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Industrial training report

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this report contain mainly initial training conducting to civil engineering undergraduates. report contains high rise building construction day to day works.

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Industrial training report

  1. 1. National Apprentice & Industrial Training Authority Report on Industrial Training At SP-Sierra Joint Venture (Pvt) Ltd Colombo 05 Sir John Kotelawala Defence University Rathmalana Name : D.S.Arachchige Student Number : ENG/13/023 Course : Bsc(Hon) Civil Engineering Field : Civil Engineering Period : 06 months
  2. 2. Report Authentication I do hereby certify that Mr. D.S.Arachchige from Sir John Kotelawala Defence University has worked in Proposed Multi-Storeyed Office Building for Commissioner General of Labour project site at Narahenpita as a Trainee B.Sc. Civil Engineer, since 22nd June 2015 to 21st December 2015. During this period he has actively participated for the Site & office works and gained well experience on construction & Site management. This project report contains about the work that he was engaged during this period. ………………………………….. D.V.S. Raju Project Manager SP-Sierra Joint Venture (Pvt) Lt
  3. 3. Acknowledgment I’m using this opportunity to express my deepest gratitude to Project Manager Mr. D.V.C Raju of the SP-Sierra Joint Venture (Pvt) Lt. His guidance and advice keep me on correct path during the training period. And CM Mr.L.Gopinath who provides facilities, coordination and assessment during the training which helps me to developed skills and construction knowledge. I would like to thank Technical Coordinator, Site Engineers and other Technical Staff provide supportive information and advice to perform the task successfully. And who support directly and indirectly to complete the task. I deeply express my sincere thanks to Chairmen and Staff of NAITA (National Apprentice and Industrial Training Authority) and Head of Department of Civil Engineering of KDU Dr. TMWRMB Samarakoon, Senior Lecture Dr. (Mrs)WCDK Fernando and Dr. WN Premadasa In additional special credit to chief operational officer Major Gen. Vajira Wijayagoonawardan of Sierra Construction(Pvt)Lt who made opportunity to involve large scale building project. D.S.Arachchige Department of Civil Engineering Faculty of Engineering General Sir John Kotelawala Defence University
  4. 4. Preface This Industrial Training Report is based on, which I performed after completion of 25 weeks of Industrial training at SP-Sierra Joint Venture(Pvt)Lt. Industrial Training Completion of 24 weeks is compulsory for the award of the Degree of the Bachelor of Science in Engineering from the General Sir John Kotelawala Defence Univercity, Sri Lanka Industrial Training program was held on 6th semester of the civil engineering degree programme curriculum and Industrial training is carried out by the National Apprentice and Industrial Training Authority (NAITA) in collaboration with the Training Division of the KDU. This report contained experiences and knowledge which I gathered during my training period from 22/06/2015 to 21/06/2015. Mainly report has three Chapters. Chapter 1 is included information about training organization, project description, hierarchy of the organization, safety of the project and welfare activities. Chapter 2 mainly described my experiences which are learned during my training and comparison with structural knowledge which I gained during academic. Chapter 2 is divided into sub topics according to which I performed and observed construction activities on the site. Finally Chapter 3 is about the conclusion of the training, which includes my development, suggestions and activities which I couldn’t perform.
  5. 5. Content 1. Introduction 1.1 About SP-Sierra Joint Venture (Pvt) Lt. …………… 1 1.1.1 Project overview ……………... 2 1.1.2 Organization chart ……………... 3 1.2 Company operation plan ……………... 4 1.3 Management Practice ……………... 5 1.4 Site Safety ……………... 6 1.4.1 Scaffolding ………………7 2. Training Experience …………….. 11 2.1 Formwork ……………... 15 2.1.1 Column Formwork ……………... 18 2.1.2 Wall Formwork ……………... 21 2.1.3 Beam Formwork ……………... 23 2.1.4 Slab Formwork ……………... 24 2.1.5 Striking & Removing Formwork ……………... 26 2.2 Reinforcement work ……………... 27 2.2.1 Column Reinforcement ……………... 30 2.2.2 Lift Core Reinforcement ……………... 32 2.2.3 Shear Wall Reinforcement ……………... 33 2.2.4 Beam Reinforcement ……………... 34 2.2.5 Slab Reinforcement ……………... 35 2.3 Surveying Work ……………... 36 2.3.1 Slab Leveling ……………... 36 2.3.2 Setting Out ……………... 37
  6. 6. 2.4 Concreting ……………... 38 2.4.1 Concreting Sampling ……………... 39 2.4.2 Concrete Placement ……………... 41 2.4.3 Compacting Concrete ……………... 44 2.5 Curing of Concrete ……………... 45 2.6 Chemical Anchoring ……………... 46 2.7 Block work ……………... 47 2.8 Machinery ……………..... 48 3. Conclusion ……………... 51
  7. 7. Abbreviation o MOL - Ministry Of Labour o KDU - Kotelawala Defence University o SP - Sapoorji Pallonji o PM - Project Manager o CM - Construction Manager o QA/QC - Quality Assurance / Quality Control o R/F - ReinForcement o GA - General Arrangement o D or dia. - Diameter o Re-bar - Reinforcing Bar o RC - Reinforce Concrete o CP - Control Point o TBM - Temporary Bench Mar o BBS - Bar Bending Schedule
  8. 8. List of Figures Figure 1: Logo of company ------------------------------------------------------------------------------ 1 Figure 2: Image of Building ----------------------------------------------------------------------------- 2 Figure 3: Organization Chart ---------------------------------------------------------------------------- 3 Figure 4: General Safety meeting----------------------------------------------------------------------- 6 Figure 5: Cup Link and arrangement ------------------------------------------------------------------- 9 Figure 6: Pull out testing --------------------------------------------------------------------------------10 Figure 7: continuous beam R/F details----------------------------------------------------------------12 Figure 8: Slab Reinforcement Detailed ---------------------------------------------------------------12 Figure 9 : Coupling Beam R/F Detail -----------------------------------------------------------------13 Figure 10: The load transfer between bars------------------------------------------------------------14 Figure 11 : plan view and elevation view of column formwork-----------------------------------18 Figure 12: LIWA Panel Arrangement-----------------------------------------------------------------19 Figure 13: LIWA system for column------------------------------------------------------------------20 Figure 14: VARIO system for column ---------------------------------------------------------------20 Figure 15: Conventional Wall Formwork ------------------------------------------------------------21 Figure 16: VARIO Shear wall Arrangement ---------------------------------------------------------22 Figure 17: MULTIFLEX Girder Slab Formwork arrangment -------------------------------------24 Figure 18: Beam & Slab Formwork -------------------------------------------------------------------25 Figure 19: shear wall panel shuttering ----------------------------------------------------------------25 Figure 20: Reinforcement Types-----------------------------------------------------------------------27 Figure 21: Bar Notation ---------------------------------------------------------------------------------27 Figure 22: (a) types of ties, (b) wire twister ----------------------------------------------------------29 Figure 23: internally threaded couple -----------------------------------------------------------------30 Figure 24: (a) Band saw machine, (b) forging machine, (c) Threading machine ---------------31 Figure 25: Lap and Crank lengh detail ----------------------------------------------------------------31 Figure 26: column R/F work----------------------------------------------------------------------------32 Figure 27: Coupling beam Reinforcement------------------------------------------------------------33 Figure 28: Shear wall Reinforcement work ----------------------------------------------------------34 Figure 29: Beam binding standard procedure --------------------------------------------------------34 Figure 30: slab and beam form leveling---------------------------------------------------------------36 Figure 31: Closed CP traverse--------------------------------------------------------------------------37
  9. 9. Figure 32: horizontal coordinate setting out procedure---------------------------------------------37 Figure 33: preparation of samples ---------------------------------------------------------------------39 Figure 34: Cube Testing Machine ---------------------------------------------------------------------39 Figure 35: Slump Test -----------------------------------------------------------------------------------40 Figure 36 : Concrete Placement ------------------------------------------------------------------------41 Figure 37 : HILTI Chemical and Gun-----------------------------------------------------------------46 Figure 38: Static Tower Crane -------------------------------------------------------------------------48 Figure 39: Ready mix Truck----------------------------------------------------------------------------49 Figure 40: Pump Car-------------------------------------------------------------------------------------49 Figure 41: (a) Bar cutter (b) angle grinder(c) bar bending machine ------------------------------50 List of Table Table 1: PPE & Uses-------------------------------------------------------------------------------------- 8 Table 2 : Conventional system components----------------------------------------------------------16 Table 3: PERI Components-----------------------------------------------------------------------------18 Table 4: formwork removal duration------------------------------------------------------------------26 Table 5: Concrete Placing Equipment & Tools ------------------------------------------------------42
  10. 10. 1 1. Introduction 1.1 About SP-Sierra Joint Venture (Pvt) Ltd SP-Sierra Joint Venture (Pvt) Ltd is international collaboration with local construction company. i.e. Sapoorji Pallonji (SP) from India and Sierra from Sri Lanka. MOL project is first project of the Sapoorji Pallonji (SP) in Sri Lanka. Partnership contribution is about 80% of total value of the project to SP. SP-Sierra Company provides quality construction services to build a remarkable landmark in the country, which have both local and foreign staff involving in engineering activities and matters. Currently working more than 40 staff in the project, especially project manager is a charted engineer from India who involved several projects in Dubai and well competence in construction industry. Other members of Construction Manager (Finishing), Site Engineers and Forman also from India. Locally, Construction Manager (Structure), Senior Site Engineers, Assistant Engineers, Technical Officer (TO), QA/QC Engineers and Forman are employed in SP Groups. Some of staff members such as Technical Coordinator, Quantity Surveyor and Engineers are provided by Sierra Company. Labour who involve in construction activities are carpenters, steel fitters, concrete finishers, electricians, plumbers, masons, riggers and unskilled labour. Few of labour are employed in company but most of direct labour are work in man power supply way. And some important activities such as formwork, steel fitting and concrete placement are open to sub-contractors. Figure 1: Logo of company
  11. 11. 2 1.1.1 Project Overview o Project : Proposed Multi-Storeyed Office Building For Commissioner General Of Labour(MOL) (Mehewara Piyasa) o Description : 36 stories including ground floor & two basements and 5 levels for vehicle parking (two basements and 1 to 3 levels) o Client : Department of Labour (DOL) o Contractor : SP-Sierra Joint Venture (Pvt )Lt o Consultant : Design Consortium Ltd (DCL) o Project management : Department of Building (DOB) o Project start : 2013/10/22 o Project ending : 2016/10/22 o Project Cost : 7891 millions o Total site area : 0.447 Ha Figure 2: Image of Building
  12. 12. 3 1.1.2 Organization Chart GENERALMANAGER PROJECT MANAGER Constructon Manager- Structure Senior Site Engineer (Formwrok) Asst.Engineers Forman Senior Site Engineer(rebar) Asst.Engineers TO Surveyor Asst.Surveyor Engineer Manager QA/QC QA/QC Engineer Forman Planniing Engineer Technical Coordinator Document Controller Draftsmans Manager Commercial QS Billing QS Contract Construction Manager- Finshing Site engineer Forman Engineer MEP Manager Admin Store Keeper Accountant Safety Manager Safety Officer Figure 3: Organization Chart
  13. 13. 4 1.2 Company operation plan SP-Sierra Joint Venture (Pvt) Lt haven’t big history but in separately two companies are well specialized in construction industry. Sapoorji Pallonji- is a leading internationally multi-business Group Which is based in India and providing services such as construction, security system, textiles, air and water purifiers, engineering goods, home appliances, shipping, publications, power, and biotechnology. It has long history in construction field and specialized in the field which is built tallest resident buildings and largest mall in India Vision “Foresting an environment that helps in the creation of knowledge & it’s applications to work, we seek to excel in all our business activities & strive to build Sapoorji Pallonji into a creative organization.” Mission “Sapoorji Pallonji & Company Co.Ltd will be the company of first choice in the construction industry. We shall be driven by our commitment to customer satisfaction.” Sierra Construction Ltd – is local specialized construction company which is started in 1981.during last decades built large scale projects such as Dabulla International Cricket Play Ground, Multi-Storied Luxury apartments, Highway etc… Vision To be the preferred infrastructure development partner in the region. Mission  Exceptional performance in all aspects of the industry.  Outstanding customer service.  Unparalleled value. Main Categories of Services  Design & build of multistorey commercial and residential buildings.  Design & build of factories and all kinds of industrial plants.  Design & build of hotels, convention centres and sports complexes.
  14. 14. 5 1.3 Management practice Management function can be divided into 04 components; planning, organizing, leading and controlling. Construction Company utilized management principle to produce effective outcome. Mainly project manager is a key person to success of the project. In the MOL project, the project manager mainly coordinates with planning engineer, construction manager, QA/QC manager, administration manager, billing and contracting department and safety manager. The Construction industry main goal is complete the task within allocated duration and allocated budget. So project manager and construction manager adopted to implement task-oriented management style in the site. Project manager conducts daily meets with different parties such as with consultant and client, structural team, finishing team and with administration and billing section. Suitable actions such delays of activities, budget controlling and project acceleration techniques will be discussed during the meeting Recruitment procedure is conducting by structured interview panel of relevant area. The interview is done by providing relevant field questionnaire, practical problems and evaluating past experience of the candidate. Construction staffs are working in such busiest situation. Therefore organization has introduced Day-off procedure which allows for any of staff member worked more than 24hr.The leaves can be taken 5 days per month but it may depend on project manager approval. Compensation is providing to employee monetary or non-monetary benefits such as bonus, overtime payment. But Engineers and other staff members not included overtime payment in this organization. But their basic payment is high than other construction companies. I had also chance to sign time on & off of labours’ in-time card. Work satisfaction situation I have given extra overtime to motivate workers. During my training period, some welfare activates such as providing lunch for working labour for opening of new office and celebrating Thai Pongal festival were organized by the company.
  15. 15. 6 1.4 Site Safety Safety is not a simple word just ignore in the construction site which cause serious injuries or permeant disable during the construction activities. In the records shows that many of injuries or permeant disable or fatal have been happened around construction sites in past decades. Therefore Site Safety management is essential in any large scale to small scale projects. Builder or Contractor first priority is fulfil safety measurements in the Site and ensure safe place or environment to workers. Workers have right to work in safe area and Employer is obliged to provide adequate safety measurements. If there is no such sufficient safety, Supervisor prohibited enforcing workers working under insecure area. MOL Project assigned Safety division, which has Safety Manager and 3 Safety Officers or Supervisor. Daily Safety Officer visit site in several time and supervising safety in the site and take necessary action. Safety officer has authority to force workers and supervisors if there have any hazard and take suitable preventative action. In the site, Riggers (who erecting scaffolding) were under Safety Officer command. Follows are main responsibilities of safety officer.  Awareness and understanding of all Safety rules and regulations in the Company.  Develop and implement safe systems of work for the project in conjunction with the Safety Manager.  Handle Riggers, erect external and internal scaffolding.  Provide or issue PPE and clothes to workers and site Staff.  Report any injuries resulting from work activities. (Include hazard area, conditions and unsafe operations etc…)  Conduct safety meeting to works as well as staff. Figure 4: General Safety meeting
  16. 16. 7 Accidents are cause due to unsafe condition and unsafe act. The most common types of accidents at sites are, o Getting hit by a falling object(material or tool fall from top) o Falling from heights o Electric shock o Another worker stand while material shifting o Getting hit by a moving vehicle o Injury due to moving machinery (ex. Power saw, drill hammer, bar bending machine etc.) o Due to inadequate light will be injured o Slip and fall while climbing the ladder during the rain
  17. 17. 8 PPE (Personal Protective Equipment) Description and uses Helmet is compulsory to be worn when working or visiting Site. Safety Officer is recommended the Helmet quality. Helmet used to protect head by falling objects, overhead load and sharp projections. (Often when going inside the scaffolding sometime our head will be hit that can be avoided.) Safety Shoes or boots are compulsory to be worn inside the Site, which are protecting falling material onto foot and prevent penetration of nails etc… Goggles are given to the workers who are engaging in breaking, cutting, drilling and welding works to protect their eyes. When works are working in bar cutting activities or Grinding activities Goggles must be worn Gloves are used to wear protect the palm of the hand. Mostly Bar benders and Mason are worn because of they are engaging in lifting of hard materials. Safety harness or Safety Belt should be worn if any worker who engaged works more than 3m height. Mainly Riggers have to be worn, because when erecting external scaffolding and safety net. Dust mask mostly worn labours who working finishing section. Welding masks are worn by Welders to protect eyes. Ear protections should be worn working large noise area such as when operating Air Compressor and Chipping activities. Safety overall Table 1: PPE & Uses
  18. 18. 9 1.4.1 Scaffolding Scaffoldings are temporary structures which are used for many purposes of construction activities such as enabling high elevation of access, covering around building and making safe platforms to deliver materials. Traditionally scaffolding system used to make safe platform such as using GI pipes (1.8m, 3m, and 6m) and Clamps. There are two clamps available; called free and fixed. MOL project initially used different scaffolding system which is called Cup Locks. Easy to erect and there is new method to lock each member. Main part of the Cup Lock system is stand (vertical member in 3m high and cups are in 500mm spacing to connect members) and Ledger(1800mm and 900mm lengths are available which is connecting to cup horizontally.) Cup links were used in internal works for binding the reinforcement of columns, lift core and shear wall, and facilitating for inspection works and used as a slab forms supporting system. Externally, cup links were used to erect around the building. But issue was cup locks are expensive, therefore external safety scaffolding system switched to scaffolding frames to cover building. Figure 5: Cup Link and arrangement
  19. 19. 10 External safety scaffoldings were erected on fixed bracket system around the building; these brackets were fixed by using expansion anchor bolts (Hilti). There are different types of anchor bolts, technical terms are used diameter of anchor bolt and barrel size. Installing of the anchor bolts should be accordance with contact document which is specified the location of anchor bolt, edge distance, spacing, drilling method, length and size and hole cleaning procedure. Installing procedure was done by drilling up to 100mm perpendicular to surface and during drilling avoid met reinforcement as possible. Hole was cleaned properly and bracket was placed in correct position. Then anchor bolts were hammered up to recommended mark (45mm). Bolt was screwed and tightened by using wrench. There is simple mechanism of the anchor bolts i.e. when screwing hardly the bolt, the barrel comes out and siding part will be griped with concrete and expanded. Therefore Anchor bolt is making hard fixed support with concrete. Usually anchor bolt resistance capacity will be tested by using hydraulic bolt tester. Test we called Pull Out test. This test is done in different situation where to check rebar anchorage acceptable like wise. Test was carried out by pressurized up to 1000psi and inspected the surface. If anchor bolt came out alone, there is bolts failure or anchor bolt came out with concrete or appear large crack it is concrete failure. Figure 6: Pull out testing
  20. 20. 11 2. Training experience When I started the training period, MOL Project was completed up to 4TH Level. Continuing mainly structural and Basement waterproofing activities were on the site. Building was divided into 3 Zones. Main sections of the site activities are Formwork, Steel Fitting (Reinforcement), Concreting and Finishing. I trained first 2 ½ months on Formwork section and remain period in Reinforcement. Intermediately, I learnt surveying works (Slab leveling, basic of setting out works), concrete placement and finishing (Block works). First day of the training I had safety instruction and introduction about the project. CM instructed me to observe activities going on the project and I studied the site layout. Especially during training, I gain experience about labour management, activities controlling, and implementing task according to standard operation in right labour on right situation. During the training I refreshed my structural knowledge which I learnt from academic. Behalf from that learnt new structural elements and features such as coupling beam, shear walls, trimmer bars and learnt new method of formwork technology, concrete placement, how to make BBS and construction procedure. And mainly I learnt about labour management which can be gained through experience. Follows are included structural elements theories which I learnt from academic and comparison with application during training. o Continuous beams - beam is a flexural member transmit gravity load to columns by internal forces. Continuous beam is indeterminate structures which are designed to resist bending moment and deflection mainly. Continuous beam generates large negative moment at the supports and positive moment at the mid-span. At the bottom main reinforcement is provided re-bar is lapped where 1/3 of beam span. At the top main reinforcement is provided to resist negative sagging moment. Vertically stirrups or links are arranged to bear shear load and to avoid cracks generating in diagonally. Stirrups spacing varies along the span and less spacing will be provided to resist higher shear force at the supports. Newly I learnt longitudinal Lacer bar (tie bar) which is inserted to large depth beam more than 750mm.
  21. 21. 12 o Continuous slabs – It is 2D element which is designed by considering 1m width continuous beam strip. Due to transverse load positive moment will be generated at the mid span and negative moment at the supports. Therefore Slab provided two layers of B1, B2 at the mid span T1 and T2 at the supports. In the site I observed that spacing of each panel, outermost bay spacing was closer than mid bay due to large bending moment at the mid span. o Column - is vertical load bearing member which transmit beam load safely to the foundation. Columns are subjected to compression load as well as biaxial bending moments. Columns are design according to BS8110 adequate longitudinal reinforcement and transvers reinforcement (stirrups). Stirrups are resisting the movement of the main longitudinal reinforcement during construction and restraining each reinforcing bar against buckling. Figure 7: continuous beam R/F details Figure 8: Slab Reinforcement Detailed
  22. 22. 13 o Shear walls – are used in building to resist lateral force due to wind and earthquakes. Mainly shear walls are predominant when designing tall buildings. There are different types of walls rectangular, barbell and flanged. Vertical reinforcement is provided to resist flexure capacity and horizontal reinforcement is provided to prevent diagonal tension failure. Arrangement of shear wall symmetrical at least one axis. Barbell and flanged shaped shear walls have greater resistance against sliding shear. o Coupling beam – lift core wall has vertical row of openings for access to services, then either side wall of opening are coupled by beams are called coupling beam. Additionally coupling beam carry axial force across beam into wall and in severe earthquake and ends of the couple beam subject to large rotational and vertical displacement. Coupling beam has small span to depth ratio therefore shear force is critical. It is necessary to provide sufficient shear reinforcement to resist. Vertical stirrups aren’t sufficient to withstand will be developed diagonal cracks at the beam ends. Diagonal reinforcements are more effective than vertical R/F and it should be well anchored into wall. o Lap length – minimum length which transfer load to concrete safely and to another bar. Load transfer to other member in the concrete is governed by the bearing of the Re-bar ribs against the concrete. In the concrete developed compressive strut with an angle of 45 degrees. In this site recommended to used lap length is 52*D. Figure 9 : Coupling Beam R/F Detail
  23. 23. 14 I have been trained as a training site engineer during period of training and studied duties and responsibilities of site engineer as follows, o Executing activities according to contract drawings and specifications, agreed procedures and method statements. o Full control the workforce on site to achieve planned task. o Ensuring that safety rules and regulations are communicated to the workforce and are fully aware. o Site surveying and setting out, dimensional control, prepare BBS, Record productivity of day work. o Monitoring all Sub-contractors work closely to ensure that the Quality of the work is as per specification and is completed on time. o Review technical aspects of Method Statements produced by subcontractors. o Preparing activities for the inspection coordinate adjustment and carry out rectification. o General site management and assign right workforce each activity o Informed or report CM or PM related issues affect to the project completion and quality. Following sub-chapter included which I performed task during training with relevant information. Figure 10: The load transfer between bars
  24. 24. 15 2.1 Formwork A rigid structure or mould fixed temporarily which is retained size, shape and the position of Structural elements (Column, Walls, Beam, Slab) until set up fresh concrete. Formwork is the single largest cost component in the concrete buildings. In some situation cost of formwork is higher than steel and concrete. Selection of suitable formwork mainly depends on project quality, time and cost of erecting and removing, safety of formwork and direct and indirect costs. Formwork should be easily fabricate, easily erect and remove and more times of reuse. There are two types of formwork solution, which are  Conventional formwork – Basic formwork solution which can be designed carpenters also. Normally used Plywood, Lumbers (2X2, 2x4), GI pipes, thread bar, Form ties, P-Cone, Props and Chains.  System formwork - Differentiate with conventional formwork which are prefabricated outside of the job. It’s made of steel or timber specific shapes and sizes. In the world there different Brands of system formwork which are PERI, Doka, Mivan etc… Formwork positioning and plumbing was done in a simplest way, first have to established edge and offset lines each structural element. For columns normally 1000mm offsets were established around column, supervisor should have to calculate offset distance from edge. For walls, kerb 200mm or 300mm offset are established by using Marking cord. Plumb bob with string will be attached where top of the form and distance will be measured by reducing the thickness of board and hanged. Top prop or chain was used to push or pull the form in correct place by observing plumb bob nib. And kicker props used to adjust correct location of the form. Sub-contractors or carpenter tried to finish job as soon as possible, therefore they generally made mistakes, not adhere to method statements and quality of the work will be reduced. Proper inspection and communication is mandatory to finish work as quality.
  25. 25. 16 In MOL Project used PERI Formwork solution and combined with Conventional system also. PERI is professional Formwork solution service provider in Germany. PERI Formwork product included self-climbing, panel and many of different types of products. Mainly in site used MULTIFLEX Girder slab formwork, LIWA panels and VARIO GT 24 Column and Wall formwork. Conventional formwork components Description and uses PLYWOOD is basic material used in any concrete construction sites. Plywood is designed in compacting layers by layer which are available different thickness in the market (18mm, 15mm). Board outer layers are smoothened to give good finish to concrete elements. Board size 1220X2440mm. Runners (2X2’’) used where corners of plywood and to lock beam side form. P-Cone with Thread bars Form tie is a clamping device on each end, are installed through the forms to resist the bursting pressure exerted by the concrete Props and chains with hook turn buckle. GI pipe – used as studs and waler in vertical form, used to lock long beam side form. Nails (2’’,3’’) used to nailed the runner and plywood Table 2 : Conventional system components
  26. 26. 17 PERI Components Description & Purpose PERI Girder- used in slab soffit forming (MULTFLEX) as primary and secondary support and for VARIO Panel design. Available sizes are 3.9m, 3.6m, 2.9m, 2.65m, 2.45, 2.15m,1.45m Weight about 5.9 kg/m Permissible bearing force 11KN Cross head - used tilt-resistant support of one or two Girders and used to overlap the girders also. Props - used to support girders. Long prop max length 4m and short prop max length about 3.5m Universal Tripod – used to combine Prop to resist topple. LIWA Panel - Steel frame panel fixed plywood board. Light weight panel sizes available 3000X750mm, 3000X600mm, 3000X500mm. Wedge Clamp – used to compensate LIWA panels Corner Connector – used to connect two orthogonal LIWA panel Wing Nut - used to anchor Tie rods Tie Rod - resist tension produced by lateral pressure of the concrete and used to lock wall forms Adjustable Props - which can use to pull and push one end, connect to Waler and other end Base plate. Steel Waler – used to support Girders and fixed Horizontally. Mainly steel walers are used in VARIO panels.
  27. 27. 18 Coupling – used to compensate(tension or compression) VAIRO panels or tighten Hook strap – used to lock Steel Waler and Vertical Girder (stud) top flange. Table 3: PERI Components 2.1.1 Column Formwork Column formwork is a vertical form or panel in different sizes and shapes, which have designed to resist initial hydrostatic pressure of wet concrete. I had chance to observed conventional method of column formwork, shuttered column was G-2 (Grid position) 900X900 column. Normally The Columns are covered up to 3m. Basically using materials are plywood, GI pipes (2’’), thread bar, form ties and P-cone (1’’). Carpenters were cut full board plywood(Tk. 18mm) into 918mm all four sides or alternatively cut 1020mm two sides and other two sides 900mm. 2x2’’ wooden runner were nailed edge of plywood sheet up to 3m. Intermediately thread bar were cut into (900- 15=885mm) and fixed P-cones both sides by using P-cone Key. One side of plywood sheet was placed into correct position of kicker and nailed (3’’nails).and hammer drill was used to make holes to insert thread bar in different heights. Studs (GI pipes) were arranged vertically app.100mm spacing. After, Form ties were screwed into p-cone head. Finally double waler (GI pipes) were installed horizontally and tightened by using form ties Key. Figure 11 : plan view and elevation view of column formwork
  28. 28. 19 When supervising conventional column formwork initially has to inspect kicker is in accurate dimensions, avoid studs spacing maximum, separates are arranged in accurate lengths, Instruct to fixed double walers perpendicular to studs and maintained horizontality of walers. Good alignment is depending on proper waler tighten. All column formwork done in LIWA and VARIO panels, which are easy to handle, less carpenters requirement and less time taken to finish the job. LIWA panels no need Tower crane to cover the reinforcement. Lightweight characteristic of LIWA panels is more effective when shuttering the column with two carpenters. When shuttering LIWA panel, good practice to remember panel should have to keep at least 200mm outer from the edge of the element to connect Corner Connector orthogonal to other side of panel. It’s important to supervise wedge clamps are fixed in three positions of the two panels’ joints to proper alignment. When casting element is large Tie rods have to install where two LIWA panel touching with Wing Nut. These Tie rods were cut more than (column size + 300mm). Two side of form were propped in four long adjustable prop and short prop. Top long prop used to adjust the formwork verticality. And short kicker prop used to positioning formwork in correct location. After completing the shuttering, top formwork dimensions accuracy, plumb of the formwork and leakages closing were Checked. It is a good trait to practice before inspection getting start. VARIO Panels are fabricating into different shapes. There were two L-shape panels lift by Tower crane into correct location and cover the Reinforcement. VAIRO panel were fabricated in the site according to drawing given by PERI Company. When design of panel, concrete pressure considered 50 KN/𝑚2 (double of fresh concrete pressure) and allowable maximum Girders spacing is about 0.3m. Two Steel Waler are supported to Girders about Figure 12: LIWA Panel Arrangement
  29. 29. 20 1.435m apart in 3m high panel. Two L-shaped VARIO panels were joining and tightening by Tie rods and wing nut. Common problems arising during job are;  Kicker is not leveled difficult to plumb and bottom create openings.  Top prop braced is in insufficient height due to that Waler got twist.  Or Anchor bolt released from concrete surface during turning props.  Crane is not available.  Over size Covering Blocks are placed difficult to close and difficult to plumb the panel.  Panels are damage during de-shuttering and inadequate Form oil pasting. Figure 13: LIWA system for column Figure 14: VARIO system for column
  30. 30. 21 2.1.2 Wall Formwork Wall formwork is a vertical form arrangement which is resisted lateral pressure exerting from fresh the concrete. Typically design of shear walls formwork Engineer should understand to design shear wall without fail until concrete gain sufficient strength. Shear walls have large amount concrete volume, therefore exerting pressure is high. When doing conventional formwork must have to supervise Studs spacing and waling spacing in gradually increased manner from the bottom. Thoroughly, have to be supervised that formwork edge closeness and have to be provided adequate props and chains to pull. Conventional wall or shear wall formwork shuttering are taken longer period than system formwork, which used number of thread bars, p-cone and form ties. Other major issues are  Need large amount Steel props and Chain with turn buckle.  Edge rigidness is not sufficient, form try to bulge.  Difficult to finish orthogonal edge or complex shapes,  Long time period to shuttering and dismantling Conventional wall form designing should have to consider wall thickness, height of the form, where location and supporting system. Location of separate or tie bars and its spacing will give good result finishing without bulge. Mainly job quality depends on carpenters skill level and experience. Normally 300mm Tk wall horizontal spacing of the separate were fixed app. 500mm and vertical spacing were setup gradually increasing manner from the bottom (200, 400,400,500,500,600,300) mm. other thing was when placing Walers, GI pipes should be long (6m) to maintain good alignment. Figure 15: Conventional Wall Formwork
  31. 31. 22 Supporting of wall form at least 03 props have to propped in vertical direction. If wall is located in corner of the building or external board is unsupported, that case Tie rods or thread bar and pulling chains are compulsory. Due to time wasting in conventional wall forms, VARIO Panels were designed required shapes and used at site. MOL Project has 10 shear walls and from them 8 of were anchored with column. Following [Figure 16] shows corner shear wall in MOL Project J/H-2. Shear wall consist of one long panel (outer panel), 04 L-shaped panels and one straight panel. I have been supervised shuttering of this corner shear wall. First outer long panel was lifted from crane and slowly covered the Reinforcement to correct position and locked temporary. Before shuttering the panel marking was done at the position of outer panel edges on the kicker for convenience. Because outer panel was heavier and difficult adjust after shuttering. That panel (cross section about 400mm at the corners) inserting space insufficient due to 400m from external scaffolding to concrete finish. Thoroughly have to ensure that below external scaffolding are anchored from wall supports otherwise working that area is insecure. Other interior panels were shuttered according to PERI drawings to correct position and inserted tie rods through tube separate (PVC conduits and plastic cone). Filler (a gap between panel) should be uniform gap because outer L-shaped panel hasn’t any support and that panel plumb depends on filler adjustment. After closing all panels angle distance of 4300mm should have to check at the top and all other dimensions also have to check. Plumbing was done same as others and ensure that tie rods were tightened properly and gaps were closed. This 900X900mm Column L-shaped panel hasn’t propped from outer and tie rods also not inserted. when pouring concrete panel try to displace outer side of the building and column plumb will be changed when lifting long panel wind speed play sever condition of unsafe. Therefore As a solution I recommended that self-climbing formwork system which has consist platform also. Figure 16: VARIO Shear wall Arrangement
  32. 32. 23 2.1.3 Beam formwork Beam formwork is a three side box including two sides form and a soffit these sides’ forms are retained initial static wet concrete load and soffit form bear initial load (imposed load and reinforcement load) and wet concrete load. Beam formwork done in conventional method first we prepared beam soffit form, which is done simply according to GA (General Arrangement) calculating the span length and width of the beam. Power Saw was used by carpenters to saw the plywood and 2X2’’wooden runner. Long GI pipes were attached along the soffit and 2X2’’ runner was nailed across it. Tower crane used to lift and lowered the soffit form in correct place. And adjustable steel props are propped along beam soffit 500 mm intervals doubly. Providing adequate supports to bear any type load is significant without deform or failure. Before beam soffit form placing, we need to fix the soffit kicker at column top. It’s important check and recheck the kicker height from the TBM where marked on column. Height can be calculated as follow, Measuring Height = Upper structural – TBM level – Beam Depth – Plywood Tk. Beam level Or (for typical floor only) Measuring Height= Typical floor Height– 1000mm – Beam Depth – Plywood Tk. (3900mm) Next step is setup the side board of beam formwork. These side boards were sawed measuring height of sides of beam plus 60mm to nailed soffit form with runner. Side board height also can be determined as follow, Sideboard Height = Beam depth – Slab Tk. – Plywood Tk. If there is Drop where; slab to beam Drop amount should be added and beam to slab Drop amount should be subtracted. Carpenters were measured that height from steel tape and nailed 2’’nails half on the board. And top of the side board 2X2’’ runners were fixed to support top slab form. When carpenters were working at the top supervisor must instruct to wear safety harness. After fixed one side of form, hammer drill used to make holes at the bottom of side form in 500 or
  33. 33. 24 600mm spacing. When inserting the separates (thread bar with p-cones) makes sure that can be resisted lateral pressure of wet concrete. For higher depth beams two separates were inserted where top and bottom of side form. These thread bar cut 15mm less than beam width. Beam side forms were locked after lowered beam reinforcement. Two workers were needed for locking work. 6000mm GI pipes were used along Side form and two 2X2’’ runners were placed and locked with form ties vertically across the GI pipes. [Figure 17] 2.1.4 Slab formwork Formwork for slabs is somewhat different than formwork of walls or columns. Slab forms are elevated; therefore, they require some type of vertical support. Also, carpenters will be working on the formwork. Slab form safety is important due to increment of static dead load and any impact load. In many instance, formwork failure happens due to inadequate shoring for slab. Shores must be secured at the top and bottom ends to prevent any movement or displacement. MULTIFLEX Girder Slab formwork system easy to erect, remove and shores also. Shoring system was done in adjustable steel props or Cup Links. Following [Figure 17] shows the slab formwork arrangement. And it is numbered sequential procedure of slab forming. Figure 17: MULTIFLEX Girder Slab Formwork arrangment
  34. 34. 25 Firstly arranged shoring system and at the top of shoring cross frokhead or U-head were placed and where primary girders overlapping position must install Cross frokhead not U-head. Then Primary girders kept 1.8m apart but near to the beam form kept 500mm spacing. Overlap length of primary girders app. 600mm. practically difficult to keep that length therefore nailed cross head with girder. For safety of slab form used 05 primary girders across 8m span. Before placing secondary girders, string was attached to corner of side form of beam. Cross heads (U- head max 1 ft. and cross frokhead max. 500mm can be screwed up) were adjusted according 200mm deep with the string. It is very convenience to slab leveling. Types of girders are selected to suitable place maintain 400mm spacing c/c of the secondary girders. Finally plywood sheets were laid down at the edge of side board were plumbed by using speed level and nailed. It is necessary to check that top side boards were nailed and joints were closed. Figure 18: Beam & Slab Formwork Figure 19: shear wall panel shuttering
  35. 35. 26 2.1.5 Striking and removing Formwork Removing or dismantling of formwork is important as the erecting of formwork. Care of removing will be depended on number of reuse and less damage. Removals of forms were done by after achieving sufficient strength of concrete bear itself. Forms Duration Columns, walls, side forms or vertical forms 12 hr. to 1 day Slab soffit span over 6m 14 days Beam soffit form 21 days Table 4: formwork removal duration But these duration varied with curing methods adopting at site and temperature of the around site. Order of removing form, 1. All vertical forms of column, wall, beam side and column head side forms should be removed first. 2. Next, slab soffit should be removed. 3. Finally, beam soffit form should be removed. Unsafe removal of forms are damaged mainly plywood corner edge and top of panel form. Basically de-shuttering of slab formworks are done in standard procedure. Initially U- head or frokhead were lowered some extent by rotating screws. Then all secondary girders were toppled on to primary girders and removed. One end sharp hook tool used to remove plywood. Scaffolding set used to catch the plywood without drop on the floor. Sometimes face difficulties when de-shuttering walls forms, best practice to use form oil (diesel with grease-non environmental friendly) before shuttering the element. When apply the form oil form should be cleaned free of debris or concrete grout. Walls de- shuttering were done by using Tower crane. Vertical forms weren’t kept longer period if not difficult to remove.
  36. 36. 27 2.2 Reinforcement work In the academic learnt that plane concrete is strong in compression force but weak in tension forces. Therefore steel bar used in mass concrete to gain tensile stresses. These structures called Reinforce Concrete Structures (RC). Practically Reinforcing bars (Re-bars) are placed as near the outside of the edge by providing sufficient cover to protect corrosion and to resist fire. Standard sizes of Re-Bars are 6, 8, 10, 12, 16, 20, 25, 32 and 40 mm. rebar have two type of Grade which are High Yield Steel-Grade 460 or Grade 500 (460N/mm2 or 500N/mm2) and Mild steel- Grade 250(250N/mm2). These two Grade of rebar denoted as T or Y and R respectively. There are several types of deformed Re-bars [Figure 19]. Mainly Ribbed Rebar (bond classification type 2) used for construction of building. Normally Re-bars are supplied 12m length but different length we can order. Storing is important in construction site. Re-bars are prohibited to store on the ground; at least 150mm above the ground should be stored. And have to keep free from oil, grease and mud to provide good bonding characteristics with concrete. Bar notation is fundamental to know, Each Reinforcement drawing are used bar notations. Figure 20: Reinforcement Types Figure 21: Bar Notation
  37. 37. 28 When working Reinforce activities thoroughly have to follow R/F (ReinForcement) Drawing. All Re-bars are cut, bended, and shaped according to R/F Drawing. As a site engineer fundamental to arrange Bar Bending schedules (BBS) by calculating dimensions according to Drawing and should have to get approval from consultants. o Bar Bending Schedule (BBS) – is a specification of bending dimensions and scheduling of bars which consists of location, Bar mark, type of bar, number of members, nu of bars, cutting length, shape code, dimensions, weight and remarks When Re-bars bending and shaping have to know the cutting length of the rebar, because when bending, re-bars are elongation some amount that depends on bar diameter. We followed BS 8666 that provided equations to different shapes. When bending different dia. Bars pulley or mandrel of the bar bending machine also varied. As example, for 32 dia.bar used 224mm pulley to bar bending machine. Bar coding and BBS aren’t learnt from academic period, in Sri Lanka used BS 8666 used to make BBS. Weight calculation also important to make billings of sub-contractors, ordering Re-bars etc... Basically, used following equation to measure weight of Re-bar per meter. Weight of bar per meter = D2 164 kg/1 m (where D is diameter of Re-bar) There are more advantages around the BBS. Mainly, o BBS require at the steel yard to supply requirement at the site. o To order the nu. of Re-bar requirement of whole project. o Supervising R/F activities to identify correct re-bar particular work. o Reduce the cutting wastage. o Can be communicated effectively with steel yard regarding site requirement. o Easily prepare billing of R/F works for sub-contractors.
  38. 38. 29 Rate of the steel is about Rs. 7,500 per 1 Ton in MOL project. During training period I observed that steel fitters (Bar benders) were used different ties on Re-bar binding. Ties wires are used to secure the Re-bar in a position during concrete placement. There are 03 types of ties mainly i.e. Snap or single tie, wrap and snap tie and U tie or saddle tie. Mostly steel fitters familiar for used snap tie used in slab, lapping Re-bar etc… but high skilled labour knew and they applied wrap and saddle tie on horizontal R/F binding on the shear walls, column ties to vertical bars where there is a considerable strain on the ties etc… (a) (b) Steel fitter are fundamental to know how to use stainless steel hacker or wire twister [Figure 22 (b)]. 16 gauge double annealed iron wire used to tie Re-bar in position. Basically wires are available in coil form. Bindings were cut into different length; half of coil for column, lapping, beams etc… and 1/3 coil for slab, walls horizontal etc… by using bar cutter [Figure 41]. Figure 22: (a) types of ties, (b) wire twister
  39. 39. 30 2.2.1 Column Reinforcement Column is vertical member which has R/F of longitudinal (main bars) and transvers (links or stirrups). These longitudinal bars must be lapped to provide structural continuity. MOL project up to 15th level 40mm dia. Bars were used. 40M bars were connected through mechanical coupler. Lap splicing can be done in three ways. Those are mechanical splicing, overlap splicing and welded splicing (not used).  Mechanical splice/ moment coupler – where the reinforcement section has congestion (generally greater than 32mm dia. bar), coupler is a good solution. Because can reduce cost (Lap length more than 2m), increasing construction speed and adequate space to flow concrete and easy to insert the poker. Coupler is used as compression and tension splice. There are several types of couplers form that internally threaded coupler is successful and popular. This coupler 90mm long and 62mm dia. General steps involved in process of making thread, Step 01[Figure (a)] - 40M bar ends too much bends are cut with Band saw machine or sheared with a shear machine. It is done in order to achieve flat surface of the re-bar. Step 02[figure0 (b)] - The cut bars are cold forged at the ends to increase diameter. 40mm bars forged into 46mm and applied pressure app. 7000- 8500psi. Step 03 [figure(c)] - the forged end of bars were threaded with a threading machine. Machine operated making thread 45 mm lengths. Step 04 - screwed coupler to one end of bar and measure accuracy by Vernier caliper. Figure 23: internally threaded couple
  40. 40. 31 (a) (b) (c)  Overlap splice –this method frequently used to lapped and tightened from iron wire of discontinued rebar and transmit the force to another re-bars. This lap length is minimum length have to provide when connection another bar. Lap length equation is provided in [Figure 25] and connecting bar has to be cranked to provide same orientation line to transfer the loads. When cranking the Re-bar refers BS8666 shape code 26, from that we can found the cutting length of the bar. It is compulsory to provide Lap length to transfer resisting moment to starter bars. At least two ties required to tighten Lap without loosening during concrete placement. Transvers reinforcements of the column called Stirrups or Links have to provide specified spacing and pattern. Stirrups were made according to BS8666 shape code 51 by reducing covering of column. When supervising thoroughly we have to check, steel fitters are inserted correct position of stirrup set and bend hooks are kept in same line. When binding R/F some practical problems arisen, those were covering issue in starter bars, stirrup set bind Figure 24: (a) Band saw machine, (b) forging machine, (c) Threading machine Figure 25: Lap and Crank lengh detail
  41. 41. 32 on the coupler due to longitudinal bars were staggered in deferent heights and sometime stirrups weren’t in accurate sizes. For column R/F work requires 04 bar benders. Scaffoldings were erected up 6m, two bar benders worked at the top and other two carrying vertical Re-bars [Figure 26] all vertical bars were lapped after stirrups were inserted at the top in correct order and correct position. Column R/F work can be completed around 8hr by supplying 04 bar benders. Thoroughly have to supervise the covering issue, stirrups spacing, lap length pattern and location. Covering placement is final part which has to check covering block size and where it is bind tightly without loosen when shuttering the forms. 2.2.2 Lift core Reinforcement Lift core is critical area of the building which is the strongest area of the building. Reinforcements were arranged vertically and horizontally and open leg ties placed where to anchor vertical and horizontal R/F. MOL project has 08 lift opening and 08 lift wall door opening. Vertical members were fitted to starter bars app. less than 200m spacing. And when connecting Re-bar specified lap length (52*D) have to provide. Horizontal R/F was installed 12 dia. re-bars and when binding horizontal bars should be in specified spacing according R/F Drawing. Wall should be sized by using steel tape or alternatively corner of wall was plumbed by using plumb bob with offset line. It is important check all length of wall edges and openings to minimize facing covering issue else when shuttering the form or problem may be major and steel will be toughed with the form. One leg ties also made 12mm dia. re- bars and arrangement have to be followed correct position and direction. And open leg ties placement should be done in interchanging way to give good interlock of R/F. Figure 26: column R/F work
  42. 42. 33 Figure 27: Coupling beam Reinforcement Vertical R/F Drawing showed the open leg ties generally called Hooks arrangement. Other thing is thoroughly has to inspect the coupling beam of the lift core walls. TBM was established by survey helpers on the lift shaft wall. From that point bottom parallel reinforcements of the coupling beam were installed with defined anchorage length or development length. It is important to supervise the diagonal reinforcement placement. All re-bars were arranged according to drawing and anchorage length with wall has to provide defined minimum value. 2.2.3 Shear wall reinforcement Flexural reinforcement or vertical reinforcement of the shear wall should be vertical as possible. Practically the starter bars in inaccurate spacing, therefore when binding vertical bars torque was used to maintain correct spacing and verticality. Transverse reinforcements were arranged horizontally. When binding reinforcement covering issues will be emerged; I have solved those issues by instructing to insert transverse reinforcement inside. Additionally I have marked the position of the hooks by studying the Drawing. Mainly I instructed to bar benders plumbed one side of wall reinforcement by attaching plumb bob at the corner or sized top horizontal distance of the wall by reducing covering. It is compulsory to eliminate the coving issues much as possible before shuttering the forms.
  43. 43. 34 Figure 28: Shear wall Reinforcement work 2.2.4 Beam Reinforcement Beam reinforcement started where intersecting the beams with column. Beam R/F can be started after completing the shuttering of beam and slab forms. Beam R/F binding have done in standard procedure followed by sub-contractor also as follow, Figure 29: Beam binding standard procedure
  44. 44. 35 1. Two or more column Links/stirrups were lowered middle of the beam. 2. To place secondary beam top support bars, temporary 25mm Re-bar bind horizontally above slab form about depth of beam. 3. As per Drawing, correct nu. of top support bars were placed on that temporary Re-bar in correct length. 4. After select suitable stirrups sizes according to drawing, stirrups were loaded to top support bar, when loading stirrups must consider stirrups’ hook side and avoid putting same side due to happen a shear line of failure. 5. According to drawing stirrups spacing were arranged and primary beam top support bar were placed on the secondary beam support bars. 6. After inserted all required stirrups to both side, hanger bars were lapped and tied up the stirrups correct position by looking covering of both sides. 7. Then bottom layer Re-bars were inserted and lapped at the correct place. 8. If there were two layers second bottom layer kept on spacers to maintain gap. 9. Stirrups should have to tie up balancing covering because covering problems would be arisen when lowering the beam R/F. 10. Beams were lowered after placing bottom covering in a 1m gap. 2.2.5 Slab Reinforcement Typically slabs have 04 layers B defined bottom reinforcement and T defined as top reinforcement. At the mid span large positive bending moment occurred therefore bottom reinforcement is only provided at the mid span and at the support both top and bottom layers are provided. Standard procedure was followed by steel fitters as follows 1. Firstly, chokes were used to mark correct spacing of bottom layer at least three places of the panel along span on the slab form. 2. Two or more steel fitters engaged in placing the correct bar B1 according to BBS. 3. B2 layer fixed at 03 places across B1 with covering block at marked position. 4. Alternative ties were made and restrict movement of layers 5. Chairs were positioned in 1m interval to stop deformed under imposed load. 6. Top reinforcement also placed as defined length from drawing and distribution bars also inserted inside top Re-bars.
  45. 45. 36 2.3 Surveying works Surveying works included mainly horizontal surveying and vertical surveying which is used to locate the structural elements correct position, verticality control, level of slab form and reinforcement etc… 2.3.1 Slab leveling Initially Dumpy level mounted and leveled the instrument by arranging the legs. Height of collimation was measured at the TBM (1000mm) by keeping steel tape. Readings were taken by using inverted staff holding to the forms. For beam soffit staff held to plywood and for slab staff held to lower girder. Figure 30: slab and beam form leveling For Beam soffit form Staff readings = floor to floor height – beam depth – plywood Tk. – Height of Collimation For slab form Staff reading = floor to floor height – slab Tk. – Plywood Tk. – height of primary and secondary girder (400mm)
  46. 46. 37 2.3.2 Setting out Horizontal surveying done by Total Station (TS), number of control points (CP) were established around proposed building to run a closed traverse [Figure 31]. Each floor temporary CP was established by mounted TS at the CP 2 and target mounted at top of slab. TCP (Temporary control points) were noted down the coordinates and by interchange the procedure, TS mounted at the top floor TCP mark and the target held at the CP2 place. Generally optical plummet was used to setting out Grid line. Basically Grid lines marked 1000mm offset from it. Marking code was used to make permanent lines on the slab, column and walls vertical face. Figure 31: Closed CP traverse Figure 32: horizontal coordinate setting out procedure
  47. 47. 38 Vertical surveying was done in steel measuring tape by placing vertically upward in the inner wall of lift shaft wall. Dumpy level was used to established TBM on each floor, TBM is a 1000mm offset from floor level which was marked on column, wall. When doing level transferring to the next floor joints may be disrupting to keep steel tape properly vertical. Maximum vertical deviation tolerance is about 3mm. each floor records have to be maintained with design coordinates and actual coordinates. 2.4 Concreting Concrete is engineered material which is mixture of coarse and fine aggregates, cement, water and admixture into different proportion. Initially mixture shows plastic characteristics (fresh concrete) remain short period, initiate chemical process of water cement reaction called “Hydration” bind with aggregate become harden very hard like rock character. Concrete has significant resistance to compressive stress and relatively weak for tension. The properties of the concrete, including its strength, weight, porous and color mainly various with constituent of the concrete. o Cement – mostly used Portland cement (OPC) is a finely powdered, grayish material that consists of calcium and aluminum silicate. Water-cement reaction occurred cement will be recrystallized. The strength of the cement paste largely depends on the water-cement ratio because of additional water produce pores on the cement. Water adding to concrete increase workability but exceeding design water amount will cause the strength reduction and subjected to cracks. o Aggregates - are covered about 60 -80% of the total volume of the hardened concrete. Aggregates are sand and crush stone of maximum 20mm size used for building construction. Gradation of particle size of the aggregate, strength, durability and weather resistance are important factors of the aggregates have to be considered. o Admixtures – are substance which used to increase workability, set time control, increase strength, longer life of slump, reducing bleeding and segregation etc… there are types of Admixtures ; accelerating, air-entraining, water-reducing and set-controlling admixtures. Widely used in Sri Lanka set
  48. 48. 39 controlling, water reducing and superplasticizer (MasterGlenium, MIRA etc…) 2.4.1 Concrete Sampling Sampling and testing of the concrete for the project is a responsibility of the QA/QC Engineer. Mainly should have prior attention of the quality of the concrete. Contractor should have to take approval from Engineer (Consultant) concrete mix design as stated in contract document. Basically several tests are conducted to obtain high-quality concrete. Those are, o Cube test (Strength test) - 150X150X150 mm standard mould was used to get three samples. Samples weren’t taken from initial and final discharge of ready mix truck. Samples were prepared from into three layers, each layer tapped in 25 time by using steel rod of 16mm dia.[Figure 32] Top of specimen leveled off by using trowel to make even surface. After 1 day cured cubes were removed from the mould and labeled (date, Grade). After that cubes were immersed into water tank. Cubes were tested in 3, 7 and 21 days by using cube testing machine [Figure 34]. Before inserting cubes, should have to measure weight and dimensions of the cubes. After placing smooth surface to compressive Figure 30: preparation of samplesFigure 33: preparation of samples Figure 34: Cube Testing Machine
  49. 49. 40 plates, machine was run and calibrated value was noted when appeared the cracks. Values were given in KN by dividing we can get compressive strength of the specific cube. o Slump test – purpose of slump test used to determine the consistency of fresh concrete and to give an indication of the amount of water used in the concrete mix. The test was conducted by using 300mm high steel cone open end both side of 100mm and 200mm dia, taper rod and steel plate. Large dia end of the cone was placed on plate then concrete was poured and tapered 25 times by using taper rod in three layers. Slowly raised and lifted the cone and the height of top of inverted cone and highest position of concrete sample distance is called “Slump”, which was measured by using ruler. Contract document specified allowable slump for C60 and C40 200mm +or- 25mm and for C30 175mm +or – 25mm. Generally when Grade of concrete increases slump also increase. If slump was in below the minimum requirement water added according to contract document but the case of exceedance of maximum limit ready mix truck will be rejected. Figure 35: Slump Test o Temperature test – temperature is important factor which will effect to the setting off concrete. Concrete will set faster in higher temperature due to that labour faced difficulties in handling of concrete. Thermometer used to measure temperature by inserting at least 3 inches. In the site C65 used where columns therefore temperature was specified in contract document. Concrete shouldn’t be exceeding ambient temperature otherwise concrete will be wastage or burnt. Concrete Inspector should have to be record arrival time of the truck, batch time, slump, unit weight, time of placement and location of pour. Maximum ready-mix can be kept
  50. 50. 41 3hr, therefore inspector should have to pay close attention of elapsed time between batching and subsequent placement. 2.4.2 Concrete Placement Entire concrete placement carefully inspected because quality of the finished concrete greatly depends on handling of concrete during placement. During concrete placement, segregation of the coarse aggregate from the mortar, or loss of free water (bleeding) from the concrete mixture must be avoided. Contractor has to select the method to facilitate concrete placement and it has to be approved from Consultant. MOL project up to 5th floor used pump car to pour concrete for slabs after that method was changed from 6th floor pump line assembled to the top of building and pump machine plant near to Labour Department side. To cast Columns and shear walls used concrete bucket by lifting from tower crane. Capacity of the pressed steel bucket is about 1 meter cube. Slab concerting done using flexible hose used to pour C30 for beam and slabs and concrete bucket used to pour C65, C40 for column head and shear wall head respectively. Figure 36 : Concrete Placement
  51. 51. 42 Equipment & Tools Uses Concrete Pump machine - An apparatus which forces concrete to the placing position through a pipeline or hose. In the Site used Schwing stetter, ready-mix truck chute arranged into pump machine bucket to pump the concrete. Pump machine contain hydraulic, mechanical, electrical and lubrication systems. Pump line (Tremie) – used to convey concrete to slab top. Vibrator (Poker) – there is two type vibrators; internally and externally, internal vibrators are used most commonly put inside the form. It consists of a poker, housing and electric shaft, driven by a mortar. Normally frequency of the vibrator within 20-700Hz. Poker vibrator was used to compact concrete. This is a vibrating tube at the end of a flexible drive. Pokers vary in size usually from 25mm to 75mm in diameter. Trowel - A flat, broad-blade steel hand tool used in the final stages of finishing operations to impart a relatively Smooth surface to concrete. Shovel – used to spreading concrete into form Table 5: Concrete Placing Equipment & Tools Common problems during placement of concrete are segregation, bleeding, water evaporation from concrete, cold joints etc… Segregation is a tendency of separate concrete mix constituent result of non-uniform proportion in the mass. Segregation mainly occurred due to poor graded of aggregates and excessive water contain in the concrete. Coarse aggregates will be separated from the concrete if concrete drop from high elevated level. When concrete placing at the stair case, is recommended to create chute and poured concrete through the chute.
  52. 52. 43 Bleeding is emergence of water newly placed concrete, simply gain of water. Result of bleeding concrete become porous, weak and in the concrete Laitance will be occurred. Laitance is a weak and nondurable material containing cement and fines. Water will be accumulated at the top of concrete surface. Proper compaction and preventing adding excessive water into concrete can be controlled bleeding. Cold joints happened due to delay of placement concrete; one layer of concrete had hardened before subsequent layer was placed. Cold joint is visible line of discontinuity in the surface. Before concrete placement pre-inspections were carried out, those are o Checking formwork alignment, location and dimensions o Forms are tightening enough to bear concrete load without bulge. o Surface clean and free of foreign material. {Before pouring concrete surface should be chipped off and laitance should be removed. Chipping is stop when appearing rough surface. Weak substance and foreign material deposit such as punch sheet have to be removed.} o Construction joints were setup according to contract document. Construction joints were placed when pouring is difficult to cover whole building. Construction joint are can be categorized into two; vertical joint and horizontal joint. Vertical joints are located 1/3 of the span. Dowel bars also placed to restrict movements around the joint. Horizontal joints are at the column, walls 3m from the bottom. o If there were rust, grease, oil and grout in the reinforcement, it should be removed. o Reinforcement lap splice arrangement should be approved from consultant or Engineer. o Levels are given by asst.surveying helpers to finish the concrete surface; therefore have to check with TBM.(due to vibration level will be changed)
  53. 53. 44 2.4.3 Compacting concrete Compaction of concrete is significant to obtain higher strength in concrete. Transported concrete contain entrapped air in voids. These voids reduce the strength of concrete and which are increased permeability. Other hand voids reduce the contract area of the reinforcement with concrete. Compaction we used another term Consolidation of concrete. Consolidation is a process of closer arrangement of solid particle with mortar during the placement of concrete by usually internal vibrators. Proper consolidation shows uniform, non-porous, hard and well bound with concrete. Poor consolidation will be occurred Honeycomb in the faces. Honeycomb is occurred mortar segregate from aggregates and creates hollow spaces around aggregates. Poor vibration during placement, congested reinforcement and stiff concrete or less workability are some factors will effect to make Honeycomb in the surface. Honeycomb can be seen in naked-eye. Treatment will be different due to advance of the honeycomb. Generally treatment was done defected area of concrete chipped off and removed loose particles cavity spaces. After proper cleaning, two emulsions were applied into reinforcement surface and concrete surface to bond adequately. After that high strength repair mortar was poured at the top of close form. When casting of vertical elements were pouring into three equal layers. One layer nearly 1m high. An internal vibrator (poker) was inserted vertically and avoided dropping the vibrator. Practically poker immersed 300mm to 500mm. operator must be convinced to avoid toughing poker with formwork and operator should notice circle influence around poker where concrete finished the consolidation. Poker immersion is restricted to few seconds and poker should be arisen after seen air bubble or surface level dropping. Otherwise too long operation may cause segregation of coarse aggregates and aggregates will be sunk. Distance of poker installment is depend on operator judgment but normally used rule of thumb is used,i.e 10 times of poker head dia. After compacting first layer, second layer poured that time poker installing have to inspect thoroughly because operator try to immerse poker into first layer, that is risky situation of safety of formwork, due to high pressure load exerted to the forms may be bulge.
  54. 54. 45 2.5 Curing of Concrete Concrete strength and quality mainly depends on curing method adopted in the site. Curing is a procedure, which provides sufficient free water in the cement paste to help the process of Hydration. It is important to achieve design strength of the concrete, hydration must be controlled. Initial setting time of the concrete is critical therefore water must be retained and prevented evaporation. Conversely explosive to the rain must be covered. When using OPC 7 days at least have to be cured the concrete. Otherwise shrinkage will induce tensile stress and appear surface cracks. When hydration process started heat will be generated, early thermal expansion also can be controlled by using curing methods. Basically temperature, humidity and wind speed are factors effect to free water content of the concrete for evaporation. Improper curing methods are lay the path of reducing the strength of the concrete and result concrete will be permeable. There are different methods of curing, in the site used spray water to expose surface of concrete and covered it from damp burlap. Times of water spraying is depends on the weather condition of surrounding. Site was adhered to do curing three times of the day. (8am, 12am and 3pm). Curing is mandatory; people were not practice to start curing after removal of formwork due to inconvenience. Sprinklers are beast solution of curing concrete slabs which is increase moisture in atmosphere; in the market there are some of new methods to improve quality of the concrete and productivity which are liquid seal coat, water proof papers, plastic sheeting etc…
  55. 55. 46 2.6 Chemical Anchoring Where Reinforcement anchorage or overlap splice are needed in cured concrete by injecting adhesive in cleaned drill hole called that Chemical Anchoring.it is widely used range of applications such as slab connection, to connect misplaced bar, vertical and horizontal connection and joint strengthening. There are popular products in the market (Hilti, Simpson, resicon etc…). According to BS 8110 (Cl .3.12.9) acceptable anchorage of bar length is equal to 12 times diameter of Re-bar. In this project used Hilti HIT-RE500 which also have a manual stating drill hole depth and diameter. Equipment and tools used, oDrilling Hammer with Drill bit (greater than installing rebar dia) oRound wire brush oHole cleaning Blower oHilti HIT-RE500SD foil pack oStatik mixer oHilti Gun Procedure of installation, 1. Rough surface drilled up to 12*D or manual specified value in perpendicular to surface. 2. Manually drilled hole cleaned by wire brush and blower. (It is important clean hole adequately to gain high stiffness.) 3. Hilti mortar installed into the gun and Statik mixer fixed at the top. 4. Injected the Hilt mortar 2/3 of hole(important to avoid air bubble injection) 5. After injection, Re-bar was inserted into hole with slight rotating movement. 6. Keep 30min to harden depends on the temperature. (If lower temp setting time high. Proper cleaned installment showed higher resisting stress value at the bond rather than cast in rebar. Foil pack can be reused by separating two mixes. Figure 37 : HILTI Chemical and Gun
  56. 56. 47 2.7 Block work MOL project masonry blocks were used to cover external walls and internal partitions. Blocks were made of cement-sand composition. Easy to use, saving labour hours, easy to cut are some of advantages of using blocks with masonry bricks. But cement blocks have low strength about 3N/mm2 and lower sound insulation properties. Blocks are available in different sizes and different types; types are hollow and solid types and sizes are, 100X400X200, 200X400X200 Masonry tools were used at the site, o Trowel – used to paste mortar o Jointer – used to finished mortar joint o Level – used to check horizontal of block bed. o Masonry plumb bob – used to check verticality o Hammer – used to break blocks Initially, setting-out lines of block wall were established by surveyors. Blocks were moisture before use, blocks were laying in stretcher bond technique and gap of the joint app. 10mm. block arranging were started from corner of the wall and before that mortar was applied straight through edge by using trowel.i.e. called bed joint, blocks horizontality is important to maintain properly to obtain good finish. Head joint (vertical joint) also has a gap about 10 mm filled mortars by using trowel. Block work verticality is important therefore masonry plumb used to rectify the vertical of the block work. Mainly the block walls weren’t laying over touch the structural beam soffit. Because walls are non-load bearing wall which are not design to bear the beam load. Therefore provided little gap filled with Rigifoam or sometimes top of the wall anchor to the beam to prevent cracks developed in the wall in the earthquake load.
  57. 57. 48 2.8 Machinery o Tower crane – which is equipped with horizontal jib to lift materials within limited horizontal movement. These are assembled at the site mainly from 04 types of tower crane commonly used supported static tower crane, which is anchored or tied to building suitable interval for extra support. Parts of tower crane cab, triangular jib, counter weight, tower mast, trolley with pulley sliding section and slewing ring. Front jib radius about 35m. o Passenger Hoist / Alimak – which is carried passenger and material and top of building and equipped with several electric motors, pinion and climbing rack. Safety of Alimak is important acceptable persons or load stated and should be adhere that. o Air compressor – is moveable machinery which is supply high pressurized water. This high pressurized water jet used to clean chipped concrete surface and used to clean slab formwork wooden dust, foreign material etc… o Dumper – used to transport aggregates, cement, blocks, concrete, props etc… where impossible to access tower crane. Figure 38: Static Tower Crane
  58. 58. 49 o Ready-mix truck – which is transported, wet concrete mix from batching plant to the site. Capacity about 5 meter cube. Components of the truck are agitator drum, water tank, hinged feed chute and discharge chute. truck mixer carry a supply of water, which is normally used to wash out the drum after discharging the concrete, before returning to the batching plant. o Pump car –is used at site to move concrete vertically, horizontally or both. The main advantage is the vertical movement. But it is used for horizontal movement also when there is no other means of horizontal movement. The major disadvantage is the large noise and vibration produced. The pump had three booms each 5m length and beyond that flexible horse pipe attached. The pump is doubled piston driven by hydraulic system and has a capacity of 10- 15 m^3/hr and which can pump at the minimum pressure up to 45m of height. Figure 39: Ready mix Truck Figure 40: Pump Car
  59. 59. 50 o Bar bending machine [Figure 41 (c)] - used to bend Re-bar required shapes. Different pulley will be fixed to different diameter bars. Can be operated to 90, 135 and 180 degrees. o Bar cutter [Figure 41(a)] - large cutting wheel mounted electrical devise which used to cut required length of re-bars up to 32mm dia. can be cut. o Angle Grinder [Figure 41(b)] – is an electric device which mounted cutting wheel used to cut steel bars, wire packs and tie rods. o Power saw - used to cut timer easily reduce time wasting formwork. This is provided with a sliding cover to the tool for protecting both the tool & the operator. (c) (a) (b) (c) Figure 41: (a) Bar cutter (b) angle grinder(c) bar bending machine
  60. 60. 51 3.0 Conclusion In the conclusion can stated that KDU Engineering faculty and NAITA have been engaged in tremendous work to exposure engineering undergraduate to developed future industrial knowledge and build the base of career. I was started training on 22 July 2015 up to 21 December 2015 by successfully completing 25 weeks. This was my first industrial training and experience expose to civil engineering field. I would like to state my first experience devoted to High-rise building construction.so I gain lot of experience and gathered knowledge about construction industry. Personally I’m happy working with this project. Real environment of construction is somewhat tough than I thought. Academic period we visited some building constructions sites but real time working environment is gained from this training period. Having theoretical knowledge helps me to solve some problems encounter during training. During the training period I learnt new structural features and standard procedure of construction works. Site management, site controlling, labour handling, material handling, perform quality task, work in critical environment, complete the task within planed time frame and deal with sub-contractors which are important parts or responsibilities have to be developed working as Site Engineer. During training I understood other upper level managerial such as construction manager, technical coordinator, QA/QC manger and Project manager role and responsibilities. When the beginning I hadn’t no idea about construction sequence and activities procedure but end of the training I have gained work as site engineer, day to day I learnt new thing mostly labour handling part not improved during academic, it should get from real time field works. Good practicing Engineer should get confident from himself by understanding and checking thoroughly not based on sub-contractors and labour decisions or confirmations. At the beginning I got some mistakes believing sub-contractor words. After that I have been practiced to check doubly if I got doubt. .
  61. 61. 52 Company has no big history and MOL is the first project Sri Lanka, due to that training development was not processing as other Sri Lankan construction companies. Trainees’ rotations for each section have not properly working, sometimes trainee work whole training period in one section. Method statements are not provided to trainee, some Indian engineers only based on work done, they weren’t teach new things. During the training I have identified some developments in the organization, which are company depends on particular sub-contractors, some works completion will delayed due contractors issues, sub-contractors groups worked only day time due to that tower crane got busy. Material management is not sufficient mainly carpenters were cut and damaged plywood, runners, Planning coordinate wasn’t adequate which was lead to extend construction cycle. Formwork solution used both Convectional and PERI difficult manage time. During the training I didn’t perform, 1. Preliminary surveying 2. Pilling , pile sheet installing 3. Excavation 4. Chemical grouting 5. Pile cap making 6. Plastering 7. Stair case 8. Masonry 9. Tilling 10. Pipelines or drainage works
  62. 62. 53 Referencing 1. Chudley, R., & Greeno, R. (2014). BUILDING CONSTRUCTION HANDBOOK. New York: Routledge. 2. (2005). Construction Inspection Manual. In CONCRETE CONSTRUCTION (p. Chapter 11). Lexington, Kentucky: Lexington-Fayette Urban County Government. 3. Manoj, S., & Jain, S. K. (n.d.). part 1 ;Behaviour and Strength. Seismic behaviour design and detailing of R.C Shear wall, 8. 4. Ozyildirim, H. C., & George, R. U. (1996). Guide for Consolidation of Concrete. American Concrete Institute. 5. Peurifoy, R. L., & Oberlender, G. D. (2011). Formwork for Concrete Strucutre. New York, Chicago, San Francisco: The McGraw-Hill Companies. 6. Post installed rebar connections -HILTI. In H. manual. 7. Robertshaw, R., & Jones, T. (2006). Reinforcement Detailing Manual. London: Arup.
  63. 63. 54 List of Figures Figure 1: Logo of company ------------------------------------------------------------------------------ 1 Figure 2: Image of Building ----------------------------------------------------------------------------- 2 Figure 3: Organization Chart ---------------------------------------------------------------------------- 3 Figure 4: General Safety meeting----------------------------------------------------------------------- 6 Figure 5: Cup Link and arrangement ------------------------------------------------------------------- 9 Figure 6: Pull out testing --------------------------------------------------------------------------------10 Figure 7: continuous beam R/F details----------------------------------------------------------------12 Figure 8: Slab Reinforcement Detailed ---------------------------------------------------------------12 Figure 9 : Coupling Beam R/F Detail -----------------------------------------------------------------13 Figure 10: The load transfer between bars------------------------------------------------------------14 Figure 11 : plan view and elevation view of column formwork-----------------------------------18 Figure 12: LIWA Panel Arrangement-----------------------------------------------------------------19 Figure 13: LIWA system for column------------------------------------------------------------------20 Figure 14: VARIO system for column ---------------------------------------------------------------20 Figure 15: Conventional Wall Formwork ------------------------------------------------------------21 Figure 16: VARIO Shear wall Arrangement ---------------------------------------------------------22 Figure 17: MULTIFLEX Girder Slab Formwork arrangment -------------------------------------24 Figure 18: Beam & Slab Formwork -------------------------------------------------------------------25 Figure 19: shear wall panel shuttering ----------------------------------------------------------------25 Figure 20: Reinforcement Types-----------------------------------------------------------------------27 Figure 21: Bar Notation ---------------------------------------------------------------------------------27 Figure 22: (a) types of ties, (b) wire twister ----------------------------------------------------------29 Figure 23: internally threaded couple -----------------------------------------------------------------30 Figure 24: (a) Band saw machine, (b) forging machine, (c) Threading machine ---------------31 Figure 25: Lap and Crank lengh detail ----------------------------------------------------------------31 Figure 26: column R/F work----------------------------------------------------------------------------32 Figure 27: Coupling beam Reinforcement------------------------------------------------------------33 Figure 28: Shear wall Reinforcement work ----------------------------------------------------------34 Figure 29: Beam binding standard procedure --------------------------------------------------------34 Figure 30: slab and beam form leveling---------------------------------------------------------------36 Figure 31: Closed CP traverse--------------------------------------------------------------------------37
  64. 64. 55 Figure 32: horizontal coordinate setting out procedure---------------------------------------------37 Figure 33: preparation of samples ---------------------------------------------------------------------39 Figure 34: Cube Testing Machine ---------------------------------------------------------------------39 Figure 35: Slump Test -----------------------------------------------------------------------------------40 Figure 36 : Concrete Placement ------------------------------------------------------------------------41 Figure 37 : HILTI Chemical and Gun-----------------------------------------------------------------43 Figure 38: Static Tower Crane -------------------------------------------------------------------------43 Figure 39: Ready mix Truck----------------------------------------------------------------------------43 Figure 40: Pump Car-------------------------------------------------------------------------------------43 Figure 41: (a) Bar cutter (b) angle grinder(c) bar bending machine ------------------------------43 List of Table Table 1: PPE & Uses-------------------------------------------------------------------------------------- 8 Table 2 : Conventional system components----------------------------------------------------------16 Table 3: PERI Components-----------------------------------------------------------------------------18 Table 4: formwork removal duration------------------------------------------------------------------26 Table 5: Concrete Placing Equipment & Tools ------------------------------------------------------42