ESTIMATE OF CRACK SPACING AND WIDTH OF HIGH STRENGTH CONCRETE FLAT PLATES REINFORCED WITH GFRP BARS

摘要

Different codes have different formulas to calculate crack spacing and crack width developed in flexural members reinforced with conventional steel reinforcement based on the analysis of results of tested beams or one-way slabs. It seems that little attention has been paid in determining the crack spacing and width in two-way concrete plates reinforced with GFRP bars. Therefore, the available code provisions for steel-reinforced members cannot be directly applied in case of GFRP-reinforced concrete members. Specially, the bond properties in GFRP-reinforced concrete members are different from the corresponding steel-reinforced concrete members. A simple, practical, and new analytical model that is capable of predicting the cracking response (crack spacing and crack width) of thick two-way concrete plates reinforced with GFRP bars is developed. The effect of the bond between the GFRP reinforcement and the surrounding concrete on the cracking behaviour of reinforced concrete member was considered in the proposed model. In this analytical investigation, the tension chord method was modified to predict the crack width of two-way plates under flexural loading. A series of experimental tests were conducted to verify the proposed model results, as well as other previous test results were used to check the applicability of the model. The validity and reliability of the model were evaluated in all of the studied cases, and the model performed satisfactorily with respect to the measured responses from the experimental works.