Load-bearing walls system
This system uses concrete load-bearing walls that could afford central
(gravity) and lateral loads. These walls could be made in situ or be used as
prefabricated walls. For the first type of concrete structure, forming is
performed by metal or wooden forms, and then the ceiling system, which is
usually in-site concrete slab, is erected on it. The upper floor walls are
executed after this stage.
These structures are executed in mass production projects in two main types,
both could be very effective. The two types are:
-
Semi-tunnel system (execution of walls with metal sliding forms and execution
of ceiling with flying table).
-
Full tunnel system (execution of walls and ceiling at the same time using
tunnel forms).
Tunnel system (with flying table)
This system has been effectively used by Ekbatan renovation and
development company in many years. �Shahrak
Ekbatan� which is the largest residential complex in Iran with
15,500 units capacity and 2,520,000 square meters substructure, has been built
in west of Tehran using this system. Also
Vavan project with 2,567 residential units and 204,295 square meters
residential substructure, and Sepah-shahr
project with 624 residential units and 59,780 square meters residential
substructure are being constructed in present by this system. Also it's
intended to construct towers of hashtgerd
project by this system.
In this system, an integrated metal forming is used which is fully assembled
for walls. The forms of external wall (end wall) lies on the wall and
slides upwards, and the internal forms could be used again in adjacent building
after separating them, so that be used in higher floor after execution of
ceiling. With respect to the considerable size of forms, the most effective
method to use this system is to use the internal wall forms for several
adjacent buildings (with respect to the execution times) commonly, so maximum
use could be made from the forms and the site. Light flying tables -made of
aluminium- are used to execute ceilings. After execution of the floor walls,
these tables are placed between the walls, and concreting is carried out after
reinforcing and box laying. It should be noted that this system has been
designed for concrete works with large amount (mass prodution) and needs many
facilities such as heavy cranes with effective long booms and high capacity. If
the mentioned facilities are provided, the system would prove to be highly
effective for its speed.
Tunnel system (ceiling and wall together)
This load-bearing wall structure system is completely similar to semi-tunnel
system in form and the only difference is the execution method; that�s to say
that in this system, the walls and ceiling forms are fully integrated and this
lead to an acceleration in execution (since walls and ceiling are executed in
one step). Also, since none of the elements of the form is left idle during
execution, simultaneous execution of a number of adjacent buildings (which is
almost an essential in tunnel system) is also a must in this system