Safe System of Work - planning.org.uk

Document ref: SSOW – Blank Template Rev: 001 Ezone Template Location 99 – Templates Author: SHE-Q Ezone Storage Location Project File Date issued: 01.2018

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Prepared For: Landsec Prepared By: Erith Contractors Ltd Queen Street Erith Kent DA8 1RP

Date: 04/12/20

Document Name: SSoW 033 – Basement Temporary Works Sequence Project Reference: D9399 PORTLAND HOUSE Client’s Project Manager: Turner & Townsend Principal Designer: Gardiner & Theobald LLP

Safe System of Work

Portland House, Bressenden Place, LONDON SW1E 5RS


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Document Production / Authorisation Record

Issue No: Name Date Position Signature

0 – Prepared By:

D.Marchant 09/12/20 Snr Project Manager

0 – Approved By:

S.Exell 14/12/20 Operations Manager

S.Exell

Document Review Register

Issue No Name Date Details of Revisions

0 N. Riches 26/06/2020 First Issue

1 D.Marchant 04/12/2020 LUL Revised basement sequence issue PH-SCL-SC-099-Y-28004-S0-P01 Rev 01

2 D.Marchant 05/02/21 Addition of scale bar / dimensions to Appendices drawings

3

4

5


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CONTENTS 1 Site Particulars ............................................................................................................................ - 6 -

Scope of Works ................................................................................................................... - 6 -

Hours of Work ..................................................................................................................... - 6 -

Constraints to Work ............................................................................................................ - 6 -

Programme / Sequence ...................................................................................................... - 7 -

Specifications ...................................................................................................................... - 7 -

Drawings ............................................................................................................................. - 7 -

Temporary Works ............................................................................................................... - 8 -

Services ............................................................................................................................... - 8 -

Asbestos .............................................................................................................................. - 8 -

2 Access / Egress Arrangements .................................................................................................... - 9 -

Site Access ........................................................................................................................... - 9 -

Workface Access ................................................................................................................. - 9 -

Welfare Arrangements ........................................................................................................ - 9 -

Traffic Movements ............................................................................................................ - 10 -

3 Resources .................................................................................................................................. - 11 -

Plant & Machinery ............................................................................................................ - 11 -

Vehicles ............................................................................................................................. - 11 -

Tools & Equipment ............................................................................................................ - 11 -

Materials ........................................................................................................................... - 11 -

Safety Resources ............................................................................................................... - 12 -

COSHH Overview ............................................................................................................... - 12 -

COVID-19 Prevention Measures ....................................................................................... - 12 -

4 Methodology ............................................................................................................................. - 13 -

Sequence ........................................................................................................................... - 13 -

Method of Work................................................................................................................ - 13 -

4.2.1 Structural Movement Monitoring ............................................................................. - 13 -

4.2.2 Site Logistics .............................................................................................................. - 14 -

4.2.3 Palace Street Loading Bay Access ............................................................................. - 15 -

4.2.4 GF Slab Assessment for Load Capacities ................................................................... - 15 -

4.2.5 Dust Control .............................................................................................................. - 16 -

4.2.6 Gym Pod Demolition & Basement Access from GF Slab ........................................... - 16 -

4.2.7 Basement Access & Mobile Cranes ........................................................................... - 20 -

4.2.8 Pile Enabling Works ................................................................................................... - 20 -


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4.2.9 Saw Cut and Break Out Pile Locations ...................................................................... - 25 -

4.2.10 Temporary Steel Support Install & Column Release ................................................. - 26 -

4.2.11 Concrete Cutting to Retaining Wall Toe.................................................................... - 30 -

4.2.12 Installation of Groundforce KD6 Trench Sheets ....................................................... - 31 -

4.2.13 Reduced Headroom Piling (Martello MP 4000 Rig) .................................................. - 33 -

4.2.14 Retaining Wall Temporary Works Installation including Plunge Columns ................ - 42 -

4.2.15 Pile Cap & Construction ............................................................................................ - 52 -

4.2.16 Site Logistics at Completion of Basement Structures ............................................... - 61 -

5 Personal Protection Equipment (PPE)....................................................................................... - 62 -

6 Competency / Supervision ........................................................................................................ - 63 -

Competent Persons ........................................................................................................... - 63 -

Supervision ........................................................................................................................ - 63 -

Additional Training / Certification..................................................................................... - 64 -

7 Permits ...................................................................................................................................... - 64 -

8 Emergency Procedures ............................................................................................................. - 65 -

First Aid ............................................................................................................................. - 65 -

Fire Emergency .................................................................................................................. - 65 -

Emergency Response Plans ............................................................................................... - 65 -

9 Environmental Considerations .................................................................................................. - 66 -

Environmental Controls .................................................................................................... - 66 -

Waste Materials ................................................................................................................ - 67 -

10 Risk Assessment ................................................................................................................ - 68 -

11 Appendices ........................................................................................................................ - 69 -

Appendix A – Sign off Sheet .............................................................................................. - 70 -

Appendix B – Arup Drawings............................................................................................. - 72 -

Appendix C – Bressenden Place Temporary Works .......................................................... - 73 -

Appendix D – Steel Frame for Column Removal and Existing Column Removal Steel Frame Support GA & Details .................................................................................................................... - 74 -

Appendix E – ARUP Structural Monitoring Specification .................................................. - 75 -

Appendix F – Martello Piling Method Statement & ITP .................................................... - 76 -


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Associated Documents

The list of associated documents below is to be referenced in conjunction with this document and are issued as standalone documents to reduce unnecessary duplication.

Roles Name & Organisation Contact Details Client James Else

Landsec Email : Tel No :

[email protected] 07798 848 679

Principal Designer

Nick Gul Gardiner & Theobald

Email : Tel No :

[email protected] 02072 093 000

Operations Manager

Scott Exell Erith Contractors Ltd

Email : Tel No :

[email protected] O7827 342239

Snr Project Manager

Daniel Marchant Erith Contractors Ltd

Email : Tel No :

[email protected] 07471 904166

Project Manager

Nick Riches Erith Contractors Ltd

Email : Tel No :


Site Manager

Gary Whittington Erith Contractors Ltd

Email : Tel No :


mailto:[email protected]







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1 SITE PARTICULARS Scope of Works

• As part of the Portland House redevelopment, Erith will demolish the existing Ground floor Structure and ground bearing basement slabs on the western elevation. The new foundations and slab will be constructed for hand over to the follow-on contractor for construction of steel frame 15 storey building. The following details the intended sequence and control measures to be undertaken throughout all phases of the works whilst ensuring the stability of the retaining wall is maintained.

• All works to be completed in accordance with approved Swanton Temporary Works Design Reports as agreed with LUL and other 3rd party assets to be protected.

• The gym pods will be demolished to enable access for reduced head room piling. • Enabling works will be undertaken within the basement including break out of topping slabs

and formation of pockets for installation of piles in design positions • Reduced head room piling will install 1050mm diameter piles in accordance with agreed

piling & foundation layout plans. The piles will be installed in accordance with the basement temporary works sequence allowing progressive release of ground structures for access to proposed pile areas as required.

• To enable the 3nr columns supporting the ground floor to be demolished, steelwork goalposts will be installed to support the ground floor slab from the Portland House tower basement.

• Due to localised demolition of the retaining wall toe to facilitate the basement construction, sacrificial Groundforce KD6 trench sheets will be installed which will also act as formwork for the pile cap constructions later in the sequence.

• The retaining wall will be propped by a steelwork frame supported from the king posts within the nearby piles. The king posts will be connected by a horizontal truss with a waler that serves as the chord of the truss and retaining wall pre-loaded jacking points.

• The seven no pile caps will be installed sequentially with surrounding excavations backfilled in accordance with the design before then progressing to the next identified pile cap area thus ensuring the disturbed ground adjacent to the retaining wall is reduced to a minimum at any one time.

• Baseline & frequent structural monitoring will be undertaken in accordance with monitoring will be under

Hours of Work

• Monday to Friday: 08:00hrs – 18:00hrs • Saturday: 08.00hrs – 13:00hrs • Sunday: By Agreement Only • Noisy work hours: 08:00-10:00, 12:00-14:00 & 16:00-18:00

Constraints to Work

• All live utilities located within the works area are to be isolated or disconnected outside the boundary by others prior to commencement.

• Isolation and certification of redundant services. Isolated services must be cut to prove as dead.


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• All live or temporary services to be sprayed up red as live. Live services will be relocated or protected prior to works starting.

• Asbestos survey of work areas and asbestos removed prior to works commencing. • All works to be completed in accordance with approved Construction issue design reports as

agreed with LUL and other 3rd party asset protection. • Temporary works assessment of the retaining wall with temporary works installed as

designed and permit to load issued. • Temporary works designed and installed to enable the demolition of 3 nr columns. • Engineers assessment of plant loadings and construction traffic of the ground floor slab and

above ground structures throughout works. • Engineers assessment of sequence by Swanton and any temporary works required installed. • Structural Movement monitoring to be undertaken in accordance with monitoring

specification and remain within agreed limits. • GF slab capacity restrictions in accordance with SCL Report PH-SCL-SC-100-Y-14001-S0-P01 • Assessment & Temporary Works required for any load which may exceed allowable limits.

Programme / Sequence

• Project Commencement 29th March 2021 • Overall Project Duration: 57 calendar weeks • Pile Enabling Works commence: 6th May 2021 • Piling & Basement Temporary Works installation commence 23rd June 2021

Specifications

• Arup specification PH-ARP-SP-XXX-S-0001 – General Structural Clauses Specification • Arup specification PH-ARP-SP-XXX-S-0002 – Specification for Instrumentation & Monitoring

(Movement) • Arup specification PH-ARP-SP-XXX-S-0003 – Demolition Specification • Arup specification PH-ARP-SP-XXX-S-0004 – Piling Specification • Arup specification PH-ARP-SP-XXX-S-0005 – General Building Earthworks Specification • Arup specification PH-ARP-SP-XXX-S-0006 – Below Ground Drainage Particular Specification • Arup specification PH-ARP-SP-XXX-S-0007 – Below Ground Drainage Workmanship and

Materials Specification • Arup specification PH-ARP-SP-XXX-S-0008 – Concrete (NSCS Part 2) Specification • Arup drawing PH-ARP-XX-XX-DR-S-000010 – General Notes

Drawings

• See 11.2 Appendix B – Arup Drawings for Drawings Register • PH - ARP- XXX-XXX-DR-S-000001 – Cover Sheet • ARP- XXX-ZZZ-DR-S-000100 – Key Plan • PH-ARP-XX-P1-DR-S-201000 – General Arrangement Piling Layout Plan • PH-ARP-XX-F1-DR-S-211000 - General Arrangement Foundations Zone A Plan • PH-ARP-XX-B2-DR-S-120810 - Demolition Basement Level 2 Zone A Plan • PH-ARP-XX-B2-DR-S-220800 - Below Ground Drainage Basement Level 2 Zone A Plan • PH-ARP-XX-B2-DR-S-220810 - General Arrangement Basement Level 2 Zone A Plan • PH-ARP-XX-ZZ-DR-S-150001 - Demolition Building Section Basement Sheet 1 • PH-ARP-XX-ZZ-DR-S-150002 - Demolition Building Section Basement Sheet 2


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• PH-ARP-XX-ZZ-DR-S-150003 - Demolition Building Section Basement Sheet 3 • PH-ARP-XX-ZZ-DR-S-620100 - Basement Details Below Ground Drainage Sheet 1 • PH-ARP-XX-ZZ-DR-S-620101 - Basement Details Zone A Sheet 1 • PH-ARP- XXX-ZZZ-DR-S-620111 – Basement Details Zone A Sheet 1 • PH-ARP- XXX-ZZZ-DR-S-620112 – Basement Details Zone A Sheet 2 • PH-ARP- XXX-ZZZ-DR-S-620113 – Basement Details Zone A Sheet 3 • PH-ARP- XXX-ZZZ-DR-S-620114 – Basement Details Zone A Sheet 4 • PH- ARP- XXX-ZZZ-DR-S-620150 – Basement Details Zone B Sheet 1 • PH-ARP- XXX-100-DR-S-625002 - Ground Floor Details Sheet 2 • PH-ARP- XXX-ZZZ-DR-S-220901-Below Ground Drainage Basement Level 2

Temporary Works

• See 11.3 Appendix C – Bressenden Place Temporary Works o PH-SCL-SC-099-Y-28004-S0-P01 Rev 01 (Design Report) o PH-SCL-DR-ZZZ-S-28001 (Basement Propping & Jacks General Arrangement) o PH-SCL-CE-099-Y-28004-S0-P01 (Design Check Certificate)

• See 11.4 Appendix D – Steel Frame for Column Removal and Existing Column Removal Steel Frame Support GA & Details

o PH-SCL-SC-ZZZ-Y-26001-S0-P01 o PH-SCL-DR-099-Y-26001-P01

• Refer to North side GF Slab Capacity Assessment PH-SCL-SC-100-Y-14001-S0-P01

Services

• Services to be isolated and certificated by Erith’s M&E contractor before starting works. Certificates to be available in the site files. A cut end will be left on redundant services. All works to start from a cut end.

• Any Live services to be demarked & protected on site. • Temporary Site Supplies / Transformers distributed for use on site. • No live gas pipes through works area. • HV electric in contiguous piled wall. All other electric to be isolated back to Portland House

switch rooms. • Four water services through demolition area to be isolated at boundary and re-routed to suit

demolition and construction sequence.

Asbestos

• All asbestos to be removed from areas prior to works starting. • All Operatives involved with the removal works will hold current asbestos awareness training

and in the event of any suspect ACM’s being encountered works will cease


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2 ACCESS / EGRESS ARRANGEMENTS

Site Access

• Site Operatives to gain access via Security Control Pedestrian Entrance off Cardinal Walk

Workface Access

• Once logged at security persons must attend site induction before commencing work. • All persons must immediately access site and remain within the site boundary. • No persons are to loiter outside the pedestrian entrance at any time. • No persons are to wear site PPE outside the site boundary unless for work activities and

instructed by ECL Supervisor.

Welfare Arrangements

• Site Facilities are located within Level 3 as detailed on site plans • Identified at time of induction


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Traffic Movements

All vehicles must be booked in at least 48hrs in advance.

Vehicle Movements via Vehicle Gate A & B off Bressenden Place

All vehicles attending site must be done so in accordance with agreed Construction Logistics Plan.

All vehicle movements within the site boundary to be directed by ECL banksman at all times.


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3 RESOURCES Plant & Machinery

• 1 x 13T excavator • 1 x 13T Tunnelling Excavator • 2 x 5T excavator • 3T Skid steer • 1 x Cherry picker • 1 x MP4000 piling rig • 1 x Telehandler • 1 x 8T crawler crane • Concrete line pump

Vehicles

• Delivery vehicles • Concrete Mixers • Tipper Lorries • Mobile Crane (Contract Lift)

Tools & Equipment

• Burning gear • Podium/ Alloy Towers • Hand tools • 4-wheel bogies • Cordless Impact Driver • Cordless Drill • Reciprocating Saw • 110v Handheld breakers • Mag drill • Jet wash • Floor Saw • Diamond Core drill • Welding plant • Genie lift

Materials

• Oxygen • Propane • Correx sheeting • Timber • Fixings • KD6 trench sheets • Cut and bent rebar • Prefabricated piling rebar cages • Concrete • Hydraulic Flat Jacks


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Safety Resources

• UXO Bomb Ordnance Desk Top Study • Task Lighting (as required) • Safety Barriers • Signage • Scaff Tags (where mobile scaffold / podium towers utilised) • PAT Test / Inspection for all electrical equipment • COSHH Register & Product Safety Data Sheets • Refer to ECL Emergency Response Plans

COSHH Overview

The following details the appointed COSHH Coordinator for the project / specific site activities:

The appointed persons will be responsible for managing and controlling all COSHH on site.

Activity Supervisor Name Contact Details Dated appointed ECL Contract Works G. Whittington 07384 114099 04/05/2020

A project COSHH Register will be maintained on site along with copies of all appropriate product safety sheets for works being undertaken.

COSHH Safety Data Information located in the following location:

ECL Site Office

COVID-19 Prevention Measures

• Wash hands on arrival, prior to entering welfare cabins, before and after breaks & as often as possible throughout the day.

• Provide hand sanitiser where hand washing facilities are unavailable (i.e., out on site, entrances and exits)

• Always maintain minimum of two-meters distance between each other • Stagger breaks to minimise close contact between staff • When storing, space out PPE and clothing as much as possible • Do not shake hands • Non-essential physical work that requires close contact between workers should not

be carried out. • Work requiring skin to skin contact should not be carried out. • Stairs should be used in preference to lifts or hoists. • Where lifts or hoists must be used:

o Maximum of 2 people in a lift at any one time o Regularly clean touchpoints, doors, buttons etc.

• Ensure that relevant signage and posters are displayed where required, including how operatives can prevent the spread and how to undertake a good level of personal hygiene when washing hands

• As much as possible, keep teams of workers together (cohorting), and keep teams as small as possible.


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4 METHODOLOGY The following details the sequence and method of work to be adopted to complete the designated activity, the information detailed below should be briefed out to ALL PERSONS involved within the activity to ensure they understand their roles and the controls to be adopted:

Sequence

1. Baseline Structural monitoring undertaken 3 months prior to commencement of piling activities in accordance with ARUP monitoring specification.

2. Demolish Gym Pods structures for access to Basement Level 3. Saw cut and break out obstructions at each of the pile locations. 4. Install temporary works to release column structures below slab in accordance with

construction sequence. 5. Lower Reduced Headroom Piling Rig through Gym voids using Mobile Crane (Contract Lift) 6. Installation of design piles in accordance with construction sequence. 7. Installation of plunge columns to piles to nearside retaining wall. 8. Installation of Groundforce KD6 trench sheets alongside retaining wall for later pile cap

construction. 9. Install steelwork to support retaining wall and apply jack loads in accordance with design. 10. Progressive demolition of GF structures for release of remaining piles. 11. Completion of Piles and progressive construction of pile caps. 12. Installation of trench sheets and excavation to pile cap formation 13. Ongoing monitoring and management of water via onsite settlement tanks & treatment. 14. Construction of pile caps in sequence with basement temporary works sequence.

Method of Work

4.2.1 Structural Movement Monitoring

Prior to commencement of activities considered to present risk of movement to nearby structures 3 months baseline monitoring will be undertaken to monitor and assess any existing movements over a period of time.

The initial point of interest is considered to be the point at which the fist pile is installed and/or when any enabling works are undertaken to the Retaining Wall structure or adjacent supporting GF structure.

The findings of this will be assessed and inputted into the current structural movement specification. Specification.

Regular monitoring will be undertaken throughout the works in accordance with ARUP structural movement specification. Refer to 11.5 Appendix E – ARUP Structural Monitoring Specification

Monitoring will be undertaken regularly by ECL onsite Engineer and will consist of Hilti nails located externally to the basement and 3d Prisms / Targets located in the basement wall structure.

Records will be retained in a report for issue and available for view by 3rd parties on a central server.

Where any trigger levels are exceeded then ECL will proceed as per agreed Monitoring Action Plan.


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Indicative locations as follows:

4.2.2 Site Logistics

During piling & basement temporary works activities the site will be fully secured at the boundary in accordance with ECL logistics plans.

All plant & vehicle movements will enter off Bressenden Place and pull within the boundary of the site.

General site logistics and ongoing works at the at the start of works when the GF remains ins tact will align with the following:


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4.2.3 Palace Street Loading Bay Access

Small plant and equipment will access the basement area from the rear loading bay off Palace Street. Access will be coordinated alongside other ongoing activities.

4.2.4 GF Slab Assessment for Load Capacities

The existing GF structure has been assessed for load capacities of Plant & equipment intended to transit throughout various stages of the works.

At no time will chosen plant and machinery exceed the allowable loads as specified with Swanton Slab Capacity assessments.

Load restrictions will be controlled using permits to load with any restrictions included within.

Any load restrictions will be briefed to all persons and will be clearly demarked on site.

Where it is foreseen that any loads may need to be exceeded then this will only be undertaken with prior assessment / modelling by Swanton and/or additional temporary works installation to support the slab structure.

Any modifications will be included within the Temporary Works Register and controlled using permit systems.


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Extract of GF structure modelling from SCL Report PH-SCL-SC-100-Y-14001-S0-P01 :

4.2.5 Dust Control

During demolition there will be a requirement for break out of concrete

All operatives will be provided with and instructed to wear minimum FFP3 dust masks with current face fit mask being used.

Where dust is produced then this will be controlled with the use of high pressure jetters to emit a fine mist only.

4.2.6 Gym Pod Demolition & Basement Access from GF Slab

Larger Plant and equipment during piling enabling & subsequent piling / Temporary works activities will be distributed from the retained GF slab through new voids created at the location of the gym pods.

Demolition of the gym pods will be formed in accordance with separate approved methodology but will consist of careful dismantling of the glass & steel structure down to Basement level ensuring to retain the surrounding GF beam structures as outlines following:


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• Exclusion zones will be formed in the basement around the base of the gym pods using Heras fencing panels.

• A Marshall will be in position at basement level in contact via 2-way radios during demolition.

• An operative will be positioned adjacent to the excavator at ground floor level with hose to wet down dust at source.

• A permit to demolish will be obtained from Erith site management. • A 13T excavator at ground level will demolish the gym pod down to ground level using

muncher attachment and load arisings into a 40yd bin sited next to it. • A burner working will be in attendance to cut through steelwork as required under an Erith

hot works permit system obtained from site management. • The burner will use a cherry picker as a working platform for working at height and/or a

harness clipped onto the excavator attachment for when working around the leading edge. • Edge protection will be installed around the gym pod before the excavator will demolish it

through to basement level. The 13T excavator will demolish the gym pod through to basement level to the required cut lines shown in red on the above.

• After the 13T has demolished what it can reach, a 3T excavator working from basement level assisted by a burner will process the debris and finish demolishing the structure down to basement level.

• All stairs & steelwork will be cut flush with the basement slab using the burning gear. • All demolition arisings will be lifted out onto Bressenden Place using the 13T excavator and

loaded into skips or waiting tipper lorries.


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4.2.7 Basement Access & Mobile Cranes

With the Gym Pods demolished this will provide opportunity for larger plant and machinery to be lifted through the voids to the basement area.

Any large plant & machinery required to be lowered to the basement will be done so with the use of mobile crane.

This will be undertaken by specialist cranage contract under a contract lift.

Prior to any mobile cranes attending site the GF slab will be assessed and any necessary temporary works installed in accordance with approved design prior to commencing.

Throughout the Enabling & Pile Installation including Temporary works ECL will also site an 8T crawler crane on site that will assist in movement of materials and equipment at ground level and down to the basement.

Progressive clearance of arisings will be undertaken on the same manner.

4.2.8 Pile Enabling Works

All piles are to be installed in accordance with approved pile design layout.

The existing basement slab & GF structure restrict piles from being installed so various pile enabling works are to be undertaken prior to arrival of the piling rig.

Where no clashes exist then sections of the basement slab will be saw cut and broken out to expose the ground below.

Where existing GF beams, columns & footings clash then these will be overcome by a combination of temporary works installations and sequenced demolition in accordance with design sequence.


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4.2.8.1 Ventilation & Protection against Fume Exhausts During use of plant and equipment within the restricted working area additional controls will be applied to ensure that the risk of expelled fumes and stagnant air movement is avoided

The works have been reviewed by specialist in air movement and ventilation. The necessary specification and controls have been determined based on the proposed plant & machinery and the volume of area to be ventilated.

ECL will protect against the risk of expelled fumes where plant and machinery is active by the following means:

4.2.8.1.1 USE OF CENTRIFUGAL FANS (FORCED VENTILATION)

Centrifugal fans will be positioned in accordance with Ventilation Specialists recommendations.

The Centrifugal Fan units will be sited in agreed locations on the upper GF slab levels.

Ducting outlets will be directed down voids within the structure

The outlets of the ducting will be relocated as required to ensure that fresh air is forced within the working area and any fumes directed away from plant activities and towards the central mole hole areas to be expelled.

During operation the specified ventilation system will ensure that any build-up of fumes is maintained within acceptable levels.

As an additional control measure the ventilation equipment will be operated in advance of any shift commencing. This will be detailed within the pre-start checks and such that the ventilation is run for an agreed period determined by an agreed number of air turnovers prior.

Similarly, the use of the ventilation equipment will be maintained for a period time after the shift finishes to provide further opportunities for fresh air to be provided to the works area. This will be

All checks will be recorded by ECL appointed persons, both pre -start and post completion.

4.2.8.1.2 USE OF EXHAUST PARTICULATE FILTERS:

Intended for use in basement excavations Exhaust Particulate filters will be fitted to the exhaust outlet of plant and machinery to ensure that particulates are removed before being expelled to the working area.

Exhaust filters will be secured in accordance with manufacturer’s instructions. Units will be monitored and serviced in accordance with the guidelines.

Periodic checks and maintenance of the filters will be undertaken as considered necessary.

NOTE: The system is such that it cannot fail to capture any particulates emitted. Instead the filters will become clogged and instead cause the machine to lose power further indicating the need for replacement of filters.

Spares will be stored on site for replacement if any urgent filters exchanges may be required.


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4.2.8.1.3 USE OF GAS MONITORS:

Gas Monitors with a loud emitting audible alarm and flashing beacons will be sited within the working area in agreed locations and such that present the highest risk of trapped gases or lack of air circulation.

The forced ventilation provided will ensure continual circulation of the air within the basement.

Any spots of gas build up will be forced to pass via the receptor fans ensuring continued measure of air quality.

This will indicate a breach of the agreed safe levels triggering the emergency preparedness & response plan to be triggered.

Upon detecting any high-risk levels of gases then the alarm will sound, and beacon operated to warn operatives who will be prompted to clear the area in accordance with approved emergency preparedness and response plan.

The system runs on a re-chargeable battery-operated system. If any batteries may run low, then further alarms will sound indicating replacement of the batteries or triggering the emergency prepared ness & response plan.

As detailed within the pre-start checks and once the ventilation has been allowed to run prior the appointed person will enter the Restricted working area where the equipment will be used to identify and record levels throughout.

Once the area has been confirmed as clear the units will be sited at the designated locations where they will run throughout the shift.

At the end of each shift the monitoring equipment will be removed from position and any batteries charged as required.

Records of checks will be recorded each day.

Gas Range Typical Alarms

Flammable gas 0-100 LEL 20% LEL

Oxygen (O2) 0-25% 19% & 23%

Hydrogen sulphide (H2S) 0-50 ppm 10 ppm

Carbon monoxide (CO) 0-500 ppm 35 ppm

https://www.altitudesafety.co.uk/wp-content/uploads/cm/d/e/detective_1.jpg


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4.2.8.1.4 RE-FUELLING & STORAGE OF FUELS / OILS

Main Fuel / oil Storage Location to be sited at GF Level within designated location suitable for refuelling by tanker as required.

Double bunded bowser to be used and secured when not in use.

Bunds to be provided capable of storing minimum 110% volume. No double stacking of fuel containers which may risk limits being exceeded should damage occur.

Drip trays/plant nappies shall be used to prevent & reduce the environmental impact of spills.

Spill kits shall be situated at refuelling / storage areas & at convenient points throughout site.

A Separate ‘satellite’ fuel storage area will be located at low level excavation area near to the restricted works area with suitable provisions for the intended shift.

As required machine operatives will manoeuvre to the fuel filling area and refuel in designated area only.

If fuels require transportation from the container to the plant or equipment the route should be suitable and enough to avoid trips and subsequent spillage.

All storage containers should be purposed / suitable for storage/transport of fuels.

Any fuel / oils not required for general use during the shift to be removed and stored at main fuel storage area; Empty fuel containers shall be removed and stored within COSHH store or disposed of as required.


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4.2.9 Saw Cut and Break Out Pile Locations

• Engineer will mark out the positions of basement slab cut outs as shown above. A 1.3m x 1.3m square will be marked out around individual pile locations to show the cut lines.

• The line of piles adjacent to the retaining wall will be broken out to the extent of the new pile cap to enable trench sheet installation in accordance with design sequence.

• The area will be CAT scanned prior to working starting and a permit to dig obtained from Erith site management.

• A 100mm core hole will be drilled in each of the 4 corners using a diamond core drill. • A diamond tipped floor saw will be used to cut through the slab from corner to corner. • Wastewater will be cleaned up using a wet vac or puddle pump and deposited into a

settlement tank. • A 5T excavator will break and dig out the concrete slab.

• Dust will be wet down at source by an operative positioned nearby with water hose. • Road plates will be used as temporary hole coverings until backfilled. • The excavator will then dig the pile locations to ensure no ground obstructions. The

excavator will break and dig out any obstructions as they are found. • All arisings will be transported to the gym pod area by the skid steer loader. The arisings will

be brought up to ground using the 13T excavator and loaded into waiting tipper lorries. • The holes will be backfilled upon completion with 6F2 material.


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4.2.10 Temporary Steel Support Install & Column Release

As identified on the plans there are a number of existing columns which clash with the installation of piles in current design positions. To allow for these columns to be removed and provide subsequent access new steel supports will be installed to take the load.

All works will be completed in accordance with separate approved safe system of work.

• Temporary steelwork goalposts in red on the above will be installed to enable the demolition of the 3nr columns.

• All steelwork will be delivered via Bressenden Place site entrance. All steelwork will be fabricated off site and lifted down to the basement using the 8T crawler crane.

• The engineer will mark out the position of the columns. • Once marked the bolt holes will be drilled and cleaned out. • The columns will be lifted and positioned using the 13T excavator. It will hold it in position

while it is fixed using 4nr 24mm bolts.

• The SHS will be lifted into position and bolts fixed as per the below.


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• The beam will be lifted and held in position using excavator / genie hoist while it is fixed as per the below.

• The L plates will then be fixed to the beams as per the below.

• Erith’s temporary works co-ordinator will inspect and sign off after finished with a permit to load issued.

• A permit to demolish will be issued by Erith site management for the 3 nr columns. • The 5T excavator will break out the columns. • Arisings will be transported to the gym pods for removal from site by the skid steer.


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4.2.11 Concrete Cutting to Retaining Wall Toe

There are a number of pile locations in close proximity to the toe of the retaining wall that needs to be cutting back for pile installation and early installation of trench sheets for formation of pile caps during later works.

The positions will be demarked by Site Engineer and the toe sections stitched drilled using s core drill rig. Cores will be extracted, and the concrete section removed using excavator.


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4.2.12 Installation of Groundforce KD6 Trench Sheets

To assist with retention of the ground beneath the retaining wall and allow for the pile cap construction sequence to progress during later works it is necessary to install trench sheets alongside the retaining wall toe in accordance with design sequence.

Trench sheets can either be installed before or after pile & lower plunge column installation.

However, trench sheets must be installed prior to connecting the upper prop and truss sections to avoid restricted access.

To assist with the placement of trench sheets within the reduced headroom the ground direct adjacent to the install position can be battered back down to 1.0m depth in the trench sheet position only.

The trench sheets will be driven into the ground with the use of a rotating side grip pile driver.

Where required a tunnelling excavator designed for working in reduced headroom conditions whilst still maintaining optimum power will be used.

The excavation will be backfilled to level and the trench sheet installed to line and level with the engineer checking it throughout installation.


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4.2.13 Reduced Headroom Piling (Martello MP 4000 Rig)

All reduced headroom piling will be undertaken by specialist contractor Martello using the MP 4000 Rig.

Piling activities will be undertaken in accordance with separate approved Method Statement & Inspection & Test Plan.

Refer to 11.6 Appendix F – Martello Piling Method Statement & ITP

Martello MP 4000 Rig


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4.2.13.1 Setting Out / Verification of Setting Out Due to the criticality of the pile positions, independent checks will be carried out on all setting out. A detailed inspection plan will be submitted for approval prior to commencement on site.

During the pile installation process, there will be several hold points, particularly during casing installation and drilling of the pile. These hold point will be detailed in the piling Inspection and Test Plan (ITP). Certain hold points will require approval prior to moving to the next stage of construction. These will include but not be limited to; overall casing length, casing verticality, as dug pile depth and casting levels.

4.2.13.2 Reduced Headroom Piling Set-up The MP 4000 Rig along with Excavator & telehandler will be lowered within the basement using mobile crane under a contract lift.

The GF slab will be assessed for load and necessary temporary works installed prior to access on site.

Once within the basement area the piling activities will be serviced from above at GF slab level.

All materials & equipment will be lowered through the voids and concrete pours will be undertaken using pumps sited adjacent to the gym pod voids.

The position will alternate between North & South dependent on the sequence of works below.


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Piling will commence with available piles in accordance with piling method statement & Swanton basement temporary works design sequence.

The rig will manoeuvre within the basement avoiding columns and low beams as required.


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Piles will be bored, and casing inserted to the required depth. Additional section will be joined and connected with casing plugs. All soils will be cleared by attending excavator and progressively cleared from the area.

MP4000 Rig Pile Bore on ECL Project

4.2.13.3 Removal of Soils & Testing ECL appointed persons to be in attendance to observe soils being cleared to check for any contaminations which may be present.

For referencing the site will split in accordance with existing grid reference points.

Soil sampling will be progressively undertaken in accordance with licensed disposal location requirements, ensuring soil grades remain compliant.

All records of soil analysis are to be retained on file. They are to be issued monthly along with copies of waste consignment notes for materials removed from site.


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Where any suspect contamination is encountered then works will cease in this area and instructions sought from ECL Supervisor.

Samples will be taken for review and where necessary a separate safe system of work will be provided for approval. This will be specific to any contaminants encountered detailing any additional controls / quarantine methods for removal from site.


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4.2.13.4 Cage Installation Cages will be inserted in pre-determined sections and trapped off at the top of the casing once fully inserted.

Additional sections will be spliced together using bulldog clips or similar and lowered within the borehole.


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The process will be repeated until at the required depth.

Where opportunities arise and there are existing voids within the GF slab our no clash with significant structure / beams then the opportunity for placement of longer casings may be possible with the use of the crawler crane from above.


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Once the reinforcement cage is secured in place then concrete will e introduced to the bore using pumped concrete and the use of a tremie as required. Upon completion the pile will be prepared for installation of plunge column where required. Where no plunge column is to be installed then the concrete will be allowed to cure for minimum 24 hours before removing any casings.