Structural repairs of existing civil structures at various locations at BARC Tarapur

Amount

Providing and fixing double tubular scaffolding system using H- frames with cup lock type on the exterior side up to seven story height made with 40 mm dia M.S. tube 1.5 m centre to centre horizontal and vertical tubes joining with cup and lock system with M.S. tubes, M.S. tube challies, M.S clamps and M.S staircase system in the scaffolding for working platform etc. and maintaining it in a serviceable condition for the required duration as approved and removing it thereafter. The scaffolding system shall be stiffened with bracings, runners, connection with building etc. wherever required for inspection of work at required locations with essential safety features for the workmen etc. complete as per directions and as approved by the Engineer -in - charge. The elevational area of the scaffolding shall be measured for payment purposes. The payment shall be made once irrespective of duration of scaffolding. Note : this item will be operated only for structural repair work at specific location

Removal of old 2 to 3mm thick APP sheet and clean the bituminous and adhesive layer from surface using mechanical,chemical treatment including labour, tools & tackles, saffolding and material charges to complete this work etc. complete as per specifications and as directed by Engineer-in-Charge.

Dismantling of RCC works carefully manually without damaging adjacent structures excluding cutting of reinforcement including stacking of steel reinforcement bars and disposal of unserviceable materials within 200 m lead as per direction of Engineer-in-charge. Note: Proper Propping and supporting to the structural members should be provided using Steel Prop Of Up To 5 MT Capacity And Up To 3.2m Height during dismantling

Dismantling brick bat coba cement based water proofing over roof and chajjas carefully without damaging adjacent structures including lowering and stacking of materials and disposal of unserviceable materials within 200 m lead as per direction of Engineer-in-charge

Lead charges for 1st 1 KM or part thereof, by mechanical transport including loading unloading, stacking / levelling etc.

Debris up to 1 km

Repair to RCC/screed cracks:

Fill all larger cracks more than 5 mm with approved equivalent polyurethane flexible sealant Complete all as per specifications and instruction of Engineer-In-charge.

Through and through cracks on the slab must be identified visually or by ponding which are more than 1mm and are visible on the RCC ceiling as well on the screed top and having drip leakages should be treated with approved equivalent PU sealant. Cut open the crack in square or U - groove manner up to minimum 6 mm size by mechanical cutter. Clean the groove with air blower to remove dust, dirt etc. Fill the cracks with approved equivalent PU Sealant after necessary cleaning.Complete all as per specifications and instruction of Engineer-In-charge.

Drilling and installing the 16 mm dia holes (nozzle spacing should be as per the drawing) about 100 mm to 200 mm deep on the surface of the member at staggered pattern . Cleaning the holes with compressed air and spiral brush to make it free from drill dust. Fixing twin lock nozzles of 15 mm original dia (to sustain pressure up to 10 kg/cm2) in 16 mm dia holes and sealing the nozzles with epoxy putty, complete all as per manufacturers specifications and as directed by Engineer-In-Charge.

Providing and injecting lean cement grout into separation joints /cracks /honeycombed areas with grouting pump at a pressure @ 1.5 to 3.5 Kg/cm2 with approved equivalent make as per tenderbook specification through the above nozzles. After grouting is completed after 24 hours, cut the nipples and seal them with polymer-modified mortar/Epoxy Putty complete all as per manufacturers specifications and as directed by Engineer-In-Charge.

Application of rust converting alkaline primer: Thoroughly clean the corroded reinforcement/steel rebar by wire brush or rotary grinder. Remove all the corrosion scales present on the bare and reach up to sound steel. Length of reinforcement bars clean of rust all around shall be measured for payment. Applying alkiline chemical rust remover with paint brush and removing loose particles after 24hrs of its application with wire brush and thoroughly washing with water and allow it to dry complete all as per manufacturers specifications and as directed by Engineer-In-Charge.

Application of two coat anticorrosive epoxy coating for bar protection against future corrosion. Coating is for old as well as newly provided steel. This system once applied on steel shall provide extended protection against future carbonation and chloride attack. complete all as per manufacturers specifications and as directed by Engineer-In-Charge.

Drilling and providing reinforcement by anchoring in existing RCC structures by drilling specified diameters of bars and anchoring with anchor resin of approved equivalent make after cleaining the holes to make dust free complete as per specifications and directed by Engineer- In-Charge. (only No. of anchorix will be measured and paid, reinforcement will be paid under relevant item).

a) 10mm dia bars in 12mm dia holes or size of holes as recommended by the manufacturer of anchor rebar.

b)12mm dia bars in 14mm dia holes or size of holes as recommended by the manufacturer of anchor rebar.

Providing Reinforcement Steel for reinforced cement concrete at all levels including supplying, preparation of bar bending schedules, cutting, bending, transporting, fixing, tieing in position with PVC coated G.I binding wire, all labour charges, cost of cover blocks in specified grade of concrete etc. complete as per specifications and drawings. Steel supplied by the contractor

Upto and including 32mm dia reinforcement: Using TMT bars of specified grades. TMT bars to be supplied by vendors as per specification in Tender book using virgin materials

Providing and fixing shear key of 10 mm Dia upto 200 depth to be embedded in concrete with Anchor Resin/epoxy as directed by Engineer-In-Charge.

Carry out application of 'Bi-polar migratory corrosion inhibitor on overall exposed concrete surface with the help of brush or low pressure air spray. Number of coats to be applied depends on the porosity and moisture content of the substrate and the weather conditions, normally 3 to 5 coats are necessary to achieve the required consumption i.e. 4ltr./ m2. Time between two coats shoud be 30 mints.Grout the corrosion inhibitor in case of excessively damaged RC sections by drilling 50 to 75 mm deep holes at the spacing of 350mm c/c with the dosing of 100ml per hole in concrete body. complete all as per manufacturers specifications and as directed by Engineer-In-Charge.

Providing & applying one coat of Epoxy Bonding agent of approved equivalent make as per tender book specification for bonding on the existing concrete surface with new surface prior to polymer/ microconcrete as per manufacturers specifications and as directed by Engineer-In-Charge.

Providing, mixing and applying ready mix polymer modified cement mortar in layers each layer not exceding 25mm thick, including trowelling with wooden tools etc. Each layer of 25mm shall be measured for payment.Bond coat should be applied after each sucessive layer.Complete all as per manufacturers specifications and as directed by Engineer-In-Charge.

Providing and placing in position M-30 grade super fluid micro-concrete, which shall be cement based prepacked single component, cloride free, non shrink, free flow, self compacting, ready to use after mixing water in specified proportions obtained from approved manufacturer as per specification and direction of Engineer-In-Charge.

a) Upto 50mm average thickness with out aggregates

Providing, centering, shuttering Form work using steel plates, timber planks for all types of structures including necessary strutting, proping, staging, supports, bracings etc. and deshuttering the same after the specified time all as per drawings, specifications and as directed by the Engineer-in-charge at all levels

For Super Structure

Properly opening existing non-structural cracks in plaster surface in “V” shape for ease of application & applying ready to use crack filler Paste as per tenderbook specification; Paste should be high quality mix of graded fillers & weather durable acrylic emulsion which is ideal to fill static cracks upto 5 mm. Complete all as per manufactures specification and instruction of Engineer-In-Charge.

Providing 20 mm thick External plastering in two coats under layer 12 mm thick with C.M 1:4 (using crushed sand) finished with a top layer 8 mm thick in C. M 1:3 (using crushed sand) including approved water proofing compound @ 2% by weight of cement or as per manufacturer's specifications, sieving of sand to required fineness, scaffolding up to 10 metres height, finishing, curing etc. complete as per specifications. and as directed by the Engineer-in-charge

Providing and painting walls with (TWO coats) of approved shade of high build protective , elastomeric water proof exterior grade paint of approved make of required shade, minimum dry film thickness of 250 microns achieved in two or more coats / as per manufacturer's specifications including preparation of the surfaces by scrapping / wire brush , scaffolding complete. Primer coat will be with approved make with water in ratio of 1:2 and 2 coats of finishing coat without water all as directed by Engineer-in-charge.

Providing cement based water proofing treatment to the new terraces, chajjas, cleaning the concrete surfaces, giving injections to the top slab as required with cement and approved waterproofing compound solution to fill up all inherent holes, voids, honeycombs etc. in the concrete slab, setting brickbat coba in waterproof mortar with necessary gradient for easy flow of water and continue the treatment along the inner faces of parapet or other adjoining wall up to a height of 300 mm in thew shape of vattas, with waterproof plaster finished smooth with trowel in cement / geru with false markings of 300 mm squares complete as directed by the Engineer-incharge

With Average thickness of 120 mm and minimum thickness at khurra as 65 mm using river sand / crushed sand

Providing and applying treatment the bends/curve/Angles of terrace using waterproofing coat and TPE tape (150mm) as per specification or complete as directed by the Engineer-incharge.

Providing and applying waterproofing coat over a roof slab, terrace, chajja etc over a one coat of Primer in the SSD condition in two coats as per specification in tenderbook, including Fibre glass mesh as a reinforcing material which is incorporated in the coating when the first coat is still in wet condition. Allow the first coat to dry for approximately 4-6 hours before applying the 2nd coat at 90° to the first coat. Ensure there are no pinholes or air bubbles on the membrane surface before applying second coat complete all as per manufactures specifications and instruction of Engineer-In-Charge.

Carbon Fiber Reinforced Polymer (CFRP) wrapping: Supplying & applying carbon FRP wraps on external concrete surface of stack as per the manufacture and technical specifications with the following procedure:- a. Applying compatible primer on the prepared substrate and allow it cure for 12Hrs.(Min), Wrapping of unidirectional carbon fiber sheets (minimum 300gsm density) on to the prepared RCC surface in Vertical orientation (1st layer) impregnating with carbon fiber matrix system using tamping roller to avoid any voids etc. of approved make as per manufacturers specifications and as directed by the Engineer-in-charge, ensuring that the fiber does not deviate by more than one degree from the intended direction, vertical and horizontal lapping the sheets not less than 150mm, along the width of sheets removal of all air bubbles and resin pockets by application of gentle pressure by created rollers and ensuring no fiber damage and no peel off at the ends of the sheets generally as per physical properties & technical specifications. a) Properties of carbon fibre (high strength) used in FRP system (as per ACI 440.2R-08) Property Value Ultimate strength ≥ 3.79 GPa Rupture strain (in %) ≥ 1.4 % Elastic modulus ≥ 220 GPa Fibre density (gm/cm3) ≥ 1.5 Fibre area weight unit area ≥ 300 gsm Carbon Fibre fabric width ≥ 500 mm b) Properties of CFRP laminate (high strength) used in FRP system (as per ACI 440.2R-08) Property Value Ultimate tensile strength in primary direction ≥ 1020 MPa Rupture strain (in %) 1.0 to 1.5 % Young’s modulus ≥ 100 Gpa

Additional 2 layers [Vertical orientation layer (2nd layer) & Horizontal orientation layer (3rd layer)] of CFRP:- Supplying and applying an additional layer of unidirectional carbon fiber sheet (Minimum 300gsm density) as described in 4a above along with the epoxy adhesive of approved make as directed by the engineer. Note:- 1)Over lapping of fibers shall be paid extra at actual. 2)Carbon Fiber Fabric saturant and top coat epoxy shall have the properties as mentioned in Technical Specification and relevant ACI codes.

Sprinkling of quartz sand on the wrapped surface after rectifying air voids, if any to make the surface rough to take any further finishes.

RACHCON INFRAPROJECTS Pvt Ltd (BID ID -3109048)