This article is about CMU Concrete Masonry Unit Installation and work procedure and details about Method statement.
CMU
1. PURPOSE
2. SCOPE
3. REFERENCE
4. RESPONSIBILITES
5. PROCEDURES
1 PURPOSE
The purpose of this Method statement is to provide procedure. work sequence and guideline for safe execution of concrete masonry work of CMU hollow blocks to be carried out in the construction of process interface buildings, Plants and refineries. All works related to this method statement shall be executed in accordance to project specification, Aramco related standards, IFC drawing, finishing schedule and related international standards including project safety requirement.
2 SCOPE
This Concrete Masonry Hollow Block Works CMU will be applied.
3 REFERENCES
a) Project Specifications & Drawings:
Standard IFC Drawing
b) Saudi Aramco Standard Drawings
AA-036602 Concrete Masonry.
c) Saudi Aramco Standards:
SAES-M-100 Saudi Aramco Building Code
SAES-Q-001 Criteria for Design & Concrete Structures.
d) Saudi Aramco Material Specification System (SAMSS)
09-SAMSS-088 Aggregates for Concrete.
09-SAMSS-097 Ready-Mixed Portland Cement Concrete.
09-SAMSS-016 Concrete Masonry and Concrete Building Bricks.
e) Saudi Aramco inspection Test Plan & Check List
SATIP-M-100-01 Concrete Masonry Units and Building Bricks
SAIC-M-1006 Concrete Masonry Unit (CMU) Compressive Strength and Aggregate Test Reports.
SAIC-M-1007 Masonry Materials Receiving and Storage Inspection & FBE Rebar and Embedment Receiving Inspection.cmuCMU
SAIC-M-1008 Concrete and CMU Surface Preparation and Protection Inspection.
SAIC-M-1008 Masonry Units Installation
f) Related International Standards
ASTM C 150 Standard Specification for Portland Cement
ASTM C 33 Standard Specification of Concrete Aggregates.
ASTM C 140 Standard Test Methods for Sampling and Testing Concrete Masonry Units and Related Units
ASTM C 129 Standard Specification for Nonloadbearing Concrete Masonry Units
ASTM C 94 Specification of Ready-Mixed Concrete.
ASTM C 476 Standard Specification for grout for Masonry
ASTM C 270 Standard Specification for mortar for unit Masonry
ASTM C 144 Standard Specification for Aggregates for Masonry mortar
ACI 305R-77 Hot Weather Concreting
ACI 530 Building Code Requirements for Masonry Structures.
4. RESPONSIBILITIES
SITE MANAGER
Site manager shall be fully responsible for implementation of all contractual requirements at the job site and shall visibly demonstrate the priority of safety in all activities. Site Manager is also responsible for implementing of job with compliance of quality requirements.
SAFETY SUPERVISOR
The Safety Manager ensures that all safety management will enforced in a ways to prevent injury to personnel, damage to Plants and/or equipment by Fires. He should provide written instruction to established work method, explain the sequence of operation, outline the potential hazards at each stage and indicate precaution to be adopted.
QC MANAGER /QC SUPERVISOR
He will be responsible for full implementation of the required minimum quality requirements, procedures and maintain project quality documentation as per applicable company inspection and test for the final acceptance and handover of documents in accordance to the quality plan.
SITE ENGINEER and FOREMEN
The Civil Supervisor and/or Foreman are solely responsible the application of painting or painting works assuring all materials installed permanently and works being implemented are in conformance with specifications and approved drawings.
INDEPENDENT TESTING LABORATORY TECHNICIAN
The Independent Testing Laboratory Technician shall be responsible for all necessary tests in the field. He shall also be responsible in recording all test results and generate reports of all tests conducted.
5. PROCEDURE
A) MATERIAL CONTROL
Referring to Approved MAR List:
1. AL-MAR-027 Concrete Hollow Block CMU -AL Hadi Factory
2. AL-MAR-075 CMU& Plastering Accessories – SFSP/IKK
3. AL-MAR-080 Lying Cement Mortar (Pro build BM 110), DCP Company
4. AL-MAR-081 CMU Filling Grout Material (Pro Build BM200), DCP Company
5. AL-MAR-043 Fiber board bitumen impregnated
Material List:
1. Concrete Masonry Hollow Block CMU Size (400200200) mm, Non-Bearing Type (ASTM 126), Fire rated (3 Hrs).
2. Concrete Masonry hollow Block CMU Size (400100200) mm, Non-Bearing Type (ASTM 126), Fire rated (3 Hrs).
3. Galvanized Steel Truss Mesh for Block reinforcement Size (15030005) mm.
4. Galvanized Steel Truss Mesh for Intersections of Walls and Corners Size (50’500) mm.
5. Fiber board bitumen impregnated
6. Lying Cement Mortar Materials, Pro-Build BM110.
7. Filling Grout mortar Materials, Pro-Build BM200.
8. Water: Mixing water for mortar shall be contained not more than 500 PPM Total dissolved solids.
B) STORING
i. CMU and its accessories shall be received, handled, stored and issued in accordance with herein specified procedure.
ii. Masonry units shall be stored above ground on level platforms that will permit circulation of air and prevent excessive moisture absorption.
iii. Masonry units shall be covered and protected from wetting prior to use.
iv. Masonry units shall be carefully handled either individually or in suitable groups to keep units whole. Sharp edges and undamaged faces shall be maintained.
C) GENERAL REQUIREMENTS
i. Special coves, corners, bull noses and other special shapers shall be furnished as indicated or required, subject to supply by manufacturers.
ii. Concrete, CMU & Brick shall be free of laitance, loose materials, oil or other materials that reduce or prevent bonding with mortar.
iii. Walls shall be laid-out to establish accurate spacing of bond pattern, to ensure uniform joint widths, and to locate openings, movement type joints, returns and offsets. Units shall be arranged in a manner which will result in few or no units to be cut.
iv. Tops of walls shall be protected with a non-staining waterproof covering when work is not in progress.
D) INSTALLATION
i. Masonry units shall be placed while the mortar is soft and plastic.
ii. Horizontal & Vertical reinforcement shall be provided as specified in IFC Drawings.
iii. Products indicated to be built into the wall shall be installed as the masonry works progresses. Spaces around built-in products shall be filled with mortar, and space allowed for caulking.
iv. Backs of metal door frames shall be filled solid with grout fill.
v. Joint width shall be made equal to difference between actual and nominal dimensions of unit being installed.
vi. Exposed joints shall be tooled thoroughly too slightly concave, with hard glassy surface free from drying cracks. Interior joints shall be flushed in similar manner.
vii. Concrete masonry units shall be laid in running bond with vertical joints not less than 9.5 mm over units in course below, unless indicated.
viii. Masonry units shall be cut with either dry/wet masonry saws.
ix. When resuming masonry works, exposed surface of set or partially set masonry shall be cleaned and loose mortar to be removed prior to laying fresh mortar.
x. Continuous wall reinforcement shall be installed in accordance with manufacturer’s installation instructions and placed in every third course. Reinforcement shall be lapped not less than 150mm and shall be connected to pre-fabricated special reinforcement at corners and intersections. Splices shall be made in a manner which will not reduce structural strength to wall and in no case shall the length of the lapped splice be less than 40 times bar diameter for tension.
xi. Vertical reinforcement shall be installed where indicated and in poured grout studs formed by vertically aligned cells of masonry unit. The vertical spacing of the joint reinforcement shall not exceed 400 mm (16 in.) and in no case shall the length of the lapped splice be less than 30 bar diameter for compression and 40 times bar diameter for tension as per UBC.
xii. The top of unfinished masonry work shall be covered to protect the masonry from the weather.
1. MORTAR
i. Machine mixed mortar, except small batches (less than 30 liters) is mixed for a period of not more than 3 minutes after all materials are in the mixer. Where hand mixing is permitted, mortar shall be thoroughly mixed in tight mortar box until required plasticity is obtained as per manufacturer specifications.
ii. No hand mixing shall be allowed on the ground.
iii. Mortar shall not be used within 2 hours of initial mixing.
iv. Mortar shall conform to ASTM C270, Type S and shall attain a compressive strength not less than 12.5 MPa (1800 psi) at 28 days.
v. When the ambient temperature exceeds 38°C, the temperature of mortar shall be maintained below 49C.
2. GROUT
i. A Grout shall be placed immediately as soon as possible after mixing.
ii. Grout spaces are free from mortar dropping, debris, loose aggregates, and any material deleterious to masonry.
iii. For vertically reinforced concrete masonry unit, grout shall be placed in all cells containing reinforcement and in lifts not more than 1,200 mm (48 in).
iv. Grout shall be consolidated at time of placing by either puddling or vibrating. Grout shall be re-consolidated by puddling before plasticity is lost.
v. Grout shall conform to ASTM C-476 and shall attain a compressive strength of 14 MPa (2000 psi) at 28 days.
3. CUTTING AND JOBBING
Slots and opening required for inserts, wires, conduits and similar items of construction shall be left open or cut. Suitable recesses or opening shall be provided at junction boxes, or other location as required.