(4E) Work Supervision Presentation for LRN Training Hom Nath Lamsal, LRN Construction Specialist August 2015 Rural Access Programme Development through access 1 Module Contents Method statements Supervision checklists Site inspection record books Site instructions Safety Rural Access Programme Development through access 2 METHOD STATEMENTS Rural Access Programme Development through access 3 Method Statements Define the way in which particular work tasks must be carried out in accordance with specifications and drawings Outline the risks involved in carrying out a particular work task and provide a step-by- step guide to carrying out the work safely Detail the labour, materials, tools, and equipment requirements for a work task Ensures that all actors involved have a clear understanding of the standard and safe process to execute a work item Rural Access Programme Development through access 4 Example Method Statement Work Item: Construction of a gabion retaining wall Procedure: Setting out of wall as per approved Working/ construction drawing Earthwork commencement only after acceptance of setting out by IoW/ARE/RE Excavation to be confined within the line of excavation as defined in the drawing, no over excavation Excavated material kept aside, no throw Foundation shoring, bracing (if required) Checking and approval of foundation: level, inward slope, soil type. Practice of trimming down outer side of trench has been noticed abundantly Rural Access Programme Development through access 5 Example Method Statement Contd. Rural Access Programme Development through access 6 Example Method Statement Contd. Procedure Contd.: Assembling of gabion boxes in open flat hard space (not inside the foundation trench), lacing of sides and diaphragms Placing of gabion boxes in foundation trench, lacing of adjacent gabion boxes to each other (no twisting of selvage wires) Stone masonry work (not dumping) in simultaneous layers in all compartments of gabion boxes (3 layers in 1 m and 2 in 0.5 m deep) Corner stones and staggered vertical joints in courses of stone Rural Access Programme Development through access 7 Example Method Statement Contd. Procedure Contd.: Horizontal bracing in each layers from each compartments of boxes looped two adjoining meshes Upper face of gabion box if not covered will have vertical bracing as above @ 2 ties/ sq.m. Compartments are filled 50 mm above the box top to allow subsequent settlement All hinges of gabion box lids will face outer face of wall Rural Access Programme Development through access 8 Example Method Statement Contd. Rural Access Programme Development through access 9 Example Method Statement Contd. Rural Access Programme Development through access 10 Example Method Statement Contd. Rural Access Programme Development through access 11 Example Method Statement Contd. Procedure Contd.: Supervising staff to inspect every layers prior to proceeding with upper layer construction Lids of gabion boxes will be tied to all diaphragms Lids then stretched to their selvage boarders and laced Simultaneous backfilling behind the gabion wall @ 15 cm layers with watering and compaction as the wall progresses Site clearance Rural Access Programme Development through access 12 Example Method Statement Contd. Requirements Labour: Skilled labour, unskilled labour Material: Gabion boxes / mattress, stone, binding wires Instruments/Tools: Auto level, pipe level, pegs, string, measuring tape (30 / 5 m), pickaxe, shovel, Doko, wheel barrow, rope, dressing hammer, plumb bob, pliers, binding tool, rammer, wire cutter Rural Access Programme Development through access 13 Example Method Statement Contd. Health and Safety: Personal Protective Equipment (PPE): All workers must wear a safety helmet, high visibility vest, gloves, and safety footwear at all times Work sign boards and barricades need to be in place Site rules must be adhered to Clear, and safe, access ways must be in place Work conducted at heights must be done by workers with appropriate training Workers must have access to a first aid facility at all times Rural Access Programme Development through access 14 Example Method Statement Contd. Gabion basket with only 3 sides complete Rural Access Programme Development through access 15 Key Notes on Construction of Masonry Wall (Dry, Mortared, Gabion, Composite) Mostly used – random rubble masonry partially coursed Stone to be sound/hard and angular in shape, free from shakes/flaws/cracks Sp. gravity not less than 2.5 85% of stone to be of size > 0.01 m3 Shall not absorb water more than 5% (in 24 hrs. immersion) Rural Access Programme Development through access 16 Key Notes on Construction of Masonry Wall Contd. (Dry, Mortared, Gabion, Composite) Spalls/chips and voids not to occupy >20% volume of wall in dry masonry Spalls and mortar not to occupy > 30% of volume of wall in mortared masonry Stone to be hammer dressed on face, sides and beds Vertical joints in every layer to be staggered and horizontal lapping not < 10 cm Rural Access Programme Development through access 17 Key Notes on Construction of Masonry Wall Contd. (Dry, Mortared, Gabion, Composite) Bond stone to be provided At least one on every 0.5 m2 exposed face Cross-section (face) to be not < 15cm×15cm A thorough bond stone for wall up to 60 cm th. For thicker walls, two or more bond stones overlapping not < 15cm Plum (vertical) stone to be embedded at 90cm interval to join successive courses Rural Access Programme Development through access 18 Key Notes on Construction of Masonry Wall Contd. (Dry, Mortared, Gabion, Composite) Foundation is to be excavated at right angle to the face batter. Beds of the stone shall be laid at right angle to the batter. Header stones are to be laid over stretcher stone in consecutive courses (layers). The uppermost layer of dry wall to be laid on edge to keep the stone intact Rural Access Programme Development through access 19 Quality of Materials and Testing Provisions Stone – visual inspection to ensure hard/sound and free of cracks/shakes Cement – cube test for compressive strength GI Wire – Zinc coating and tensile strength test Gradation, CBR,PI, MDD, OMC for subgrade and pavement layers Rural Access Programme Development through access 20 SUPERVISION CHECKLISTS Rural Access Programme Development through access 21 Supervision Checklists A tool for site manager to ensure high standard of site supervision Includes critical activities that needs to be checked Requires collection of evidence, e.g. photos Any changes/variations in the work are noted in the supervision checklists Rural Access Programme Development through access 22 Sample Supervision Checklist 1 Setting out: SN Description Yes/ No 1 Is the location/chainage of structure correct? 2 Is the setting out work true to line? 3 Is the setting out work true to level? 4 Are the excavation lines true to line? Rural Access Programme Development through access 23 Sample Supervision Checklist 2 Excavation and construction of Foundations: SN Description Yes/ No 1 Is the foundation work true to line? 2 Is the foundation work true to level? 3 Is the slope of the foundation platform correct? 4 Is there any side casting of spoils? 5 Is the foundation soil appropriate? Rural Access Programme Development through access 24 Sample Supervision Checklist 3 Production, placing, and filling of gabions: SN Description Yes/ No 1 Are the gabion boxes properly laced? 2 Are the gabion boxes properly braced? 3 Is the stone quality of the right standard? 4 Are the corner stones correctly placed? 5 Are the vertical joints alternating? Rural Access Programme Development through access 25 Sample Supervision Checklist 4 Other works: SN Description Yes/ No 1 Are safety measures complied with at all times? 2 Are there adequate temporary works in place? 3 Are there any works to be measured which will covered up? 4 Are there any changes/variations required compared to the drawings? Rural Access Programme Development through access 26 Rectification of Works If defects are found while inspecting the works, necessary instructions are to be issued for rectification Different procedures for RBG and contractor works to issue instructions in case of non-compliance with the specifications and drawings Rural Access Programme Development through access 27 SITE INSPECTION RECORD BOOKS Rural Access Programme Development through access 28 Site Inspection Record Book Daily record of site activities, also called Daily Site Diary Maintained by site supervisor (normally lowest tier of supervision), but reviewed and signed-off regularly by the RE Used to maintain a constantly up to date record of the site, and the works Rural Access Programme Development through access 29 Site Inspection Record Book Contd. Site Inspection Record Book must include: Site weather conditions Details of on-going, and planned, activities No. of labours on site No., and type, of equipment on site Type and amount of materials on site Details of any work stoppages Details of any verbal direction given on site Record of monitoring/supervision visits and advice from other project personnel (ARE, RE, DTL, DC, DDC, DTO, etc.) Rural Access Programme Development through access 30 Example Site Inspection Record Book Daily Site Diary Weather consdition: Date: Road Name: Package no. Contractor/ RMUC: Activities: SN Location Description Labour (no.) Material Equipment Comments: Recorded by: Siganture: Name: Designation: Rural Access Programme Development through access 31 SITE INSTRUCTIONS Rural Access Programme Development