DETERMINATION OF K_R EXTENSION RESISTANCE BASED ON CRACK COHESIVE FORCE IN CONCRETE USING PRACTICAL ANALYTICAL APPROACH

To compute double-K fracture parameters and new extension resistance for three-point bending beams, the practical analytical approach assumes linear or bilinear cohesive stress distribution in fictitious fracture zone. It transforms the integral expression of stress intensity factor at the crack tip into a simple algebraic expression by using a simple function rather than Green’s function. With this method, numerical integration can be avoided and the calculation is simplified. Test results of three-point bending beams with different sizes are employed to compare the practical analytical approach with traditional numerical integration method in computing extension resistance based on crack cohesive force. It is demonstrated that no visible difference is observed in the resistance curves from the two methods. The practical analytical method has a high accuracy in computing new extension resistance.