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The program now includes a database of Simpson Strong-tie joist and beam hangers, allows you to select these hangers as the bearing support member, and automatically selects a hanger if you select Unknown.
The hangers are selected from a database program provided by Simpson, which is incorporated into the Sizer installation.
The Species Dialog of database editor and/or the materials database files have been modified to account for the different resistance values for Simpson Hangers based on the material species of both the supporting member (header) and the supported one (the main member being designed by Sizer.)
For sawn lumber and glulam, the Simpson Hanger resistances are based on the specific gravity of the material. Specific gravity between .42 and .49 is considered S.P.F and above .49 it is Doug-Fir.
A disabled input called Species Group has been added, which shows one of D.Fir-L, Spruce-Pine-Fir or Northern depending on the specific gravity entered. Northern represents specific gravity less than 0.42.
No changes were necessary to the materials database for these materials.
For structure composite lumber (SCL), the input is enabled and called SCL Type, and offers the choices LVL - DF/SP, LVL – SPF, PSL, and LSL. The existing default LVL database file has been modified to be LVL - DF/SP.
For structure composite lumber (SCL), the input is enabled and called Flange Species with choices D.Fir-L and Spruce-Pine-Fir. The existing default I-Joist database file has been modified to be D.Fir-L.
All inputs for this have been added to the Supports for Bearing Design data group.
Simpson hanger has been added to the support Type input list. The existing Hanger choice is renamed Other hanger.
Simpson hangers are not available for oblique members but are available for sloped members.
The selection of Simpson hanger applies to end supports only, and selection and design will be done only for end supports only. If All supports or any other selection that includes interior supports is selected, then then ordinary Hangers are used for the interior supports.
The Material changes to Header when Simpson hangers are selected, shows materials from both beams and joists. Steel members are not included in the list.
This shows the species for selected Material, as it currently does.
The Grade field is re-tasked to show the section sizes for the selected species, in a b x d format.
Bearing at support end is invisible.
A checkbox indicates that the header is a ledger, which is a member assumed to be affixed to a hard material such as concrete so that nails in the face flange cannot penetrate more than the member thickness. It is active for lumber and SCL materials only.
A checkbox indicates that the header is a nailer, which is a member assumed to be affixed to the top of a member of another material such as a steel I-beam, so that they lie on the flat rather than upright like other members.
Bearing length is disabled and shows Unknown when the hanger selection is Unknown, and the hanger bearing length from the Simpson database otherwise.
Bearing width is disabled and shows Same as beam or Same as joist.
These inputs are unaffected by the hanger selection.
The For unknown bearing length… data group is renamed Hanger options when Simpson Hangers are selected. All existing inputs are invisible, and the inputs described below are included instead.
An unlabelled input box has the selections All, Face mount, Top flange, used to filter the hanger list returned by the Simpson database program.
The model input lists the available hanger models given the selections for main member and header, ordered by the cost index value supplied by Simpson.
It is headed by the choice Unknown. Only Unknown will appear if any data needed to select the hangers are not available, such as main member size or no. of plies.
For sloped members, the program lists appropriate angled hangers, showing Simpson’s special information code like SLU5, meaning 5-degree upwards slope.
The fasteners list box used to distinguish those hanger models that have different capacities for different fasteners used on one or more of the flanges of the hanger. It is only when a hanger is selected that has this situation, to allow you to differentiate the repeated hanger model.
The fasteners are designated as Face, Side, or Top, according to which of which of these flanges have differing fastener specifications. If two or more of the flanges have different fastener selections, then the following precedence is used \-Top, Face, Side.
The hanger resistance assuming duration factor CD = 1 and the cost index of the selected hanger are shown in text fields labelled Resistance and Cost index, respectively.
For each load combination, the program queries the database for the resistance corresponding to the load duration of that load combination and uses that for bearing capacity of both the main member and the supporting member. It is then compared to the factored reaction at that support.
The Simpson database resistance includes the bearing factor CB, so Sizer does not calculate or apply a CB factor.
For those load combinations that have an uplift reaction on one or more of the Simpson hanger supports, the program compares the uplift resistance to the factored uplift reaction. Note that it is only Simpson hangers that have uplift design; it is not otherwise incorporated in Sizer.
For load combinations including wind, earthquake, or live loads without snow loads, the program selects a resistance according to the load duration. For dead-only combinations (CD = 0.9), snow load combinations (CD = 1.25), or roof live/construction combinations (CD = 1.25), the resistance for live loads (CD = 1.0) is used then multiplied by the load duration factor. Note that except for dead-only loads, this could lead to non-conservative design; however, these load combinations rarely result in uplift loading.
For materials species with a specific gravity less than 0.42, the lower limit for Spruce-Pine-Fir, the resistance is multiplied by the ratio of the specific gravity to 0.42. This procedure was authorized by Simpson Strong-tie.
When Unknown is selected, the program cycles through all possible fasteners in order from lowest to highest cost index, until it finds one that passes both the uplift and the bearing design criteria.
To determine the minimum required bearing length used in determining the limits of the design span; the member is considered to be supported by a generic hanger or a "non-wood" member; i.e. as if it were supported by a steel plate, and the compressive strength of the main member is used to calculate the min. required length.
After a hanger is selected, the bearing length determined by the flange length B of the hanger and the calculated minimum required bearing are used to determine a new design span, and the beam re-analysed and designed
Under the beam material specification, for each support with a distinct Simpson hanger, a string of information is output giving the model number, a special information code giving for example the angle of the hanger used for sloped members, the fasteners for each flange, and, if necessary, whether backer blocks or web stiffeners are required.
In the Reactions and Bearing table, the fields for Cb, Cb support, and Fcp sup are irrelevant and disabled. The support resistance shows the factored resistance of the selected hanger. The Length shows the length B of the bottom flange of the hanger.
If any of the supports with a Simpson Hanger experience uplift, then rows are added for Uplift resistance and the KD factor used for the critical uplift load combination.
If the program fails for uplift design, a new design criterion is added to the red failure warning message in the Design check output called Uplift restraint.