.png)
The Hollow Section Splice is intended for the design of splice connections in rectangular, square and circular hollow sections. The hollow section splice designs for major and minor moments, axial force and shear forces arising from forces acting in the major and minor axes directions. The hollow section splice will also design for torsion forces. For hollow splice connections, the bolts are placed outside the section and so the end plate must project beyond the section. For rectangular and square hollow sections, bolts are place above and below and to the left and right of the section, and are termed top/bottom bolts or side bolts. It is possible to use only side or top/bottom bolts in an RHS or SHS splice connection. With a CHS splice the end end plate design is always based on a circular end plate.
The default layout of the hollow section splice connection is shown below. The default section is an RHS with 2 bolts top and bottom and 2 bolts per side.
The General area provides inputs to name the connection brief and also to apply a title to the current loadcase, for non-linked connection design. In the case of a linked connection design, the loadcases and load cases titles will be taken from the Masterframe model. The default layout of the General area is shown below.
.png)
Title - input the title of the overall connection. This will appear in the connection output
Load Case Title - the title for the currently selected loadcase. In a linked model this will be the title from the Masterframe loadcase
The Forces area provides inputs for the design of standalone hollow splice connections. In the case of a connection linked to a Masterframe model, the forces will be taken from the analysis model for the various loadcases setup in Masterframe. The default loads in a standalone connection are zero. To input a value, each row is selected using the mouse and the required value input in each row. To set a loadcase to be included for printing, select the Print Case row and set to drop down to Yes. Loadcases are selected using the top menu drop down.
.png)
Axial (kN) - input the required connection axial force. Compressive forces are input as +ve values
Shear x-x (kN) - the shear force due to loading in the major axis direction
Shear y-y (kN) - the shear force due to loading in the minor axis direction
Moment x-x (kNm) - moment due to load in the major axis direction
Moment y-y (kNm) - minor axis moment
Torque - the factored torque acting on the connection. Clockwise direction is taken as positive.
Print Case - shows whether or not the current load case has been set to print
The Beam Properties area provides input to define the section that is to be spliced. This area also provides inputs to define the type of bolts used and the bolt grade and diameter. In the case of an RHS section, the Beam Properties area also provides an input to define the orientation of the rectangular section. The default section is a 350x150x8 RHS with 20mm Grade 8.8 bolts. In the case of a connection linked to a Masterframe model, the section size and type will be taken from the Masterframe model.
The default Beam Properties area is shown below.
.png)
Beam - indicates the currently selected beam section
Steel Grade - indicates the selected steel grade for the selected section
Section Type - indicates the currently selected section type
Section - indicates the currently selected section size
Rotate RHS? - indicates whether the RHS is aligned with the major axis vertical or not
Bolt Details - displays the currently selected bolt diameter and grade
When the section type is changed to an SHS, the input area is the same as for an RHS. Is is possible to define an SHS to be rotated, though due to the symmetry of the section, this does not amend the calculations nor change the results.
When the section type is changed to an circular hollow section, the input area amends to remove the Rotate option, which is not relevant to a circular hollow section.
To input the required bolt parameters, the Bolt Details row can be expanded by clicking on the arrow to the left of the Bolt Details row. The expanded area is as shown below.
.png)
Bolt Grade - indicates the grade and diameter of the currently selected bolts
Bolt Diameter - indicates the selected bolt diameter. To select a bolt diameter, click to select the row and use the drop down options
Hole Dia - click to select and use the drop down options to select the required bolt diameter as a function of the selected bolt diameter
Slip factor - the slip resistance factor ks for preloaded bolts
Long shank - select whether the bolt has a long or standard shank length
The End Plate area provides inputs to define the properties of the end plate. These inputs give control over the end plate thickness, steel grade and dimensions, as well as providing input to control the weld grade and size. For end plates used with square or rectangular sections, the end plate width and height can be input manually, or the end plate can be sized automatically based on the bolt diameter and the user defined edge distance. In the case of a circular end plate for use with a circular hollow section, the plate diameter can be input, or the end plate sized automatically on the basis of the input CHS and defined bolt edge distance.
The default end plate area is shown below.
.png)
Thickness - the currently selected end plate thickness
Width - the currently set end plate width. An input of zero means the end plate will be auto sized based on the chosen section and bolt edge distances
Depth - the currently set end plate height. An input of zero means the end plate will be auto sized based on the chosen section and bolt edge distances
Welds - the currently selected weld throat size
Plate Grade - the current steel grade for the end plate
To input the required end plate parameters, each row in the End Plate area can be expanded by selecting each row and inputting the required values. In the case of the welds, clicking on the arrow to the left of the row will expand the Welds area. The expanded Welds area is shown below.
.png)
Full butt weld - define the weld to be a full penetration butt weld
Weld size - the weld throat size in millimetres
Deep fillet pen - define the depth of the deep penetration fillet weld
If, in the Connections Defaults the weld type has been set to partial penetration butt welds, then the Deep fillet pen input will be noted as Partial pen prep to reflect the type of weld specified.
For rectangular and square hollow sections, the bolts inputs are defined for the top and bottom or side zones, with each bolt zone using a separate input area. The default RHS Top & Bottom Bolts area is shown below.
.png)
Edge Distance - the currently set edge distance for the bolts
Pitch - the bolt centre-to-centre spacing
Number of bolts - the currently set number of bolts in the top and bottom bolting zones
To modify the input parameters, select each row and input the required value.
For rectangular and square hollow sections, the bolts in the side zones are defined separately from the top bolts. The default RHS Side Bolts area is shown below.
.png)
Edge Distance - the currently set edge distance for the bolts
Pitch - the bolt centre-to-centre spacing
Number of bolts - the currently set number of bolts in the top and bottom bolting zones
To modify the input parameters, select each row and input the required value.
For circular hollow sections, the splice connection design is based on a circular end plate with bolts equally spaced around the end plate. The default CHS Bolts input area is shown below.
.png)
Edge Distance - the currently set edge distance for the bolts
Number of bolts - the currently set number of bolts in the top and bottom bolting zones
Ideally any splices in a member in compression would be located at or near a point of lateral restraint or a point of inflexion. Where this is not possible, account needs to be taken of the second order effects which will be additional to the forces and moments in the member at the splice location. The second order effects as additional moments due to strut actions, moments due to lateral torsional buckling and amplification of the moments due to the eccentricity of the axial force in the member due to the deformed shape under the applied moments.
The SCI Advisory Desk have produced the advice note AD 243 which provides a methodology for determining the additional second order effects. Background to the method covering the need for such additional moments is given in SCI AD 314, with an explanation of the second order effects given in SCI AD 244.
The default Internal Moments area is shown below. The default values are all zero.
.png)
Moment(xx), max (kNm) - the maximum major axis moment between lateral restraints
Lex, Ley - the effective lengths in the major and minor axes.
Lzx, Lzy - the distance from the splice location to the nearest point of inflexion in the major and minor axes
mx, my - the moment modification factor for flexural buckling about the major and minor axes
mLTB and Pb - the equivalent uniform moment factor for lateral torsional buckling and the bending resistance strength for lateral torsional buckling
In both the standalone design and a design for a linked Masterframe model, the user is required to determine the inputs for the Internal Moments. To input the required parameters, expand the line by selecting the arrow to the left of the row.