دانلود رایگان مقاله انگلیسی رفتار ساختاری ستون های فولادی مستطیل شکل جدار نازک سرد - الزویر 2018

abstract

Cold-formed rectangular steel columns with large and thick walls are increasingly applied in engineering recently. The section dimension and wall thickness have increased continuously to 800 and 22 mm, respectively, which causes the significant differences of cold-formed effects between cold-formed rectangular steel columns with thin and thick walls. Therefore, the mechanical performance and design method of cold-formed rectangular steel columns with thick walls should be studied. In this study, two section dimensions (700 mm × 20 mm and 600 mm × 16 mm) were selected for the axial load test and analysis of cold-formed rectangular steel columns with large and thick walls. The conclusions are as follows. (1) The indirect cold-formed rectangular steel columns have lower cold-formed effects than direct cold-formed rectangular steel columns. (2) Cold-formed rectangular steel columns with large and thick walls have high-bearing capacity under axial loads, which are manifested by local plate instability. (3) Calculation formula of ultimate bearing capacity with considerations to local plate buckling is proposed. The calculated and test results are in accordance with numerical simulation results.

5. Conclusions

On the basis of the experimental study and numerical simulation analysis of the bearing capacity of cold-formed rectangular steel columns with thick walls under axial and eccentric compression loads, the conclusions are summarized as follows:

(1) For indirect cold-formed rectangular steel columns, the yield strength is 16%–19%, and the ultimate strength of the corner location is 8%–11%, which are higher compared with those of the side location, when the section dimension is 600–800 mm and the thickness ranges between 16 mm and 22 mm. The cold-formed effect of indirect cold-formed rectangular steel columns is lower than that of direct ones. The calculated results of yield strength formula that considered the coldformed effect in North America/Australia/New Zealand Design Specifications for Cold-formed Steel Structure are close to test results. The calculated results are applicable to the yield strength of cold-formed rectangular steel columns with thickness over 16 mm.

(2) Local buckling of plates is the main axial compressive failure mode of cold-formed rectangular steel columns with thick walls. The stability coefficients of 2.4 m high steel columns with the section dimensions of 700 mm × 20 mm and 600 mm × 16 mm are 0.979 and 0.949, respectively, which indicates their good local stability.

(3) According to the test and numerical simulation data, the local bucking coefficient is introduced in the standard formula. Given the effects of the local buckling of plates on ultimate bearing capacity, the calculation formulas of ultimate axial compressive bearing and ultimate eccentric bearing capacities of cold-formed rectangular steel columns with large and thick walls are proposed. The calculated results conformed to the test and numerical simulation results.