VSL's innovations Dampers on test Penny's Bay in HK

tion
Competitive
post-tensioned
steel truss form
Purpose
VSL in Chile has developed
a footbridge design for
complete construction
solutions in concrete that uses
one continuous structure
across all spans. A formwork
system was needed.
Description
The construction of the forms
starts with the assembly of
the modules on the floor.
After that the various
modules are stressed
together with individual
strands. All the modules are
lifted into position as one
unit. The post-tensioning in
the form is released after
completion of the post-
VSL modular form traveller
Purpose
This formwork system for construction of cast in-situ bridges using
the FC method was developed for easy reuse from project to project,
to minimise investment in new steel and equipment and to reduce
redesign costs for individual projects.
Description
An overhead system was selected due to its more favourable
introduction of support reactions into the deck, its reduced selfweight
and its possible use for cross-sections with more than two
webs. VSL’s modular traveller features:
• use of grade 40 steel with no need for SHS;
• a traveller launching system which provides longitudinal fixity for
both uphill and downhill launching, through the use of doubleacting
long-stroke jacks connected by pins to the rail beam;
• rear tie-down of the traveller with 2 x 4 stress bars, all of them
located outside of the webs.
Performance
The main performance characteristics are:
• bridge alignment - gradient up to 5%,
horizontal curve greater than 500 m,
superelevation up to 5%;
• segment geometry - segment length
up to 5m, segment weight up to 180t
(for a single box; higher for multiple
boxes), single or multiple cell box
girder, vertical or inclined webs;
• pier table length - minimum length
7.2m, minimum length for
simultaneous installation of a pair
of travellers 8.2m. ■
tensioning of the footbridge. Each
module is then removed separately.
Advantages
•Pours are completed without
interrupting the traffic; vertical and
horizontal clearances are
maintained during construction.
• The system is easy to mount and
dismount.
• Use of post-tensioning reduces the
force in the bolts in each
connection, and allows control of
vertical deformation. ■
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