Aluminum Design Manual 2010 Pdf Download
Curtis Boykins
Released in February 2020, this book is an invaluable resource to understand designing and constructing structures out of aluminum. It is divided into 9 critical sections detailing rules for determining the strength of aluminum structural components, buckling constants for welded and unwelded alloys, alloy and temper designation systems for wrought and cast aluminum alloys and more.
Aluminum alloys are strengthened by tempering, which is achieved by heat treatment or cold working. The heat of welding offsets the increased strength gained by tempering, and this strength reduction zone typically extends 1 inch (25 mm) in each direction from the centerline of a weld. For welded connections, designers need to know the weld-affected tensile ultimate strength. Both the weld-affected tensile ultimate strength and the weld-affected tensile yield strength are required to design welded built-up members. Furthermore, the base metal and filler metal alloys in a weldment often differ and, consequently, the weld-affected strengths of both are needed.
While screw chases provide economical connections for aluminum members, the pull-out strength of fasteners in the chase has not been addressed in structural design standards. The 2020 Specification is the first to include a pull-out strength for screws in screw chases, which for -inch-diameter fasteners is given as:
The block shear strength provision in previous Specification editions was similar to an earlier AISC approach in which the strength was the lesser of yielding on the gross shear area with rupture on the net tensile area and yielding on the gross tensile area with rupture on the net shear area. In the 2020 Specification, the block shear strength is now taken as the shear rupture strength on the average of the net and gross shear areas plus the tensile rupture strength on the net tensile area. The revised strength is more accurate and less cumbersome to compute.
Web crippling was the only case of concentrated forces on flanges or webs addressed in previous editions of the Specification for Aluminum Structures. In the 2020 Specification, the web crippling strength for extruded shapes (Figure 3) is revised and made less conservative, and flange local bending and web local yielding are added. The strengths for these three cases are similar to those in the 2016 AISC steel Specification, as the rationale for these strengths can be equally applied to both aluminum and steel.
Around 1960, several aluminum highway bridges were built in the U.S. Consequently, and since its first appearance in 1967, the Specification for Aluminum Structures has addressed both bridges and buildings with a different set of safety factors for each. For example, while the Specification set a safety factor on tensile rupture of 1.95 for buildings, the safety factor for tensile rupture was 2.20 for bridges. In this regard, the aluminum Specification has differed from its steel counterpart, the AISC Specification for Structural Steel Buildings, which from its beginning in 1923 has addressed building structures only.
When AASHTO developed the first LRFD bridge design specifications in the 1990s, they used the Specification for Aluminum Structures as the source of the nominal strengths for aluminum structural components and established resistance factors for aluminum bridges. Consequently, when the first LRFD Specification for Aluminum Structures was published in 1994, it addressed buildings only and left load and resistance factor design of aluminum highway bridges to AASHTO.
However, allowable strength design safety factors for aluminum highway bridges lingered in the Specification for Aluminum Structures, even though allowable strength design is no longer used for bridges. The 2020 Specification drops references to bridges, thus limiting its scope to building structures, defined in the Specification as a structure of the type addressed by a building code. As with the AISC steel Specification, the aluminum Specification may reasonably be applied to all structures designed, fabricated, and erected in a manner similar to buildings, with building-like vertical and lateral load-resisting elements.
Just as the AISC has adopted a six-year cycle for revisions to the steel Specification, the Aluminum Association is considering a six-year interval between revisions to the Aluminum Design Manual. Because the IBC has a three-year revision cycle, a six-year cycle may be more suitable for standards like the Specification for Aluminum Structures that are referenced by the IBC. This also has the benefit of reducing the frequency of changes to design standards, thereby allowing design professionals to master them better.
Aluminum properties are available in the database and the values are based on the ADM values (See Aluminum Database). You may also input your own basic shapes and the properties will be calculated automatically.
The Aluminum tab on the Member Spreadsheet records the design parameters for the aluminum code checks. These parameters may also be assigned graphically. See Modifying Member Design Parameters to learn how to do this.
You may assign a unique Label to all of the members. Each label must be unique, so if you try to enter the same label more than once you will get an error message. You may relabel at any time with the Relabel options on the Tools menu.
The member Length is reported in the third column. This value may not be edited as it is dependent on the member end coordinate listed on the Primary Data tab. It is listed here as a reference for unbraced lengths which are discussed in the next section.
The Cm value is influenced by the sway condition of the member and is dependent on the member's end moments, which will change from one load combination to the next, so it may be a good idea to leave these entries blank.
For all aluminum codes, Cb Coefficients depends on the moment variation over the unbraced length as described in ADM Chapter F. If this entry is left blank, it will be calculated automatically.
If all the exclusion criteria are met, the original area and moment of inertia values will be retained without applying the stiffness adjustment multiplication factors. This ensures that certain types of HR members, when using the AISC 13 code, maintain their original stiffness characteristics.
This message is displayed when the member is not defined with a database shape, is defined as a double section, or an Aluminum code is not specified on the Model Settings, or no units were specified.
This message is reported in the detail report when the member axial force is low (less than 5% of capacity). This is done so that beam members with very low axial forces will give similar code checks whether in tension or compression.
The 234 page manual contains information on aluminium design, alloy selection, joining, profile tolerances, surface quality, surface treatment, machining, corrosion and structural calculations, among other things. It is an invaluable guide for anyone who wants to improve their understanding of aluminum design. The manual is available digitally in seven languages.
The current update includes new sections about ecodesign and benefits related to sustainability in general. Within the manual you will find photographs, illustrations, tables and technical information about all things aluminium.
The Aluminum Design Manual (ADM) provides guidelines for designing and sizing welds for aluminum structures. The following are some basic rules and properties to consider when sizing welds for aluminum:
Weld type: The type of weld (e.g., fillet weld, groove weld) should be selected based on the application, load-bearing requirements, and geometry of the structure. Fillet welds are typically used for connecting plates or sections at right angles, while groove welds are used for butt joints, T-joints, and corner joints.
Material thickness: The thickness of the aluminum material being welded affects the required weld size. Thicker materials generally require larger weld sizes to ensure adequate strength and load-carrying capacity.
Weld strength: The Aluminum Design Manual provides minimum and maximum allowable weld strengths based on the material's alloy type and temper. The weld strength should be checked against the required strength for the specific application.
Weld size: The size of a weld refers to its throat thickness, which is the minimum distance from the root of the weld to its face. The throat thickness of a fillet weld is determined by multiplying the leg length (the distance from the root to the toe of the weld) by the sine of the included angle (usually 45 degrees for fillet welds). For groove welds, the throat thickness is equal to the depth of the weld's penetration.
Effective length of welds: The effective length of a weld refers to the length over which the weld is capable of transferring loads. The Aluminum Design Manual provides guidelines for calculating the effective length of welds based on the type of connection and loading conditions.
Weld spacing and edge distances: Adequate spacing between welds and edge distances (the distance from the edge of the material to the centerline of the weld) are essential to ensure proper stress distribution and avoid stress concentrations that can lead to weld failure. The Aluminum Design Manual provides minimum spacing and edge distance requirements based on the weld size and material thickness.
Weld quality and inspection: The quality of welds should be checked according to the guidelines provided in the Aluminum Design Manual, which includes visual inspection, non-destructive testing (NDT), and destructive testing methods as needed. Weld quality is critical to ensure the long-term performance and reliability of the welded structure.
Precautions for welding aluminum: Aluminum welding requires special considerations due to its material properties, such as its high thermal conductivity, sensitivity to heat, and susceptibility to oxide formation. Proper welding techniques and procedures, as outlined in the Aluminum Design Manual, should be followed to ensure strong and durable welds.
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