Imposed Deformations for Material Behavior

The concrete and steel materials were subjected to similar strain cycles. The patterns of the cycles were the same, but the amplitudes were different (reinforcing steel typically reaches maximum strains of 10%, while concrete reaches maximum strains of 6% with nonzero stresses).

Then different loading patterns were imposed on the materials, as follows:

Run 1. Unidirectional incremental strain in tension.
Run 2. Unidirectional incremental strain in compression only.
Run 3. Three cycles of tension and compression to a low maximum-strain level (Tension first).
Run 4. Three cycles of compression and tension to a low maximum-strain level (Compression first).
Run 5. Three cycles of tension and compression to a high maximum-strain level (Tension first).
Run 6. Three cycles of compression and tension to a high maximum-strain level (Compression first).
Run 7. Numerous cycles of increasing amplitude (3 cycles per amplitude) to a high maximum-strain level in Tension only.
Run 8. Numerous cycles of increasing amplitude (3 cycles per amplitude) to a high maximum-strain level in Tension only.
Run 9. Numerous cycles of increasing amplitude (3 cycles per amplitude) to a low maximum-strain level in Tension & Compression.
Run 10. Numerous cycles of increasing amplitude (3 cycles per amplitude) to a high maximum-strain level in Tension & Compression.

These strain histories are tabulated below and shown graphically in the two figures below for concrete and for reinforcing-material, respectively.

Table 1. Strain histories

Run	Concrete Material	Steel Material
1	+0.010	+0.20
2	-0.035	-0.20
3	+0.005, -0.005	+0.02,-0.02
4	-0.005, +0.005	-0.02,+0.02
5	+0.05,-0.05	+0.2,-0.2
6	-0.05,+0.05	-0.2,+0.2
7	+0.00005,+0.00025,+0.0005, +0.0025,+0.005,+0.0075,+0.01	+0.0005,+0.001,+0.005,+0.05,+0.10,+0.15,+0.20
8	-0.00005,-0.00025,-0.0005, -0.0025,-0.005,-0.0075,-0.01	-0.0005,-0.001,-0.005, -0.05,-0.10,-0.15,-0.20
9	+-0.00005,+-0.00025,+-0.0005, +-0.0025	+-0.001,+-0.005,+-0.01, +-0.02
10	+-0.00005,+-0.00025,+-0.0005, +-0.0025,+-0.005,+-0.0075, +-0.01	+-0.001,+-0.005,+-0.01, +-0.02,+-0.05,+-0.10, +-0.15,+-0.20

Figure 1. Concrete-Material Strain History:

Figure 2. Steel-Material Strain History: