1. EMERGING TRENDS IN CIVIL ENGINEERING BY : JATIN ARORA, ANUJ ARORA, AKSHAY RUHIL RAHUL CHHOKAR

2. NDT’S ON STRUCTURES

3. NDT-NON DESTRUCTIVE TEST: Detect Defects, Dimensions etc. without Damaging Material.

4. TESTS ON STRUCTRES NON DESTRUCTIVE TEST DESTRUCTIVE TEST

5. NDT Advantages Access to hidden items – “see through walls”Better investigations with NDTRapid accumulation of dataGenerally less expensive than destructive testingEvaluation and quality assurance

6. NDT Disadvantages More than one test method may be required Environmental conditions may effect or distort results Some conditions cannot be determined with a reasonable degree of accuracy without destructive testing

7. Typical Conditions to Verify Location and spacing of embedded items Mild reinforcing steel, post-tensioning, conduit Masonry ties and hardware Locating hidden flaws and defects (voids, trapped moisture, poor consolidation, etc.) Corrosion damage assessmentConcrete propertiesReinforcing steel properties

8. METHODS FOR NDT ON STRUCTURES: IMPACT-ECHO METHOD SCHMIDT/REBOUND HAMMER TEST COVER METER

9. Impact-Echo Method It is a technique used for flaw detection in concrete surface.

10. Impact-Echo Based upon evaluation of stress waves generated by an elastic impact on a concrete surface Originally developed at Cornell University and NIST by M. Sansalone and N. Carino P – Compression waves R - Rayleigh waves S - Shear waves

11. Impact-Echo Propagating P-waves generated by impact event. Multiply-reflected waves are detected by surface sensor. Reflected waves set up a resonance condition having a characteristic frequency Analogous to a bell’s tone

12. Impact-Echo Effective in determining thickness of slabs and depth of flaws in plate structures Does not work on beams & columns

13. IMPACT ECHO Applications Thickness of members – d,b Location of internal defects Voids / delaminations Repair quality assurance Internal damage ASR / DEF / ACR

14. IMPACT ECHO Summary – Requires significant experience – Powerful method for flaw detection – Applications to quality control – Verification of results is critical

15. REBOUND HAMMER TEST OBJECTIVE : Determine the Compressive Strength of concrete.

17. WORKING OF SRH

18. Rebound value V/S Compressive Strength

19. Advantages & Disadvantages Easy to Handle Quick Inexpensive Used only on Smooth surfaces Age of Specimen

20. COVER METER TESTING OBJECTIVE : Determine Nominal cover.

21. PRINCIPLE Works on Electromagnetic Pulse Induction method

22. HOW IT WORKS???

23. ADVANTAGES & DISADVANTAGES High Accuracy Economical Not Influenced by Moisture Limited Detection Range Spacing depends on Cover depth.

24. Refrences: Wikipedia.com Civil2010.net NIST Jounral

25. THANK YOU……..