Investigating the flexural behavior of ASR‐damaged RC beam through internal stress and cracking development using 3D Rigid Body Spring Model

The alkali‐silica reaction (ASR) is one of the durability issues that affect the safety of concrete structures. Numerical simulation is useful for monitoring the internal condition of a reinforced concrete (RC) structure with ASR damage and predicting its long‐term behavior. Since discrete methods of simulation suit situations where concrete undergoes durability issues associated with expansion and cracking, a mesoscale discrete analysis method known as the three‐dimensional Rigid Body Spring Model (3D RBSM), as already used to simulate concrete ASR damage at the material scale, has been further developed to simulate ASR damage at the structural scale. In this development, the aggregate is not separately modeled and expansive elements are included to simulate ASR expansion, allowing a larger element size (1–2 cm). The number of elements and computation time are reduced to less than 1%. This proposed model is used to simulate ASR damage in a RC beam and the beam's residual flexural capacity. The simulation allows the internal stress and cracking condition to be visualized, leading to an explanation as to why the loading capacity of a RC beam is not affected by ASR damage: first, almost no cracks form at the core of the beam section due to the stirrup confinement, so the effective depth of the cross section is maintained after ASR damage; second, the tensile reinforcements have already yielded although ASR damage exists. Besides, the inhibited development of shear cracks may be one of the reasons for the slight improvement of flexural capacity of the damaged‐RC beam in experiment and simulation.