Construction Methodology Guide

CONSTRUCTION METHODOLOGY I. INTRODUCTION Services supplied by the Company Equipment, tools and materials supplied by the Contractor Work to be performed by the Contractor II. PROCEDURE 1. Construction: A. Materials handling and Distribution B. Site Preparation 2. Building Structure: A. Reinforcement B. Formworks Floor slab Walls Columns 3. Concrete Works: A. Walls and columns B. Floor slab C. Masonry and Plastering 4. Waterproofing Works 5. Metal door/jamb or hardware 6. Controls A. Setting up controls B. Scheduling, cost and document control 7. Testing of material 8. Demobilization III. SUMMARY OF CONSTRUCTION PROCEDURE I. INTRODUCTION Services supplied by the Company Engineering and design of the structure Delivery of all construction materials to the site Site technical assistance Basic equipment, tools and materials supplied by the Contractor Cargo truck         Dump truck Backhoe Plate compactor Bagger mixer Concrete vibrator Bar bender/cutter Welding machine Work to be performed by the Contractor   Site preparation Building construction and finishing MOBILIZATION Simultaneous with the transport of equipment during mobilization is the setting up of temporary facilities, securing and preparation of site for execution of the works. Areas identified as ideal location for storage of materials and as staging area will be properly secured and set-up. Part of these works will be provisions for temporary drainage system, water and power supply. One vital part of the works is the provision of a temporary access to the actual project site. MANPOWER Contractor’s key staff shall be mobilized prior to commencement of the works. This will include the Project–In-Charge, Project Superintendent, Head Office Engineer, QC/QA Engineer, Safety Engineer, Supervisors and all other key staff deemed vital for the project. Labor shall be employed in compliance with existing local ordinance. At this stage, contact will be established with the relevant authorities to arrange the necessary temporary facilities permits and to arrange for whatever local services are available. SECURITY AND HOARDING FENCE Security will be provided and the site will be guarded round the clock. It is conceived that the existing Security Fence will improved and be maintained by the Cordillera Horizon General Construction. PROCUREMENT We have identified the major work packages in our method statement and upon award of contract are ready to mobilize. Upon award of contract a Procurement Program and Early Warning Schedule will be established and used to co-ordinate and control the procurement of all major elements. This will include the Nominated Subcontractors, Direct Contractors and Owner Supplied Materials (whichever will be applicable) together with the release of information. II. III. PROCEDURE 1. CONSTRUCTION A. Material and Handling Distribution Material deliveries will be checked at the entrance of the site by the materials controller and directed to the allocated storage area where they will be unloaded. The storage areas will be controlled by a materials controller who will ensure that the materials are identified, labeled, stacked and stored in the correct manner and to the manufacturer’s recommendation. Materials will be distributed in pallets where possible. Loading-out platforms serviced by the mobile crane will be used. Horizontal distribution within the building will be provided by barrows, pallet trucks or hand carrying or appropriate. Storage generally will be provided in temporary site stores, open storage areas or within the building in designated areas. Materials will be stored and protected in accordance with the manufacturer’s instructions. Separate storage areas and enclosures will be provided for inflammable materials, which will not be stored in the building during construction. B. Site Preparation Upon award of Contract, survey stations and main grid lines will be established. Structural excavation works will commence. Local sumps and drainage ditches will be established to control rainwater runoff and any ground water (unlikely). Diesel pumps will be used to dewater the location. Steps of Site Preparation 1. Site clearing 2. Site surveying 3. Soil testing 4. Site plan design 2. BUILDING STRUCTURE A. Reinforcement Within the yard the steel will be cut and bent into required lengths and shapes. The reinforcement cages will be fabricated in the areas as designated and will then be placed in the required areas. Stages items Document verification Check shop drawing and BBS are approved and correct revision obtained Material approval Approved materials to be used Setting out and preliminary activities Check setting out is done as per approved shop drawings. Check access permission , equipment and scaffolding permission Rebar installation Installation of rebar to be done as per approved drawings and BBS. Proper cover to be maintained using approved spacers and chairs. Please check the ff as per approved shop drawings: 1. Diameter of rebar 2. Nos. Of rebars 3. Spacing for stirrups 4. Locations and lengths of overlaps 5. Starter bars, additional bars, dowel bars for oter structures to be provided 6. Top level of rebar correct as per the setting out done by the surveyor MEP Check all the electrical installations/ opening are done as per the approved shop drawings Check any mechanical services/ openings are provided as per approved shop drawings Check any other MEP services to be installed are done as per approved shop drawing Final inspection Visual inspection after completion of rebars erection. B. Formworks The majority of the formwork and support system work will be from the stock held within the group. The philosophy is to use proprietary formworks system with maximum standardization. Traditional timber formworks will be fabricated for specific applications on the basis of low reuse. Assembly will take place within the storage/working area. All significant repairs to formwork and cleaning, other than those that may be accomplished at the workplace shall be carried out in the workshop areas. B.1. Floor slab As the construction of the concrete frame is paramount to the speedy completion of the project, the floor slabs will be constructed using conventional and table forms. A formworks system similar to “Aluma” will be utilized to facilitate the construction of the slabs with the aim to: a). Shorten the construction time. b). Shorten formwork striking and material handling time. c). Effective control in quality. Typical equipment employed will comprise: a). Aluminum truss table or the likes with sufficient load span capacity. b). Lifting trolleys c). Plywood sheathing material. d). Base jacks to assist in the raising and the lowering of the table. B.2. Walls In general, the shear walls will be constructed using a set of storey full height shutters. Typical equipment required will comprise: a). Externally braced frame with lifting brackets b). Plywood faced panels c). Internal and external working platforms d). Trailing Platform The shear walls will be casted independently from the floor slab and will progress to stay ahead of the floor slab construction. A typical casting sequence will be: The day following placement of concrete, the internal forms will be stripped, raised and secured to the top of the wall by means of anchor screws previously cast into the top of the previous pour. The internal form is then cleaned. Reinforcement is fixed to the next lift of wall The external forms are now stripped, rolled back and cleaned The external forms are raised and anchored to the top of the previously cast wall. The forms are finally leveled and plumbed ready for the next pour. B.3. Columns Column formworks will be made from 1/2 plywood. To accommodate the varying sizes of columns to be constructed, the forms to be used will be adjustable. The column forms will have lifting hooks, plumbing units, access platforms and ladders attached. 3. CONCRETE WORKS In order to reduce the workload on the tower crane, it is our intention to pump the concrete by means of the concrete pump. This will be situated at ground floor level with a delivery line rising within the building to a placing boom that will supply concrete for the floor slab that will be casted. 1. Walls and Columns Concrete will be placed and compacted in layers with internal vibratory concrete pokers. The layers will not exceed the contract requirements. Trunking will be used to deposit the concrete so as not to cause segregation during the concrete placement. 2. Floor Slabs Concrete will be placed and compacted, working away from one end of the slab towards the other. The concrete will be compacted using vibratory concrete pokers and finished by means of steel or wooden float, depending on the type of finish required. Typical Sequence for Floors a) Erect slab conventional; table formwork and infill areas. Where there is a variance in levels, the table can be raised or lowered by the use of hydraulic jacks and adjustable legs. b) Erect beam sides and slab edge formwork. c) Position lightweight block void formers, if required, and box outs once slab is sufficiently advanced. d) Position beam reinforcement, fix column starter bars and fixes floor slab reinforcement. e) Floor slab concrete will be pump into location and thoroughly vibrated using vibrating pokers. f) After a 24-hour slab curing period, column and wall reinforcement and formwork will be erected and concrete placed into position. g) Once concrete to the slab has attained sufficient strength, slab forms can be struck and the slab re-propped as necessary. Beams will remain propped until the concrete has attained sufficient strength. h) During the erection sequence, the tower crane will be used for all hoisting and positioning of materials as required. 3. Masonry and Plastering All masonry walls shall start after all forms and shoring at the ground floor has been cleared. Concrete hollow blocks to be used shall conform to the specifications. Mortar for setting blocks shall be in the proportion specified in the plans and specifications. All masonry shall be laid plumb and true to line and built to the thickness and bond required with the courses level and bond uniform. Vertical and horizontal reinforcements shall be of standard sizes and laid on required spacing. Sealants and compressible filler below slab/beam soffit & concrete walls/columns will be placed. Materials for plastering shall conform to the standard mix proportions by volume. Base coat shall be applied first prior to the finish coat as required by the thickness. 4. WATERPROOFING WORKS Waterproofing whether elastomeric, capillary or membrane type shall be of high quality standard materials as required by the plans and specifications. Areas or surfaces where waterproofing is to be applied shall be thoroughly clean and dry to assure positive bonding result. Application shall be in accordance with the approved procedure as specified. As required by the specification, test will be done after completion of every area. 5. METAL DOORS/JAMBS & HARDWARE Owner supplied materials shall be of approved standard as shown in the plans and design specifications. It shall be prefabricated on shop. Prior to delivery on site all door and frame shall have proper mark or tag for identification. Door frame shall be first to install on the provided wall openings. Plumpness shall be checked prior to mortar pouring. Door panel shall follow, maintaining its alignment, standard tolerances and gaps. After which is followed by the installation of door hardware. 6. CONTROLS Upon award of the contract we will implement a series of control techniques to aid the management of the project. The main control procedures will include the following: Master Program Target Program Short Term Program Procurement Program Early Warning Schedule Information Release Schedule Construction Progress Monitoring Delivery Schedules Material Budget / Use Monitoring Labor Utilization Monitoring Reports and analysis from all of the above will be in the form of written reports, schedules and graphical presentations. Management of the project using these control procedures would require the holding of regular and “ad hoc” site meetings. A. Setting up controls Our first objective is to confirm the feasibility of our tender submission targets and to setup procedures to achieve them. We will finalize negotiations with prospective sub-contractors and suppliers to satisfy our requirements that they could meet our conditions in order to draw a Procurement Program. We will review our Information Release Schedule that has been derived to meet construction targets. This will also integrate the flow and preparation of Sub-contractor’s shop drawings and the required schedule of release of information from all sources. All action required for any activity to commence on site will be drawn together in our Early Warning Schedule. This will include items such as information release, inquiries, orders, samples, work visits, inspections, manufacture delivery and progress. This will cover all suppliers, other subcontractors, nominated subcontractors as well as our own direct works. In order to meet our contractual timetable we will draw a Target Program that will impose time savings over project duration. This would serve as contingency and is a normal practice within our system. The time savings as mentioned is not guaranteed considering it being a projection, but rather our estimate of the best case scenario for the project. From the target program we can form a summary of the whole works called a Master Program , which will be submitted to the engineer and by that an overall assessment of contract progress can be made. We will then prepare Short Term Programs and job lists that will cover a two-week period of the Target Program. This will be updated progressively and weekly. This is a means of communicating the main site program requirements through the section supervisors of the workforce. B. Scheduling, cost and document control To facilitate our work programs we normally use a combination of word and excel programs for our cost control and documentation systems. 7. TESTING MATERIALS Prior to installation or placing of construction materials such as steel reinforcements, concrete, and others, our CQC/materials engineer shall see to it that samples are taken in random from the delivered items and will be subjected for material testing. Before any testing will commence, the Construction Manager or his authorized representative will be notified. 8. DEMOBILIZATION A group of workforce shall be formed to facilitate the cleaning of the site prior to turnover. This group shall be responsible in making all the necessary cleaning and moving-out activities. IV. SUMMARY OF CONSTRUCTION PROCEDURE A. PREPARE SITE: Excavate site to depth and width specified on contract drawings Place safety barrier or tape or safety cone near excavation site where appropriate. B. BUILDING CONSTRUCTION: a.) Preparation and installation of Reinforcement steel bars b.) Concrete Formworks c.) Concrete Pouring/ wall pouring d.) Plastering/ Finishing/ Painting