8.2 Test Program
241
Fig. 8.1 Tensile stress–strain curves of 20# steel, reprinted from Wu et al. (2019), copyright 2020,
with permission from Elsevier
Table 8.4 Material properties of 20# steel
Coupons Width × Thickness
(mm)
Yield stress (MPa) Ultimate stress (MPa) Rupture strain
1
9.81 × 3.04
302.6
503.6
0.14
2
9.85 × 3.02
318.1
508.5
0.17
3
9.85 × 3.02
338.3
511.8
0.17
4
9.87 × 3.03
320.2
509.9
0.31
5
9.86 × 3.03
313.4
501.6
0.35
Average
318.5
507.1
0.23
displacement rate of 1 mm/min. Several Linear variable differential transformers
(LVDTs) were employed in the axial compression test. The middle lateral deformation of each specimen was measured by one LVDT with the measuring capacity of
500 mm installed at the middle height of the column. Four LVDTs with the measuring
capacity of 100 mm were symmetrically arranged around the top of the column to
obtain the vertical displacement at the top of the column, while two LVDTs with the
maximum range of 50 mm were symmetrically placed at the steel bottom plate to
obtain the vertical displacement of the bottom plate. Hence, the net vertical deformation of the specimen could be obtained by subtracting the displacement of the
bottom plate from the top displacement.