PIER & PILE HEAD BREAKING AND DEMOLITION-METHOD STATEMENT

LIST OF CONTENTS

1.0 INTRODUCTION

2.0 SCOPE OF WORKS

3.0 CONSTRUCTION PROGRAMME

4.0 REFERENCE & STANDARDS

5.0 CONSTRUCTION EQUIPMENTS

6.0 SITE ORGANIZATION

7.0 SEQUENCE OF WORKS

7.1 Scenario A: Pier column height is more than 8 m from the ground.

7.2 Scenario B: Pier column height is less than 8 m from the ground.

 1.0 INTRODUCTION

This method statement covers for pier and pile head breaking and demolition
for pier column. The demolition works are necessary due to design change
issues or defects founded in the structure, therefore the Contractor need to
reconstruct the pier according to the respective latest drawing. After the
demolition works have been completed and inspected to the satisfactory of
the Engineer, the proceeding of subsequent reconstruction works will be
according to other method statements which will not be mentioned here.

2.0 SCOPE OF WORKS 

The present scope of work includes demolition of pier and pile head.

3.0 CONSTRUCTION PROGRAMME 

The construction programme for the aforementioned work will be carried out
in coordination with the interfacing parties.

4.0 REFERENCE & STANDARDS 

All the reference standards as per the construction specification

5.0 CONSTRUCTION EQUIPMENTS 

a. Hydraulic Excavator (Caterpillar D330-200kw) with breaker, crusher and bucket.
b. Compressor – capacity of 150 cfm.
c. Jackhammer Compressor (big) - 35 to 45 kg.
d. 100 tons mobile crane.
e. Generator – capacity of 15 to 20 kva.
f. Welding machine.
g. Acetylene / Oxygen Gas Cylinder and cutter.


6.0 SITE ORGANIZATION 

The following staff will be made available on site to comply with the approved
construction programme:

.. Construction Manager – supervising site activities.
.. Site Engineer – Coordinates with subcontractors for the Execution, Quality
and Safety of works.
.. Site Engineer (Subcontractor) – Execution, Quality and Safety. Follow up
Quality Control Procedures and submission of quality forms and records on
daily basis coordinate with Main Contractor.
.. QA/QC Inspectors – ensure work complies with regulatory standards,
drawings, specs and Quality Plan Foremen Operators, Steel Fixers, etc.
(Subcontractor).
.. Surveyor – to carry out setting and survey works.
.. Safety Engineer is responsible to ensure the project safety plan and all on
going works comply with all safety regulations as required.
The site organization chart is as follows:

7.0 SEQUENCE OF WORKS 

The sequence of works is illustrated by the sketch and description below. The
breaking and demolition works can be divided into 2 scenarios:

A) Pier column height is more than 8 m from the ground.
B) Pier column height is less than 8 m from the ground.


7.1 Scenario A: Pier column height is more than 8 m from the ground. 

Step 1: Installation of scaffolding and green net around pier

The demolition site will be fenced or barricaded. Installation of scaffolding and
green net around pier to prevent the debris of concrete and dust spread out to
the vicinity.



Step 2: Welding of temporary rebar and breaking around pier

Select 4 pair of pier reinforcement and full fillet welded them with 4 number of
the temporary rebar. The length of full fillet weld shall not be less than
300mm. This will form 4 numbers of lifting hooks. Each hook is then fixed with
shackle and sling wire and connected to the hoisting beam for lifting by crane.
Air compressor with jackhammer will be used for the breaking of concrete.
The breaking of pier starts from a distance of 3 meter from the top of pier.
Concrete cover will peel off exposing the pier reinforcement. Water will be
sprayed to reduce the heat and dust.


Step 3: Pier reinforcement to be cut

Gas cutter will be used to cut off the all the surrounding pier reinforcement
except of 4 pair of reinforcements that to be used as next sequence of lifting
hooks.


Step 4: Breaking the inner core of pier

After the removal of the outer perimeter of the pier reinforcement, the
breaking of the centre inner core of the pier will commence. During this
operation, the crane shall be full time lifting the upper portion of the pier. Upon
final hacking, the 3 m length of concrete pier can be lifted up by the crane.
Repeat Step 1 to Step 4 until the pier height is less than 8m, further
demolition method shall follow scenario B.

7.2 Scenario B: Pier column height is less than 8 m from the ground. 

Step 1: Installation of protection barricade and blue sheet.

This is to prevent the debris of concrete and dusts do not spread out on to the
vicinity.

Step 2: Mobilization of hydraulic excavator.

The mobilization of demolition specialist will commence. The hydraulic
excavator with breaker and crusher will start to break pier starting from the
top of pier.

Step 3: Breaking around pier.

The breaking around the pier and cutting of rebar will be executed by the
hydraulic excavator.


Step 4: Breaking stops at ground level.

As soon as the breaking of pier reaches the ground level, the breaking work
has to stop to prevent further accidental damage of pile reinforcement.


Step 5: Ground excavation to expose the pile head.

Before start of excavation the working area will be properly barricaded.
Excavate with care to expose the pile head and below the foundation level.
The depth of excavation will be 2.050 m ~ 2.150 m below the foundation level.
The cut of level of the pile will be marked on the pile using the grind cut of
50mm depth around the pile perimeter. This is to define the level and form a
straight edge.

Step 6: Manual air compressor breaker until pile cut off level.

Manual air compressor breaker will be mobilized for the pile cap breaking.
Breaking and gas cutting of rebar shall be with care to avoid damage to the
pile reinforcement.

Step 7: Ground excavation to expose the pile head.

The breaking of concrete will stop at the pile cut off level. Joint inspection with
the Engineer to inspect the condition of the pile cut off level and the pile
reinforcement. If no further comment from the Engineer the pile cap and pier
construction shall commence according to the separate method statement for
Pile Cap Construction DM001/E/ACW/EFW/EPC/MT/DCC/401050 B2 and method
statement for Pier Construction DM001/E/ACW/EFW/EPC/MT/DCC/401059 C1.


Step 8: Site cleaning and demobilization.

The debris of concrete will be transported out side the site by dump truck and
disposed at approved Dubai Municipality disposal area.