MID/AN/114

The work consists of strengthening of four existing RCC concrete pillars by providing RCC jacketing to enhance their load carrying capacity and overall structural stability. The work shall include careful removal of existing plaster and loose or damaged concrete by mechanical chipping, thorough cleaning of the exposed surface using wire brushing and compressed air, and treatment of exposed reinforcement with approved anti-corrosive coating wherever required. Shear connectors/dowel bars shall be fixed into the existing column using approved epoxy anchoring compound to ensure proper bonding between old and new concrete. Additional longitudinal reinforcement bars along with lateral ties and stirrups shall be fixed as per structural requirement. Approved bonding agent shall be applied on the old concrete surface before placing concrete. Proper centering and shuttering shall be provided around the column maintaining correct alignment and dimensions. Concreting shall be done using M25 grade concrete including mixing, placing, compacting with mechanical vibrator, finishing and curing for the specified period. The scope of work further includes providing, fabricating and fixing MS channel sections between each two RCC pillars to improve lateral stability and structural rigidity. The work shall include supplying standard ISMC 150 channel sections of approved make, cutting to required lengths as per site measurements. Proper alignment and leveling shall be ensured before welding or bolting. Necessary gusset plates, cleats and stiffeners shall be provided wherever required. All welding work shall be carried out by skilled welders and finished smoothly. The steel sections shall be cleaned and provided with one coat of red oxide zinc chromate primer followed by two coats of synthetic enamel paint for corrosion protection. The job also includes providing and fitting of four Girders of specification (ISMB 200) on top of the strengthened RCC pillars. The girders shall be of approved ISMB section conforming to relevant IS specifications. The work includes cutting, fabrication, edge preparation, welding of base plates, and provision of anchor bolts embedded in the RCC jacketing for proper seating. The girders shall be lifted using crane or chain pulley block and placed accurately on the pillar tops with proper alignment and leveling to ensure uniform load transfer. Welding or bolting shall be carried out as per structural requirement, including provision of stiffener plates wherever necessary. All weld joints shall be ground smooth and painted with one coat of primer and two coats of synthetic enamel paint. The job includes cost of materials, carriage and hire charges of materials, tools and tackles required for the job, labour charges for skilled and semi skilled labour etc.