Horizontal Bracing (Beam)

The Horizontal Bracing (Beam) connection type is used for the design of bracing members connecting to a horizontal beam where the bracing is located in the predominantly horizontal plane, such as occurs in roof bracing. The connection can comprise of a combination of left right or middle bracing located either side of the beam. There is no option to consider an incoming beam supported by the main beam. The beam can be orientated with it's web vertically aligned, or rotated so that the flanges are aligned vertically.

The default layout of the Horizontal Bracing (Beam) connection is shown below.

General

The General area of the property grid provides basic inputs for defining the connection brief and load case titles as well as setting inputs globally for this connection. The General input area also provides inputs to define the main beam section properties and also the properties of the bolts. The layout of the General area is shown below

Title - input the title for the connection design brief.

Load case title - input a title for the currently selected load case

Print Case - controls whether or not a load case will be available for printing

Section - indicates the current selected beam section size and type and steel grade

All plate grades - set the steel grade for all plates used in the connection. Click on the row to change the grade

Beam Left/Right - indicates the current selection for the main beam indicating if the beam extends to the left, right or both to the left and right

Bolt Details - displays the current selected bolt grade and diameter for the connection.

Brace on Major Axis - indicates the current selected orientation of the beam

To set the beam section, the Bolt Details area is expanded by clicking on the arrow to the left of the Section row. The Bolt Details area is shown below.

Steel Grade - displays the current set steel grade

Section type - displays the current section type

Section - shows the currently selected section

Cell Depth - indicates the overall beam depth where cellular beams are used

The selected bolt grade and diameter apply to all the bracing connections within a single design brief. Therefore, it is not possible to set different bolt diameters for different parts of the connection within the one design brief. To define the bolt grade and diameter, the Bolt Details row is expanded by clicking on the arrow to the left of the row. The expanded Bolt Details area is shown below.

Bolt Grade - the bolt grade can be set by expanding the Bolt Grade row. This will reveal a drop down from which the bolt grade can be selected

Bolt Diameter - the bolt diameters are set by expanding the Bolt Grade row from which the required grade is selected

Hole diameter - the diameter of the bolts holes can be selected from the drop down option

Slip factor - set the required slip resistance factor using the drop down options

Top Arrangement

The Top Arrangement input area provides inputs to define the geometrical arrangement of the bracing on the 'upper' side of the beam. The upper side is defined by looking at the on plan drawing of the connection. These inputs control the arrangement of the bracing. Unlike other bracing connections, this connection type can only have bracing members connected to the beam.

The default layout of the Top Arrangement area is shown below.

Top Arrangement - indicates whether the beam has "Top" bracing or not

Has Top Left Brace - indicates whether or not the top left brace is present

Has Top Middle Brace - indicates whether or not the top middle brace is present

Has Top Right Brace - indicates whether or not the top left brace is present

The bracing arrangements assumes a continuous gusset plate for all connection geometries. Thus, where only a top left and top right brace are present, they are assumed to connect to a single gusset plate - it is not possible to define separate gusset plates for each connection.

Top Gusset(s)

The Top Gusset area allows for the definition of the properties of the top gusset or gussets, where a top bracing connection is defined in the Top Arrangement input area. The number of input rows displayed here reflects the set up of the top gusset - where only a gusset is provided, the the provided inputs are for the top gusset and top gusset welds only. Where the top arrangement includes a column, then a lefty and/or right gusset input area will be provided to reflect the bracing arrangement. Where a top left and top right gusset occur, it is, therefore, possible to have differing gusset properties and styles for the top left and top right gusset.

With a gusset only connection, the default layout of the Top Gusset area is as shown below.

Each row controls the definition of the properties of the gusset or the welds between the gusset and the beam and column. The inputs for each set of parameters are accessed by expanding the relevant row by clicking on the arrow to the left of the row.

The expanded Top Gusset inputs area is shown below.

Auto Size - indicates whether or not the auto size option is active

Thickness - indicates the current gusset plate thickness

Brace clearance - the current defined minimum distance from the end of the brace to the beam or column

Bolt edge dist - the current set minimum edge distance for the bolts relative to the gusset edge

Chamfer at brace - the current setting for the chamfer in the gusset plate corners where the corner intersects a bracing member

Chamfer projection - the current minimum projection of the chamfer beyond the brace element

The Auto size option uses the input minimum distances such as the bolt edge distance or the bolt geometry along with the brace setting out point and any horizontal or vertical offsets (see the Top Brace input area) to determine the geometry of the gusset plate. The size and shape of the gusset can be amended by turning off the Auto Size option. Doing so will provide the user with additional inputs. The Auto Size option can be turned off by selecting the Auto Size row and then using the drop down option to select 'No'. Once set to No, this input area modifies to provide input to determine the size of the gusset and chamfers. This modified area is shown below.

Height - the current gusset plate height

Width - the current gusset plate width

Thickness - the current plate thickness

Offset - the current offset of the gusset along the member axis. The default is zero.

Top Left - the current dimensions of the top left chamfer

Top Right - the current dimensions of the top right chamfer

Bottom Right - the current dimensions of the bottom right chamfer

Bottom Left - the current dimensions of the bottom left chamfer

Where a Gusset plate has multiple bracing members connected to it, the shape is set automatically. However, for a gusset plate with a single brace, which can occur where only a single bracing member occurs or where there is a left and right brace either side of a central column but the Separate Gussets option has been set, then the software will allow the user to specify the shape or style of the gusset plate for use with the Auto Size option. This is done by selecting the bracing style which added to the Left Gusset area. The modified Left Gusset input area is shown below.

To select the required gusset plate shape or style, the Style row is selected and the required option selected from the drop down. Once the required option is selected, the graphics update to show the revised connection shape. The available styles are knuckle, straight, tapered, triangle or square. When amending the bracing style, this may also change some of the connection setting out due to a potential change in the connection geometry.

The welds on the gusset to beam and/or column can be defined by expanding the Left Gusset welds area. This is done by clicking on the arrow to the left of the row. The expanded area is as shown below.

Full butt weld - indicates whether the weld is a full penetration butt weld or not

Weld size - indicates the current weld size. An input of zero uses a default weld size based on the gusset thickness

Partial pen prep - indicates the depth of a partial penetration weld

If the Default weld type is set to use deep penetration butt welds rather than partial penetration butt welds with an overlay of fillet wield, the Top Gusset Welds area will reflect this by including a deep fillet pen row instead of the partial pen prep row, as shown below.

Top Brace(s)

The Top Brace area provides inputs to control the parameters of the bracing on the 'upper' side of the connection. This includes inputs to define the section type and size along with inputs to define the bracing angle, bracing force and the setting out of the bracing and bolts. For bracing members design based on an integrated Masterframe model, the section size, forces and angle are determined from the frame geometry and the loads are taken the from the Masterframe loadcases.

The default display is shown below where a top left, top middle and top right brace are included. The number of rows is determined by the set up of the bracing in the Left Arrangement area.

To expand the required row, click on the arrow to the left of the row. Each expanded area contains the same options for each available brace. The expanded top left row is shown below.

Section - indicates the current selected section type, section size and steel grade

Axial - the axial force in the bracing for the currently selected load case. Tension forces are input as a positive value

Angle - the angle of the brace measured from the horizontal

Brace Setting Out - input area to define the setting out of the brace member. The area is expanded by clicking on the arrow to the left of the row

Bolt Geometry - input area for the bolts connecting the brace. The area is expanded by clicking on the arrow to the left of the row

k comp. factor - the effective length factor for the gusset compression capacity check

The bracing member section is defined by expanding the Section area. This is done by clicking on the arrow to the left of the row. The expanded default area is shown below.

Steel Grade - displays the current set steel grade

Section type - displays the current section type

Depth (mm) - shows the current section depth

Thickness (mm) - displays the current section thickness

The steel grade is set by selecting the row and using the drop down to define the steel grade. The section type is defined in a similar manner, by using the drop down options to set the required section type. For standard sections other than flats, the section is chosen using a drop down list. When sections other than a flat is chosen, the Depth and Thickness rows will not be shown and instead a Section row will be displayed, as shown below.

The Brace setting out position and parameters are defined in the expanded Brace Setting Out area. The default area is shown below, which uses the member centrelines and the bolt distance from the nearest edge of the gusset as for the setting out.

Origin - displays the current set origin point. The default setting is to use the member centreline intersection points

Offset Horizontal - the current horizontal offset of the bracing centreline from the origin point

Offset Vertical - the current vertical offset of the bracing centreline from the origin point

End Location - displays the current setting to determine the end position of the brace as specified using the relative position of the end bolts

End Clearance - displays the current set minimum end distance from the end of the brace to the beam or column

The setting out dimension for the end location will change depending on the end location option chosen. For a bolt distance from the gusset option, the minimum distance from the last bolt row to the outer edge of the gusset plate is used. When the end location is set to use the minimum end clearance, then the dimension input required is the end clearance, and the last row of the Brace Setting Out area will change to reflect this.

Brace Setting Out Origin

The brace setting out origin is determined by the centreline of the bracing member and the intersection point with the member it is connected to. In a horizontal brace to a beam, the origin point for setting out is then the intersection of the bracing centreline with the beam. The software provides two options to determine the origin point based on where the brace centreline intersects with the beam. The origin can be defined to be the point where the brace centreline meets the beam centreline, the Member Centreline(s) option, or the intersection of the bracing centreline with the outer face of the beam web or beam flange (depending on the beam orientation), the Flange Intersection option.

Horizontal and Vertical Offsets

The horizontal offset allows the position of the bracing member to be offset horizontally relative to the origin point. The angle of the bracing remains as specified, thus the horizontal offset is a wholesale shift of the brace member horizontally. The vertical offset works in the same manner by shifting the brace vertically. Both positive and negative inputs can be specified. However, where the other input parameters control, it may not be possible to offset the bracing member by the specified amount. This can then result in changes to the overall connection geometry.

Since the brace position relative to the gusset plate is determined not only by the origin point and both the horizontal and vertical offsets, but by the end location setting and minimum end distance as well as the specified minimum brace clearance value, amending the horizontal and/or vertical offsets can result in a change in the relative positioning of the brace member relative to the origin as well as resulting in a change in the size of the gusset plate itself.

Since both the horizontal and vertical offsets affect the positioning of the bracing relative to the intersection of the brace centreline and beam centreline, specifying a horizontal and/or vertical offset will result in additional moments being generated in the main section. These forces are shown in the calculation outputs.

Bolt Geometry

The bolt geometry for the brace connection is defined by expanding the Bolt Geometry area. This is done by clicking on the arrow to the right of the Bolt Geometry row. The default area layout is shown below.

Bolt Rows - displays the current defined number of bolt rows

Row Spacing - displays the current set bolt spacing dimension. The bolt spacing is specified in millimetres

Bolt columns - displays the number of bolt per column

Column Spacing - indicates the spacing of the bolts in each column where multiple bolts have been defined in the Bolt Columns input.

Edge distance - displays the current edge spacing for bolts. An input of zero means the bolts will be aligned on the brace centreline when there is a single bolt per column

End distance - shows the current end distance from the end of the brace member to the first column of bolts

Staggered bolts - displays the current setting for the bolting pattern

To amend any of the above parameters, select the required row and then either input the required value or, in the case of the Staggered Bolts, use the drop down to select the required option.

k comp factor

The k comp factor input provides the ability to specify the effective length factor for the compressive strut design for a gusset plate where the bracing member is in compression. This input is used where the bracing arrangement or bracing member type does not fall into the scope of Section 8.5 of SCI P358.

Bottom bracing

The input areas for the bottom bracing are the same as for the top side, with input areas to allow the definition of the bottom bracing arrangement of brace and gusset members and a bottom column along with inputs for the bracing member section type and size and bracing geometry. For details of the use of the bottom input areas, see the corresponding top inputs detailed above.