Raw Mill Silo

1

Radial cracks, further resulting in delamination of concrete

2

Buckled section of the silo(28 mt. level)

3

PT duct (About 40% empty)

4

Additional MS reinforcement welded with existing reinforcement and anchored to parent concrete

5

Patching the damaged concrete section with micro-concrete in vertical strips

6

Ongoing repair on the rear side (subjected to tension)

7

Silo after completion of repair

Make OR Break Factor

Cradles were suspended from the 85mt-high silo top to conduct repairs

THE CHALLENGE :

  • A raw mill silo was tilting, bulging and buckling at a height of 28 mts. to 40 mts., resulting in unsafe operating conditions. Our initial survey revealed multiple discrepancies:
  • For the required foundation size of 2720m², the actual size was 641m²
  • Silo wall though 350mm thick and structurally sound had no space left to pour concrete because of the PT duct and reinforcements
  • PT forces applied were 80% of hoop forces instead of the regulation 60%
  • PT ducts were filled up to 60-70% instead of the regulation 97%.

THE ODDS :

  • Tight deadline of 6 months
  • Work to be carried out under partial operating conditions
  • Local bursting of concrete encountered
  • Soaring summer ambient temperatures of over 50º C

OUR RESPONSE :

  • Designed and modified material and methodology
  • Conducted extensive trials on site
  • Grouting of the RCC sell with high-strength epoxies
  • Provided additional reinforcement
  • Patched damaged concrete sections with micro-concreting