Experimental evaluation of the tension stiffening behavior of HSC thick panels

The experimental investigation presented in this paper summarizes the test results of nineteen reinforced concrete panels. This research is focused on providing a clear understating for the tension stiffening response of thick high strength concrete (HSC) and normal strength concrete panels used for containment structures for nuclear power plants and offshore structures. Major variables include the concrete’s strength, reinforcement spacing in the concrete section, thickness of the concrete cover, and applying the axial load in axial and/or biaxial directions. The contribution of the concrete’s matrix between cracks is obtained by considering the difference between the bare bar and panel response.The average tension stiffening contribution of HSC is found to be higher during the crack formation and stabilized cracking stages, compared with NSC panels. Concrete tension stiffening contribution between cracks for thick HSC panels is dependent on the spacing of the reinforcement in the concrete matrix. Applying the load in two directions causes an obvious decrease in tension stiffening response, compared with panels subjected to axial loading. A relevant constitutive model to simulate the tension stiffening response for HSC panels is recommended.