Abstract:
Thermal stresses are regularly experienced by silos due to the temperature of their stored material
clashing with the atmospheric temperature on site. This is most prominent in the case of hot stored
material conflicting with cold winter temperatures. In Reinforced Concrete (R.C) silos these
stresses are experienced as tensile stresses in a circular outwards direction and are to be resisted
by the vertically placed steel reinforcement bars.
Thermal stresses are however, rarely discussed and brought up in discussion regarding R.C silos
unlike the more known stresses due to weight of stored material, wind, and seismic action. This
leads them to often be neglected leading to silos being under designed and issues such as cracking
begin to emerge during the silo’s operation phase. The need for retrofitting arises to keep the silo
operational and to prevent future damages that might cause complete structural failure. Depending
on the retrofitting technique selected however this can lead to high costs, notable additional load
being placed on the silo, large time periods where the silo cannot be operated, and the reduction
of the silos maximum storage capacity.
Carbon Fiber Reinforced Polymers (CFRP) are composite materials consisting of carbon fibers
that have proven to be an efficient and lightweight solution for the repair of deteriorated structures
in the construction industry. For silos specifically they can be attached externally leading to
minimum disturbance of operations and no reduction in storage capacity. Their high strength and
light weight have led to them being widely used in developing countries but they find themselves
being underutilized in Pakistan.
This project highlights the significance of thermal stresses on the design of an R.C silo by using
commonly used design codes as well as showcases the capability of CFRP to act as a competent
retrofitting technique that is sufficient to deal with said thermal stresses.
