Silo Chimney & Cooling tower
RCC Silo in Rourkela

RCC Silo in Rourkela
Problem:
- After putting to use, the silo reported major cracks due to construction error
Solution:
- Steel supports were provided for supporting the hopper internally.
- Cracked sections were rebuilt using thixotropic mortar.
- Minor cracks were grouted with epoxy based chemical.
- Silo was externally wrapped with alternate layers of vertical and Horizontal Light weight GFRP and CFRP wraps.
RCC Silo in Dala, Varanasi

RCC Silo in Dala, Varanasi
Problem:
- Poor workmanship during construction of 70.0 m high RCC Silo by slip form method
- Bulging of Silo at few locations and out of plumb construction at certain location
- Poor quality of Concrete
- Bulging and eccentric construction causing excessive localized stress leading to minor cracks
Solution:
- Finite element analysis was carried out to know nature and intensity of stress at critical locations
- FE Model from level of 19m to 68m. Eccentricity was modeled based on the input data
- It was found that several FRP overlays are required for retrofitting
- Instead of conventional wrap system, factory made composite profiles were used and fixed at site by chemical adhesive and mechanical anchors
- Exhaustive grouting with polymeric cement slurry and low viscosity monomer was carried out
- Project was completed in 180 working days
RCC Chimney in Karnataka
RCC Chimney in Karnataka
Problem:
- The 60m tall and 2.9m diameter RCC chimney at Goa minerals, Dharwad showed sway of 273mm due to construction error.
- This resulted in excessive moments at different levels of chimney.
Solution:
- Complete design build solution to take care of this additional moments of chimney.
- A hybrid system of carbon laminates and wraps at bottom and helical GFRP wraps at top was designed and executed by Sanrachana Team
- Cracked sections were rebuild using thixotropic mortar
- Minor cracks were grouted with epoxy and silo was externally wrapped with alternate vertical and Horizontal GFRP and CFRP wraps.
- Protective UV resistant Coating was applied on FRP System.
Chimney for Nirlon Ltd
Chimney for Nirlon Ltd
Problem:
- The 40m tall RCC chimney at Nirlon LTD, Goregaon old factory premises converted to an IT park, was damaged due to corrosion and concrete spalling was visible.
- Tough non-functional chimney was to be retained to preserve the history of the area.
Solution:
- Cracked concrete was removed and RCC structure was grouted with epoxy to improve microstructure.
- Anti-corrosion treatment was given to rebars and additional reinforcement was added wherever required and coated with corrosion inhibitors.
- Lost concrete section was rebuilt using Micro Concrete and Thixotropic repair mortar.
- From durability aspect the whole structure was treated using vertical and horizontal CFRP wraps
- Use of CFRP kept the dead weight low and helped to maintain the original cross section size
- Protective UV resistant PU coating was applied on the chimney.
NTPC Cooling Tower, Faridabad

NTPC Cooling Tower, Faridabad
Problem:
- RCC cooling tower requires regular maintenance because of severe exposure conditions
- Top and bottom ring beams were damaged by corrosion of steel reinforcement
- Work had to be completed as per the shutdown schedule of plant
Solution:
- Anticorrosive treatment was done on exposed steel
- Section was rebuilt using epoxy-latex mortar, followed by application of glass fiber wraps
- Job was completed in 90 days in synergic manner without hampering plant schedule
“Sanrachana ensured timely completion and co-operated to adjust our shut down requirements. The job was executed as per contract specifications and by following stringent safety norms.” Engineer incharge, NTPC Faridabad.
NTPC Bhilai
NTPC Bhilai
Problem:
- The cooling mechanism was enclosed in an aged building that required retrofitting
- Corrosion effects such as spalling was visible in several locations.
Solution:
- Anti-corrosion treatment was performed on all exposed steel bars
- Polymer modified mortar was used to plaster over the treated portions
- Fiber wrapping for confinement and additional strength
- 0.3 mm thick moisture protection coating for durability of the structure..
Masonry Chimney
Masonry Chimney
Problem:
- 46m tall 6m diameter 60-year-old masonry chimney of industrial plant, had major vertical cracks which were over 12mm wide
- Tension bolts of Hoop ring have been found to have failed
- Chimney was designed only for gravity and wind loads. Adjoining structure constructed later, was imposing lateral thrust on it, for which it was not designed.
Solution:
- Creating a separation between the chimney and adjoining structure.
- Micro-fine cement grouts for filling cracks
- Stitching of cracks using SRM-C wrap (carbon fiber wrap)
- Additional confinement provided using glass fiber wrap (SRM-G Wrap)
- Design-build solution offered by Sanrachana