|
|
|
|
|
Different hold-downs are designated in Shearwalls for the following different means of publishing displacement and capacity values. There are three possible sources of vertical hold-down displacement that affects shear wall deflection:
Similarly, the capacity of the hold-down takes into account the possible failure in tension of the bracket or strap, the anchor bolt in tension, and the connection of the horizontal fasteners to the wood studs.
The published data may include all or just some of these sources. For displacement, sources that are not included are calculated separately by Shearwalls. For capacity, sources that are not included are neglected by Shearwalls, with an appropriate warning message.
The hold-down displacement/capacity data source(s) used in Shearwalls are
Assembly Displacement/Capacity
Displacement values refer to entire hold-down – bracket or strap, anchor bolt, and horizontal fasteners. Capacity takes into account tensile capacity of brackets and straps, and wood-connection capacity of horizontal fasteners. Anchor bolt displacement applies to a maximum length, elongation of portion greater than that length is analysed separately.
Separate Slippage/Connection Capacity, Combined Elongation/Tensile Capacity
Displacement values refer to the elongation of the brackets or straps plus the anchor bolt, to a maximum length. Elongation past the maximum length is analysed separately. Capacities include only the tensile capacity of the brackets and anchor bolt. Slippage of fasteners is calculated by Shearwalls, and wood connection capacity of the horizontal fasteners is not considered.
Separate Slippage/Connection Capacity, Separate Elongation/Tensile Capacity
Displacement values refer to the elongation of the brackets or straps only. The entire anchor bolt length is analysed separately. Capacities include only the tensile capacity of the brackets. Wood connection design of the horizontal fasteners is not included, and capacity of anchor bolt is not considered.
These properties are set via options for each hold-down in the Hold-down Database Editor.