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content Chapter 1: method statement for erection of pc-I girder Outline Preparation work Transportation PC - I girder to erection span Erection PC - I girder to design position 4.1 Erection PC - I girder of span 4.2 Erection PC - I girder of span Unloading PC-I girder on its final position ( final lifting ) chapter 2: procedure for construction of diaphragm,deck slab, parapet and lighting pole Outline Procedure for construction of precast plat 2.1 Casting concrete precast plat on the groud 2.2 Installation of precast plat by crane Procedure for construction of diaphragm 3.1 Preparation works 3.2 Installation of suspend support system 3.3 Installation of bottom formwork for diaphragm 3.4 Installation of rebar for diaphragm 3.5 Installation of side form for diaphragm 3.6 Casting concrete of diaphragm 3.7 Curing and remove of formwork Procedure for construction of deck slab, parapet,lighting pole and railling 43.1 Preparation works 43.2 Assembly of supportand system and formwork 43.3 Installation of rebar for deck slab 43.4 Casting concrete of deck slab 43.5 Curing concrete and remove formwork of deck slab Procedure for construction of parapet, lighting pole and railling 5.1 Preparation works 5.2 Installation of rebar for parapet 5.3 Installation of formwork for parapet 5.4 Casting concrte of parapet 5.5 Remove formwork and curing of parapet 5.6 Installation of railling steel 3.6 Construction of parapet 4.7 Installation of railling steel Chapter 3: construction of other items Construction of bearing and expansion joint Construction of water proofing and asphalt pavement 3 Soil backfill of abutment Finish bridge APPENDIX 1:Calculation of gantry crane APPENDIX 12: Calculation of gantry craneformwork and support of diaphragm APPENDIX 3: Calculation of formwork and support of deck slab Method statement for erection pc-I girder construction of superstructure and construction other items Chapter 1: method statement for erection of pc-I girder Outline - This method statement describes the transportation and erection procedure of PC –I girder using fram A, trolley cart and gantry crane - It is applicable for Khe Can Bridge Base on construction schedule and site condition, other method of erection for the remaining girders shall be proposes and submitted separately prior to construction - Summary of produced PC – I girders for erection: No 21 Span A1-P1 P1-A2 Length 24m 24m Unit pcs pcs Quantity 5 Remark Preparation work - Installation of horizontal shifting and longitudinal shifting by rail P43 and wood sleeper Foundation of the horizontal shifting and longitudinal shall be compacted and leveled adequately Ground condition of care working area shall be checked - The gantry crane working area shall be compacted and leveled adequately Ground condition of care working area shall be checked and the concrete plate shall be installed to ensure the stability - Check the fram A, trolley cart and gantry crane capacity base on the calculation requirement Other facilities such as temporary supports for I girder, wooden plates etc, shall be also prepared to ready - Elastomeric bearing pads shall be set prior to erection of girder - Length of the girder shall also be measured before the erection works Marking point shall be made on the PC-I girder and on the its designated final location of the girder on the top of pier head Marking point on the girder shall be measured from the girder’s center up to the center of the bearing location as shown below Transportation PC - I girder to erection span - The girder from stock yard shall be loaded to trolley cart by fram A After temporary supports by timber, shifting girder to longitudinal shifting by chain hoist Lauching girder to erection span by trolley cart Before and during transporting work, the girder shall be fixed carefully with trolley cart - Lifting equipment and tools such as trolley cart,PC bar and shackle shall be checked visually before use If damage or defect is found, it shall be rejected to use and replaced by news ones - Sequence transport: + Transportion PC-I girder from girder stock yard No2 to erection span + Transportion PC-I girder from girder stock yard No1 to erection span Erection PC - I girder to design position 4.1 Erection PC - I girder of span - The girder shall be erected one by one up to final designed position Installation gantry crane on the abutment A1 and pier P1 Installation wind bracing cable - Installation rail P43 to shifting girder on abutment A1 and pier P1 - Transport girder from girder stock yard 012 to erection span 01 - The girder shall be lifted step by step to final designed position: • Erection girder No 01,02 to design position + Erection and shifting girder to temporary support by gantry crane + Temporary support to keep PCI beam After,installation temporary support of gantry crane on abutment A1, dismount support B of gantry crane on abutement A1 + Shifting girder to design position by chain hoists 5T + Temporary supports by timber shall be provided for girder • Erection girder No 03,04,05 to design position + Reinstallation support B of gantry crane on abutment A1 + Erection and shifting girder to design position by gantry crane + Temporary supports by timber shall be provided for girder 4.2 Erection PC - I girder of span 2: • Then repeat the same cycle for the span 012 5.Unloading PC-I girder on its final location ( final lifting ) + Unloading PC_I girder on its final location by tow jack hydraulic 50T + At the time of unloading the girder on its final location, location of girder shall be controlled in direction of transverse and longitudinal as shown below Marking on the girder shall be checked and it shoud be matched with the line provided on top of the pier head which is the centerline of the bearing + After correction of girder, soffit of each girder shall be checked, to determine gaps between girder and the bearing pad If gaps occurred this shall be treated by filling dry cement + When girder unloads on its final location, necessary support shall be installed to prevent movement and falling of the girder Use timber as bracing support and after installation of several girders, diaphragm horzontal rebar shall be connected chapter 2: procedure for construction of diaphragm,deck slab, parapet lighting pole and railling Outline - This method statement describes the work procedure for construction of diaphragm, deck slab parapet lighting pole and railling steel - This method is applicable for Khe Can bridge Procedure for construction of precast plat 2.1.Casting concrete precast plat on the ground - Precast plat shall be casted by formwork on the ground - Procedure for construction: + Installation of bottom form ( formwork 2x1m) + Installation of side form (V80x80x10) + Installation of rebar + Installation of wood form + Casting concrete + Finish and curing 2.2.Installation of precast plate - RC panel shall be installed on I girder just after erection for safety of the area and make I girder stability - Installation of precast plate by crane Procedure for construction of diaphragm 3.1.Preparation work - Material and required equipment for the construction shall be mobilized and inspected before working - Anchor bar of anchor system shall be set up and get approved Method statement for installation of anchor system shall be submitted separatly - Rebar for diaphragms shall be fabicated following the approved working drawings - All construction joint for diaphragms on the girder shall be treated before erecting 3.2.Installation of suspend support system - Firstly , the suspend support system with platform for diaphragm shall be assembled on the ground before erecting and then it shall be set up by crawler crane to the position - This suspend system shall be connected with hanging frame by round bar D32 and fixed during working for intermediate diaphragm work 3.3.Installation of bottom formwork - The metal formwork shall be used for diaphragm construction - Bottom form of intermediate diaphragms shall be supported by combine angle steel connected with girder by hanging system - Bedding sand and plywood shall be used for bottom form of end diaphragm 3.4.Installation of rebar - Material test of rebar shall be carried out in accordance with inspection and test plan, prior fabrication - Rebar shall be installed in accordance with approved working drawing Fixing and splicing of rebar shall be done by iron wire Splicing length and location shall be in accordance with working drawing Installed rebar shall be free from dirt, rust, oil or the other material that might reduce the bond - Concrete spacer shall be used to keep the required concrete covering - Inspection and approval by the Engineer shall be carried out prior setting of side forms 3.5.Installation of side form - Metal formwork shall be used and shall be conformed to the shape Lines and dimensions shown on working drawing - All formwork shall be cleaned free from dust, grease and other foreign matter and shall treated by releaseagent before installation - Sides formworks of diaphragm shall be fixed by tie rod D16 and turnbuckle 3.6.Casting concrete - After getting approval of the Engineer for the rebar and form work, the concrete work shall be commenced Prior to start , tighetness and stability of the form work shall be carefully cheked - Concrete for diaphragm shall be carried out by crane with bucket Vibrator shall be used to compaction - During casting have to check stability of side form and bottom form The top elevation of diaphragm shall be elevated by manual with trowel 3.7.Curing and remove of form work - After casting, all exposed surface of the structure shall be covered by curing sheet - Bottom form for diaphragm shall be removed after the concrete has achieved 90% of the designed concrete strength - After removed bottom form for intermediate diaphragm, suspend support system shall be lowered by crane Procedure for construction of deck slab 4.1 Preparation work - Prepare necessary equipments and materials shall be used and checked its condition - Install PC panel again at diaphragm portion as deck slab bottom forms Layout of the concrete panels shall be on accordance with the panel layout indicated on the approved working drawings - Checking concrete area at the top of PC I-Girder for construction joint - Cleaning of rebar and fabricate rebar following the approved working drawings 4.2.Installation of hanging system and form work - Hanging system including bottom form, platform, and handrail and PC bar system for deck slab shall be pre-assembled in the block by block length of 1m on the ground - After completing of assembly work, this system shall be set up to the position by crawler crane - The hanging system shall be fixed to the girder by beam H200x200 - After completing of fixing all support system, the elevation of bottom form work shall be adjusted following design level by the PC bar system - Important point are treatment all gaps including gaps between PC-I girders and concrete panels, gaps between PC-I girder flange anf bottom form of cantilevel slab, gaps between formwork itself o Gaps between concrete panels and PC-I girder or between concrete panels itself shall be filled by cement mortar o Gaps between PC-I girder flange and bottom form of cantilevel slab shall be treated by jaking and if necessary some proper material shall be inserted such as sponge or rubber sheet… o Gaps between formwork itself shall be filled proper material such as sponge or rubber sheet… - After completing of gaps treatment, all form surfaces shall be cleaned and sprayed release oil and then starting of installation rebar 4.3.Installation of rebar for deck slab - Rebar shall be fabricated in accordance with the shape and dimention as shown approved working drawings - Installation of rebar in a workmanship manner provides concrete spacers and properly tired with wires Fixing and splicing of rebar shall be used iron wire 0.9mm or large diameter Splicing length and location shall be accordance with working drawing - Installed rebar shall be free from dirt, rust, oil, or the other material that might reduce the bond - Install all necessary block out which shall be used for parapet construction, bridge drainage pipe, light pole base and block out for expansion joint Detail drawing and layout for block out shall be indicated on the working drawing - Inspection and approval by the Engineer shall be carried out prior to cast concrete 4.4.Casting concrete of deck slab - After getting approved of the Engineer for the rebar and formwork, the concrete work shall be commenced Prior to start, tightness and stability of the formwork shall be carefully checked A working platform shall be placed on the top of surface deck slab for work efficiency and safety - Concrete bucket and crane shall be used for pouring concrete into structure Water shall be sprayed on form, rebar and surface of lean concrete prior to cast concrte Necessary block out for utilities shall be checked before casting concrete - Provide level or reference guide for finishing of deck slab Such elevation guide shall be set approximately every 3m – 4m pitch for all deck slab area - Basically, concrete shall be poured from lower part to higher part in longitudinal direction in one continuous casting span - At the time when concrete was discharged, concrete shall be immediately vibrated Vibrator shall be applied to area of concreting on a vertical position at circular area of 45cm radius - Tightness of the formworks shall be inspected regularly by the pouring guard make sure that no deformation of forms In case displacements occur, adjustment shall be necessary carried out before casting continues - After placing concrete, top surface shall be hand-finished by wooden or steel trowel for establishing the desired elevation Finishing for deck slab shall be uniformly flat Straightness of straight edge shall be checked by string before using each time 4.5.Curing concrete of deck slab - After casting concrete, the surface of slab shall be covered by curing sheet - To prevent cracks, curing method shall be strictly followed by providing sufficient cover and adequate watering during curing period 4.6.Remove of side form and bottom forms - Removal of form works and support shall be carried out after concrete has achieved the 90% of the designed concrete strength - Using crane lowering hanging system This hanging system shall be removed on the ground 5.Procedure for construction of parapet and railling 5.1 Preparation works - All materials and equipment to be used shall be set up and check its condition - Provide line making on deck slab for reference prior to install forms based on the approved working drawings - Treatment for construction joint - FPabrication or rebar following the approved working drawings - Preparation of formwork, apply necessary form release oil 5.2 Installation of rebar for parapet - Rebar shall be installed and fixed with wires in workmanship manner besed on approved working drawings and considering the required concrete cover - Standing rebars of lighting pole shall be installed in the proper position - Embedded items such as electrical conduits and anchor bolts for railing shall be installed in proper position - Location for all embedded items shall be referred to the submitted working drawings - After installation, rebar must be inspected by the Engineer 5.3 Installation of formwork for parapet - All formwork shall be cleaned free from dust, grease and other foreign matter and shall be treated by releaseagent before installation - Flat side form and uneven side form shall be installed following the line marking to ensure te alignment and dimension of the parapet based on the working drawings - At the position of stub rebars for lighting pole, side from shall be blocked out - Tightness and stability of the formwork shall be carefully checked - Inspection and approval by engineer shall be executed prior to casting concrete 5.4 Casting concrete of parapet - The installation of electrical conduits, pull boxes and the anchor bolts should be set and thoroughly check first before the commencement of concrete casting at parapet - Cleaning inside the form and water should be sprayed on construction joint - Casting concrete for parapet shall be carried out by using crane and concrete bucket - Vibators shall be used for compaction and surface finishing work is done by steel trowel - Vibator should be applied to area of concreting in a vertical position at to 10 seconds at one place - All ends of u-bolt thread shall be wrapped with pvc tape for protection - After casting, parapet should be immediately covered by curing sheet for curing 5.5 Removal of form work and curing - Removal of form works and support system shall be carried out after concrete has achieved the 90% of the design concrete strength - Form works shall be carefully removed so as not to damage the newly casted concrete - Jack shall be released to removal of form works - Concrete surface shall be done by using curing mat 5.6 Construction of railling steel - Welding railling: Railling shall be welded in the workshop The Engineer will require confirmation as to the suitability of the details contained in the welding plan, by tests as prescribed in the AWS "Standard Qualification Procedure".After welding, Railling shall be painted in the workshop - Installation of railling in the site: + Erection of railling to design position by crane + Sequence of erection: Span Span A1 A2 - use of temporary or permanent stanchions, beams and bracing - connection details - erection camber diagrams to show the vertical position of the structure at each stage of the erection process - design calculation to cover the various stages in the erection process Chapter 3: construction of other items - Installation of bearing and expansion joint A- Installation of bearing : Elastomeric bearing pads shall be set prior to erection of girder: The bearings shall be clearly marked with their longitudinal and transverse axes, their type number and their intended locations in the Works Unless otherwise approved by the Engineer bearing beds shall be of non-shrink grout conforming to ASTM C1107, Grade A +All Bearing shall be installed by manual All bearings shall be set horizontal in both directions and shall be positioned so that the inscribed longitudinal axis is parallel to the structure axis at the point of support, unless otherwise noted on the Drawings + Girder shall not be placed on bearings until mortar reaches the required strength (compressive sample strength) of at least 30 Mpa B- Installation of expansion joint - The roadway expansion joints shall be installed in accordance with the Manufacturer's instructions and this specification - The manufacturer shall provide a technical representative to be present at all times while the expansion joint device is being installed - The expansion joint shall be anchored as required by the Manufacturer The expansion joint shall be accurately set and securely supported at the correct grade and elevation and the correct joint opening as shown on the Drawings - Prior to the installation of the expansion joint the recess in the bridge deck shall be scabbled to remove all laitance, and cleaned by water jet or similar approved method - Immediately prior to installation, the joint shall be inspected by the Engineer for proper alignment, proper stud placement and effectiveness - No bends, kinks or defects in the joint system shall be allowed Any joint system exhibiting bends, kinks or defects due to transporting or as a result of mishandling shall be removed from the work site, and replaced, at the expense of the Contractor - Each expansion joint shall be fabricated as a single entity, unless stage construction or excessive length prohibits monolithic fabrication It shall fit the full width of the carriageway as indicated on the Drawings - Expansion joint systems shall be set to the proper width for the ambient temperature at the time of installation This information is indicated in the contract documents or instructed by the Engineer - After the expansion joint has been set to its final line and grade, the recess opening shall be filled with non-shrinkage grout Prior to grout placement, all existing concrete surfaces shall be dampened with water The uppermost surface of the concrete placement shall be given a broomed finish Construction of waterprooding and surface coures 2.1 Construction of waterproofing - Concrete surface shall be preparaded in accordance with the manufacturer’s instructions - Concrete surface shall be flat chisel hand grinding to level design - Use compressed air for clearing the surface, pit waterproofing by acetylen lamps and paste onto surface This work done by the method of rolling The deck waterproofing membrane shall be a proprietary waterproofing system of the thickness indicated on the Drawings and as approved by the Engineer, and shall be applied in accordance with the manufacturer’s recommendations 2.2 Construction of surface coures + Sequence of construction + Step 1: Construction of water proofing layer covering the RC slab of bridge + Step 2: Construction of the first layer of surface coures (4cm) + Step 3: Construction of water proofing layer covering the first layer + Step 4: Construction of the layer of surface coures (4cm) Soik brackfill of abutment.Đắp đất sau mè Granular backfiling Khi hoàn thiện phần đào kết cấu, chỗ đào lên chưa đắp trả qui định Điều 2.6.1 “Đắp trả vật liệu cấp phối” Điều 2.6.2 “Đắp trả vật liệu thấm nước” thuộc Mục 03200 “Đào kết cấu” phải đắp trả lại cho với bề mặt cuối sử dụng vật liệu chấp thuận 3.1 Đ.p trả vật liệu cấp phối Material The material shall be well graded crushed or uncrushed gravel, stone, rock-fill or natural sand or a well mixed combination of any of these Grading requirements for the material are as follows: Maximum size Passing 4.75 cm mm 25% sieve Passing 90% mm 0% to 10% 0.075 sieve Plasticity Index to 10 max Construction The granular backfill shall be placed in layers not exceeding 15cm (measured before compaction) and compacted to a density of 95% of the maximum dry density determined according to AASHTO T180-D (a) Mô tả Công việc gồm việc cung cấp, đắp đầm nén vật liệu đắp cấp phối gần phần kết cấu Các diện tích rải vật liệu “Khu vực bị ảnh hưởng” phần kết cấu định thể Bản vẽ theo dẫn Tư vấn giám sát (b) Vật liệu: Vật liệu sử dụng phải loại sỏi, đá, đá hộc nghiền nhỏ không nghiền cát tự nhiên hỗn hợp trộn loại vật liệu Sau yêu cầu mức độ cấp phối vật liệu: Kích thước tối đa Lọt sàng 4.75 mm Lọt sàng 0.075 mm Chỉ số dẻo cm 25% đến 90% 0% đến 10% không 10 (c) Thi công Đắp trả vật liệu cấp phối hạt phải đắp thành lớp không dày 15cm (đo trước đầm chặt) đầm chặt mức độ 95% tỷ trọng khô lớn qui định tiêu chuẩn AASHTO T180-D 3.2 Permeable backfill.Đắp trả vật liệu dạng thấm Material Material shall be hard, clean, crushed rock or gravel complying with the following grading : Sieve Size 63 mm 37.5 mm % Passing by Weight 100 85 – 100 19 mm – 20 9.5 mm 0–5 Construction: The method of construction will be at the discretion of the Contractor, but details must be submitted for the Engineer's approval before commencement of the work All details of the permeable backfill shall be as shown on the Drawings and the degree of compaction shall be as instructed by the Engineer 3.2 Construction of subbase and base - Construction sequence same methoade construction of subbase, base for road 3.4 Construction of aquarter corner cutoff dike (a) Mô tả Công việc gồm việc cung cấp bố trí vật liệu đắp trả chọn gần kết cấu theo qui định Tiêu chuẩn Kỹ thuật vị trí qui định Bản vẽ theo dẫn Tư vấn giám sát (b) Vật liệu Vật liệu sử dụng phải vật liệu cứng, sạch, đá sỏi nghiền tuân theo cấp hạt sau % lọt sàng theo Kích trọng lượng thước sàng 63 mm 100 37.5 mm 85 – 100 19 mm – 20 9.5 mm 0–5 (c) Thi công Biện pháp thi công thực băng phương pháp thủ công Finish bridge3.3 Bảo vệ kết cầu Nếu thiết kế đắp bên mố, tường cánh, trụ hay tường đầu cống cần phải lưu ý khu vực gần kề kết cấu, khơng đầm đến mức gây lật gây áp lực lớn vào kết cấu Trong trường hợp ghi vẽ, đất đắp sát mố khung cuối cầu không đổ cao đáy tường lưng mố khung đặt kết cấu phần Khi chuẩn bị đắp hai bên tường bê tông kết cấu dạng hộp, công tác thi công cần đảm bảo cao độ đắp hai bên kết cấu phải xấp xỉ Hoàn thiện cầu - Dredged, widened, clearance flow - Dismantle, move temporary works, machinery outside construction - Moveing waste and material outside construction ... construction: + Installation of bottom form ( formwork 2x1m) + Installation of side form (V80x80x10) + Installation of rebar + Installation of wood form + Casting concrete + Finish and curing 2.2.Installation... suitability of the details contained in the welding plan, by tests as prescribed in the AWS "Standard Qualification Procedure".After welding, Railling shall be painted in the workshop - Installation... then starting of installation rebar 4.3.Installation of rebar for deck slab - Rebar shall be fabricated in accordance with the shape and dimention as shown approved working drawings - Installation
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