Ground condition of care working area shall be checked and the concrete plate shall be installed to ensure the stability.. Before and during transporting work, the girder shall be fixed
Trang 1content Chapter 1: method statement for erection of pc-I girder.
1 Outline.
2 Preparation work.
3 Transportation PC - I girder to erection span.
4 Erection PC - I girder to design position.
4.1 Erection PC - I girder of span 1.
4.2 Erection PC - I girder of span 2.
5 Unloading PC-I girder on its final position ( final lifting ).
chapter 2: procedure for construction of diaphragm,deck slab, parapet and lighting pole.
1 Outline.
2 Procedure for construction of precast plat
2.1 Casting concrete precast plat on the groud.
2.2 Installation of precast plat by crane.
3 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.
4 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.
5 4 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
1 Construction of bearing and expansion joint
2 Construction of water proofing and asphalt pavement
3 Soil backfill of abutment
4 Finish bridge
Trang 2APPENDIX 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
superstructure and construction other items Chapter 1: method statement for erection of pc-I girder
1 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:
Trang 3No Span Length Unit Quantity Remark
2 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
3 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 1
+ Transportion PC-I girder from girder stock yard No1 to erection span 2
4 Erection PC - I girder to design position.
4.1 Erection PC - I girder of span 1.
- 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 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
Trang 4 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
Trang 5chapter 2: procedure for construction of diaphragm,deck slab, parapet
lighting pole and railling
1 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.
2 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
3 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.
Trang 6- 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
release-agent 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.
4 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.
Trang 7- 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
Trang 8- 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
release-agent 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.
Trang 9- 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 5 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 1 → Span 2 → 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
Trang 10Chapter 3: construction of other items
1. 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.
2. Construction of waterprooding and surface coures
2.1 Construction of waterproofing.
- Concrete surface shall be preparaded in accordance with the manufacturer’s instructions