strengtherning of 230kv bus 1 north structure at 230kv ss villupuram

All the areas which are under consideration for the repair & rehabilitation are to be provided with double legged scaffolding independent of the work having two sets of vertical supports. The supports shall be sound and strong, tied together with horizontal pieces over which scaffolding planks shall be fixed. Supply and fixing of scaffolding with bracing including cost of all material, all labour charges etc.,

Labour charges for chipping the spalled and old concrete of the slab. Check for the phenopthaline test and if there is no change in colour chip the same further down until, reaching the good or uncontaminated concrete. Clean the surface and make sure that surface is clean and free from loose particle at an average thickness of 50mm.

Clean the rebars using the rust remover if there exists any rust, otherwise clean the rebar free of foreign material. Mix the base and hardner of the zinc rich epoxy resin mechanically using a slow speed heavy duty drilling machine fitted with mixing paddle. Apply the mixed materials to the cleaned rebar and allow it to dry complete.

Providing slurry tight form work including strutting, propping, etc., which should not deform or leak due to pressure of micro concrete shall be fabricated in position using 6mm thick commercial plywood as per the required line and length at all different floor levels as per the standard specification-complete. Form work should be rigid to prevent loss of micro concrete at all stages & appropriate to the methods of placing & compacting as per standard specification. It should be made of suitable material. The form work should be coated with shutter release agent prior to fixing. The rate shall include the cost of all the operations and etc.,

Micro Concreting for the damaged structural element like slab/beam/column by Stocking sufficient quantity of micro concrete and 12mm downgraded chips on site to enable the completion of the pouring in a continuous operation. An approved concrete mixer or a slow speed heavy duty drilling machine fitted with mixing paddle shall be used. Mix the micro concrete and the 12mm down grade chips in the ratio of 1: 0.5 (one part of Rendroc RG and 0.5 part 12mm down chip) by weight with required quantity of water powder ratio 0.16 and place the same to the prefixed formwork well before the epoxy jointing compound dries up. Remove the formwork after 24 hours in the case of columns and after a period of 72 hours in the case of slab and beam and check for any surface defects and if so apply the polymer modified mortar - complete. The rate shall include the cost of all the operations and complete.