New Saale bridge near Hammelburg
NOEratio loadbearing formwork combined with NOEplast textured formliners cuts down construction time
A new bridge is being built to carry the B27 road over the Fränkische Saale. The existing structure can no longer cope with the volume of traffic. The appearance of the new bridge is based on that of its predecessor. The designers achieved this look by using a textured formliner from NOE-Schaltechnik, Süssen. In order to complete the works within the tight schedule, contractor Arlt called on a special NOE service: the textured formliner was premounted onto NOEratio loadbearing formwork and delivered to site ready for immediate use.
Arlt Bauunternehmen GmbH, Frankenheim, is constructing a 173-m-long bridge on the B27 near Hammelburg. The new bridge replaces a prestressed concrete bridge, which was built in 1955 and now struggles to cope with today’s traffic volume of 8,500 vehicles per day. Traffic safety will also be improved by the inclusion of a new combined pedestrian and cycle way. The new structure spans the Fränkische Saale and improves flood protection by providing a larger opening for the river than did the previous bridge.
The new bridge is located four metres to the north of the existing, which will remain in operation for the whole of the construction period, with the advantage that traffic flow will be able to continue almost without disruption. The new seven-span structure will have a prestressed beam and slab deck with two main longitudinal members. The contractor installed 1.5 m diameter bored piles to form the foundations. So that the bridge achieves an improvement in traffic flow and looks better than the existing, the project team decided to form the pier surfaces up to a height of 2.13 m using textured formliners. This proved to be a cost-effective way of meeting the local council’s wishes for a natural-looking stone facing. The chosen texture was “Kufstein” manufactured by NOE-Schaltechnik because this natural stone facing design came very close to the appearance of the old bridge. The surface reproduces the look of hand-chiselled natural stone blocks laid in stretcher bond. Once the structure acquires a little patina, only an expert will be able to tell whether the facing is real natural stone or a textured concrete surface. The textured formliners were installed in such a way that they could be extended to any length and height.
Textured formliners for textured concrete
The manufacturer markets textured formliners under the name NOEplast and has a range of about 100 standard designs. In addition, NOE-Schaltechnik can create textured formliners from the customer’s own design ideas. All textured formliners have different sizes and thicknesses. Dimensional stability is ensured by a glassfibre fabric backing. NOEplast textured formliners can be reused up to 100 times, depending on the material and workmanship.
The textured formliners have to be attached to the formwork panels to produce the chosen texture in the concrete. For concreting in horizontal forms – as is often the case in precast concrete factories – it is enough to simply place the formliner into the form. For vertical use – e. g. on site – it must be glued directly to the formwork panel or a supporting board. The supporting board is then attached to the formwork. As soon as the textured formliner is secured against slipping, a special release agent is applied and the concrete is then poured into the form. When the concrete has hardened adequately, the formwork can be stripped and the results exposed to view.
NOEratio loadbearing formwork
The pier formwork was made up of NOEratio panels. This loadbearing formwork system with prefabricated elements was conceived specially for engineering structures and systemised building construction. It consists mainly of H 20 timber beams and steel profiles for the bracing members. Thanks to the 25-cm pattern width and a wide range of accessories, the system offers a great deal of flexibility of application. With the H 20 facing support boards and bracing bolted into place, the formwork is outstandingly resilient and torsionally stiff. Bracing is positioned at levels 400 + 1250 + 1250 + 1250 mm on all standard elements up to 6000 mm height. This allows elements of different heights to be combined without undue complications up to a height of 6000 mm. Depending on the tie rod spacing, formwork based on NOEratio can withstand a concrete pressure of up to 50 or even 60 kN/m².
Formwork and texture – a complete service from a single source
Engineers from NOE’s Cottbus subsidiary assisted the contractor by supplying a detailed reuse formwork plan, the textured formliner construction drawings and elevations for the piers and abutments to help ensure the work on site went smoothly and without problems. NOE Cottbus also took responsibility for fixing the textured formliners onto the formwork. Everything was delivered to the site near Hammelburg ready for immediate use. This saved contractor Arlt valuable time and above all working hours, which was very important in view of the tight timetable – indeed, the contractor had to build the bridge’s six piers over a period of just six weeks.
NOE is the only manufacturer on the market that can supply textured formliners, concrete formwork, reuse plans and concreting schedules all from a single source. This relieves the customer of much of the arduous coordination work and conveniently reduces the number of project contacts. The support NOE-Schaltechnik provided allowed the contractor to work efficiently and smoothly to construct the works by the planned completion date.
Design: Staatliches Bauamt Schweinfurt
Construction planning and structure: Arlt Bauunternehmen GmbH, Frankenheim, Germany