Method Statement for CMU (Concrete Masonry Unit) Block Work

In this Article today we will talk about the Method Statement for Blockwork | Concrete Block Masonry | Concrete Masonry Unit Advantages and Disadvantages | Blockwork Construction | Architectural cmu Block | Blockwork Construction Detail | Architectural Masonry Block | Block Work Construction Procedure | Block work method statement

What is CMU WALLS?

CMU walls (CMU) are the standard size blocks used in building construction, CMU is the most widely used building material available due to the variety of looks that can be obtained using them; concrete masonry walls will help reduce time wastage.

These walls have a variety of patterns and textures, this not only makes them share the choice of exterior and interior walls but also a more reliable choice of a solid foundation.

Concrete blocks are made of reinforced concrete (Portland cement and agg, sand and fine gravel).

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Concrete Masonry Unit Advantages and Disadvantages

Advantages of CMU Walls:

1. Concrete masonry units are bigger than conventional bricks, it’s cheaper to put a CMU system.
2. Galvanized steel reinforcements strengthen the CMU walls helping them to bear more weight without cracking.
3. These types of walls have an excessive tolerance for heavy loads, helps a stone going through different bricks, plaster, and tile constructing components.
4. They are additionally useful in areas that have extreme climates such as hurricanes and tornadoes.
5. Furthermore, the durability of CMU systems extends the lifetime of buildings and minimizes the necessity for constant maintenance. Method Statement for Blockwork

Disadvantages of CMU Walls:

1. CMU walls soak up important amounts of moisture.
2. They are often covered with a protective glaze or weatherproofed to stop water penetration.
3. These systems are heavier than wooden or steel, they lack flexibility for walls with completely different shapes and dimensions.
4. Concrete blocks also occupy large amounts of space, since their low thermal resistance value makes them difficult to insulate.
5. Finally, hiring contractors may be costly depending on the geographic area.

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Method Statement for Blockwork:

Objective:

The objective of this method statement is to define the general guidelines for masonry works. Concrete Block Masonry

Purpose & Scope:

The purpose of this method statement is to define the work procedure for block works. Works shall be carried out in compliance with the drawings, project specifications and materials. Concrete Masonry Unit Advantages and Disadvantages

Reference and Standards:

• Saudi Aramco Engineering Standard (SAES-Q-001)
• Project Specifications
• International Building Code 2009
• Cast-ln-Place Concrete (Section 033000)
• Quality Requirements (Section 014000)
• Grout for Unit Masonry (ASTM C476)
• Mortar for Unit Masonry, Proportion Specification (ASTM C270) Project Drawings Issued for Construction (IFC)
• American Concrete Institute (ACI-301 & ACI-304)
• Contractor Site Safety Plan (CSSP)
• Section Properties of Concrete Masonry Walls (NCMA-TEK 14-1B) Multi-wythe Concrete
• Masonry Walls (NCMA-TEK 16-1 A) Concrete Masonry Unit Advantages and Disadvantages

Responsibilities:

• 4.1: Project Manager:

  It is overall responsibility of PM to organize resources to perform construction activities as per project specifications, in compliance with quality, schedule and safety requirements. Concrete Masonry Unit Advantages and Disadvantages

• 4.2: Construction Manager:

  It is the responsibility of CM that construction activities are executed according to the relevant project specifications, in compliance with quality, schedule & safety requirements. Blockwork Construction

• 4.3: Civil Engineer:

  Civil Engineer shall monitor and manage all the masonry block installation as per IFC drawings and project specifications under safe conditions in accordance with contractor site safety plan.

• 4.4: Surveyor:

  Surveyor will be mobilized to the site before starting of any masonry block installation. Mark out exactly all the lines where masonry blocks are laid as shown in the IFC drawings. He will assist the contactor and client QC inspector to verify the layout for installation and other embedded items location as per IFC drawings. Blockwork Construction

• 4.5: QA/QC Inspector:

  QA/QC Inspector will make sure the following items and all field inspection will carry out under project specification 014000 related to the quality requirement services:
  • • He will ensure that mock-up and materials are approved before starting the work.
    • Work should be carried out as per latest revision of drawings.
    • Plumpness and levelling are within the tolerable as per ACI 301.
    • He will coordinate with the SAPMT for required inspection as per approved ITP.
    • He will keep the record of all inspection and testing reports related to the activity.

Safety Inspector:

Safety inspector would be responsible for following items: Blockwork Construction

• • • He will make sure that all construction activities would be carried out under approved CSSP.
    • He will make sure that all workers have proper PPEs.
    • He will make sure that proper certification and inspections of equipment prior to start the work.
    • He will inspect and confirm the physical installation barricades for any equipment used operations defined under CSSP.
    • He will make sure the provision safe access for work area and will carry the inspections.
    • He will make sure the provision of flagman/banks man to assist the operator to warn the people for movement of equipment.
    • He makes sure the presence of work permit (Cold work permit) and list of involved personal at site.
    • All signals, signs and will not be removed from site until work completion.
    • He will produce the Job risk assessment prior to commence the activity and will identify the hazards before starting of activity. Architectural cmu Block

Work Procedure & Methodology:

• 1) Construct a masonry wall mock-up panel to represent the selected interior masonry finish, colour, texture characteristics, and bond pattern for inspection and approval.
  • • Construct wall at least 1.5 meters long by 1.5 meters high.
    • Locate where directed by Client Representative.
    • Include bond pattern, joint profile, mortar colours, and plaster finish.
    • Include reinforcement as indicated on Contract Documents.
    • Erect entire mock-up with methods representative of standard, daily construction and in-progress cleaning practices.
    • Mock-up sample panel must receive approval in writing by Saudi Aramco before proceeding with masonry installation.
    • Once accepted, mock-up sample panel will be used as the standard of quality for masonry work on the project.
    • Leave mock-up sample panel in place until project completion
• 2) Do not wet concrete masonry units prior to laying.
• 3) Do not use calcium chloride in mortar or grout.
• 4 Potable water will be used for grout and mortar mixtures.
• 5) Before placing metal masonry accessories, remove loose rust, dirt and other coatings.
• 6) Before starting installation of block check if preceding activities have been inspected and approved. The surveyor will mark out the layout for the block work using current layout drawings. Architectural cmu Block
  • • 140mm &100 mm thick blocks shall be used for external walls and 100, 150, 200mm for internal walls or as per approved shop drawing details.
    • Blocks shall be properly laid on a full bed of mortar and Keep the courses levelled & perpend vertically aligned.
    • All bed and vertical joints are to be spread with mortar to ensure complete and solid bedding through the full thickness of the wall.
    • Maintain openings as per the drawing and cut units to accommodate frames, conduit, fixtures, recesses and other MEP work.
    • Block work shall built to the respective dimension, thickness and height mentioned on the drawing.
    • In cavity wall construction, both sides are to be carried up together and tied with wall tie as per approved sample, while maintaining the 5 mm Air gap distance, install 55mm approved thermal sheets, after three to five rows of block Tie.
    • fasteners are started to be fixed consequently with equal displacement according to approved dimension.
    • Where built-in items are to be embedded in cores of hollow masonry units, place a layer of metal lath in the joint below and grout mortar into core.
• 7) Build masonry to accommodate the work of other trades, including chases and recesses as shown or required.
• 8) Leave openings in masonry as required for subsequent installation of equipment and services. Make openings in designated locations and in exact size required and complete masonry work after installation of equipment, matching adjoining masonry. Provide lintels for all openings.
• 9) Where cutting is required, use power saws to provide clean, sharp unchipped edges. Do not use wet cutting techniques with concrete unit masonry.
• 10) Lay exposed masonry in running bond except where other bonds are indicated at special features. Lay concealed masonry in running bond, or lap units at least 2 inches (51 mm). Avoid use of masonry units of less than 1/2 size. Do not use units with less than nominal 4 inch (102mm) horizontal face dimensions at corners and jambs. Interlock wythe at corners and offsets in each course with masonry bond.
• 11) Prevent splashing and soiling of masonry near ground level by spreading sheet material to cover soil or masonry faces. Protect horizontal masonry elements from mortar dropping.
• 12) Cover or shade masonry units and mortar materials and use cool water for mortar whenever ambient air temperature is hot as mentioned in the Project Specifications.
• 13) Cover tops of incomplete masonry elements with waterproof sheet material when masonry work is not underway.
• 14) All marked lines must be clearly visible prior to masonry block installation.
• 15) The concrete surfaces to be cleaned prior to masonry block installation.
• 16) Dampen the concrete surfaces and lay the first course of masonry block with bed mortar.
• 17) Perform all grouting by means of Low-lift or High-lift Technique. For Low-lift technique, lift shall not exceed 4 feet (1.2 m) in height. For High-lift technique total wall height shall not exceed 12 feet (3.7 m), with each lift not exceeding 4 feet (1.2 m). Leave 20mm empty from the topmost side of blocks for construction joint.
  • a) Grout Mixture: ref. (ASTM C476) Architectural cmu Block
    • Proportion by Volume
      • • 1) Portland Cement: 1 part. Block Work Construction Procedure
        • 2) Hydrated Lime: 0 to 1/10 part.
        • 3) Fine Aggregates: 2% to 3 times the sum of volume of cement and lime material
        • 4) Coarse Aggregates: 1 to 2 times the sum of volume of cement and lime materials
    • Or premix masonry grout (as approved).
  • b) Mortar Mixture:
    • • – Mixture of Portland cement, sand, and water
      • – Or Premix dry mortar (as approved) Architectural cmu Block

• 18) Reinforcement:

  • Vertical:

    • • For exterior walls, with or without openings, with horizontal dimension of more than 4 m between supports (columns or intersecting walls), use 12 mm diameter deformed bar spaced at 800 mm
      • For exterior walls, without opening, with horizontal dimension less than 4 m between supports, no vertical reinforcement required.
      • For Parapet and Boundary walls use 12 mm deformed bar spaced at 600 mm.
      • Steel bars 12 mm will be embedded in the raft or slabs before pouring accordance to the IFC drawings and approved shop drawings or to be anchored after pouring and fix the rebar in the holes by approved chemical injection fastening Architectural cmu Block

  • Horizontal:

    • • For exterior walls, provide 3.8 mm diameter ladder type at every 2 courses. Whichever is approved will be implemented during installation. Block Work Construction Procedure

  • Cavity Wall Ties:

    • • Provide MW11 cavity wall ties spaced at 600 mm horizontal and 400 mm vertical. Architectural cmu Block

  • End Wall Ties:

    • • Embed the ends of wall ties in mortar joints, at least 13mm into the outer face shell of hollow units. Embed wire wall ties at least 38mm into the mortar bed of solid grouted hollow units. Do not bend wall ties after being embedded in grout.

  • Lap Reinforcement:

    • • Lap reinforcing a minimum of 6 inches (152 mm).
• 19) Curing arrangement shall be provided for 3 days.
• 20) Lintel, trim and coping will be implemented accordance to the IFC drawings (1B- 0106-350-2-CS-DD-S002) and approved shop drawings and minimum bearing at each jamb 200 mm.
• 21) Inspection and Handover of activity:
  • a) Prior to laying masonry blocks, clean the concrete surfaces. The surveyor will mark all masonry wall lines as per latest IFC drawings The Civil Engineer will verify all lines and submit Request for Inspection of Line Marking and Surface Preparation to QC Inspector for inspection and approval by Consultant.
  • b) After laying masonry blocks, The Civil Engineer will submit RFI of Installed Masonry Blocks to QC Inspector for inspection and approval by Consultant.
• 22) For closing the chases, ducts, filling, piping work will be implemented with grout, foam fill all around and accordance to the IFC drawings. Architectural Masonry Block

Quality Inspection: Method Statement for Blockwork

• Inspection Test Plan (ITP) specific to project requirements shall be made and inspection activities are recorded either on the forms as given under “Related Documents”.
• He will ensure that mock-up and materials are approved before starting the work.
• Embedded parts (if any) should be checked carefully from before cast-in- place of concrete. Architectural Masonry Block
• He will ensure that approved inspection checklists were followed.
• Keep a complete record of inspection reports with location and date. Block Work Construction Procedure

Precaution and Safety Instructions:

• Laying of masonry blocks to be allowed only after Aramco approval.
• Area Supervisor ensuring that all work is undertaken in accordance with the specified work scope.
• All personnel know the locations of fire extinguishers, communications, manual Alarms, and exit points.
• All personnel knowing emergency assembly points, wind direction and escape routes, emergency contact numbers. Block work method statement
• All personnel must know the listing for general alarms, knowing different tones, warning/ hazard status lights.
• Safety inspector advises and is consulted by the area authority for confined space entry certificates, area permits, and high- risk activities.
• Ensure that all personnel involved use necessary PPE (Personal Protective Equipment)
• Carry out check daily toolbox and safety talks.
• Keep non-essential workers clear of machinery whilst it is in operation.
• Working area safety barricading is required to avoid accidents.
• Provide deep excavations with ladders for escaping during emergency.
• Properly inspect all equipment, prior to use, to avoid equipment failure. Architectural Masonry Block

Protection of Finished Work:

• The masonry block surfaces shall be cleaned and free from all foreign matters etc. Scrape off adhered mortar particles by hand, using non-metallic tools.
• The freshly masonry wall installed must be protected from any mechanical disturbances cause by vibration. Architectural Masonry Block

Tools and Equipments for Method Statement for Blockwork

The following tools and equipment shall be required to perform the works:

• Total Station
• Water Truck
• Air compressor
• PPE’s Block Work Construction Procedure
• Shovel, floats & hand trowel
• Nail Gun
• Table Grinder for block cutting
• Scaffolding Platforms
• Electric Drill
• Mixer Machine
• Wheel Barrow
• Masonry Saw
• Right Angle
• 3M long aluminium straight edge
• Spirit level
• Water level
• Measuring Tape
• Line dory
• Plumb Block Work Construction Procedure

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5. Method Statement for Excavation Compaction and Backfilling | Civil Works

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Conclusion:

Full article on Method Statement for Blockwork | Concrete Block Masonry | Concrete Masonry Unit Advantages and Disadvantages | Blockwork Construction | Architectural cmu Block | Blockwork Construction Detail | Architectural Masonry Block | Block Work Construction Procedure | Block work method statement. Thank you for the full reading of this article in “The Civil Engineering” platform in English. If you find this post helpful, then help others by sharing it on social media. If any formula of BBS is missing from this article please tell me in comments.