Pultrusion : Manufacturing of bridge

component

CONTENT INTRODUCTION EXAMPLES OF COMPOSITE BRIDGE AROUND THE WORLD PULTRUSION METHOD OF MANUFACTURING OF BRIDGE COMPONENT CASE STUDY

PIER

TRUSS

MADE OF CONCRETE

MADE OF FRP

1. 38m span Lleida Footbridge, Spain

2.60m long opening Fredrikstad Bridge in Norway

3. 40m long Fiberline BridgeKolding, Denmark

EXAMPLES:-

4.Pratt Truss Footbridge, Chalk BridgeLee Valley Park, Walthamstowe

5.West Mill FRP Road Bridge (Oxford, UK)

PULTRUSIONPultrusion is a continuous molding process whereby reinforcing fibers are saturated with a liquid polymer resin and then carefully formed and pulled through a heated die to form a part. Pultrusion results in straight constant cross section parts of virtually any shippable lengthContinuous fibre tows are drawn through a resin bath The tows are then pulled through a heated die and cured

1 - Continuous roll of reinforced fibers/woven fiber mat2 - Tension roller3 - Resin Impregnator4 - Resin soaked fiber5 - Die and heat source6 - Pull mechanism7 - Finished hardened fiber reinforced polymer

PULTRUDED SECTION

There are two forms of pultrusion products:

The first category consists of solid rod and bar stock produced from axial fiberglass reinforcements and polyester resins.These are used to make fishing rods and electrical insulator rods, which require high axial strength

The second category is structural profiles, which use a combination of axial fibers and multidirectional fiber mats to increase a set of properties that meet the requirements of the application in the transverse and longitudinal directions.

Raw materials

ResinsUnsaturated polyester resin (UP)Phenol resinsPolyurethane

Reinforcing fibersGlass fibre reinforcementsContinuous filament matsWoven fabrics non-woven fabrics

APPLICATIONSPipes Electrical insulators Structural applications Supports and panels for truck trailers, door supports for cars, ladder rails Pressure tanks Aircraft flooring Rods, stringers and stiffeners in aircraft, car leaf springs

Advantage-Increased Strength

(fiber processed under tension)

-High Fiber Content-Consistent Quality-High Production -Low Labor Required-Low Cost

Disadvantages• The process is mainly

suitable for constant cross sectional areas. Tapered and complex shapes can not be produced with this method.

• Control of fiber orientation is not possible in the pultrusion system.

• Thin wall parts can not be produced with this system.

CASE STUDY ON FIBRELINE BRIDGES: KOLDING, DENMARK

TECHNICAL SPECIFICATIONS

• Total Length - 40 m•Number of stays -8•Width, total -3.2 m •Tower, height -18.5 m•Total weight -12 tonnes •Designed load capacity -500 kg/m2

The Fiberline pedestrian and cyclist bridge was the first of its kind to cross a railway line. The Fiberline bridge is an asymmetric cable-stayed bridge manufactured of Fiberline standard GRP profiles. Only the bolts for assembly and the abutments at the foundations are made of stainless-steelFiberline structural profiles are manufactured by PULTRUSION, a method which ensures consistent quality that can be reproduced.

Standard profiles

The bridge was constructed of 12 different Fiberline standard profiles.

The expected life time is minimum 100 years. The bridge, which is uninfluenced by rain, salt and sub-

zero temperatures, is expected to require only cosmetic maintenance over the coming 50 years or more, reducing maintenance costs considerably compared to traditional bridges of steel, concrete or wood.

CONCLUSION

It has been shown that FRP composites have the potential to revolutionize the construction of long span bridges, producing more efficient and cost-effective structures. They will also dramatically increase durability, reducing through-life costs and disruption due to maintenance. Initial long span applications are expected to be in footbridges, but the same advantages and possibilities are considered viable for road and possibly rail bridges.

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