Abstract:
This study consists of three parts: 1) Part A: Limiting Height Evaluation for
Composite Wall Tests, 2) Part B: Mid-Span Deflection Evaluation for Composite Wall
Tests, and 3) Part C: Nominal Axial Strength Evaluation for Wall-Braced Wall Stud
Columns.
The purpose of Part A is to develop experimentally-based limiting heights for
interior, nonload-bearing wall panels. Lateral load is applied perpendicular to the gypsum
board sheathing over the entire panel. Testing for the composite wall tests complies with
ICBO ES AC86 and ASTM E 72-80 using a uniform, vacuum chamber loading on
vertical 4-foot-wide specimens. Limiting heights for specific deflection limits are
developed over the range of typical design loads.
The test specimens for Part B are the same wall panels used in Part A. The panels
are treated as simply supported beams for the analysis. The objective of Part B is to
properly reflect the influence of the following factors in the calculation of mid-span
deflection for the panel: connection slip, local buckling, perforations in the stud web, and
effects from joints in the sheathing. Predicted deflections based on an upper bound for
connection rigidity were closest to experimental deflections.
The objective of Part C is to evaluate the axial strength of composite wall stud
panels. The panels are similar to those of Part A except the studs are load-bearing and an
axial load is applied to the centroid of the gross cross section, and no lateral loads are
applied. The bracing effect from wallboard and fasteners is represented by continuous
elastic springs over the length of the column. The column is subject to flexural buckling
and torsional-flexural buckling. Using 1) the differential equation of equilibrium, and 2)
an energy method, the flexural and torsional-flexural buckling loads are evaluated.
Equations to determine the buckling loads are developed considering typical end-conditions.
Local buckling effects and nominal buckling stress are determined according
to 1986 and 1996 AISI specifications. Predictions and observed strengths from the
limited experimental database were in good agreement. The predictions accurately
represent the overall torsional-flexural buckling failure for the gypsum board-braced wall
studs and its independence of stud spacing.
