A study of seismic steel plate shear walls using box columns with or without infill concrete
Date Issued
2012
Date
2012
Author(s)
Huang, Hsuan-Yu
Abstract
Steel Plate Shear Walls(SPSWs) have evolved into an effective lateral force resisting system in recent years. However, it is still not widely adopted in Taiwan construction practice. This may be due to the following three reasons: 1) The capacity design of the boundary elements must be checked by using the strip model, which may be complicated and time-consuming. 2) According to the AISC seismic building provisions, the column plastic hinge should be designed to form only at 1st story column bottom end. Therefore the design result for the 1st story column may not be economical. 3) In Taiwan, built-up box columns are commonly adopted. However, most of the past studies of SPSWs focused on wide flange boundary columns. If the boundary columns in the SPSWs are concrete filled steel box column or bare steel box column, the inner column flanges connected to the steel panel would be subjected to the out-of-plane pull-out forces when the tension field action develops. These vertical boundary members also have to resist the axial force and the in-plane bending moment at the same time.
Allowing the inner column flange to go into minor yielding under the pull-out effects, this study proposes the column flange capacity design methods. It considers two simplified models, fixed clear-span beam and flat-portal frame for steel box column with and without infill concrete respectively, and the full tension field pull-out effects to design the inner column flanges. The Von Mises yielding criterion of plane stress is used to estimate stress distribution of inner column flange subjected to column axial force, in-plane moment and column flange out-of-plane pull-out moment.
In order to investigate the seismic responses of SPSWs using box columns with and without infill concrete, and to verify the effectiveness of the proposed column flange capacity design requirements that prevent the plastic hinge from forming at top end of bottom column under maximum considered earthquake, three full-scale two-story SPSW specimens were tested in National Center for Research on Earthquake Engineering. Each specimen is 3.42-meter wide and 7.64-meter tall. The 2.6mm-thick low yield strength steel plates and the same boundary beams were adopted. Three different column sizes were designed for the three specimens considering the column inner flange out-of-plane flexural requirements. They were named NSB, NCB and WCB in which Specimen NCB and WCB used concrete filled box column, and Specimen NSB used bare steel box column without infill concrete.
Results of the ABAQUS pushover analyses and the cyclic tests up to a roof drift of 0.04 radians confirm that the proposed column flange flexural requirements and column capacity design are suitable for seismic SPSW using box columns with or without infill concrete. It could achieve both good seismic performance and economy. The specimen NCB having minor yielding in inner column flanges and the 1st story column plastic deformations spreading over the mid-high of the column still possessed rather good load-carrying capacity. In addition, infill concrete for steel box column enhances the compression capacity and local buckle resistance. However, under the steel panel pull-out forces major yielding of the inner column flanges in Specimen WCB was observed. This design should be avoided as significant permanent plastic deformations could develop.
Subjects
steel plate shear walls
box column
concrete filled box column
tension field action
column flange out-of-plane deformation
seismic design
capacity design
Type
thesis
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