STRUCTURAL METHOD STATEMENT - Islington

M O a s s o c i a t e s

A.S. Onisiforou BSc MSC CEng MICE – 58 Camlet Way Barnet Herts EN4 0NS T 020 8275 0611 F 020 8588 5995 E [email protected]

STRUCTURAL METHOD STATEMENT

LANDATREAROF78ESSEXROAD

LONDON

N18LT

CLIENT:MRTARESTI

DATE:AUGUST2016



SITE PREPARATION AND SECURITY Security hoarding to be erected to maintain site security and safety around the construction

area. Fencing to be strategically positioned to create safe working zones as well as to provide

ongoing protection during the various construction phases and ensure safety of the public and

visitors.

The new basement area will almost cover the entire site area apart from the zone required to

construct the enclosing retaining walls. The public footway will be screened off during the

construction period of the whole works and permission to block the footway will be sought from

the Council.

CONSTRUCTION METHODOLOGY The basement will be formed using the installation of bored cast in-situ reinforced concrete piles

along the open perimeter of the site. Either contiguous or secant piles will be selected depending

on the findings of the soil investigation. The interaction with the adjacent ground is the same

irrespective of the type of piles opted for.

The piles will be designed and constructed by the specialist piling contractor to sustain the

various loads both during excavation/construction and service on completion ensuring

continuous retention of the earth around all four boundary sides. A reinforced concrete capping

ring beam with horizontal props across the site, will be formed to provide top lateral restraint to

the piles prior to excavation. The boundary flank wall of the existing rear addition, will need to

be underpinned by conventional underpinning methods of ‘hit and miss’ sequential pins. The

retained rear wall of the rear addition will be supported on a steel beam A, spanning across the

site and supported on the new external retaining walls ( on capping beam) and the inner side wall

will be supported on a steel beam spanning from steel beam A and the rear wall of the main

building prior to commencement of the excavation.

The horizontal props will need to be positioned strategically across the side to enable excavation

by machinery.

Once the excavation reaches the formation level, the reinforced concrete floor slab will be formed

and adequately dowelled into the retaining piles. Waterproof Caltite concrete or other equivalent

will be considered to form the floor slab and wall finish against the internal face of the piles.

On completion of the floor slab the ground floor slab will be placed formed with precast pre-

stressed concrete T beams with infill dense concrete blocks and structural topping. Once the

Ground Floor plate is complete, the Basement Construction Phase will be deemed completed.



Piling construction methodology

1. Set up site and mobilise all necessary labour, plant and materials.

2. The contiguous bored pile wall will then be constructed in accordance with the detailed

design and in accordance with the separate Method Statement depending on type of

auger piles the soil investigation will recommend. The piles will be designed to act as a

propped cantilever to support the ground and the surcharge of any adjacent structures

in the temporary and permanent cases. The piles will also be designed to act as a free

cantilever, to a limited depth of excavation, say approx. 1.0-1.5m, to aid the installation

of any temporary works for the propping of the top of the piles.

3. Upon completion of the piling the pile heads will be prepared/cut down and the capping

beam to the top of the piles constructed. The capping beam will need to be designed to be

the permanent prop and to span horizontally across the sides of the basement.

4. A reduced level excavation will be carried out across the site to approx 1.0-1.5m (exact

depth subject to detailed design).

5. Install horizontal temporary propping if required to the capping beam adjacent to the

rear of the existing property and at mid-span if necessary subject to detailed design.

6. Continue with reduced level excavation to formation level.

7. Prepare surface of excavation.

8. Concrete blind the surface.

9. Fix reinforcement in accordance with the Engineer’s drawings.

10. Fix stop ends and cast base slab, complete with kicker for the walls/step in slab.

11. Fix wall reinforcement, and wall shutters and cast walls.

12. Fix precast pre-stressed concrete T beams with infill dense concrete blocks and fix

reinforcement and stop ends and cast structural topping to form ground floor slab.

13. Once the ground floor slab has cured the falsework stop ends is then struck.

14. Tidy up and clear site of all surplus materials.

SITE SPECIFIC CONSTRAINTS

Neighbouring Properties

1. Ensure that the entrance/driveways to adjacent properties remains unimpeded at all

times during the course of the works.

2. Ensure that the road is kept clean, swept and washed down at all times.

MATERIALS

1. All spoil/surplus materials to be moved to the skip/stockpile by mechanical

dumper/wheelbarrow/conveyor and to be removed from site by a muck away/grab

wagon/skip as appropriate.



2. All concrete is to be delivered to site by ready mix concrete wagons and distributed to

the required location on the site by either a concrete pump, dumper or wheelbarrow

dependant upon the location/quantity.

3. Steel reinforcement is to be delivered to site with a Hiab wagon and loaded directly into

the site. The reinforcement will then be distributed by hand/machine to the required

location.

4. General building materials are to be delivered to site with a Hiab wagon and loaded

directly into the site. The materials will then be distributed by hand to the required

location.

PLANT

1. Mini/midi-sized piling rigs are to be used for the formation of the contiguous bored pile

wall.

2. Mechanical excavators/dumpers will be used for the bulk excavation and the transport

of spoil and concrete and they are to be operated only by competent operators holding

the relevant certificates.

3. When carrying out the bulk excavation a conveyor will be erected to transport spoil

from the working area to the skip.

4. A compressor is to be used for powering pneumatic clay spades/breakers and concrete

vibrating pokers.

5. Concrete pumps will be sourced externally and operated by a competent operator.

6. Hand power tools i.e. disc cutters, skill saws are to be operated only by competent

operators.

GENERAL SAFETY

1. All standard PPE is to be warn at all times i.e. Safety Helmets, Safety Boots, and Hi Vi

jackets.

2. Specific PPE i.e. Safety Googles, Ear Defenders, Gloves, Wet Weather Gear is to be

warn for specific tasks in accordance with the Risk Assessments.

3. All personnel on site are to be aware of their responsibilities to themselves and their

fellow workers.

4. Safe and clear access to and from the site and all working areas is to be maintained at all

times during the course of the contract.

5. General rubbish is to be cleared away from site continually and must not be allowed to

accumulate, particularly as the site is very constrained.

6. All excavations are to be protected when not attended and the sides of excavations are to

be supported/shored as instructed.



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STRUCTURAL METHOD STATEMENT - Islington