Fler bilder 
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Lek Bridge, Vianen, Netherlands
Weekly Cycle Shortened
Balanced Cantilever Construction over the River Lek
The “Lekbrug” spans the River Lek with seven sections forming a total length of 532 m. A variable box girder cross-section, with laterally-mounted diagonal bracing, carries the 29 m wide slab.
Apart from a cost-effective solution using PERI VARIO wall girder formwork for the foundations and piers, PERI engineers also provided a logical and sound concept for the cantilever:
External formwork
The external web formwork was designed to adapt to the varying web heights. For the smaller web depths it was positioned over the slab formwork and therefore did not have to be converted.
The pre-cast columns for the carriageway and web connection areas were an obstacle for the forming of the slab. Due to this, PERI designed the slab formwork to fold downwards behind the columns thus allowing an uninterrupted passage over the area. Lowering of the lightweight components was done manually, which avoided the need for expensive hydraulic equipment.
Internal formwork
The web heights as well as the angles between the bottom slab and web varied from section to section.
Through the double SRU waler construction and segment-coupled SRU walers, compensating the changes in angles on the bottom plate proved to be no problem. Moving was carried out inexpensively using a standard chain hoist.
In the box girders, the foldable web formwork allowed reinforcement work to be carried out on the left and right sides independently, which ensured free access to the web itself.
PERI’s formwork solution allowed the originally planned weekly cycle to be reduced by half a day.
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VARIO GT 24 Formbalkar
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Norbert Klopf
Senior Superintendent
“I’ve worked with various PERI systems over the past 15 years and the cooperation with PERI engineers has always been very good. The balanced cantilever construction with folding technology allowed us to pass over the pre cast columns when moving to the next cycle. We achieved a fantastic surface quality, which also met the architect’s expectations!”
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PERI Handbook 2005 Formwork
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