Method statement for Typical LG Self-Launching over 35m Span Straight

Construction, Method Statement
1. INTRODUCTION
1.1 GENERAL

The purpose of this procedure is to describe the Self-Launching of Launching Gantry and the Erection of 35 meters-long spans straight.

1.2 SCOPE OF WORK

Erect viaduct superstructure of Ho-Chi-Minh-City Metro Line 1 Project using the span-by-span method.

1.3 WORKING DRAWINGS

Prior to commence the work at each area, working drawings will be prepared and submitted to the Employer’s Representative separately. Designated areas for the works will be shown in the working drawings separately submitted in due course.

1.4 DEFINITIONS

LG Launching Gantry WT Winch Trolley MG Main Girder SB Spreader Beam FS Front Support FH Front Head RS Rear Support RH Rear Head AS Auxiliary Support HS Hanging System CG Centre of Gravity

2. RELEVANT SPECIFICATIONS, STANDARDS AND DOCUMENTS

• Kinematics drawing FVR-TEC-DWG-3240-006 • Front Support fixation FVR-TEC-DWG-3240-008

3. CONSTRUCTION PROCEDURE
3.1 GENERAL

The Launching Gantry, upon completion of the erection of a span, must then move forward to take up the position on the top of next pier in order to erect the next span. This procedure of advancing the gantry from one span to the next is termed as self-launching.

As soon as the launching gantry is advanced to the next span, the launching gantry position is required to be checked with respect to longitudinal, transverse direction and the level.

In general, the requirement for the longitudinal direction would be to place the launching gantry such that the centre of gravity of the gantry is at the centre of the span being erected. The requirement for the transverse direction is, generally, that the line connecting the centre points of the launching gantry in plan between the two piers passes through the centre of gravity of the span being erected.

Segment lifting and hanging can only begin after the launching gantry has been positioned according to the requirements and following the Check-List and approval of LG supervisor. The sequence of steps for the self-launching and positioning of the launching gantry for erection is referred to the kinematics drawings in Attachment #2 : Typical 35 meters-long span : FVR-TEC-DWG-3240-006 Site operations shall only be carried out based on the kinematics drawings prepared by FVR JV and not on any other document / drawings.

3.2 LAUNCHING GANTRY KINEMATICS

The various steps pertaining to the launching gantry kinematics for self-launching and positioning the gantry ready for erection of the segments is described below :

When a span has been erected, ie. the permanent pre-stressed tendons installed and the span lowered on temporary bearings, the LG can be launched forward for erecting the next span.

Phase 1 :  Span is erected and LG is ready to be launched  Ensure longitudinal brakes on RS and AS are locked with pins

 Extend the 4 hydraulic bearing jacks of AS, until the jacks are engaged (Pressure around 50 bars)  Engage ringnut on jacks and release pressure

Auxiliary Support (AS)  Rear Support (RS)   Front Support (FS)

Longitudinal Brake Locked Locked Unlocked Bearing Jacks Engaged Engaged Engaged Bearing Jacks Stroke 800 mm 229 mm Long (6551 mm)

 Extend the 4 hydraulic jacks of RS, to free ringnut, read pressure shall be around 79 bars per jack  Wind ringnut to allow retraction of piston  Retract RS jacks

Auxiliary Support (AS)  Rear Support (RS)   Front Support (FS)

Longitudinal Brake Locked Locked Unlocked Bearing Jacks Engaged Disengaged Engaged Bearing Jacks Stroke 800 mm 229 mm Long (6551 mm) Phase 2 :

 Release longitudinal brake on RS, by removing pin  Move RS, until gap from its axis and pier axis = 1600 mm (as per drawings) NOTE : Take a measure tape and follow the drawings NOTE : Slow down when RS approaching FS by selecting slow speed on remote

Auxiliary Support (AS)  Rear Support (RS)   Front Support (FS)

Longitudinal Brake Locked Unlocked Unlocked Bearing Jacks Engaged Disengaged Engaged Bearing Jacks Stroke 800 mm Retracted Long (6551 mm)  Install the longitudinal brake on RS Auxiliary Support (AS) Rear Support (RS) Front Support (FS) Longitudinal Brake Locked Locked Unlocked Bearing Jacks Engaged Disengaged Engaged Bearing Jacks Stroke 800 mm Retracted Long (6551 mm)

 Extend the 4 bearing jacks of RS, until the jacks are engaged (Pressure around 50 bars) NOTE : While extending jacks, wind the ringnut at same time to keep max 10 mm gap from top of ringnut and jack body (To minimize stroke travel distance in case of a hydraulic failure in the system)  Engage ringnut and release pressure  Detension the stressbar in FS legs and remove the stressbar  Extend lowering jacks on RS, until extension around 150 mm, engage ringnut o Clearance between FS and Pier around 150 mm

Auxiliary Support (AS)  Rear Support (RS)   Front Support (FS)

Longitudinal Brake Locked Locked Unlocked Bearing Jacks Engaged Engaged Disengaged Bearing Jacks Stroke 800 mm 229 mm Long (6551 mm)

 Release the longitudinal brake on AS, by removing pin  Operate RS lateral jacks to ensure MG is centred to the RS .
Auxiliary Support (AS) Rear Support (RS) Front Support (FS) Longitudinal Brake Unlocked Locked Unlocked Bearing Jacks Engaged Engaged Disengaged Bearing Jacks Stroke 800 mm 229 mm Long (6551 mm)

 Lock the longitudinal brake on AS with pin

SAFETY NOTE : Keep fingers clear of gap, use ringnut spigot tool to turn. Phase 3 :

 Retract FS legs 1m to its short position and lock with pins NOTE : FS has to be retracted to compensate the cantilever deflection created by FS weight when it arrive on next pier head.

 Relocate the WT, such as it is in line with RS  Link with pin the WT and the RS together, to allow the MG launching

Auxiliary Support (AS)  Rear Support (RS)   Front Support (FS)

Longitudinal Brake Locked Locked Unlocked Bearing Jacks Engaged Engaged Engaged Bearing Jacks Stroke 800 mm 229 mm Short Position

 Disengage longitudinal brake on RS and AS, by removing pins  Launch forward MG by 9.20 m (Keep a fix point and watch the MG’s marks)

Auxiliary Support (AS)  Rear Support (RS)   Front Support (FS)

Longitudinal Brake Unlocked Unlocked Unlocked Bearing Jacks Engaged Engaged Engaged Bearing Jacks Stroke 800 mm 229 mm Short Position Phase 4 :

 Install longitudinal brake on RS and AS with pins  Unlink WT and AS, by removing pin

 Move forward FS, until be above tie down bars installed on pier (FS axis to pier axis = 700 mm) SAFETY NOTE : Safety Factor against overturning = 2.16 > 1.50  Extend FS, until touch the top of pier  Stress 2 Ø40mm tie down bars : 645 kN per bar (Pressure to be determined with jack information)

Auxiliary Support (AS)  Rear Support (RS)   Front Support (FS)

Longitudinal Brake Locked Locked Unlocked Bearing Jacks Engaged Engaged Disengaged Bearing Jacks Stroke 800 mm 229 mm Short Position  Extend FS, until its long position  Fully retract RS lowering jacks and make sure ringnuts are not engaged (Clearance between ringnut and base around 2 mm)  Release pressure

Auxiliary Support (AS)  Rear Support (RS)   Front Support (FS)

Longitudinal Brake Locked Locked Unlocked Bearing Jacks Engaged Engaged Engaged Bearing Jacks Stroke 800 mm 229 mm Long (6551 mm)

Phase 5 :

 Relocate the WT, such as it is in line with RS  Link with pin the WT and the RS together, to allow the MG launching

Auxiliary Support (AS)  Rear Support (RS)   Front Support (FS)

Longitudinal Brake Locked Locked Unlocked Bearing Jacks Engaged Engaged Engaged Bearing Jacks Stroke 800 mm 229 mm Long (6551 mm)

 Disengage longitudinal brake on RS and AS, by removing pins  Launch forward MG by 17.70 m (Keep a fix point and watch the MG’s marks)

Auxiliary Support (AS)  Rear Support (RS)   Front Support (FS)

Longitudinal Brake Unlocked Locked Unlocked Bearing Jacks Engaged Engaged Engaged Bearing Jacks Stroke 800 mm 229 mm Long (6551 mm)

Phase 6 :  Install longitudinal brake on RS and AS with pins  Unlink WT and RS, by removing pin  Move forward the WT, until gap from MG front end and WT axis around 8000 mm  Extend AS bearing jacks, to free ringnut  Wind ringnut to allow retraction of piston

Auxiliary Support (AS)  Rear Support (RS)   Front Support (FS)

Longitudinal Brake Locked Locked Unlocked Bearing Jacks Engaged Engaged Engaged Bearing Jacks Stroke 800 mm 229 mm Long (6551 mm)

 Release pressure from bearing jacks on AS  Retract AS bearing jacks Safety Factor against overturning = 2.25 > 1.50

Auxiliary Support (AS)  Rear Support (RS)   Front Support (FS)

Longitudinal Brake Locked Locked Unlocked Bearing Jacks Disengaged Engaged Engaged Bearing Jacks Stroke Retracted 229 mm Long (6551 mm)

Phase 7 :

 Release the longitudinal brake on AS, by removing pin  Move forward AS, until gap between its axis and MG end around 26000 mm

Auxiliary Support (AS)  Rear Support (RS)   Front Support (FS)

Longitudinal Brake Unlocked Locked Unlocked Bearing Jacks Disengaged Engaged Engaged Bearing Jacks Stroke Retracted 229 mm Long (6551 mm)

 Install longitudinal brake on AS with pin Auxiliary Support (AS) Rear Support (RS) Front Support (FS) Longitudinal Brake Locked Locked Unlocked Bearing Jacks Disengaged Engaged Engaged Bearing Jacks Stroke Retracted 229 mm Long (6551 mm)

Phase 8 :

 Relocate the WT, such as it is in line with RS  Link with pin the WT and RS, to allow MG launching

Auxiliary Support (AS)  Rear Support (RS)   Front Support (FS)

Longitudinal Brake Locked Locked Unlocked Bearing Jacks Disengaged Engaged Engaged Bearing Jacks Stroke Retracted 229 mm Long (6551 mm) Phase 9 :

 Release longitudinal brake on RS  Launch forward MG by 11.10 m (Keep a fix point and watch the MG’s marks)

Auxiliary Support (AS)  Rear Support (RS)   Front Support (FS)

Longitudinal Brake Locked Unlocked Unlocked Bearing Jacks Disengaged Engaged Engaged Bearing Jacks Stroke Retracted 229 mm Long (6551 mm)

 Install longitudinal brake on RS with pin  Unlink WT and RS, by removing pin  Self-launching completed  LG is ready to erect

Auxiliary Support (AS)  Rear Support (RS)   Front Support (FS)

Longitudinal Brake Locked Locked Unlocked Bearing Jacks Disengaged Engaged Engaged Bearing Jacks Stroke Retracted 229 mm Long (6551 mm)

  4. RESOURCES TO BE USED 4.1 EQUIPMENT TO BE USED Equipment to be deployed for the LG self-launching.

No. Description Specification Quantity Unit Remarks 1 Setting-out instruments 1 set 2 Drill 1 set 3 Grinder 9” 1 set 4 Grinder 4” 1 set 5 Hand tools 1 set 6 Jacks 1 set 7 Pump 1 set 8 Chain 1 set 9 Slings 1 set 10 Shackle 1 set 11 Safety signs 1 set 12 Water pump 1 set

Note: Above stated quantity of equipments could be changed if any required and necessary.  

4.2 MANPOWERS TO BE DEPLOYED

Manpowers to be deployed for the filling works as per sections are listed below. No. Description Detail Quantity Remarks 1 General superintendent of the 3 LG of project FVR 1
2 Supervisor of the concerned LG FVR 1
3 Site engineer FVR 1
4 Skilled workers FVR 10

Note: - Number of manpower could be changed according to site condition. - This manpower shall be deployed on site.

4.3 MATERIALS TO BE USED

Materials to be used for the filling works as per sections are listed below. No. Description Sources 1 Hydraulic oil DIN 51524/part 2 June 1979 ISO VG ref AGIP IP BP CASTROL ESSO MOBIL SHELL CHEVRON H-LP 46 46 OSO 46 Hydrus 46 Energol HPL 46 Hyspin HPL 46 Nuto H 46 DTE 25 Tellus 46 EP Hydraulic Oil 46 2 Diesel oil Local supplier

Note: Description and sources of materials could be changed according to site condition, subcontractor, schedule, quality, etc.

######5. INSPECTION TESTING PLAN

Inspection records will be kept for all critical activities particularly for the positioning of the launching gantry supports, the stroke level and pressure of the supports jacks. Inspection sheets, test reports, material certificates and all the other documents to be collected are listed in the ITP. Each inspection activities are performed by the this table No. WORKS DESCRIPTION RESPONSIBILITY 1.0 PRE-LAUNCH
1.1 Pier strength + Height of pier cap LG Supervisor 1.2 Weather forecast LG Supervisor 1.3 Span segments have been castled and ready for delivery LG Supervisor 1.4 Bearing support and alignment jack are been installed on pier cap LG Supervisor 1.5 Generator diesel fuel level LG Supervisor 2.0 LAUNCHING GANTRY SELF-LAUNCHING 2.1 Launch of Gantry LG Supervisor

6. OCCUPATIONAL HEALTH AND SAFETY CONTROL

The Hazard and Risk Assessment (HRA) has been carried out in the form of the Job Safety Analysis (JSA) to include those activities which are specially associated with the self-launching of Launching Gantry. These are reviewed by the HSE Officer to ensure that all the hazards have been identified and adequate control measures are in place. All personnel shall wear the appropriate PPE at all times.

6.1 JOB SAFETY ANALYSIS (JSA) / HAZARD ANALYSIS & RISK ASSESSMENT (HRA) / SAFE WORK METHOD STATEMENT (SWMS)

The JSA has been completed by the Technical Department and has been reviewed by the HSE Department. It should also be reviewed by the work crew prior to activities being performed. The document has identified the hazards associated with the activities involved in the self-launching of launching gantry and details the measures to be adopted to minimize or eliminate those risks identified. Attachment #1

6.2 TOOLS AND EQUIPMENT

All tools and equipment for the task shall be in safe condition and fit for its purpose. Where applicable, registration papers, certifications shall be produced and tests certificates will be available for inspection. At the start of each shift, equipment shall be visually checked for mechanical and structural soundness. All equipment shall be carefully examined and all hoses and couplings checked for the leaks and general condition.  

7. ATTACHMENTS

ATTACHMENT #1: HAZARD AND RISK ASSESSMENT (HRA)   ATTACHMENT #2: KINEMATICS OF SELF-LAUNCHING AND FRONT SUPPORT FIXATION DRAWING   ATTACHMENT #3: LAUNCHING GANTRY OPERATIONS (INCLUDING THE CHECKLIST)