STRUCTURAL REHABILITATION OF BUILDING, REPAIRS TO CHAJJA, EXTERNAL PLASTERING AND OTHER CONNECTED ITEMS AT BASE HOSPITAL IN AOR OF AGE B/R BHDC UNDER GE (EAST) DELHI CANTT-10

M&L for followings :- (A) Perpration of Surfaces:- (i) Removing plaster & finishes from all exposed / damaged portion of columns, slabs & beams (ii) After cleaning gently removing cover concrete using pneumatic/electric chipper or any other approved tool in entire portion of structural member (removal of cover concrete shall be done to an extent when reinforcement is visible) (iii) Removal of cover concrete with under cutting of up to a depth of 20mm beyond reinforcement around full circumference & full length of bar where directed. (concrete shall be stripped to an extent concrete substrate is exposed and cleaning all around. (iv) Cleaning exposed concrete substrate by using water jet. (v) Removing visible rust along the length of reinforcement using hand tools as approved. (The Engr-in-charge may order sand blasting if rust is approved) (vi) Any other work as directed by Engr-in-charge to present clean surface for determination of type of repair to be carried out complete all as specified and directed. (B) M&L for providing rust proof /anti corrosive treatment to bars :- (i) Apply a single coat of Alkaline rust converting primer on alround bars new & old as recommended by the manufactuer (iii) Apply two coats of polymer modified anti corrosive cementitious coating with a total thickness of 2mm coat on bars alround new & old as recommended by the manufactuer. Note : Anti corrosive treatment shall be continuous espcially in the regions where pitting, imperfections, etc were present on the surface of the bars. It is important that the rear portions of re bars (those towards the concrete substrate) should not be left without coating.

M&L for providing PMM (Polymer modified cementitious mortar) :- (i) Dry sub strate surface and free of debris & dust (ii) Applying Epoxy bond coat on the sound substrate using approved spray machine or suitable brushes & ensuring that no pin holes are visible.(In case pin holes are still visible after a coat, a second coat shall be applied to ensure absence of pin holes). (iii) Immediately after application of epoxy bond coat as above apply PMM (Polymer modified cementitious mortar) of atleast strength equivalent of M-40 concrete of average 25 mm thickness. Note : Application of PMM shall be preferably be in coats of appx 10mm thickness. PMM work shall be executed in fairely rapid successions so as entire work is completed with in 30 mins). PMM shall be pre packed ready to use. (iv) PMM surface to be moist cured for three days followed by air curing in temperature as recommended by manufactuer complete all as specified and directed.

Description all as per item No. 02.00 here-in-before but exc 25mm thickness but not exc 35 mm thickness.

M&L for treatement of cracks found in the core concrete :- (i) Opening of crack by making a ' V' notch/groove of size 12mm x 12mm over the entire length of the crack as identified by the Engr-in-charge. (ii) cleaning ' v' notch/groove of all dust/debris/loose material (iii) Drilling hole of 16mm dia and about 40mm deep along the length of crack @ (300 mm c/c or thickness of structural member whichever is less) Note : In case length of crack is found less than 300 mm then min 2 holes shall be drilled. (iv) Inserting 12 mm dia flexible PVC one way injection nipple in the hole drilled above and fixing the nipple with the help of fast setting epoxy putty. (v) seal the surface around the nipple and the area of crack between successive nipples polymer modified mortar to ensure that there is no leakage from any gap. (vi) Allow the polymer modified mortar to cure for 24 hours and ensure that firmly fixed in postion. (vii) cleaning nipple one by one commencing from the top to bottom in case of column and one by one in alternate direction incase of beam/slab using blow compressed air followed by water injection. An Ensuring that there is no obstruction in free flow of grouting materials complete all as specified and directed. (viii) Injecting " resin with very low viscosity monomer by mixing resin and hardener in proportions recommended by manufacturer to achieve strength equivalent to M-40 concrete by using injection gun equipped with pressure gauge & valves for controlling of flow of compressed air & resin. Note : pressure shall be in the range of 1-2 kg/sqm and shall be done in nipples one by one as per order recommended by manufacturer. Mixing of resin and hardenere shall be mixed in small quantities so as it is consumed with in 30 minutes. Before use mixer shall be stirred thoroughly.

Item No 4.00 Contd/----- (ix) Allow entire effected surface to cure for 24 hours. (x) cutting out projected parts of the nipple & seal the hole in the nipple with epoxy putty as recommended by manufacturer. (xi) cleaning exposed surface of substrate off any dust /loose material after ageing of the grout as recommended by manufactuer.

M&L for treatement of core concrete when found to be porous/honeycombed :- (i) Marking the area in marker as directed by the Engr-in-charge. (ii) Drilling holes of 16mm dia in an orthogonal grid on exposed cone of member @ 150 mm c/c both way, depth of the hole shall be about 60% of the element thickness. (iii) clean the drill hole using compressed air removing the dust/dirt. (iv) Inserting 12 mm dia flexible PVC one way injection nipple in the hole with the annular space around the nipple sealed with epoxy putty. It shall be ensured that the injected grount does not leak. (v) Allow the nipple to cure for 24 hours. (vi) Injecting " Resin with very low viscosity monomer by mixing resin and hardener in proportions recommended by manufacturer to achieve strength equivalent to M-40 concrete by using injection gun equipped with pressure gauge & valves for controlling of flow of compressed air & resin. Note : pressure shall be in the range of 2-3 kg/sqm and shall be done in nipples one by one as per order recommended by manufacturer. Mixing of resin and hardenere shall be mixed in small quantities so as it is consumed with in 30 minutes. Before use mixer shall be stirred thoroughly. (vii) Allow entire effected surface to cure for 24 hours. (viii) Cutting out projected parts of the nipple & seal the hole in the nipple with epoxy putty as recommended by manufacturer. (ix) Cleaning exposed surface of substrate off any dust / loose material after ageing of the grout as recommended by manufacturer.” Note : The rate quoted against structural Item including for provn sufficient steel props ,bracing, scaffolding etc upto 4 storied building to strengthen the existing structure while execution till achievement of required strength.

Supply & fixing 8mm or 10mm dia steel sheer connector in grid pattern in between old core and new concrete as wherever directed by Engr-in-charge and as specifed by manufactuer including drilling hole of depth of 100 mm and chemical anchoring with pure epoxy resin anchoring mortar (Master flow 935 of BASF or equivalent FOSROC/SIKA). (The cost of drilling hole &chemical anchoring with epoxy resin is inclueded in this item) complete all as specified and directed.

Demolition of cement concrete (reinforced) of any description and as in column, beams, slabs, parpapet wall, drops, chajjas, shelves etc not other specifically provided for and removal of debris out side MOD land complete all as specified and directed.

M&L for Providing & Pouring Micro concreting M-40 grade :- (i) Dry concrete substrate surface and free of debris & dust (ii) Applying epoxy bond coat on the sound concrete substrate using approved spray machine or suitable brushes & ensuring that no pin holes are visible. (In case pin holes are still visible after a coat, a second coat shall be applied to ensure absence of pin holes). (iii) Immediately after application of above bond coat as above pour prepacked dual shrinkage compensated. Micro concreting M40 grade, using approved mixing machines/ pumping under pressure via approved pneumatic pump at the locations to be repaired in RCC beams & columns, slab, chajjas etc, upto 100 mm thickness of micro concrete. The rate shall include cost of all materials (except re-bar) labour charges for mixing, pouring concrete, cost of tools, lead & lift of materials, transportation etc., to carry out the complete work complete all as specified and directed. Note : The cost of micro concrete M-40 grade & Epoxy bond coat is inclueded in this item.

Description all as per item No 09.00 here-in-before but over 100mm and upto 200 mm thickness by mixing approved size and percentage of aggregate (30% if not provided) by weight of micro concreting as per manufacturers instructions without compromising on strength.