ECCM16 - 16 TH EUROPEAN CONFERENCE ON COMPOSITE MATERIALS, Seville, Spain, 22-26 June 2014 1 PROBLEM OF STRESS CONCENTRATION AND DEFORMATION IN THE USE OF MULTILAYER GFRP (GLASS FIBRE REINFORCED POLYMER) IN BEARING STRUCTURES T. Stefic a* , A. Juric a , P. Marovic b a J.J.Strossmayer University of Osijek, Faculty of Civil Engineering Osijek, Drinska 16a, HR-31000 Osijek, Croatia b University of Split, Faculty of Civil Engineering, Architecture and Geodesy, Matice hrvatske 15, HR- 21000 Split, Croatia¸ *tstefic@gfos.hr Keywords: multilayer GFRP, stress concentration, local collapse, linear and nonlinear numerical model. Abstract The paper analyses a problem concerning concentrated stress in the use of multilayer GFRP carriers. Due to concentration of stress excessive deformation and local collapse occurs much sooner than the material stress peak is achieved. The paper shows the testing of the material samples and the carriers with two different spans. Also the linear and nonlinear numerical analysis was conducted. In the end the comparison of the results and a proposal for the design calculation is shown. Also the material improvement on the critical concentration places is proposed. 1. Introduction Through progress in production of civil engineering materials every new day the market introduces more new, improved, advanced and better materials. Engineering structures demand a vast amount of specific characteristics of a material in order to fulfil the basic demands which the structures, constructive and non constructive elements, are demanding. The basic advantages that glass fibre composite that is reinforced polymer has are small specific weight, resistance to corrosion or different kind of material deteriorating due to atmospheric influence on the unprotected structure. This is a common problem with civil engineering structures made from traditional materials. GFRP (glass fibre reinforced polymer) is already well implemented into civil engineering constructions through primal or secondary bearing structures in bridges or different plateaus and as different sandwich plate like systems [1,2,3]. Besides independently GFRP is being used in combination with other materials, commonly traditional building materials in order to improve some of their poorer characteristics [4,5]. 2. The analysed GFRP carrier The material that the GFRP carriers were made of was tested on samples (figure 1.) and the results are shown in the diagram (figure 2.)