Method Statement -Concrete and Pile Repair

1.0 OBJECTIVE

This Work Method Statement is to outline the sequence of activities, method and resources needed for the operation of repairing for structural element.

 

2.0 SCOPE OF WORKS

This method statement shall be used for structural repair for (your project name). Details of the procedures contained herein may be modified based upon actual ground condition and site requirements.

 

3.0 REFERENCES

Ø  Construction Drawings

Ø  Approved Shop Drawings

Ø  Project Specifications

4.0 RESPONSIBILITIES

Ø  Safety Officer/Supervisor

Ø  Site Manager

Ø  Project Engineer

Ø  Site Supervisor

 

5.0 MATERIALS

Ø  Sika MonoTop – 610MY

Ø  Sika MonoTop – R

Ø  Sika Grout 215

Ø  Axel Mortar 302i

6.0 PLANT, MACHINERY AND EQUIPMENT

Mixer machine, wheelbarrows, wire brush, angle grinder, measuring tapes, and other handy tools.

 

7.0 HANDLING AND STORAGE OF MATERIALS

Handling             - Transport of materials shall be carried out by lorry or other suitable machinery.

Storage               - Covered and raised above floor level.

 

8.0 WORK METHODOLOGY 

Method 1 – Re-cast Concrete Structure

              i.            Identify and demarcate the member which needs to be demolished.

            ii.            Erect adequate temporary props to support the affected slab and beam.

           iii.            Demolish the severe concrete structure by means of hacking with pneumatic tools. Ensure the edge of the concrete is clean, sound and free from dirt or dust.

           iv.            Care should be taken not to damage the existing reinforcement.

            v.            Bonding Preparation - Apply one coat of bonding agent Sika Monotop – 610MY at the edge of existing concrete to receive new concrete.

           vi.            Formwork – Erect formworks at the demolished area and secure the formwork with suitable ties.

         vii.            Request for work inspection as per inspection checklist for concreting.

        viii.            Pour the concrete with waterproofing admixture to the prepared formwork. Ensure the concrete has sufficient vibration during concreting.

           ix.            On completion carryout joint inspection to sign on inspection checklist for post concrete.

Method 2 - Concrete Repair- Formwork Grouting

         i.            Based on structural repair layout, mark on existing structure such as concrete honeycomb.

        ii.            Surface Preparation - Cut and hack around at demarcated honeycomb area with suitable tool and equipment.  Ensure all loose concrete must be removed down to sound concrete. (Note: Do not use an impact hammer greater than 15 pound)

      iii.            Clean existing reinforcement and clean/remove debris or loose concrete fragments from the rectification area.

      iv.            Request for work inspection as per inspection checklist for concrete repair.

        v.            Formwork –Install formworks that cover the size of the repair area including place a layer of sponge at the perimeter with suitable tied.

      vi.            Install Inlet and Outlet - Drill two rows (upper and lower part) of 25mmØ holes on the formwork to insert 25mmØ UPVC pipe with spacing of 600mm c/c.

     vii.            Mix the pre-bagged polymer modified shrinkage compensated high strength grout – Sika Grout with adequate water in a mixing drum. 6mm to 10mm aggregate shall be added and mixed with the grout at a ratio of 1:1 by weight to minimize heat generation.

   viii.            The Sika Grout 215 concrete grout is then poured into the pump. Pump the grout into the form work with the lowers injection port until the grout is going out from the upper port.

      ix.            Curing - Leave the formwork in place for at least 24 hours. Upon removal of the formwork, cure the exposed surfaces immediately with water.

        x.            On completion carryout joint inspection to sign on inspection checklist for concrete repair.

 

Method 3 - Concrete Repair- Formwork Grouting for honeycomb depth > 20mm

              i.            Based on structural repair layout, mark on existing structure such as concrete honeycomb.

            ii.            Surface Preparation - Cut and hack around at demarcated honeycomb area with suitable tool and equipment.  Ensure all loose concrete must be removed down to sound concrete. (Note: Do not use an impact hammer greater than 15 pound)

           iii.            Clean existing reinforcement and clean/remove debris or loose concrete fragments from the rectification area.

           iv.            Request for work inspection as per inspection checklist for concrete repair.

            v.            Formwork –Install formworks that cover the size of the repair area including place a layer of sponge at the perimeter with suitable tied.

           vi.            Install Inlet and Outlet - Drill two rows (upper and lower part) of 25mmØ holes on the formwork to insert 25mmØ UPVC pipe with spacing of 600mm c/c.

         vii.            Flowable Sika Grout 215 - Place about 4.0 to 4.4 litres clean water into clean container; add the whole bag of Sika Grout 215 (25kg) while continuously mixing. After mixing, stir lightly with a spatula for few seconds to release any entrapped air.

        viii.            The Sika Grout 215 concrete grout is then poured into the pump. Pump the grout into the formwork with the lowers injection port until the grout is going out from the upper port.

           ix.            Curing - Leave the formwork in place for at least 24 hours. Upon removal of the formwork, cure the exposed surfaces immediately with water.

            x.            On completion carryout joint inspection to sign on inspection checklist for concrete repair.

 

Method 4 - Concrete Hand Patch Repair (for area < 0.5m2 at depth < 20mm)

              i.            Based on structural layout, mark on existing structure such as concrete honeycomb.

            ii.            Cut around demarcated honeycomb area to eliminate feather edge.

           iii.            Surface Preparation - Repair area shall be clean, sound and free from all loosely adhering particles.

           iv.            Bonding Preparation - Apply one coat of bonding agent Sika Monotop – 610MY “wet on wet” to the rectify area.

            v.            Request for work inspection as per inspection checklist for concrete repair.

           vi.            Concrete Mixing - The cement mortar Sika Monotop – R should be mixed in a clean drum. Place 3.4-3.5 litres of water into the drum and add Sika Monotop - R slowly while mixing.

         vii.            Application - Work wet on wet the mixed mortar well into the rectify substrate, using a placing suitable tool, compact well. Steel trowel the final coat if required.

        viii.            On completion carryout joint inspection to sign on inspection checklist for concrete repair.

 

Method 5 – Injection Grouting for Rectification of Spun Pile

              i.            Based on piling layout, mark on the affected pile.

            ii.            Request for work inspection as per inspection checklist for concrete repair.

           iii.            Clean existing reinforcement and clean/remove debris or loose concrete fragments from the rectification area.

           iv.            Flowable Sika Grout 215 - Place about 4.0 to 4.4 litres clean water into clean container; add the whole bag of Sika Grout 215 (25kg) while continuously mixing. After mixing, stir lightly with a spatula for few seconds to release any entrapped air.

            v.            Insert the 75mm UPVC pipe into the pile hole.

           vi.            The Sika Grout 215 concrete grout is then poured into the pipe.

         vii.            Curing – Cover the pile head for at least 24 hours. Upon removal of the cover, cure the exposed surfaces immediately with water.

        viii.            On completion carryout joint inspection to sign on inspection checklist for concrete repair.

 

Method 6 – Pile Head Repair

              i.            Based on piling layout, mark on the affected pile.

            ii.            Request for work inspection as per inspection checklist for concrete repair.

           iii.            Ensure that the base is properly prepared, removed of all loose concrete debris, oil, dirt and is then primed with Axel Primer S at 50 microns DFT for stubborn surface (if any).

           iv.            After the floor is prepared, mix Axel Mortar 301i with Part A and B with a hopper or mixer drill for 5 minutes until the mix is homogeneous. Trowel the mix over the prepared floor with a metal trowel. Use Axel Solvent 914 to clean trowel before each application for smooth finishing.

            v.            After the pile has been hacked or prepared, mix Axel Mortar 302i with a hopper, mixer drill or hand mix (for small quantity) for 5 minutes and then mould the grout to a “moth ball” and press it over the prepared surface. Use a glove and wet it with soap water to even out the grout to a smooth finish.

           vi.            Only use spatula hand mixing for small quantity batching.

 

Method 7 – Broken/Damaged Pile Repair

              i.            Based on piling layout, mark on the affected pile.

            ii.            Request for work inspection as per inspection checklist for concrete repair.

           iii.            Ensure that the base is properly prepared, removed of all loose concrete debris, oil, dirt and is then primed with Axel Primer S at 50 microns DFT for stubborn surface (if any).

           iv.            After the floor is prepared, mix Axel Mortar 301i with Part A and B with a hopper or mixer drill for 5 minutes until the mix is homogeneous. Trowel the mix over the prepared floor with a metal trowel. Use Axel Solvent 914 to clean trowel before each application for smooth finishing.

            v.            After the pile has been hacked or prepared, mix Axel Mortar 302i with a hopper, mixer drill or hand mix (for small quantity) for 5 minutes and then mould the grout to a “moth ball” and press it over the prepared surface. Use a glove and wet it with soap water to even out the grout to a smooth finish.

           vi.            Only use spatula hand mixing for small quantity batching.

 

9.0 HEALTH, SAFETY & ENVIRONMENT PROGRAMME

 

9.1  Health & Safety

Ø  Safety induction to be conducted to all new workers that involved to this activity and safety toolbox meeting shall be conducted every day to remind the workers about concerning the safety.

Ø  All workers shall be provided with PPE (Personal Protective Equipment) and shall be always worn on site. Safety Officer / Safety Supervisor shall ensure all the workers wear all the safety equipment provided.

Ø  All workers shall be advised to report any accident or injury to supervisor.

Ø  Proper and adequate provision of temporary signage’s and barricades at diversion and temporary haul road as necessary (if applicable).

Ø  Permit to work must be applied for night works (if any).

 

9.2  Environment

Ø  All workers shall educate on good environmental management practices and well-disciplined to environment.

Ø  The garbage bin shall be provided at the working area and supervisor shall ensure its must be collected regularly and disposed-off at the approved dumpsite.

Ø  All workers shall ensure that all tools and equipment machinery are in good condition to avoid any oil leakage that could harm to environment.