Study on Shear Performance of Cold-formed Steel Composite Wall with New Type of stud

The shear resistance of single oriented-strand board wall and single gypsum board wall can be improved in different degrees by increasing strength of steel. The experimental data of literatures were used, and the test specimens had been simulated and validated by ABAQUS finite element analysis. According to the research, it showed that the compressive bearing capacity of the new stud composite wall was much better than the common stud composite wall, so the establishment and research of all models had been based on the new section stud. The analysis results show that when using new type of stud the shear resistance of the single oriented-strand board wall can be improved efficiently by increasing strength of steel, but the shear resistance of the single gypsum wall can be increased little.


Introduction
Cold-formed steel composite wall is the main bearing member in the cold-formed thin-wall steel residential building system. According the research [1,2], the compressive bearing capacity of the new stud composite wall is better than the common stud composite wall due to the vertical compressive bearing capacity of the new section stud is higher than that of the common section stud, which makes it possible for low-rise cold-formed thin-wall steel residential buildings from low to high. Therefore, the research of this paper had been based on the new section stud as shown in Fig2.1. In this paper, ABAQUS is used to validate the finite element analysis model of literature [3,4]. The conclusion can be used as the reference for the theoretical analysis.

Establishment of Finite Element Model
In literature [1], the size of studs with C section was 102×50×12×1.0mm.The size of top and bottom tracks with U section was 104 × 65 × 1.mm and 104 × 45 × 0.75mm respectively. The thickness of single gypsum board was 12mm. In literature [2], the size of studs with C section was 89 ×44.5×12×1.0mm.The size of top and bottom tracks with U section was all 92×40×1.0mm. The thickness of single orient-strand board was 12mm.The boundary conditions of top and bottom tracks were shown as Fig2.2. The panels were connected to the studs and tracks by screws. In literature, diagram of structure details for combined wall was shown as

Verification of the finite element modeling
The cold-formed steel shear wall models had been tested and verified as shown below. The test results were used to verify the correctness of the finite element models, which had the single orientstrand board wall and the single gypsum board wall.
The finite element and test results [1] of the single gypsum wall were shown in  The finite element and test results [1] of the single orient-strand board wall were shown in Table 3    Finally, it showed that the finite element model can be used to simulate fact condition of coldformed steel composite wall with the single orient-strand board and gypsum board, in terms of yield load, yield displacement, peak load, peak displacement and failure modes.

Shear performance of different wall panels in different steel strength
In this section, the shear resistance of single oriented-strand board wall and gypsum board wall had been studied by changing the strength of steel. The results of each index were shown in Table 4.1 As Table.4 shown above, the shear resistance of the single gypsum board wall with steel strength of 345MPa, 550MPa can be more increased 1.52%, 1.64% than steel strength of 235MPa only. The shear resistance of the single oriented-strand board wall with steel strength of 345MPa, 550MPa can be increased 26.66%, 49.97% than steel strength of 235MPa respectively. The failure modes of two kinds of walls were different. Gypsum board was a kind of brittle material. The net section of gypsum wall board was snapped at edges that had screws. The steel framing had not yield at this time，the shear resistance of single gypsum board wall had little impact by increasing strength of steel. The toughness of oriented-strand board was better than gypsum board. When the orient-strand board wall suffered shear from the self-tapping screws, it did not immediately occur brittle fracture, but the screws in sheathing had a small amount of slip [5]. And it can drive frame to resistance horizontal shear force together, so the shear resistance of single oriented-strand board wall can be improved efficiently by increasing strength of steel [6].

5.Conclusion
In this study, the shear resistance of the single oriented-strand board wall can be improved efficiently by increasing strength of steel when using new type of stud. The shear resistance of the single gypsum wall can be increased little by increasing strength of steel.