Bouc–Wen-like hysteresis model with asymmetry and versatile pinching for deteriorating reinforced-concrete elements

The Bouc–Wen model and subsequent improvements are widely used to simulate the hysteretic behaviour of mechanical elements subjected to load reversals. Within such class of analytical models, an enhanced version is proposed. Elaboration is simple, nevertheless it features: (i) convenient parameters to govern deteriorating stiffness and strength, (ii) asymmetry, and (iii) versatile pinching. The latter capability is necessary for variously pinched loops observed in the experimental tests on reinforced-concrete elements. Relevant parameters have physical meaning, consistent with phenomenological application of the model at the member scale. Depending on such parameters, the reloading branch can be made initially concave, convex, or almost linear. The proposed model is validated by simulation of cyclic and pseudo-dynamic experimental test results available in the literature. An asymmetric T-beam, and code-conforming and substandard columns failing under either flexure or shear, are considered. The error on force is normally distributed with mean value less than 4% and standard deviation less than 9% of the experimental strength. The greatest errors on final energy and residual displacement are on the order of 20% with severe damage. The proposed model proves to be effective to simulate the hysteretic response for engineering performance assessment of building and bridge elements.