Top Down Constuction Method pps

TOP-DOWN CONSTRUCTION METHOD
TOP-DOWN CONSTRUCTION METHOD

Use of diaphragm wall as the side support
Use of diaphragm wall as the side support
for the earth
for the earth

Construction progress upwards and
Construction progress upwards and
downwards at the same time
downwards at the same time

Savings in construction time
Savings in construction time

Schematics and pictures give ideas on
Schematics and pictures give ideas on
ongoing activities during construction
ongoing activities during construction

Diaphragm Wall Installation
Diaphragm Wall Installation

Conventional Open-cut
Conventional Open-cut
& Bottom-up
& Bottom-up
Construction Method
Construction Method

(For comparison with
(For comparison with
Top-Down Method)
Top-Down Method)

Conventional Open-cut & Bottom-up
Conventional Open-cut & Bottom-up
Construction Method (For
Construction Method (For
comparison with Top-Down Method)
comparison with Top-Down Method)

Top-Down
Top-Down
Construction
Construction
Method
Method

Top-Down Construction Method
Top-Down Construction Method

Main Advantage of Top-Down Construction
Main Advantage of Top-Down Construction

Details of Top-Down
Details of Top-Down
Construction Method
Construction Method

Excavation to Level -1
Excavation to Level -1

Excavate to Level -2
Excavate to Level -2

Compaction and leveling of
Compaction and leveling of
basement slab for reinforcement
basement slab for reinforcement
and concrete works
and concrete works

Circular ramp beam and wall
Circular ramp beam and wall
supported on bored column
supported on bored column

Excavation work of Level -3 in progress, use of clamp-shell for exc.
Excavation work of Level -3 in progress, use of clamp-shell for exc.

Excavation of Ramp Level -3 to - 4 in progress
Excavation of Ramp Level -3 to - 4 in progress

More excavation work in progress
More excavation work in progress

More excavation work of lower levels inprogress
More excavation work of lower levels inprogress

Above ground, structure works in progress
Above ground, structure works in progress

Typical basement reinforcement slab ready for concreting
Typical basement reinforcement slab ready for concreting

Concreting of
Concreting of
basement slab
basement slab
for top-down
for top-down
construction
construction
method
method

Top-down construction work in progress
Top-down construction work in progress

Complete construction of project
Complete construction of project

Another example of top-down construction
Another example of top-down construction

Another example of top-down construction
Another example of top-down construction

Conclusion

Conclusion

Need careful consideration for use in HCMC
Need careful consideration for use in HCMC
since method is new here
since method is new here

Ideal for 5 basements or more
Ideal for 5 basements or more

May need some soil improvement
May need some soil improvement
techniques and good dewatering system
techniques and good dewatering system

Equipment for these works may not be
Equipment for these works may not be
readily available in HCMC
readily available in HCMC

Handling of excavated soil material require
Handling of excavated soil material require
planning, keeping in mind marine clay at
planning, keeping in mind marine clay at
upper level and silty sand at lower level
upper level and silty sand at lower level