not mix generations without an appropriate design basis.
Read the lesson register and outstanding review notesCheck your understanding
Practice
A concrete floor is estimated at 15 kN/m² factored, on beams at 5.0 m centres. Estimate the line load on a beam, in kN/m.
Practice
A take-down says 3500 kN is applied and 3000 kN arrives at the foundations. What percentage of the applied load is unaccounted for?
Practice
A beam has 3217 mm² of tension steel in a 350 × 650 section with d = 589 mm. What is the steel ratio As/(b d), as a percentage?
Practice
A finding increases demand by 15% on a member whose utilisation was 0.50. What is the utilisation afterwards?
Practice
A beam's self-weight is taken on its full 650 mm depth rather than its 450 mm downstand, on a 350 wide section. By how much is the line load overstated, in kN/m?
Practice
How many of the 17 design values in this course's active standards profile are still NOT verified against their published source?