shoring manual for shallow excavations groundforce

Contents Introduction Selection Flowcharts

Flowchart 1 Two Frame, Nominal toe-in Flowchart 2 Propped Cantilever Flowchart 3 Vertishore

Soil Description Chart Design Check Certificate Standard Designs (Two Frames, Nominal toe-in)

2.0m Deep Cohesive 2.0m Deep Granular 2.5m Deep Cohesive 2.5m Deep Granular 3.0m Deep Cohesive 3.0m Deep Granular

Standard Designs (One Frame, Propped Cantilever)

1.5m Deep Cohesive 1.5m Deep Granular 2.0m Deep Cohesive 2.0m Deep Granular 2.5m Deep Cohesive

Equipment Drawings

Manhole Brace Frames Walers

Standard Design Documentation

Design Request Form General Method Statement Risk Assessment Checklist Box Design Statement

Technical Literature Operator User Guides

Shoring Manual for Shallow Excavations

Introduction

This manual is intended to enable a competent person to specify the shoring requirements for relatively small, shallow, trenches or manhole type excavations up to 3m maximum depth in reasonable ground conditions without producing a scheme specific design. The flowchart shown on the next page is a guide to enable the contractor to assess whether the generic designs enclosed in this document are sufficient or if a scheme specific design will be required. Calculations

The designs contained in this document have been carried out using Groundforce Shorcos specialist temporary works design software, GFsafe. The designs have been based on a set of basic assumptions which the contractor or user must assess have been met. If any parameter exceeds the assumptions stated below then the contractor should obtain an excavation specific design. The calculations have been carried out in accordance with the following authoritative documents:

Piling Handbook. CIRIA Special Publication 95: The Design & Construction of Sheet-Piled Cofferdams. CIRIA Report 97: Trenching Practice.

Design Assumptions

The designs have been based on the following basic assumptions. If any or these are not met, the contractor should seek a scheme specific design.

These standard designs are only valid when used in conjunction with Groundforce Shorco equipment.

The excavation is less than 3m deep If the ground is mainly Cohesive it should be a reasonably firm, (see page 4 for guidance). If the ground is mainly Granular it should be reasonably compacted, (see page 4 for

guidance). The excavation is not located within the vicinity of sloping ground e.g. an embankment

i.e. the ground must be reasonably flat. No abnormal surcharges exist or are likely to exist within close proximity to the

excavation. No ground water is present. Excavations are short term i.e. less than four week duration.

Notes

1. The use of this manual does not remove the responsibility from the contractor in providing a safe excavation and place of work under the CDM 2007 regulations.

2. A site specific risk assessment must be carried out prior to commencing work. 3. The correct use and application of this document is entirely the responsibility of the user. 4. If in doubt contact Groundforce Shorco on 0800 000345

Temporary Works Design Appendix B Internal Checking Certificate: INTERNAL CHECK: Category 1 (see design procedure for explanation) This design has been prepared by the Groundforce Shorco (GFS) technical department in accordance with their documented design procedure (a copy of which is available on request). Great professional skill and care has been taken to provide a safe and workable solution in accordance with the principles set out in BS 5975:2008 section 9. and the Construction (Design and Management) Regulations 2007 as far as is reasonably possible.

The shoring temporary works schemes is described by the documents referenced below

o Shoring Manual for Shallow Excavations covering the following designs: o CO-EX-2, GR-EX-2, CO-EX-2.5, GR-EX-2.5, CO-EX-3, GR-EX-3,

CO-EX-1.5-PC, GR-EX-1.5-PC, CO-EX-2-PC, GR-EX-2-PC, CO-EX-2.5-PC I certify that reasonable professional skill and care has been used in the design of the Temporary Works schemes identified and described by the above referenced drawings and other documents: Signed: Name: Duncan Pearson

Date: January 2011

Title/Position: Design Manager I certify that reasonable professional skill and care has been used in the checking to Category 1 of the Temporary Works schemes identified and described by the above referenced drawings and other documents and that the design is fit for purpose. In addition I certify that the Engineer who completed the above designs is competent to carry out their duties and that they have exercised reasonable professional skill, care and diligence under CDM 2007. Signed: Name: Tony Gould

Date: January 2011

Title/Position: Technical Director

Depth 2.00m

0 m

1 m

2 m

20 kN/m

COHESIVE GROUND (Minimum Soft to Firm)


0.4m -1.7kN/m-GROUNDFORCE GROUNDFORCE Frame/Waler

1.2m 11.7kN/m-GROUNDFORCE GROUNDFORCE Frame/Waler

Key:-Nett Pressure (Max) 10.0kN/mBending Moment (Max) -2.8kNm/m

Design Model Bsc Piling No Earth Support - Rigid Calculated on no earth support Design at Construction Stage

Depth of Dig

Groundforce Software Licensed to:

Title :2.0m Cohesive

Contract :Various Contractor:-

Designer :Groundforce Reference:CO-EX-2 Date:23/07/2010 Construction Stage Rev: -

GFsafe Version 1.3.6 Copyright VP plc 2003

Issued for Construction.

Support Information Frame 1 Type: GROUNDFORCE Frame/Waler Level: 0.40 m WLL: Varies Load: -1.7 kN/m Frame 2 Type: GROUNDFORCE Frame/Waler Level: 1.20 m WLL: Varies Load: 11.7 kN/m

Sheet Pile Definition 8.5kNm/m > 2.8kNm/m(Bending Capacity is Adequate)

Sheet Type: Groundforce Std. SD33 Allowable Moment = 8.5 kNm/m Moment of Inertia = 81.4 cm /m

Youngs Modulus (E) = 210.0 kN/mm Allowable Stress = 186.0 kN/mm Section Modulus = 48.4 cm/m

Pressure Model: BSC Piling Load Model: Rigid sheet about lower frame

Support Type: No Earth Support






SUMMARYINPUT

Excavation Depth 2.0 mSurcharge 20.0 kN/mActive Water Depth 10.0 mPassive Water Depth 10.0 mWater Density 9.81 kN/mMin Fluid Density 5.0 kN/m

SOIL PROFILE y(kN/m) y'(kN/m) C(kN/m) () Ka Kp Kac Kpc delta Depth (m) Soil Name

0.0 COHESIVE GROUND (Minimum Soft to Firm)

18.60 8.80 30.00 0.00 1.00 1.00 2.00 2.00 0.00

SOLUTION

DESIGN SOLUTIONSupport Type No Earth SupportPressure Model BSC Piling methodPassive Softening N/AWater Balancing N/A

SHEET Z cm/m I cm /m Allowable Stress N/mm Allowable Moment kNm/mSheet Type

Groundforce Std. SD33 48.40 81.40 186.00 8.50

DESIGN FORCES Maximum DepthSoil Pressure 10.0 kN/m 2.0 mCurrent Bending Moment -2.77 kNm/m 1.2 mMaximum Bending Moment 2.77 kNm/m 1.2 mShear Force 6.4 kN 1.2 m

Current Support DetailsDepth m Load kN/m GROUNDFORCE Equipment 0.4 -1.7 GROUNDFORCE Frame/Waler 1.2 11.7 GROUNDFORCE Frame/Waler

Maximum Support Loads Depth (m) Load (kN/m) GROUNDFORCE Equipment 0.4 0.0 GROUNDFORCE Frame/Waler 1.2 11.7 GROUNDFORCE Frame/Waler

2.0m Deep Excavation Cohesive Ground

Summary: Maximum Sheet Bending Moment = 2.8kNm/m Maximum Frame Load = 11.7kN/m Suitable Sheets: Groundforce Std SD33 Trench Sheets (330mm wide, 3.4mm thick) Capacity = 8.5kNm/m Length = 2.0m + required up-stand (up-stand assessed by contractor) Suitable Frames: a) 2.0m to 3.0m Four sided excavation, use: Groundforce Double Acting Manhole Brace Leg A (WLL = 65.0kN/m) [GF-DA-A] b) 3.0m Long Trench (two sided support), use: Groundforce 3.0m Aluminium Waler (WLL = 18.7kN/m) [GF-AL-3] c) 4.0m Long Trench (two sided support), use: Groundforce 3.9m HD Steel Waler (WLL = 40.4kN/m) [GF-HD-4] d) 5.0m Long Trench (two sided support), use either: Groundforce 5.0m Aluminium Waler (WLL = 28.5kN/m) [GF-AL-5] Groundforce 5.0m Standard Steel Waler (WLL = 18.0kN/m) [GF-STD-5] Groundforce 5.0m HD Steel Waler (WLL = 28.0kN/m) [GF-HD-5] Groundforce 5.0m Super HD Steel Waler (WLL = 53.6kN/m) [GF-SHD-5]

Depth 2.00m

0 m

1 m

2 m

20 kN/m

MADE GROUND - Granular (Well compacted)




Toe 0.5m



Depth of Dig


Title :2.0m Granular


Designer :Groundforce Reference:GR-EX-2 Date:23/07/2010 Construction Stage Rev: -









GroundforceSoftware Licensed to:.


Contract :VariousContractor:-

Designer :GroundforceReference:GR-EX-2Date:23/07/2010Construction Stage Rev: -

GFsafe Version 1.3.6Copyright VP plc 2003

SUMMARYINPUT


SOIL PROFILEy(kN/m) y'(kN/m) C(kN/m) () Ka Kp Kac Kpc deltaDepth (m) Soil Name

0.0 MADE GROUND - Granular (Well compacted)

18.30 10.30 0.00 32.00 0.31 3.25 0.00 0.00 0.00

SOLUTION

DESIGN SOLUTIONSupport Type No Earth Support Toe = 0.5 mPressure Model BSC Piling methodPassive Softening AppliedWater Balancing Not Applied

SHEETZ cm/m I cm /m Allowable Stress N/mm Allowable Moment kNm/mSheet Type



Current Support DetailsDepth m Load kN/m GROUNDFORCE Equipment0.4 -0.8 GROUNDFORCE Frame/Waler1.2 26.6 GROUNDFORCE Frame/Waler

Maximum Support LoadsDepth (m) Load (kN/m) GROUNDFORCE Equipment0.4 0.0 GROUNDFORCE Frame/Waler1.2 26.6 GROUNDFORCE Frame/Waler

2.0m Deep Excavation Granular Ground

Summary: Maximum Sheet Bending Moment = 6.7kNm/m Maximum Frame Load = 26.6kN/m Suitable Sheets: Groundforce Std SD33 Trench Sheets (330mm wide, 3.4mm thick) Capacity = 8.5kNm/m Length = 2.5m + required up-stand (up-stand assessed by contractor) Suitable Frames: a) 2.0m to 3.0m Four sided excavation, use: Groundforce Double Acting Manhole Brace Leg A (WLL = 65.0kN/m) [GF-DA-A] b) 3.0m Long Trench (two sided support) No walers suitable c) 4.0m Long Trench (two sided support), use: Groundforce 3.9m HD Steel Waler (WLL = 40.4kN/m) [GF-HD-4] d) 5.0m Long Trench (two sided support), use either: Groundforce 5.0m Aluminium Waler (WLL = 28.5kN/m) [GF-AL-5] Groundforce 5.0m HD Steel Waler (WLL = 28.0kN/m) [GF-HD-5] Groundforce 5.0m Super HD Steel Waler (WLL = 53.6kN/m) [GF-SHD-5]

Depth 2.50m

0 m

1 m

2 m

20 kN/m







Depth of Dig




Designer :Groundforce Reference:CO-EX-2.5 Date:23/07/2010 Construction Stage Rev: -












Designer :GroundforceReference:CO-EX-2.5Date:23/07/2010Construction Stage Rev: -


SUMMARYINPUT




18.60 8.80 30.00 0.00 1.00 1.00 2.00 2.00 0.00

SOLUTION





Current Support DetailsDepth m Load kN/m GROUNDFORCE Equipment0.6 -1.0 GROUNDFORCE Frame/Waler 1.6 16.7 GROUNDFORCE Frame/Waler

Maximum Support LoadsDepth (m) Load (kN/m) GROUNDFORCE Equipment0.6 0.0 GROUNDFORCE Frame/Waler 1.6 16.7 GROUNDFORCE Frame/Waler

Depth 2.50m

0 m

1 m

2 m

3 m

20 kN/m





Toe 0.8m



Depth of Dig




Designer :Groundforce Reference:GR-EX-2.5 Date:23/07/2010 Construction Stage Rev: -



Support Information Frame 1 Type: GROUNDFORCE Frame/Waler Level: 0.60 m WLL: Varies Load: 7.7 kN/m Frame 2 Type: GROUNDFORCE Frame/Waler Level: 1.60 m WLL: Varies Load: 24.6 kN/m









Designer :GroundforceReference:GR-EX-2.5Date:23/07/2010Construction Stage Rev: -


SUMMARYINPUT




18.30 10.30 0.00 32.00 0.31 3.25 0.00 0.00 0.00

SOLUTION





Current Support DetailsDepth m Load kN/m GROUNDFORCE Equipment0.6 7.7 GROUNDFORCE Frame/Waler1.6 24.6 GROUNDFORCE Frame/Waler


Depth 3.00m

0 m

1 m

2 m

3 m

20 kN/m







Depth of Dig
















Designer :GroundforceReference:CO-EX-3Date:23/07/2010Construction Stage Rev: -


SUMMARYINPUT




18.60 8.80 30.00 0.00 1.00 1.00 2.00 2.00 0.00

SOLUTION






Maximum Support LoadsDepth (m) Load (kN/m) GROUNDFORCE Equipment0.8 0.0 GROUNDFORCE Frame/Waler 2.0 22.5 GROUNDFORCE Frame/Waler

Depth 3.00m

0 m

1 m

2 m

3 m

4 m

20 kN/m





Toe 1.0m

Key:-Nett Pressure (Max) 23.2kN/mBending Moment (Max) 6.7kNm/m


Depth of Dig




Designer :Groundforce Reference:GR-EX-3 Date:23/07/2010 Construction Stage Rev: -












Designer :GroundforceReference:GR-EX-3Date:23/07/2010Construction Stage Rev: -


SUMMARYINPUT




18.30 10.30 0.00 32.00 0.31 3.25 0.00 0.00 0.00

SOLUTION




DESIGN FORCES Maximum DepthSoil Pressure 23.22 kN/m 3.0 mCurrent Bending Moment 6.68 kNm/m 2.84 mMaximum Bending Moment 6.68 kNm/m 2.84 mShear Force 16.73 kN 2.0 m



Depth 1.50m

0 m

1 m

2 m

20 kN/m




Toe 0.6m


Design Model Bsc Piling Free Earth Condition Calculated Toe length based on FOS Toe:0.6 Free earth FOS:3.37 Design at Construction Stage

Depth of Dig




Designer :Groundforce Reference:CO-EX-1.5-PC Date:28/07/2010 Construction Stage Rev: -



Support Information Frame 1 Type: GROUNDFORCE Frame/Waler Level: 0.30 m WLL: Varies Load: 3.0 kN/m





Support Type: Free Earth Toe-In




Designer :GroundforceReference:CO-EX-1.5-PCDate:28/07/2010Construction Stage Rev: -


SUMMARYINPUT




18.60 8.80 30.00 0.00 1.00 1.00 2.00 2.00 0.00

SOLUTION

DESIGN SOLUTIONSupport Type Free Earth Support Toe = 0.6 mPressure Model BSC Piling methodPassive Softening AppliedWater Balancing Not Applied



DESIGN FORCES Maximum DepthSoil Pressure 7.5 kN/m 1.5 mCurrent Bending Moment 1.33 kNm/m 1.11 mMaximum Bending Moment 1.33 kNm/m 1.11 mShear Force -2.96 kN 1.6 m

Current Support DetailsDepth m Load kN/m GROUNDFORCE Equipment0.3 3.0 GROUNDFORCE Frame/Waler

Maximum Support LoadsDepth (m) Load (kN/m) GROUNDFORCE Equipment0.3 3.0 GROUNDFORCE Frame/Waler

1.5m Deep Excavation Cohesive Ground Propped Cantilever


Depth 1.50m

0 m

1 m

2 m

20 kN/m




Toe 1.0m



Depth of Dig




Designer :Groundforce Reference:GR-EX-1.5-PC Date:28/07/2010 Construction Stage Rev: -












Designer :GroundforceReference:GR-EX-1.5-PCDate:28/07/2010Construction Stage Rev: -


SUMMARYINPUT




18.30 10.30 0.00 32.00 0.31 3.25 0.00 0.00 0.00

SOLUTION







1.5m Deep Excavation Granular Ground Propped Cantilever


Depth 2.00m

0 m

1 m

2 m

20 kN/m




Toe 0.7m



Depth of Dig




Designer :Groundforce Reference:CO-EX-2-PC Date:28/07/2010 Construction Stage Rev: -












Designer :GroundforceReference:CO-EX-2-PCDate:28/07/2010Construction Stage Rev: -


SUMMARYINPUT




18.60 8.80 30.00 0.00 1.00 1.00 2.00 2.00 0.00

SOLUTION







Depth 2.00m

0 m

1 m

2 m

3 m

20 kN/m




Toe 1.1m



Depth of Dig




Designer :Groundforce Reference:GR-EX-2-PC Date:28/07/2010 Construction Stage Rev: -












Designer :GroundforceReference:GR-EX-2-PCDate:28/07/2010Construction Stage Rev: -


SUMMARYINPUT




18.30 10.30 0.00 32.00 0.31 3.25 0.00 0.00 0.00

SOLUTION







2.0m Deep Excavation Granular Ground Propped Cantilever


Depth 2.50m

0 m

1 m

2 m

3 m

20 kN/m




Toe 0.85m



Depth of Dig




Designer :Groundforce Reference:CO-EX-2.5-PC Date:28/07/2010 Construction Stage Rev: -












Designer :GroundforceReference:CO-EX-2.5-PCDate:28/07/2010Construction Stage Rev: -


SUMMARYINPUT




18.60 8.80 30.00 0.00 1.00 1.00 2.00 2.00 0.00

SOLUTION







DESIGN REQUEST FORM (V 2.0 08/09) Technical Department, Bruntcliffe Lane, Morley, Leeds, LS27 0LZ Tel. +44(0) 845 602 9963 Fax. +44(0) 113 252 6538 Email. [email protected]

Page ___ of ___

CHECKER: WEIGHTING: DESIGN REF: **GROUNDFORCE USE ONLY**

CREATOR: AREA: HANDLER:

1. GENERAL INFORMATION

CLIENT: DATE DESIGN IS REQUIRED:

1a. Please ensure that all the contact and site details are completed.

SITE: APPROXIMATE START DATE: 1b. We will generally need a minimum notice period of 48 hrs for design turnaround. NOTE: More complex designs will probably take longer to complete.

MAIN CONTRACTOR: SCHEME STATUS

Tender

NEAREST CITY / POSTCODE:

Live Scheme

SITE CONTACT DETAILS:

(NAME + FAX + TEL)

CONTACT EMAIL:

CDM CO-ORDINATOR: Name and Email

1c. This information is mandatory for us to comply with CDM 2007 requirements. Note that a CDM co-ordinator has to be appointed by the client for all notifiable projects.

T/WKS CO-ORDINATOR Name and Email:

2. EXCAVATION INFORMATION

PURPOSE of EXCAVATION:

SUPPORT SYSTEM TYPE: (Other please specify in section 7)

CLIENT SPECIFIED

FRAME LOAD(S):

MULTIPLE FRAMES:

PROPPED CANTILEVER: CANTILEVER:

2a. Please only select one of the excavation type options. Also note that all cantilever schemes or excavations > 6m deep will not be undertaken on a verbal soil description i.e. a relevant borehole to an appropriate depth is required.

(Specify in Section 7)

EXCAVATION DIMENSIONS: LENGTH: (m)

WIDTH: (m)

DEPTH: (m)

OTHER: (See Note 2b.)

2b. Please ensure that for all non- square or rectangular excavations a detailed sketch or AutoCAD drawing is supplied. Please provide a sketch in section 7. 2c. If clear opening dimensions are specified, we will make an additional allowance for deflection when specifying the overall excavation size.

SHEET TO

SHEET

CLEAR OPENING INSIDE

FRAMING

APPROX EXCAVATION DURATION: < 12 WEEKS: > 12 WEEKS:

2d. For durations > 12 weeks more onerous design parameters may apply. Refer to Technical Services for clarification.

3. SHEET & FRAME DETAILS

EQUIPMENT TYPE: (Specify preference below subject to stock location and holdings)

MOST ECONOMICAL: LIGHTEST:

3a. The options specified are to assist with ensuring we provide the most cost effective design proposal, however it must be stressed that the solution will be subject to design approval. 3b. This information is only required if limitations apply. * Specify any additional handrail requirements if applicable. ** Interlocking sheet piles only

STRUTS ALLOWED:

NO

YES

LOWER FRAME(S) ONLY

NO KNEE BRACES

CLEARANCE BELOW LOWEST

FRAME: (m)

N/A

OTHER: (Specify in section 7)

SHEET TYPE: (Specify below) MAX SHEET LENGTH: (m) N/A

MAX SHEET TOE IN: (m)

N/A

LAPPED

INTERLOCKING

SHEET UPSTAND*: (m)

N/A

NO TOE SOUTION:

CORNER PILES REQUIRED**: OTHER:

(Specify in section 7)


Page ___ of ___

4. PREFERRED METHOD OF SHEET INSTALLATION (PRE-DRIVEN WILL BE THE DEFAULT METHOD)

PRE DRIVEN:

DIG & PUSH:

SLIT TRENCH:

2 STAGE: (See note 4)

4. The 2 stage option is when the lower frame(s) is removed once a blinding slab has been cast and cured.

5. GROUND INFORMATION

INFO PROVIDED: BH OR TP REF TO BE

USED FOR THIS DESIGN:

GROUND REDUCTION / REDUCED LEVEL: (Specify or indicate below) 5a. Please ensure that ONLY the relevant

ground information is supplied. It is the contractors responsibility to provide representative ground information on which the design will be based.

BH OR TP: (Must be attached to this design request)

VERBAL: (Specify below)

GROUND DATUM LEVEL:

(m AOD)


REDUCED DATUM LEVEL:

(m AOD)

WATER LEVEL: (m BGL)

DE-WATERING METHOD:

Note the dewatering method should relate to the sheet type specified.

SOIL LAYER ID: VERBAL SOIL LAYER DESCRIPTION: DEPTH: (m)

5b. For guidance on soil properties and descriptions please a soil identification help sheet can be provided on request. 5c. Note that no design work can be carried out on verbal soil descriptions unless a valid signature is present. 5d. The contractor MUST provide confirmation of the ground conditions prior to a full temporary works design being completed.

LAYER 1:

LAYER 2:

LAYER 3:

LAYER 4:

LAYER 5:

NOTE: THE SIGNED DECLARATION IN SECTION 10 IS TAKEN AS CONFIRMATION OF VERBAL SOIL INFORMATION

6. SURCHARGE / SITE INFORMATION

PLANT SURCHARGE: 30 TONNE (10kN/m)

45 TONNE (15kN/m)

60 TONNE (20kN/m)

6a. The excavator size / type should be specified.

SPECIFIC SURCHARGE: DISTANCE FROM EXCAVATION (m)

SURCHARGE DETAILS (Please provide a sketch in section 7 if required)

6b. Please ensure that if a surcharge is present this section is completed to the fullest extent to ensure economic design.

RAILWAY: 6c. Provide specific details of building loads e.g. foundation details.

ROAD:

BUILDING:

CRANE: 6d. The cranes outrigger specifications MUST be provided to ensure an accurate surcharge is allowed for.



Page ___ of ___

7. SCHEME SPECIFIC SKETCH / ADDITIONAL INFORMATION

7. For all additional information and specific requirements not allowed for on the request form please complete in this section.

8. ANCILLARY REQUIREMENTS (FOR QUOTATION PURPOSES)

INSTALLATION KIT: LIFTING CHAIN: EXTRACTOR: 8. If this section is not completed it will be

assumed that no ancillaries are required and therefore not included on the quotation.

QRS: DRIVING CAP: OTHER: (Specify in Section 7)

9. DESIGN CHECK CERTIFICATES REQUIRED (NOTE ALL ARE CHARGEABLE) 9. This refers to a detailed check with written certification; the check being completed by another member of the dept. Note: A basic check will always be carried out as part of the design procedure.

INTERNAL: (See note 9)

FORM C: (CAT 2 or 3) EXTERNAL:

10. CUSTOMER DECLARATION (SEE NOTE 10)

IMPORTANT NOTE: A FULL DESIGN WILL NOT BE PREPARED UNLESS A VALID CUSTOMER SIGNATURE IS PROVIDED BELOW

CUSTOMER SIGNATURE: (print name underneath) POSITION: DATE:

10. This signature authorises Groundforce to prepare a temporary works design scheme and that the information contained in the brief is a true representation of site conditions. Note: charges may apply for subsequent revisions requiring lengthy re-design work.

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Temporary Works Design General Method Statement:

Title: Site: Design Reference: Revision: Designer:

To be read in conjunction with any relevant notes relating to the specific scheme within the full design submission and the contractors own site specific safety method statement. 1 General Statement 1.1 Identify the works area, safety zones & access requirements prior to commencing work

on the excavation. 1.2 Survey the works area for overhead / buried services prior to commencing work on the

excavation & take appropriate action as deemed necessary. 1.3 Enclose the total works area using suitable barriers & provide appropriate pedestrian /

vehicle barriers where necessary. 1.4 Identify a suitably qualified & competent person to inspect the works at regular

intervals and to ensure that the design parameters as stated in the design brief are not exceeded

1.5 Set out the extent of the excavations. 1.6 Ensure adequate lifting facilities are available for all stages of the support operation. 1.7 Carry out additional Risk Assessments as appropriate. Groundforce are able to supply a

generic hazard identification document on request. 1.8 All equipment is to be installed in conjunction with the specific equipment installation

instructions as supplied with the delivery documentation. 2 Support Sequence Pre-Drive Method of Installation 2.1 Pitch, plumb & align each trench sheet / pile and drive to full depth using the

appropriate piling hammer ensuring that the minimum specified toe in has been achieved below formation level.

2.2 Excavate down inside the sheets and create a level working platform at the first frame level.

2.3 Install and fully pressurise the first frame as shown on the relevant drawings supplied by Groundforce design and technical services department.

2.4 Secure each component of the first frame at the approximate positions indicated by hanging from the top of the trench sheets / piles using the primary hanging chains provided.

2.5 Excavate down through the frame(s) and create a level working platform at the next frame level.

2.6 Install and fully pressurise the next frame as shown on the relevant drawings supplied by Groundforce design and technical services department.

2.7 Hang each component of the frame at the approximate positions indicated from the frame directly above using the secondary hanging chains provided.

2.8 Repeat steps 2.5 to 2.7 until all levels of shoring are installed as detailed on the relevant drawings supplied by Groundforce technical services department.

2.9 Excavate down through the shoring frame(s) to formation level, complete the excavation by manual trimming to avoid over digging & undermining the trench sheet / pile toe in.

2.10 At the first opportunity cast a blinding layer across the full base of the excavation (preferably within the same shift) to protect the base from passive softening caused by surface / groundwater ingress.

Base / Blinding Strut. (Only Relevant If Temporary Frames Are Incorporated In Design)



2.11 Cast the base / blinding strut out to the sheets to the required thickness. 2.12 Allow the base / blinding strut to achieve the required cube strength. (Usually

10N/mm2). 2.13 Once the base / blinding strut has gained adequate strength, starting with the lowest

frame remove the temporary frames in sequence. 2.14 Construct the permanent works as per manufacturers / engineers instruction. 2.15 Backfill the excavation to the underside of each shoring frame in sequence

depressurising and removing each frame in turn. If the backfill material is concrete ensure a suitable de-bonding agent is applied to the trench sheets / piles.

2.16 Backfill to existing ground level. 2.17 Extract the trench sheets / piles. 3 Support Sequence Slit Trench Method of Installation 3.1 In small sections (say 3.000m) excavate a narrow trench to formation level. 3.2 Pitch the trench sheets / piles against the back face of the trench and backfill the

trench with the previously excavated material. 3.3 Repeat steps 3.1 & 3.2 until all the trench sheets / piles are in position around the

perimeter of the excavation. 3.4 Using the excavator & driving cap provided push / drive the trench sheets / piles down

to achieve the minimum specified toe-in. Note:- If the specified sheet toe-in cannot be achieved using the excavator bucket then use either a air driven impact hammer or machine mounted vibratory hammer to achieve the specified toe-in.

3.5 Excavate down inside the sheet and create a level working platform at the first frame level.

3.6 Install and fully pressurise the first frame as shown on the relevant drawings supplied by Groundforce technical services department.

3.7 Hang each component of the first frame at the approximate positions indicated from the top of the trench sheets / piles using the primary hanging chains provided.

3.8 Excavate down through the frame(s) and create a level working platform at the next fame level.

3.9 Install and fully pressurise the next frame as shown on the relevant drawings supplied by Groundforce technical services department.

3.10 Hang each component of the frame at the approximate positions indicated from the frame directly above using the secondary hanging chains provided.


3.12 Excavate down through the shoring frame(s) to formation level, complete the excavation by manual trimming to avoid over digging & undermining the trench sheet / pile toe-in.

3.13 At the first opportunity cast a blinding layer across the full base of the excavation (preferably within the same shift) to protect the base from passive softening caused by surface / groundwater ingress.

Base / Blinding Strut. (Only Relevant If Temporary Frames Are Incorporated In Design) 3.14 Cast the base / blinding strut out to the sheets to the required thickness. 3.15 Allow the base / blinding strut to achieve the required cube strength. (Usually

10N/mm2).



3.16 Once the base / blinding strut has gained adequate strength, starting with the lowest frame remove the temporary frames in sequence.

3.17 Construct the permanent works as per manufacturers / engineers instruction. 3.18 Backfill the excavation to the underside of each shoring frame in sequence de-

pressurising and removing each frame in turn. If the backfill material is concrete ensure a suitable de- bonding agent is applied to the trench sheets / piles.

3.19 Backfill to existing ground level. 3.20 Extract the trench sheets / piles. 4 Support Sequence Dig & Push / Drive Method of Installation 4.1 From existing ground level excavate down approximately 0.500m around the perimeter

of the excavation. 4.2 Place the first level of shoring in the excavation and extend out to the approximate size

of the excavation. 4.3 Pitch the trench sheets / piles between the frame and the face of the excavation and

push / drive down to refusal using the excavator & driving cap provided. (Note:- on deeper excavations it may prove more practical to start excavation with shorter sheets / piles to ease machine bucket access).

4.4 Pressurise the frame such that the trench sheets / piles can just be pushed down behind the frame, alternatively place wedges between the frame and the trench sheets / piles at the corners of the frame to allow the remaining central trench sheets / piles to be pushed down.

4.5 Hang the frame from the corner trench sheets using the primary hanging chains provided.

4.6 Carefully excavate down inside the frame until it is possible to install the next frame ensuring that the central trench sheets / piles are pushed down as the excavation proceeds achieving a minimum 0.5m toe-in.

4.7 Once the next frame level has been reached pressurise the frame as detailed in step 4.4.

4.8 Hang the frame from the frame directly above using the secondary hanging chains provided.


4.10 Excavate down through the shoring frame(s) to formation level, complete the excavation by manual trimming to avoid over digging & undermining the trench sheet / pile toe-in.

4.11 Ensure that the trench sheets / piles have been pushed / driven down below formation level to achieve the specified toe-in.

4.12 Now secure the first frame from the top of the central trench sheets / piles using the additional primary hanging chains provided.

4.13 Remove hanging chains and any wedges from the corner sheets and remove the remaining earth from the corners of the excavation whilst at the same time pushing down the corner trench sheets / piles.

4.14 Ensure that the corner trench sheets / piles have been pushed / driven down below formation level to achieve the specified toe-in.

4.15 Pressurise all of the shoring frames fully. 4.16 At the first opportunity cast a blinding layer across the full base of the excavation

(preferably within the same shift) to protect the base from passive softening caused by surface / groundwater ingress.

Base / Blinding Strut (Only Relevant If Temporary Frames Are Incorporated In Design)



4.17 Cast the base / blinding strut out to the sheets to the required thickness. 4.18 Allow the base / blinding strut to achieve the required cube strength. (Usually

10N/mm2). 4.19 Once the base / blinding strut has gained adequate strength, starting with the lowest

frame remove the temporary frames in sequence. 4.20 Construct the permanent works as per manufacturers / engineers instruction. 4.21 Backfill the excavation to the underside of each shoring frame in sequence de-

pressurising and removing each frame in turn. If the backfill material is concrete ensure a suitable de-bonding agent is applied to the trench sheets / piles.

4.22 Backfill to existing ground level. 4.23 Extract the trench sheets / piles.

Temporary Works Design Appendix C Generic Risk Assessment:


ACTIVITY: TEMPORARY WORKS DESIGN FOR EXCAVATION:

Risk Associated with Activity:

Precautions to be taken to reduce the risk:

Comments:

1. General stability or failure of the shoring system due to incorrect installation and/or lack of supervision and co-ordination on site.

Read and understand ALL the accompanying documentation, including installation instructions, design drawings, design notes, method statements, risk assessments and all other information supplied by Groundforce. Appoint a Temporary Works Co-ordinator (or responsible person), to supervise the whole of the works, ensuring that the final end-user (if not the co-ordinator) is fully briefed and conversant with the equipment, the method of installation and scheme layout. Note: Ancillary equipment such as Restraining Chains are provided to safeguard against accidental system failure. These must be used at ALL times and in accordance with the design and installation instructions.

Ensure full and correct receipt of all supporting information. Additional copies of any documents can be supplied upon request. Responsibilities should include: - Checking the temporary

works design and its appropriateness to actual site conditions.

- Compliance to the temporary works design and ALL other scheme documentation.

- Site monitoring of the works and continual assessment of risk.

- Efficient flow of information between the site and Groundforce representatives.

2a. Contaminated ground.

2b. Failure of shoring

system due to effect of contamination.

- Check with planning supervisor if contaminated ground is to be expected in location of excavation. - Continually monitor by sight, smell and use of gas detection equipment of excavated profile and excavated material for possible contamination. - If excavation is known to be in contaminated land check with shoring supplier that structural integrity of shoring equipment will not be compromised through contact.

- Method of work to be specified to accommodate contamination.

- If suspected contaminated ground is encountered cease work immediately and inform safety co-ordinator.

3. Position of excavation relocated.

- Check if appropriate borehole log has been used. - Check if surcharge details have changed. - Check if depth has changed - REFER BACK TO TEMPORARY WORKS DESIGNER TO RE-WORK DESIGN.






Comments:

4. Soil profile encountered different to that used in temporary works design.

- Continually monitor soil profile. - temporary works co-ordinator to check 'actual' profile against 'design' profile.

- If 'actual' varies from design immediately inform temporary works designer to check design stability.

- If variance in profile is deemed to be significant ceases work until design has been re-checked.

5. Groundwater characteristics.

- Continually monitor and record groundwater characteristics, ie. rate of flow, strike levels. - Temporary Works Co-ordinator to check 'actual' groundwater parameter with 'design' characteristics.

- If 'actual' varies from design immediately inform temporary works designer to check design stability.

- If variance in characteristics is deemed to be significant ceases work until design has been re-checked.

6. Change in depth of excavation.

- If depth is to be varied immediately inform Temporary Works Designer to re-work design based on altered depth.

- Do not exceed design depth without design being re-worked.

7. Change in plan dimensions (trench width) of excavation.

- If dimensions are to be varied immediately inform Temporary Works Designer to re-work design based on altered depth.

- Do not exceed dimensions without design being re-worked.

8a. Change in surcharge.

8b. Introduction of

new surcharge.

- Ensure that surcharge assumptions are correct eg.: i. weight of excavator. ii. position of spoil. iii. Position of adjacent roads and

batters. - Monitor if new surcharges are introduced eg.: i. new haul road adjacent. ii. large plant positioned near dig. iii. spoil dumped near dig

excavation.

- Immediately inform Temporary Works Designer of change so design can be re-worked.

9. Unknown structures/ services encountered.

- Note position and nature of structure and services and inform Temporary Works Designer to assess impact on design.

10. Ground reduction details.

- Ensure all ground reduction details (batters, etc) as specified in temporary works design are complied with. If not, inform Temporary Works Designer to re-work design.






Comments:

11. Groundwater control.

- Ensure the proposed method of groundwater control is as per that used in the 'basis of design', ie. do not sump pump when well point de-watering has been specified. - See activity number 5 - Groundwater Characteristics.

12. Stability of shoring system during use.

- Ensure system has been installed as per the Temporary works design. - Continually monitor equipment for signs of overloading eg. deflection, deformation.

- IF IN DOUBT REFER BACK TO TEMPORARY WORKS DESIGNER.

13. Stability of adjacent structure/batter.

- Continually monitor adjacent structures/batters for movement. - If excavation in or around embankments/batters carry out stability analysis, eg. slip circle checks.

- IF IN DOUBT REFER BACK TO TEMPORARY WORKS DESIGNER.

14. Instability of excavation during extraction of shoring system.

- Work to an approved method of work to ensure stability of excavation during extraction of equipment. - Identify where 'short term stability' is being assumed when considering the stability of the excavation during extraction.

15. Temporary Works Design checked by external organisation.

- Prior to commencing work ensure all relevant external organisation are issued with temporary works design for checking purposes.

16. Change of Method Statement.

- If method statements incorporating temporary works designs are amended, ensure the original design assumptions are not compromised.

Rev E 06/04/10

Technical Note No.6

Trench Lining Systems - Design Statement

Trench Boxes Groundforce Shorco supplied trench boxes have been designed (in accordance with BS EN 13331-1: 2002) to support the worst ground conditions that can reasonably be expected to be encountered within the dimensional capabilities of the panels, including the upper panels. It is therefore not normally necessary to carry out site-specific soil pressure calculations. Exceptions to this however are in high surcharge applications, the proximity of sensitive structures, deep (greater than 4m) excavations in very poor ground e.g. very soft clays and wide (greater than 3m) trenches.

In addition, all trench box systems supplied by Groundforce Shorco have been verified and approved by the German regulatory body TBG to accommodate their block (uniform) pressure diagram shown below. The pressure values tabulated include large safety allowances and can therefore be used for most trench lining applications without further calculation.

TBG Allowable Soil Pressure Diagram

The following table indicates the maximum depths that Groundforce supplied boxes can be used up to without further calculation (subject to the conditions stated earlier).

Box Type Maximum Depth (m)

Allowable Uniform Panel Pressure (kN/m2)

Backhoe (trench and manhole types)

4** 20

Mini Mini Multi-box

4** 4**

35.4 31.8

Standard Standard Multi-box

5.2** 5.2**

44.2 34.1

Premier / Magnum

6.6** 6.0**

38.1 34.1

Manhole box 5.5** 51.6 for 2.5m & 3m long panels, 44.2 for 3.5m panels, 38.7 for 4m panels), 40 for 4.7m panels

Rolling Strut 4# 34.1# **Based on a lower and two upper panels # Base box only, with strut in the highest position

Rev E 06/04/10

Note that the allowable pressures at the maximum stated depths comfortably exceed the TBG pressure requirements. As a further guide for the selection of the best system, the tractive forces required to extract boxes can be considerable. The following table can be used as a guide for excavator sizing.

Trench Box Extraction Forces

Where the end wall of a trench requires support it is essential that no lateral load is applied to the box struts. Purpose made end closure panels are available for closing off the ends of boxes if required. Any contractor designed end support members must thrust off the ends of the box panels. The structural adequacy and integrity of non-standard end support members is the responsibility of the contractor. Note: Groundforce does not recommend the practice of flying trench boxes above the base of the excavation as this can potentially overload the lower struts. Drag Boxes Drag boxes as their name suggests are intended to be pulled or dragged through the excavation as the work proceeds. They are therefore designed to be used in pre-dominantly stable ground conditions in battered excavations. They therefore act as shields to protect the workforce rather that provide positive ground support as in the case of a trench box. Drag box plates do have a working load capacity commensurate with their height and would evidently provide support in the case of ground movement. However it is not industry policy to provide site-specific designs with this equipment type. Any assessment for the use of drag boxes should be carried out at site level where first hand knowledge of ground conditions and hence short-term ground stability is available.

Rev E 06/04/10

Chain attachment points on boxes All boxes are equipped with two types of chain attachment points. Handling points as the name suggests are provided at various locations around the box panels to enable them to be slung for assembly purposes in both horizontal and vertical planes. Lifting points are much heavier duty constructions designed to take the full weight of the box including extraction forces when pulling them out of the ground. These points are located in the top of the box panels and are denoted by red paint. Notes:

1. Lifting points can be used for handling purposes but handling points must not be used for lifting assembled boxes.

2. Chain attachment points have been designed in accordance with BS EN 13331-1: 2002. clause 7.4.

3. No separate certification is required for these points under LOLER MAP system boxes The modular aluminium panel box system is a lightweight yet high strength box system that can be assembled by hand and lifted and handled by backhoe type excavators. Using just three main components - panels, struts, and corner posts, the system provides great versatility by allowing 2, 3, and 4 sided support as the job demands. Note that MAP boxes do not fall within the scope of BS EN 13331-1:2002

MAP Panel Length Maximum Depth (m)

Allowable Uniform Panel Pressure (kN/m2)#

990mm 4.8* 100.0 1600mm 4.8* 60.0

* Panels are 600mm high, posts are either 1200mm or 1800mm high. # assuming two struts per individual post

Installation Installation and on-going inspection must be under the supervision of a competent person. User guides are available for all equipment referred to in this document.

Note: A toolbox talk DVD is available for box installations. Ring 0800 000 345 for details.

DA Manhole Brace rev A

Double Acting Manhole Brace Individual legs are assembled to produce is a 4-sided telescopic hydraulic bracing frame which is used in conjunction with trench sheeting to support square or rectangular excavations from 1.5m up to 8.3m long. Legs are constructed from high yield steel sections and incorporate a double acting hydraulic ram. This means the legs can be both expanded and retracted hydraulically thus greatly simplifying installation and removal procedures. In addition some legs have a pinned rough adjustment facility which increases the operating range of the legs.

OPERATORS USER GUIDE

EQUIPMENT IDENTIFICATION

Leg

Type

Leg Weight

(kg)

Beam Width (mm)

Leg A 2000 3000 260 180 Leg B 3000 4000 305 180 Leg C 4000 5000 390 180

Leg D 5000 6000 445 180 Leg E 6000 7000 627 180

490 2200 3100 250 200 690* 2900 4600 440 220

900M* 4500 6500 650 240 900S* 6300 8300 650 200 TD0 1310 1860 80 140 TD1 1740 2740 106 140 TD2 2660 3660 191 180 TD3 3460 4460 247 180 TD4 4260 5260 326 190

Operating Range (external)

Min max

(mm)

290 1500 2250 145 200

Leg A Leg B Leg C Leg D Leg E 490 690 900M 900S TD0 TD1 TD2 TD3 Leg A 3 3 3 3 3 2 2 2 2 2 2 2 2 Leg B 3 3 3 3 3 2 2 2 2 2 2 2 2 Leg C 3 3 3 3 3 2 2 2 2 2 2 2 2 Leg D 3 3 3 3 3 2 2 2 2 2 2 2 2 Leg E 3 3 3 3 3 2 2 2 2 2 2 2 2

490 2 2 2 2 2 3 3 3 3 2 2 2 2 690 2 2 2 2 2 3 3 3 3 2 2 2 2

900M 2 2 2 2 2 3 3 3 3 2 2 2 2 900S 2 2 2 2 2 3 3 3 3 2 2 2 2 TD0 2 2 2 2 2 2 2 2 2 3 3 3 3 TD1 2 2 2 2 2 2 2 2 2 3 3 3 3 TD2 2 2 2 2 2 2 2 2 2 3 3 3 3 TD3 2 2 2 2 2 2 2 2 2 3 3 3 3 TD4 2 2 2 2 2 2 2 2 2 3 3 3 3

290

2 2 2 2 2

3 3 3 3 2 2 2 2 2

290 2 2 2 2 2 3 3 3 3 3 2 2 2 2

Groundforce D/A Leg AE

Groundforce D/A Mechshore 490 leg (290 & 690 legs are similar)

Manhole Brace TD0TD4

Legs marked thus* include a rough adjustment facility

Groundforce D/A Mechshore 900M leg (900S leg is similar)

Leg Compatibility Chart


Handling of Equipment

Lifting

Manhole brace frames must be lifted using certified 4-leg chains of adequate capacity. Groundforce are able to hire out suitable chains. The contractor should carry out a detailed risk assess-ment before any lifting takes place.

WARNING: Restraining chains act purely as a back up support in the unlikely event of a hydraulic failure. It is essential that certified lifting chains are used to take the weight of equipment before depressurising the hydraulic rams.

RESTRAINING CHAINS MUST NOT BE USED FOR LIFTING OPERATIONS UNDER ANY CIRCUMSTANCES

Equipment Identification HYDRAULIC RAM SECTION Double Acting Manhole Braces incorporate a double acting hydraulic ram which allows fine adjustment of the overall length in both directions. 1m of hydraulic adjust-ment is available on all legs except the TD0 Manhole Brace leg which has 500mm of adjustment and the 690 Leg which offers 900mm of hydraulic adjustment. Double acting hydraulic rams enable the legs to be both expanded and retracted by a hand or motorised hydraulic pump. ROUGH ADJUSTMENT UNIT The 690, 900M & 900S Manhole Braces include a sliding section with 3 No. adjustment positions at either 375mm or 490mm intervals. The rough adjuster offers up to 980mm of adjustment dependant on the position of the shear pin. Working ranges at each pin position are given below;

** Hydraulic Ram layout may differ depending on the type of Manhole Brace.

Leg / Operating Range Pin 1 Pin 2 Pin 3

690 2.9m3.8m 3.3m4.2m 3.7m4.6m

900M 4.47m5.47m 4.97m5.97m 5.47m6.47m

900S 6.3m7.3m 6.8m7.8m 7.3m8.3m

Restraining chains are hooked over the top of the trench sheets using the sheet hook then connected to the frame lifting lugs by D shackles. A minimum of eight chains will be required per brace or as indicated on any drawings supplied. Some adjustment in overall length of the chain will be necessary to ensure all sup-port points are level and to remove any slack. Shorten-ing chains to the required length is achieved by insert-ing the D shackle in the appropriate chain link.

Restraining chains are also used to connect lower level frames to the frame above, and should be positioned directly beneath the upper chains or as indicated on any drawings supplied. Any required adjustment in length can be achieved by the same method as for the hanging chains.


INSTALLATION TYPICAL METHOD OF INSTALLATION

Note: The method of shoring installation will vary depending on the ground conditions encountered and the plant used. Groundforce rec-ommend pre-driving of sheets where possible. Please contact the tech-nical department for further advice. The contractor should undertake a detailed site safety risk assessment prior to undertaking any shoring work.

1. The excavation should ideally have a timber frame or other suitable support set on the surface. The excavation is carefully dug to about 1m deep which is normally about the level of the top frame. Trench sheets are placed in each corner of excavation and toed in to refusal.

2. The frame can either be installed leg by leg or as a frame depending on the weight of the legs and the capacity of the lifting device.

3. Before lowering the frame into the excavation, it is recommended to pump out each leg in turn to approximately 150mm smaller that the excavated dimensions, allowing for the width of the trench sheets.

4. Using a certified 4-leg sling, lower the frame into the excavation and set level using wooden blocks,

5. On each leg in turn, connect both valves to the pump using hoses provided, open the lock-off valve and pump out the legs until the pin-holes line up with each other (refer to the instructions shown on the next page). If not already done, connect the legs together using the corner pins provided and continue to pressurise the frame to the required PSI.

6. Attach restraining chains to each corner of the frame and secure to the top of the corner trench sheets. There must be adequate sup-port to all frames at all times. A minimum of two chains per leg is recommended

7. On each leg in turn, close the lock-off valve, depressurise the hoses and disconnect the hoses from the frame.

8. The remaining trench sheets may now be placed and driven down behind the frame along each side of the excavation.

9. Ensure that the sheets are driven ahead of the excavation at all times whilst digging to approximately 200mm below the level of the 2nd frame.

10. Repeat steps 3 to 7 for the second frame and subsequent frames, lowering the frame down inside the upper frame(s).

11. Restraining chains are used to secure the lower frame(s) to the frame above. Again a minimum of two chains per leg is recommended

12. Once the final frame is installed correctly, continue to dig to forma-tion level, driving sheets as necessary.

13. Blind the base with at least 50mm of concrete


The drawings and photographs below are indicative of the hydraulic connections to be made to facilitate either extension or re-traction of the hydraulic rams.

HYDRAULIC CONNECTION DETAILS

Manhole Brace Leg AD Manhole Brace Leg TD0TD1

Manhole Brace Leg 290,490 & 690 Manhole Brace Leg 900M900S

NOTE: ON DOUBLE ACTING LEGS IT IS ESSENTIAL THAT BOTH PUMP HOSES ARE CONNECTED TO THE RAM COUPLINGS

OTHERWISE THE HYDRAULIC RAM WILL NOT OPERATE.


DOS AND DONTS DO:-

9 Read and understand the scheme drawing (if sup-plied) before starting work

9 Inspect all components at start of every shift 9 Prepare a lifting plan, assess weights correctly and

use appropriately certified lifting equipment during installation and removal.

9 Ensure all pins, clips and bolts are correctly fitted 9 Install the frame level, the right way up and in accor-

dance with he scheme drawing 9 Use only lifting points for chain attachment 9 Provide edge protection or handrail panels 9 Attach a minimum of four hanging chains, one in

each corner or as indicated on the scheme drawing 9 Keep personnel clear of excavator slewing zone 9 Always use a banksman 9 Locate underground services before excavating

DON`T:-

8 Exceed 1500 psi. installation pressure 8 Over tighten lock off valves 8 Use pins and bolts other than those supplied by

Groundforce 8 Install cross struts in positions other than specified on

the scheme drawing 8 Allow excessive amounts of spoil to collect on top of

the frame members 8 Use excessive force during installation / removal 8 De-pressurise frame components without adequate sup-

port (other than provided by the hanging chains) being in place

8 Drag the frame out of the ground without releasing the pressure

8 Strike the frame during excavation 8 Use shoring fluid other that that supplied by Ground-

force

RAM EXTENSION 1. Ensure there is sufficient shoring fluid in the pump reser-

voir. The Groundforce shoring fluid mix properties are 3 parts clean water to 1 part shoring fluid concentrate. No additional antifreeze is required

2. Ensure the hoses and couplings are clean and then connect both of the hydraulic hoses from the pump to the ram.

3. Open the lock off valve on the ram by at least 2 anticlock-wise turns but no more than 4 turns). [If using a motorised pump ensure the control level is set to neutral when opening the lock off valve].

4. Set the control valve on the pump to expand and oper-ate the pump to expand the leg out to the required dimen-sion. Carry out this operation for each leg in turn.

5. Reconnect the hoses to the first ram. The ram should then be pressurised to 1500 PSI (indicated on the pump pres-sure gauge) Do no exceed 1500 PSI.

6. Close the ram lock off valve by turning fully clockwise - Do not to over tighten.

7. Disconnect the hydraulic hoses from the ram, and re peat the same procedure for all frame legs. Ensure that all hose quick release fittings are clean prior to each re-connection.

RAM RETRACTION 1. Ensure the frame is fully supported by packing the under-

side of the frame and checking that the hanging chains are in position.

2. Connect the hydraulic hoses from the pump to the ram, as per the procedure outlined above.

3. Open the lock-off valve on the ram (2-turns anticlock-wise). [If using the motorised pump ensure the control lever is set to neutral when opening the lock off valve].

4. Set the pump control to retract and operate the pump to retract the ram until the corner pin can be released.

5. Release the pin and pump in the ram so the leg is clear to lift out.

6. Repeat the same procedure for each leg.

HYDRAULIC RAM OPERATION There are two pumping stages required for installing any frame in an excavation:- 1. Prior to installing the frame, pumping out the legs individually to the approximate excavation dimensions. 2. Once the frame has been lowered into the ground, expanding the frame to bear against the trench sheets and finally pres-

surising each leg of the assembled frame to the required installation pressure (1500 psi). All Manhole Brace systems will be supplied with either a hand pump or a motorised pump, depending on customer preference. The following procedures outline the extension and retraction stages to be followed if you are installing th

shoring manual for shallow excavations groundforce

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