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Allowable Stress Design (ASD) Method

In allowable stress design (ASD), the Designer must size the anchorage such that the service load does not exceed the allowable load for any anchor:

Tservice ≤ Tallowable
Vservice ≤ Vallowable

The Designer must read the allowable load from the applicable table and adjust the allowable load for all applicable design parameters for the anchor, such as spacing, edge distance, in-service temperature or allowable-stress increase for short-term loads. Load-adjustment factors for anchors are applied cumulatively. For adhesive anchors, the designer must also ensure that the service load does not exceed the allowable load of the steel insert.

For anchors subjected to simultaneous tension and shear loading, the following equation must be satisfied, where the value of n is product-specific. Use a value of n=1 unless otherwise specified in the applicable products' load table.

( Tservice ) n    +   ( Vservice ) n    ≤  1.0
Tallowable Vallowable

Linear interpolation of allowable loads between embedment depths and/or compressive strengths shown in the load tables is permitted. Linear interpolation of load-adjustment factors in the edge distance and spacing tables is also permitted.

 

The allowable loads in this catalog are derived from full-scale testing, calculations, and/or experience. In general, the allowable load is determined by taking the average ultimate load from full scale tests and dividing by a safety factor (Ω).

Tallowable =  Tultimate    ;    Vallowable  Vultimate
Ω Ω

For some anchors, the average ultimate load and/or allowable load is also controlled by anchor displacement limits.

The allowable loads for steel inserts used with adhesive anchors is determined as follows:

For threaded rod:

Tallowable = 0.33 FuAg ;
Vallowable = 0.17FuAg

For Grade 60 rebar:

Tallowable = (24,000 psi)Ag ;
Vallowable = 0.17(90,000 psi)Ag

Where:
Ag = Gross cross-sectional area of the insert


threaded insert steel type
Where:
Fu = Ultimate tensile strength of steel insert
 
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