WHAT IS THE DIFFERENCE BETWEEN ALLOWABLE STRENGTH (ASD) AND DESIGN STRENGTH (LRFD)?
“Steel design, or more specifically, structural steel design, is an area of knowledge of structural engineering used to design steel structures. The structures can range from schools to homes to bridges.
In structural engineering, a structure is a body or combination of pieces of rigid bodies in space to form a fitness system for supporting loads. Structures such as buildings, bridges, aircraft and ships are all examples under steel structure. The effects of loads on structures are determined through structural analysis. Steel structure is steel construction material, a profile, formed with a specific shape or cross section and certain standards of chemical composition and mechanical properties.
There are currently two common methods of steel design: The first (and older) method is the Allowable Strength Design (ASD) method. The second (newer) is the Load and Resistance Factor Design (LRFD) method.
The table on our ICC report reflects the two methods that engineers use to reduce the ultimate capacity to an in service load – these methods are ASD and LFRD. ASD is the old fashioned method of dividing the ultimate load by a safety factor. LRFD is a newer approach based on factored loads. Engineers use one of these methods in their design (they don’t switch back and forth within the same design), so having both in the report serves the engineer. Users of the report need to know the design approach being used in order to select the proper available load.”
DO THE 750 SD AND 175 SD SELF-DRILLING I-LAG SCREWS COMPLY WITH ASTM C635 AND ASTM C636?
Please click link for documentation – ESR-3135 Interpretation letter
WHAT ARE THE GAUGE TOLERANCES FOR SHEET METAL?
Please see this PDF for information on gauge tolerances for sheet metal – Standard Sheet Metal Gauges.