SHEAR RESISTANCE MECHANISMS OF HIGH-PANELIZED SHEET WALLS WITH BURRING HOLES

Shear stiffness and large deformation behavior

Abstract

 High-panelized steel sheet shear walls with cold formed edge stiffened burring holes are applied to flat offices, stores, and warehouses in seismically active and typhoon or hurricane prone regions. A 3.53~4.53 m long × 0.455 m wide sheet containing the vertically aligned burring holes (dia.: 200mm) with a pitch of 320mm is hot-dip zinc–alumi–magnesium alloy-coated steel (nominal yield stress: 295N/mm2, thickness: 1.2mm). The burring holes are created by cold pressing a sheet with small-radius holes and contain ribs (curvature radius: 10mm) and cylinders. The edges of the sheets are connected to studs and tracks using drilling screw (dia.: 4.8mm). The end studs are built-up members (□−75×75×2.2: two members + C−150×75×15×3.0) and connected to anchor bolts via tension load connectors. The cross-rails are [−110×50×2.2 and connected to studs to be designed to strengthen the bearing capacities. A configuration with burrs on the inside and smooth on the outside enables the construction of omitting the machining of holes for equipments and thinner walls with simplified attachments of finishings.

 The shear load-story angle relations by in-plane shear experiments showed that the values of shear stiffness without bending effects of 3.53~4.53-m-height walls were almost same and gradually decreasing according to the deformation increasing. The values of ultimate strength of the walls were also almost same, using cross-rails which were installed at equal pitches. The walls that receive the in-plane shear force allowed shear stress to concentrate in intervals between the burring holes and showed no local deformations at story angles until 1/200. The walls at 1/100 story angles showed local waveforms created on the tangents in the intervals between the burring holes, and no large out-of-plane waveform which was effectively prevented by burring ribs.

 Design methods for evaluating the allowable shear loads of the walls at story angles from zero to 1/200, are developed, using the idea of decreasing the band-width of the inclined tension field in the intervals between the edge-stiffened burring holes, which is like post shear buckling behavior that Dr. Basler proposed for plate-girder designs. The design formulas to evaluate the shear loads of the wall at story angle from 1/200 to 1/100 are also developed, using the idea of balanced forces between the horizontal components of the tension in an interval between the edge stiffened burring holes, the compressions of the resisted holes and the horizontal shear forces at a group of screw connections of the sheet and the stud, which are derived from preventing stud deformations by cross-rails.