Monday, April 7, 2008

WMS Steel Structure

WORKS METHOD STATEMENT

STRUCTURAL STEEL WORK


TABLE OF CONTENTS


1.0 WORK ORGANISATION
2.0 DESIGN CONSTRAINTS AND COORDINATION
3.0 CONTRACTING METHODS
4.0 PROCUREMENT METHODS
5.0 RESOURCE PROVISIONS
6.0 LOGISTICS PROVISIONS
7.0 MATERIAL MANAGEMENT SYSTEMS
8.0 CONSTRUCTION METHODS AND TECHNOLOGY
9.0 CONSTRUCTION PHASING AND WORKFLOW
10.0 TRAFFIC MANAGEMENT AND MONITORING
11.0 SAFETY PROGRAMME
12.0 QUALITY ASSURANCE AND CONTROL PROGRAMMES
13.0 INDUSTRIAL RELATIONS POLICIES
14.0 ENVIRONMENTAL MONITORING PROGRAMMES
15.0 APPENDICES


1.0 INTRODUCTION

This Work Method Statement is describes the construction method intended for the site installation of the structural steel works at Private Hospital Project Jalan Tun Razak

2.0 DESIGN CONSTRAINTS AND COORDINATION

Not Applicable.

3.0 CONTRACTING METHODS

Since PCSB is liable for the performance of any Sub-contractor, it is vital that only companies with proven track records in the relevant activity will be engaged as Sub -contractors.

It is acknowledged that before any part of the works can be sublet, the approval of the Employer’s Representative is required.

The Conditions of Contract have been reviewed by PCSB and particularly those conditions in respect of Sub-contractors. The conditions are bespoke for this project and therefore be required to be reflected in any form of Sub-contract utilized on the project.

Please refer to PHOS-CN-010 to PHOS-CN-030 for the Contract Procedures.

4.0 PROCUREMENT METHODS

Please refer to PHOS-PR-010 to PHOS-PR-030 for the procurement procedures.
5.0 RESOURCE PROVISIONS

5.1 Manpower/Labour

The number of manpower/labour to be used during the earthworks activities have been identified in the Manpower Histogram.

5.2 Plant Equipment

Typical plant equipment to be used shall consist of:

~ Grease
~ Duct Tape
~ Levelling spirit
~ Welded holding down bolt template
~ 45 T mobile crane



6.0 LOGISTICS PROVISIONS

The logistic control shall be in accordance with the approved Site Logistic Plan and includes wheel wash facilities and traffic management.

7.0 MATERIAL MANAGEMENT SYSTEMS

Please refer to PHOS-CP-040 for the Material Control Procedure.

8.0 CONSTRUCTION METHODS AND TECHNOLOGY

8.1 Installation of Holding Down Bolt

1. Pre – Concreting Stage

• The template and anchor bolt are bolted together. The template used assures that the bolts are positioned correctly.
• The template and concrete reinforcing rebar will be welded together using additional rebar to ensure the position of the anchor bolts is correct. Both top and bottom nuts are tightened to hold the anchor bolts in place.
• The markers on the template are accurately surveyed and positioned
• In the job site, four additional 16 mm diameter rebar will be welded to the reinforcing bars
• The exposed nuts and threaded bars are then greased and taped with ducts tapes for protection during concreting by other contractors and then followed by our grouting

2. Pre – Grouting Stage

• A set of formwork is made along the perimeter of the concrete stump accordingly to the elevation and correct setting out
• The duct tape and nuts are then removed. The templates are then raised to a height of 100 mm above the grouting level
• The markers on the template are accurately re – surveyed and realigned if necessary
• Grout tubes are inserted into the formwork sleeve and grout is then poured into the sleeve
• The template is removed when the grout hardens

8.2 Erection of Lower Roof (Trellis)

Erection Stage – 1

• Preparation works are required to be carried out to determine the level of the column base and if necessary, various thicknesses of steel shims plates are required in order to achieve to the specified height of the overall structure
• Scaffolding needed to be erected on roof slab for easy access to erected structure
• Upon completion proceed with the erection of the steel column marked C1, C2, C3 and C4 respectively in position as shown. Lifting sling of 16 mm diameter x 6 meter long with one end hook to lifting block while the other fixing to a 7 m/ton capacity shackle bolted to a lifting lug provided
• Then erect the columns into position and tightening of all anchor bolts are required. During this process, check the verticality of the column individually


Erection Stage – 2

• Upon the completion of stage 1, proceed with the installation of the main tie girder marked B1 and B2 in position with 2 numbers of 16 mm diameter x 6 mm long lifting wire sling bolted with shackle to lifting lugs provided
• The main tie girder is required to be installed with temporary brackets bolted to column prior to the final adjustment and the execution of the welding works.

Erection Stage – 3

• Then proceed with the installation of the secondary tie girder marked S1, S2 and S3 accordingly with temporary bolting connection
• Upon erected in position and bolted, check the verticality of the column and center line offset between two tie girders to meet the required measurement. The offset point has to be determined during the fabrication at workshop
• The marking of actual position of the secondary tie girder are required to be carried out in advance during the fabrication prior to the commencement of the erection activities

Erection Stage – 4

• After determined the sound verticality and offset measurement required, proceed with the erection of the primary tie girder marked P1, P2, P3 and P4 into position as shown

Erection Stage – 5

• In order to achieve the stability of the erected structure, temporary wire sling are required to be erected diagonally braced as indicated in dotted lines
• Turnbuckle is required at one end of the wire sling for verticality adjustment
• Upon sound stability has been achieved, proceed with the erection of subsequence column marked C5, C6, C7 and C8 respectively
• Refer to stage 1 erection sequence for column installation




Erection Stage – 6

• Refer to stage 2 erection sequence for main tie girder installation

Erection Stage – 7

• Upon installation of the main tie girder in position proceed with the erection of the secondary tie girder marked S4, S5, S6, S7, S8 and S9 subsequently
• At this junction temporary bolted brackets needed for ease erection activities and adjustment during the installation of the next stage

Erection Stage – 8

• Then proceed with the installation of the trellis structure as shown
• All trellis structure is being fabricated into a fully welded segment module form in order to expedite the erection process
• During the erection process, 4 numbers of 16 mm diameter x 6 m long wire sling with 4 numbers of 7 m/ton capacity shackle bolted to lugs provided

Erection Stage – 9

• After the completion of the trellis installation, proceed with the erection of the outer most columns marked C9 to C20 as shown
• Refer to stage 1 erection sequence for column installation

Erection Stage – 10

• Then proceed with the installation of main tie girder marked B5, B6, B7 and B8 respectively

Erection Stage – 11

• The installation of the roof secondary tie girder marked S10 to S15 and perimeter channel members marked M1 to M4 as shown

Erection Stage – 12

• The installation of the gutter channel members as shown

Erection Stage – 13

• Upon completion of the stage 11 and 12 erection sequence, proceed with the installation of the roof purlins bolted to secondary tie girder by cleats provided
• A barge of purlins to be placed on roof structure with crane and installed manually to position until the completion of the whole structure.


Erection Stage – 14

• A bird’s eye view of the complete erected roof structure for zone 3
• Refer to erection sequence 1 to 13 for the installation of zone 1, 2 and 4 of which are similar structural arrangement throughout

8.3 Erection of Upper Roof (North and South)

Erection Stage – 1

• Preparation works are required to be carried out to determine the level of the column base and if necessary, various thicknesses of steel shims plates are required in order to achieve to the specified height of the overall structure
• Scaffolding needed to be erected on roof slab for easy access to erected structure
• Upon completion, proceed with the erection of the steel columns. Erection started with the ‘V’ shape column and followed by the L shape column. Lifting sling with shackle is hook to the column end and lifted to its position which is on top of the wind truss column. This column is welded to the wind truss column
• After finish erecting the ‘V’ column, the main column is erected. Lifting sling is tied to the bend area and columns end. Additional long rope is placed at the column end which is used to control the swinging and to pull the column to its position
• Adjust the columns into position and tightening of all anchor bolts are required. During this process, check the verticality of the column individually

Erection Stage – 2

• Upon the completion of stage 1, proceed with the installation of the tie beam. The erection is started from one end to another end
• Once the tie beam is erected, immediately the gutter frame support is installed which is welded to the columns

Erection Stage – 3

• Then proceed with the installation of the purlins and roofing sheets. The erection is completed.

8.4 Erection of Upper Roof (Main Atrium)

Erection Stage – 1

• Preparation works are required to be carried out to determine the level of the column base and if necessary, various thickness of steel shims plates are required in order to achieve to the specified height of the overall structure.
• Scaffolding needed to be erected on roof slab for easy access to erected structure
• Upon completion, proceed with the erection of the steel columns. Erection started with the ‘V’ shape column and followed by the ‘L’ shape column. Lifting sling with shackle is hook to the column end and lifted to its position which is on top of the wind truss column. This column is welded to the wind truss column.
• After finish erecting the ‘V’ column, the main column is erected. Lifting slings is tied to columns and placed to the stump.
• Adjust the columns into position and tightening all the anchors bolts. During this process, check the verticality of the column individually.

Erection Stage – 2

• Upon the completion of stage 1, proceed with the installation of the transfer beam which is sitting on the columns that we erected previously
• Once the beam is installed, roof beams is erected which is sitting on the transfer beam
• Installation of the tie beam is started when the roof beam is installed completely
• Subsequently, trellis can be erected. The gutter is attached to the trellis

Erection Stage – 3

• Then proceed with the installation of the purlins and roofing sheet. The erection is completed

8.5 Erection of Floor Beam (Main Atrium)

Erection Stage – 1

• Preparation works are required to be carried out to determine the level of the column base and if necessary, various thicknesses of steel shims plates are required in order to achieve to the specified height of the overall structure
• Scaffolding needed to be erected for easy access to erected structure
• All wind truss structure to be fabricated in panel frame which consisted of lower and upper panel as shown. Temporary bolting connections are required for the installation of the upper panel for verticality adjustment prior to the execution of welding works.
• Upon completion of the above basis requirement, proceed the installation of the lower panel frame marked L1 with 2 numbers of 7 m/ton capacity lifting shackle

Erection Stage – 2

• Upon the completion of stage 1, anchorage bolts are required to be tightened and to check verticality of the erected panel prior to the release for next lifting
• Then proceed with the installation of the lower panel frame marked L2 as shown to check verticality of L2 before the installation of the intermediate tie member marked T1 as shown




Erection Stage – 3

• All intermediate tie members are required to be erected between the lower panel frame L1 and L2 respectively before the installation of upper panel frame. The verticality required to be checked throughout the L1 and L2 structure prior to the installation of U1 and U2
• Similar erection sequence to be followed as stage 1 and 2 for the installation of upper panel frame U1 and U2

Erection Stage – 4

• Then proceed with the installation of main tie girder marked E in position. The erection of the main tie girder to be carried out by a 150 m/ton capacity crawler crane with extended fly jib attached to a main boom.
• At this junction, the working radius of the crane is estimated at 52 meter with a safe working load (swl) of 4.3 m/ton. The ultimate dead load of the main tie girder is approximately 3.6 m/ton the swl factor at this working radius is 15%.
• The main tie girder to be bolted firmly to the wind truss prior to the release of the lift. This will secure the main tie girder in position prior to further attachment of inner tie beams as shown.

Erection Stage – 5

• The next erection sequence is the installation of the main girder marked ‘B’ as shown. The dead load of this section is estimated at 7.90 m/ton at a working radius of 32 meter and the ultimate lifting capacity of the crawler crane is 9.40 m/ton which show a swl factor of 15% within the specified working radius
• In order to ensure the stability of the erected girder during the process, a temporary wire sling with turnbuckle on one end are required to be braced to existing R.C structure as indicated.

Erection Stage – 6

• After the structure has been secured, proceed with the installation of the secondary tie beam marked ‘E’ as shown
• Adjustment on the turnbuckle can be made if necessary for the installation of the secondary tie beam which to be bolted between web of main tie girder marked E’ and ‘B’ respectively

Erection Stage – 7

• Then proceed with the erection of the primary tie beam marked ‘F’ as shown until the structure are completely install





Erection Stage – 8

• Upon completion, then proceed with the installation of the intermediate tie beam marked ‘G’ with both ends bolted to web of primary tie beam marked ‘F’ as shown

Erection Stage – 9

• The erection works on intermediate tie beam are to be carried out completely and tightening of all bolting connection before the erection of outer floor beam
• Then erect the main tie girder marked B1, B2, B3 and D respectively. At this stage, temporary staging is required for access during the installation

Erection Stage – 10

• The intermediate floor beam marked ’C’ are required to be installed in position. All connection joints to be bolted and tightened prior to next erection sequence
• No erection works to be carried out at level 7 until the completion of intermediate. Floor beam marked ‘C’ installation and bolted.

Erection Stage – 11

• Then proceed with the erection of the wind truss structure in fabricated panel frame as per stage 1 to stage 3 erection sequences.
• The tie back of L1 panel frame to R.C structure are required prior to the stability of the erected structure throughout the process
• Ensure that structural verticality and offset distant are being achieved throughout the erection process prior to the installation of main tie girder marked A, B4 and H respectively

Erection Stage – 12

• Then complete the erection sequence for lower panel and secure firmly before proceed to upper panel frame refer to stage 3 for erection sequence
• Similar process of erection as per stage 11 for tie back

Erection Stage – 13

• Then proceed with the erection of the wind truss upper frame as shown
• Repeat stage 4 erection sequence until complete





Erection Stage – 14

• Upon completion proceed with the installation of main tie girder marked A, B4, and H accordingly. All bolting connection joints needed to be tightened prior to the release for next lift

Erection Stage – 15

• Lastly, erect all the intermediate floor tie beam marked G throughout until completed

Erection Stage – 16

• A bird’s eye view of the complete erected view of main atrium structure

8.6 Erection of Granite Frame

Erection Stage – 1

• Preparation works are required to be carried out to determine the level of the granite frame base and if necessary, various thickness of steel shims plates are required in order to achieve to the specified height of the overall structure
• Scaffolding needed to be erected for easy access to erected structure
• The holding down bolt holes needs to be drilled on concrete before the installation of granite frame. Anchor stud from Hilti will be used for this purposed and the bolt have to be installed before the frame is erected.

Erection Stage – 2

• Granite frame is assembly on ground before it is erected tom the specified location. The installation will start with triangle tower and followed by the middle top trusses (intermediate truss in between two towers).

Erection Stage – 3

• The tower will be erected once the framing is done assembled on ground
• Two towers need to be installed before the top middle truss can be erected. Once the middle truss has been erected, the frame is ready for installation of the granite stone by the stone’s contractor

Erection Stage – 4

• The erection process is repeated until the granite frame is fully installed along the grid line



8.7 Erection of Wind Truss

Erection Stage – 1

• Preparation work such as lifting lugs has to be done before wind truss can be erected. 2 numbers of 25 mm thick lifting lug are welded to the side (top) of the wind truss. Partial penetration is applied for this welding connection.
• Upon completion of the above, wind truss are not ready to be erected until the level of column has been carried out. If necessary, various thicknesses of steel shims plates are required in order to achieve to the specified height of the overall structure
• Once the preparation work is completed, wind truss can be erected at any time
• Two cranes are required for this type of erection due to the loads of the truss and also due to the size of the member (long and heavy). Another reason for using 2 cranes is to position the truss from horizontal to vertical and also to protect the truss from damage (dragging on the ground) when lifting is in progress. The cranes that will be used for this erection is one tower crane and one 45 ton crawler crane.


Erection Stage – 2

• When the cranes are ready, the crawler crane will be positioned near the base of the truss while the tower crane will be positioned near the top of the truss. Once the truss is hooked to the cranes ( hooked to the provided lifting lug using shackles and lifting belt), truss will be lift concurrently about few meters (3 to 4 meter) high from the ground
• At this stage, the tower crane will lift the truss higher and higher while the crawler crane will adjust the truss to vertical position
• Once the truss is in vertical position, unhooked the crawler crane from the truss and tied 2 or more long ropes to the bottom of the truss. The workers will use this rope to control the truss from swaying when the tower crane swings the truss to its position. Once the truss is placed to the stump, workers will bolt the truss to the holding down bolt
• However, in order to make sure that the column is shifted when doing the erection, the members in between columns will be installed after the columns are erected. Therefore, scaffolding is required while installation of this member is in progress. The process of erection will be repeated until the entire wind truss is erected.

8.7 Erection of Wind Truss

8.7.1 Surface Preparation

• The surface to be coated shall be inspected to ensure that all the prepared surface meets the requirements of specifications
• Solvent cleaning may be used to remove oil, grease, dirt and other contaminants from surfaces prior to painting
• Ensure the damage, broken and loosely adhering coat are removed and feather edged before recoating
• Verified that time interval between surface preparation and coating is not exceeded

8.7.2 Mixing

• Ensure that the mixing is done in accordance with the manufacturer’s recommendation and the painting manual
• Monitor the mixing to see that a through blending of the pigment and the vertical or the component accomplished weather by approved mechanical vibrators or by manual
• Monitor the addition of catalysts, thinner or other constituents to ensure that they used in strict accordance with the manufacturers recommendation
• It may be necessary to consider the use of sieves or strainer to ensure proper mixing and / or blending
• Make sure that cleaning solvent and thinner used to clean brushers, spray equipment or containers is not added to the coating material

8.7.3 Application

• Ensure the coating material applied the number of coats and dry film thickness of each coat is as shown in the approved painting schedule
• No coating system will be applied to any surface whose temporary is below 5 degree C or above 60 degree C unless the coating is especially formulated for these conditions
• Equipment and method of application shall be recommended by the coating manufacturer and approved by the client representative
• Verify that coatings are applied events without runs or sags
• Ensure that each coat has the correct dry film thickness before applying the next coat
• Verify the coating are cured the specified times / temperatures as recommended by the manufacturer


8.7.4 Thickness

• Dry film thickness of coating on steel or ferrous surface shall be measured with a thickness gauge such as the Elometer or Microtest magnetic type gauge or approved equals
• Fry film thickness of coating on non ferrous surface shall be measured with micrometer depth gauge or approval means
• When wet film gauge are used during application, a reasonable allowance shall be made for the subsequent loss of thickness due to the evaporation of volatile solvents when present


8.8 Installation of Spandek

• To measure the exact length and quality of roofing sheet on site
• Preparation of cutting list for rooring deck supplier to roll the metal deck as per require quantity and length
• Install spandek by following the bellows steps :

a. Measure spacing between box beam to box beam
b. Calculate the distance to be off set from beam for the first piece of spandek
c. Lay the first piece of spandek and use self tapping screw to screw at all purling location
d. Lay the second piece of spandek with the end rib lapping to the first piece
e. Repeat step ‘d’ until completion

• Care should be taken to ensure that sufficient workers are available to move the roofing sheets in unison without causing any damage to the roofing sheets
• Install ‘L’ shape flashing along roofing sheet in contact with the box beam.


9.0 CONSTRUCTION PHASING AND WORKFLOW


During secant wall and bored piling construction, excavation for ground anchor installation and basement formation will commence in available areas, generally moving from grids 27/H towards 1/A.


10.0 TRAFFIC MANAGEMENT AND MONITORING

The Logistic Manager and the traffic management contractor shall be responsible for the management and control of the traffic in and out from the construction site.


11.0 SAFETY PROGRAMME

Please refer to PHOS-HS-010 Health and Safety Plan.


12.0 QUALITY ASSURANCE AND CONTROL PROGRAMMES

Please refer to Appendix 15.1 for the Inspection and Test Plan and Appendix 15.2 for the Checklist.


13.0 INDUSTRIAL RELATIONS POLICIES

Not Applicable


14.0 ENVIRONMENTAL MONITORING PROGRAMMES

Please refer to PHOS-EMP-001 Environmental Management Plan


15.0 APPENDICES

15.1 Inspection and Test Plan

15.2 Inspection Checklist Form
15.3 Job Safety Analysis
15.4 Erection of Lower Roof (Trellis)
15.5 Erection of Floor Beam (Main Atrium)

2 comments:

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