Procedia Engineering 40 ( 2012 ) 423 – 427

1877-7058 © 2012 Published by Elsevier Ltd.doi: 10.1016/j.proeng.2012.07.119

Steel Structures and Bridges 2012

Composite GFRP Deck for Bridge Structures

B. Stankiewicza*

aOpole University of Technology, Opole, Poland

Abstract

Composite material of glass fiber base is very promising material for future structures. It is possible to create bridge span consists of steel main beams and GFRP deck, according for example ASSET system. The author’s research is about parameters of composite material of bridge deck like alternative for concrete one. Identification of kind of glass fiber and type of polymer matrix or type of adhesive with steel or concrete, there are very interesting directions of searching line. The paper will be presented the results of DTA and spectroscopy analysis of GFRP composite, according own paper author’s research. It will be described the examples of bridges where GFRP deck have been constructed with main steel beams. The text will give horizon of future author’s research of this kind of bridges. Future model stress and fatigue analysis will be showed by main topics. Presented kind of bridges are good alternative for traditional structures by long durability, anticorrosion, light deck with imposing stress parameters. © 2012 Published by Elsevier Ltd. Selection and review under responsibility of University of Žilina, FCE, Slovakia.

Keywords: Bridge structures, Steel main beams, GFRP deck, Pultruded GFRP material, Static and Fatigue testing

1. Introduction

GFRP bridge deck is the alternative to heavy popular concrete deck, which has got poor durability, for bridges where there are steel main beams. Bridge deck has been made of fiber reinforced polymers (FRP) are beneficial for maintenance purposes and case of the replacement of the deck to accommodate any increased traffic demand. Many kinds of FRP decks can be found recently. Most of them can be classified into the modular type or the sandwich type. The former consists of multiple unit modules. A unit module is typically fabricated by the pultrusion process. The modules are bonded in the field to construct a bridge deck. The latter consists of hard skins. In practice the modular type is more preferred than the sandwich type because it is easy to carry such a type economically to construction site. The behavior of the modular types of the bridge decks was tested by many researchers. Because of the characteristic of the pultrusion process, the deck is anisotropic

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E-mail address: b.stankiewicz@po.opole.pl

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424 B. Stankiewicz / Procedia Engineering 40 ( 2012 ) 423 – 427

[5]. A composite bridge deck also provides greater durability and reduced maintenance costs over the life of the bridge [6]. Compared to concrete and steel that have been used as bridge deck material in the past, FRP material has the advantage of light weight and anti-corrosion [7]. GFRP bridge decks have been thoroughly tested in both laboratory and field settings. Static tests typically indicate an extremely high factor of safety for strength, while fatigue test show little to no degradation after millions of load cycles. Field load tests commonly verify in-place performance and validate the initial design assumptions. From coupon tests through full-scale multi-beam assemblies, results consistently GFRP bridge decks high strength, durability and its tendency to meet or exceed project requirements [5]. The perfect example of such a structure is Friedberg Bridge is 21.5m long and consists of two steel beams covered by a new pultruded multicellular deck, see Fig 1. The bridge elements are clad with a polymer concrete material to resist weathering. A big advantage of the system is its low weight, so the bridges can be pre-assembled or prefabricated in far longer lengths than their corresponding steel or concrete structures. German bridges that carry heavy traffic are subject to span limitations, so to achieve the necessary load-carrying capacity, either carbon composite, which is expensive, or a combination of glass fibre-reinforced polymer and steel can be used. The entire deck was prefabricated with no cast in situ concrete edge beams for the anchorage of guard rails. The installation time was minimal and there were no rest periods for curing of in situ concrete or wearing. The German bridge is a lightweight structure that was assembled adjacent to the highway and then lifted into position with only the minimum of disruption to traffic. The bridge deck has a frame structure, which meant that the cross-section of the superstructure was able to be reduced and consequently the vibrations of the light bridge deck were reduced. The reinforced fibre bridge deck has no cut-outs or holes for bolts (girders are bonded directly to the composite material), which guarantees that its stiffness is not compromised and reduces the time for assembly and installation [1],[2].

Fig 1. Bridge GFRP deck with steel girders being lifted and hoisted into place (Friedberg Bridge in Germany)

2. Parameters of GFRP composite material for bridge deck

The costs of GFRP products are higher than conventional materials, therefore it is sensible to restrict their use to members that are susceptible to corrosion. For bridge superstructures, this means that decks can build out of FRP, while the main girders are made of conventional materials such as steel. Available FRP decks can generally be classified into two categories: pultruded hollow sections and hand lay-up sandwich panels. Pultruded decks consist of a row of prismatic bars that are manufactured through an automatic process. These hollow sections have a wall thickness that varies from 5 to 15 mm and an overall dimension of approximately 200 mm x 400 mm. Owing to the continuous manufacturing process, the fibre direction is mostly longitudinal.

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The panels are formed by adhesively bonding the bars together. The bars are connected to the slab during assembly or previously at the factory in transportable sizes. The pultruded deck sections generally have a span of 2 to 3 m between the main girders. Symmetric adhesively-bonded double-lap joints composed of pultruded GFRP laminates bonded using an epoxy adhesive system were examined under axial tensile, compressive and reversed fatigue loads. The pultruded GFRP laminates, supplied by Fiberline A/S consisted of E-glass fibers and isophthalic polyester resin. The fiber architecture of the laminates is shown in Fig 2a (according own author’s research). The laminate comprises two mat layers on each side and a roving layer in the middle, with a thin layer of polyester veil on the outer surfaces of the laminate. An estimation of the nominal thickness of each layer derived by optical microscopy is given in Fig 2b. The longitudinal strength and Young’s modulus of the GFRP laminate were obtained from tensile experiments, according ASTM D3039-08, as being 307,5 ± 4,7 MPa and 25,1 ± 0,5 GPa respectively by Prof. T. Keller research [10]. Over time, the weather has taken its toll on these reinforced concrete decks. Rainwater and de-icing chemicals applied to road-way surfaces during the winter months have seeped through many concrete decks and cause corrosion of the internal reinforcing steel and deterioration of the concrete bridge decks. Bridge decks out of pultruded fibre reinforced polymers (FRP) are a promising new option for the construction of road’s bridges. The highly corrosion resistant material is reducing maintenance costs and traffic interference due to construction and use. Fibre reinforced polymers (FRP) seem to hold some advantages over known conventional material such as concrete deck (connected with main steel beams), for example: low weight, high degree of prefabrication, short erection time through pre-assembly, easy handling on site, corrosion resistance. Paper author’s first part of research of GFRP bridge deck (using ASSET composite modular system) took part at AGH University of Science and Technology in Prof. J. Wasylak’s Laboratory of Glass Technology and Amorphous Coatings Department. The analysis consisted of:

spectrometer analysis of chemical constitution of glass fiber in polymer matrix, using ICP-MS Elan 61000 by Perkin Elmer,

identification of material according Fourier spectroscopy in infrared with FTS-60 MV Bio-Rad, electronic scan microscopy (SEM/EDAX) for estimate of morphology of composite, see Fig. 2, DTA analysis for estimation of physics and chemical transformation of glass fiber, as at Fig. 3.

(a) (b)

Fig 2. Microstructure of GFRP panel deck: (a) cross section of composite; (b) independed fibre of GFRP in polymer matrix

426 B. Stankiewicz / Procedia Engineering 40 ( 2012 ) 423 – 427

400 600 800 1000 1200 1400

852

T

Temperatura [oC]

Fig 3. DTA curve for indvidual glass fiber from composite

3. Static and fatigue investigation of structure model – steel beams connected with GFRP deck

Stress concentrations due to concentrated wheel loads are critical for the thin walls of the GFRP deck. The polymer concrete using for the surfacing of pavement can bear tension and shear stresses. The surfacing system and the top flange of the FRP deck are assumed to be in composite action. Thus, the stress is distributed over a larger area. In addition, the polymer concrete surfacing reinforces the FRP deck flange. This approach is similar to the design concept for orthotropic steel superstructures. One of the main objectives of the research program is to investigate the load bearing behavior of the steel – FRP composite girders and to determine the effective width of the FRP deck acting as a compression flange to the steel girder.

Second interesting direction of investigation is searching if composite action between steel girders and GFRP deck is achieved which reduces the vertical displacements by approx. 20% compared to the steel stringers alone, according Prof. J. Knippers research [4]. Third point of future research is how to improve mixture of polymer concrete in order to have better parameters of it in bridges applications. How to construct surface of polymer concrete on bridge decks, by technology process to have less crakes in the future.

There are static and dynamic tests are planning (according paper author’s research) in laboratory at Opole

University of Technology (modern laboratory at Civil Engineering Faculty) in fatigue option and future observation of destroyed material of GFRP deck and polymer concrete using X’Pert test machine at Hochschule fur Technik in Stuttgart. The observation of effective connection between steel beam and GFRP deck during static and dynamic tests are one of the most interesting matters of composite system. Comparison of model analysis and numerical analysis is important two. Research of composite model, using GFRP panels, on quasi-seismic load is unknown, now. There are many questions on filed how improve this system for future all realizations [8-12].

4. Conclusions

The use of fibre composites has great potential in bridge building. The possibility of pre-assembling in the hall allows for rapid installation on site [3]. For example in 2011 Karrebaksmide Bridge in Denmark with GFRP deck and steel main structure of moving span was constructed. Many steel footbridges with light GFRP deck were built in Denmark and Nederland, some of road bridges, in this system, were made in Great Britain, USA, Canada. Traditional bridge decks are heavy and have poor durability but effective connection systems

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and better durability of pavement, which covered GFRP deck, at road bridge structures are very important directions in searching scale. GFRP deck is good alternative for old steel bridges, which need to exchange heavy old deck. Imposing stress and fatigue parameters of glass fiber polymer give possibilities of modern shape of bridge structures using long-life material and coexistence traditional main part of bridge – steel girders with light, anticorrosion deck.

Fig 4. Karrebaksmide Bridge in Denmark with GFRP deck and steel main structure of moving span

References

[1] Benmokrane B., Cousin P. : University of Sherbrooke GFRP Durability Study Report. April 2005. [2] Benmokrane B., Chaallal O., Masmoudi R.: Glass Fibre Reiforced Plastic (GFRP) Rebars for Concrete Structures. Construction and Building Materials, Vol. 9, No. 6, pp. 353-364, 1995. [3] Berg A.C., Bank L.C., Oliva M.G., Russell J. S.: Construction and Cost Analysis of an FRP Reinforced Concrete Bridge Deck. Construction and Building Materials. 7 April 2005. [4] Knippers, J.: Innovative Design Concepts for Composite Bridges in Germany Proceedings of the COBRAE Conference 2005, EMPA Düsendorf 2005. [5] Moon D.Y., Zi G., Lee D.H., Kim B.M., Hwang Y.K..: Fatigue Behaviour of the Foam-filled GFRP Bridge Deck. Composites: Part B 40 (2009), pp. 141-148. [6] Moon D.Y., Zi G., Lee D.H., Kim B.M., Hwang Y.K..: Fiber Reinforced Plastic Deck Profile for I-Girder Bridges. Composite Structures 67 (2005) . [7] Park K.T., Hwang Y.K., Lee Y.H., Kim S.M.: Performance Verification of a New Pultruded GFRP Bridge Deck-to-Girder Connection System. Composite Structures 81 (2007), pp. 114-124. [8] Pavese A., Bolognini D., Peloso S. Seismic Behaviour of R.C.: Hollow Section Bridge Piers Retrofitted with FRP. 13th World Conference on Earthquake Engineering. Vancouver, Canada, August 1-6, 2004. [9] Resing R.; Shahrooz B.; Hunt V.; Neumann A.; Helmicki A.: Performance Comparison of Four Fiber-Reinforced Polymer Deck Panels, Journal of Composites for Construction May/June 2004, pp. 265-274. [10] Sarfaraz R., Vassilopoulos A., Keller T.: Experimental investigation of the fatigue behaviour of adhesively-bonded pultruded GFRP joints under different load ratios. International Journal of Fatigue 33 (2011), pp. 1451-1460. [11] Stankiewicz B. GFRP applications in bridge structures. International Conference Concrete and Concrete Structures, Zilina, 15-17 October, 2009. [12] Stankiewicz B. The examples of GFRP bridge decks. Glass & Ceramic, Warsaw, nr 1/2011, pp. 7-10.