Effect of CFRP Layer Orientation on the Behavior of Shear-Strengthened Steel Plate Girders

Abstract

The present paper investigates experimentally the impacts of fiber layer orientation on the structural behavior of CFRP strengthened steel-plated girders that are subjected to shear. Three of these girders were considered strengthened girders whereas the last one represents the reference girder. Each of the four steel-plated girders was tested aside and in different periods of time using the shear buckling test. A point load was applied to the center of the top flange of the four girders using Avery hydraulic machine. A laminated carbon fiber reinforced polymer sheet (CFRP) was fully adhesively attached to the web area of the three girders. The attached carbon fiber sheet took different patterns: either on one side or on both sides. Such a step helps to evaluate the most effective strengthening technique of each of the girders using CFRP composite. To check the behavior and the increase in the ultimate shear capacity of the girders, several parameters were examined. Results have revealed that both the unstrengthen and strengthened girders of different orientations of CFRP showed a similar stiffness behavior at a relatively low load levels. However, when the load is increased, the stiffness behavior significantly is increased in the three strengthened girders, compared to the strengthened girders. It has further shown that the ultimate shear load of the three strengthened girders were higher than that of the reference girder. Such a result can clearly be exemplified by the obtained ranges: 19.56% and 25% depending on the orientation of the CFRP laminates. Following Von Mises stresses, the researcher was able to predict the ultimate shear load of the four girders and to figure out the arrived at results from the four experimental tests.