Truss Panel Points

The Truss Panel Points mode enables to design and check the joints of the truss with the bars made of double angles or rectangular (square) hollow sections. The mode implements a wide range of the types of joints:

• joint between a brace member and the truss chord (regular joint) (Fig. 1, 2);
• joint where the chord changes its cross-section (Fig. 4);
• erection joints (Fig. 5);
• support joints (Fig. 3, 6).

This mode performs the following checks in compliance with EN 1993-1-1:2005 and EN 1993-1-8:2005:

• resistance of structural members (plates, bearing stiffeners (end-plates), gusset plates);
• resistance of welded connections (connections between the brace members and the gusset plates, connections between the chord members and the gusset plates, connection between the plates and the chord in the joints where the chord section changes and in erection joints, connections between the support gusset plate and the bearing stiffener (end plate) in support joints of the truss);
• resistance of bolted connections (connection between the bearing stiffener (end-plate) and the support structure);
• a number of structural and assortment constraints.

(a)	(b)	(c)
(d)	(e)	(f)
(g)                                          (h)
(i)	(k)	(l)
Figure 2. Regular joints in trusses with elements made of rectangular (square) hollow sections

(a)	(b)
(c)	(d)
Figure 4. Joints where the chord changes its cross-section in trusses with elements made of double angles

The Truss Panel Points dialog box contains six tabs: Type of Joint, Materials, Forces, Joint Members, Structure, and Drawing.

The Type of Joint tab contains buttons which are used to select the type of a truss joint (Regular Joint, Section Change, Erection Joint, or Support Joint) and to specify its configuration. You can define the type of cross-section for the bar members of the truss by using the respective buttons in the Structure group.

This tab also enables to specify the materials used in a joint of a truss with the bars made of double angles or hollow sections. A steel grade for these members can be selected in the Steel dialog box, which is invoked by clicking the Angle steel and Gusset plate steel buttons.

The Type of Joint tab also contains the Stamp button used to fill in the stamp of the drawing, which will be generated automatically once the structural design of the truss joint is completed. The Stamp dialog box is described in Rigid Column Bases.

The Forces tab is used to specify axial forces N_t acting in the bar members of the truss joint. Clicking the Add button adds a new row to the table of internal forces, where you have to enter the values of internal forces for the current design combination of loads. There can be any number of design combinations of loads. The default units of measurement for axial forces are tonnes. The drawing next to the table of internal forces defines the positive directions of internal forces in the sections of the truss members.

The Joint Members tab is used to specify the dimensions (width and height) of panels adjacent to the considered truss panel point (parameters a, b, c, and d). The default units of measurement for the dimensions of truss panels are meters. The Section group is used to specify the cross-sections of members connected in the considered joint and their orientation with respect to the truss plane.

The Type of section buttons enable you to select:

It should be noted that the set of Type of section buttons depends on the design of the joint specified in the Structure group of the Type of Joint tab.

Each member of the truss joint is assigned a number (e.g., ). To assign profiles to the truss members, you have to select the respective radio button of the member and select a profile from the list of assortments of rolled profiles. The specified cross-sections of the members of the truss joint can be checked in the Preview window, which can be invoked by clicking the Preview button ().

You have to specify the position of the gusset plate by clicking the respective buttons in the Position of the gusset plate group. The thickness of the gusset plate can be selected from the respective drop-down list, which provides a set of thickness values according to the assortment of sheet and plate steel.

The Structure tab provides a draft of the design for the truss joint.

To perform a check of the load-bearing capacity of the specified structural design of the truss joint, you have to specify all design parameters of the joint. The parameters include the sizes and thickness of structural members of the joint, leg lengths of welds, sizes which determine the mutual arrangement of members, diameters of bolts, the number of bolts, the number of bolt rows, etc. The parameters of the joint are entered in the table on the left. Leg lengths of the fillet welds are entered in the table at the bottom of the dialog. The default units of linear measurement are millimeters.

Clicking the Design button drops down a menu. If the first item, All parameters are not specified, is selected, the automatic selection of all parameters of the joint design is performed and it is assumed that the parameters of the joint design are not specified (are equal to zero), and their previously specified values are ignored. If the Some parameters are specified menu item is selected, the program will automatically determine the values of the undefined (are equal to zero) parameters from the conditions of the adequate resistance and structural constraints defined by the standards with fixed values of the specified parameters.

Moreover, this mode calculates the value of maximum factor K_max (a utilization factor of restrictions), indicates the type of the check in which this maximum took place, and generates the drawing of the joint design of the MS (metal structures) stage.

Clicking the Calculate button will perform the check of the load-bearing capacity of the specified joint members and of the connections between them according to the selected building code. The result will include the value of maximum factor K_max (a utilization factor of restrictions) and the type of the check in which this maximum took place. A complete list of checks and values of the respective utilization factors of restrictions can be obtained by clicking the Factors button.

Table 1. A list of the load-bearing capacity checks of the members and connections of the truss joints

Once you switch to the Drawing tab, the application performs a check of the joint similarly to the Calculate mode. If the results of analysis of the parameters of the joint members do not contradict the structural and standard requirements, a drawing of the joint design of the MS stage will be generated.

The functionality of the Report button and of the controls in the Drawing tab is similar to that described for the Rigid Column Bases mode.