XFEM4U Beams

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Beams

Preface

In the graphical screen beams can be added very easy by drawing them. Select this item in the function bar. Beams are drawn as a 'polyline' just as you know it from AutoCAD. The begin node from a following beam is the end node of the last drawn beam.

It is possible, but not necessary, to draw nodes before you insert the beams. You can also start with drawing the beams, in this way the nodes will be inserted automatically.

When you draw your first beam, the dialog box shown below appears. In this box you can, among other things, insert the beam connections and the profile of the beam. Use the escape-key or click the right mouse button to end the drawing of the beams.

As you are drawing a beam, help lines (horizontal and vertical) will appear connected to the previous inserted nodes. Often the node, to which you want to draw the beam, has the same x- or y- or z-value as the previous one. In this way it is easy to insert nodes. Obviously you can adapt the coordinates afterwards numerically or by moving the node.

While drawing a new beam, a dimension line parallel to the beam in one of the main directions x,y or z will appear. You can, just as you know it from AutoCad, immediately insert the distances numerically by entering the value / values from your keyboard. There are 3 possibilities for drawing a beam:

1. Drawing a beam with a known length in one of the main directions.

The value will appear in the dimension line. Here you can type in the distance. By the use of the enter-key the input is closed and the beam with that length will be added.

2. Drawing a beam using relative Cartesian coordinates (dx, dy, dz).

First you enter the distance in x-direction. The value will appear in the dimension line. Thereafter you type a semicolon ";" and the distance in y-direction. The value will appear in a second input field. Next you type a semicolon ";" and the distance in z-direction. The value will appear in a third input field. By the use of the enter-key the input is closed and the beam is added.

3. Input of relative cartesian coordinates (dx, dy, dz) or absolute cartesian coordinates (x, y, z).

Press the space key and the dialog box below appears. Here you can enter relative coordinates or absolute coordinates directly.

In this way, you can quickly insert your construction.

When you draw a beam for the first time, a profile needs to be chosen / inserted. There is asked what kind of profile you want to add. Also when you insert a new profile, there is asked which kind of profile you want to add.

Subsequently the following dialog box of the profiles is shown. See Profiles

Changing a beam

Changing a beam is possible by clicking on the beam with the left mouse button, and subsequently choose for properties by clicking with the right mouse button. There is a more easy way, namely a double click on the beam. Consequently the following dialog box will be opened.

Beamproperties: General

Beam number

The number of the beam.

Length

The length of the beam in mm.

From node no.

The number of the begin node.

To node no.

The number of the end node.

Flip

By the use of this function, you can turn around the beam orientation. The begin- and end node will be switched.

Angle x-axis

The angle in which the local coordinate system can rotate around the x-axis.

The clockwise direction is positive.

Layer

Beams can optionally be drawn in layers. This corresponds to the functionality of AutoCAD. The layers can be set visible or invisible. (on/off). You can adapt the names of the layers. See Display options

Orientation node

The number of the orientation node. This is a node in the local x-y plane or in the x-z plane.

Split into structural member sections for analysis

Setting whether, for the determination of the force distribution (framework calculation), the beam has to be split in in partial beams when nodes are found on the beam. This function is enabled by default.

Self-weight automatically generated.

Setting whether the dead weight of the beam needs to be generated. This function is enabled by default. See XFEM4U Analysis

Surface load bearing

Setting whether the beam carries the surface load or not. See also XFEM4U Loads

Profile Name

Here you choose the profile type

Angle

The angle of the profile. That is the angle relative to the local coordinate system. Usually this is zero degrees. When you want to for example enter the column rotated (so loaded at it's weak axis) you fill in 90 degrees

New Delete Properties

You can also add new profiles and delete profiles. Choose for Properties when you want to adapt the profile data and/or want to select another standard profile type from the profile database.

With every new profile, there is asked what kind of profile you want to add.

Tapered beam

You can optionally enter a tapered beam (Non-prismatic beam). The tab "Profile end" is activated. Here you can enter the 2nd profile at the end of the beam. Attention! The basic shape of the profile section (H-, U-, L-shape, etc.) must match that of the profile at the beginning of the beam.

For calculation background. See Tapered beam

z

With this the profile is orientated relative to the schematic line. ( The schematic line is the line from the begin node to the end node) z is the distance in the local z-direction between the schematic line and the reference line of the profile. The reference line of the profile is showed in the middle by default, but can be set at the top, middle or bottom.

Torsion reduction

Percentage by which the torsion stiffness of the beam is reduced. Specifically for concrete beam grids, it is allowed to reduce the torsion stiffness in case of compatibility torsion. Thereby the occurring torsion moment is lower, and less torsion reinforcement is needed. (stirrups and longitudinal reinforcement)

Beam connection begin and end

Here you enter how the beam is connected at the begin node and at the end node. There are multiple options.

You can make use of the most common / standard connections:

Fully fixed

Tx=A(Absolute), Ty=A, Tz=A, Rx=A, Ry=A, Rz=A. (That is the standard setting)

Hinge

Tx=A, Ty=A, Tz=A. There is no transfer possible between moments, only shear force and normal force.

Tension only

This works the same as a hinge support, the only difference is that tensile forces (positive normal forces) can be transferred.

Springer connection

You can also add a beam with a springer connection. Tx=S(Spring), Ry=S en/of Rz=S. You also need to insert the spring constant Kx, Cy and/or Cz in kN/m resp. kNm/rad

Input per beam

This gives you the possibility to adapt the input for every new beam.

Beamproperties: Eurocode

EN 1993-1-1 / EN 1995-1-1

Specifically and only for the check according to Eurocode 3: EN 1993-1-1 respectively Eurocode 5: NEN-EN 1995-1-1data can be inserted.

Beam group

Specifically and only for the lateral-torsional buckling resistance check a beam group can be inserted here. XFEM4U automatically detects for which beams this qualifies. Only the beams which are connected by a fully fixed connection to this particular beam and have the same profile will be showed. You can select which beams should be taken into account. For this group you subsequently enter the length between the lateral restraints and the buckling length out of plane.

Lateral torsional buckling

Amount of lateral supports / distances between lateral supports

This is only relevant for the check of lateral torsional buckling. You can enter the lateral supports for the top and the bottom flange.

There are 3 options:

1. Number: The amount of lateral supports. That are the extra (lateral supports) between the supports distributed over the length of the beam(group)

2. Distances: The lengths between the lateral restraints from the beginning of the beam (group). The syntax is length1 length2 amountxlenght3.. etc. For example 3000 3x2200 2800

3. Node numbers: Selecting the node numbers which are in the beam group.

Buckling lengths Y-axis and Z-axis

The check according to Eurocode 3: EN 1993-1-1 is based on a geometric non linear force distribution. This means that the buckling of the beams in the plane of the frameworks is provided implicit in the force distribution. For every load combination the internal stability is determined iteratively. By default the buckling length around the y-axis is equal to the beam length. The buckling length around the z-axis is equal to the biggest lateral torsional buckling length. You can also enter different values for both the buckling lengths. See also Buckling.

Note: Regardless of whether the profile is rotated with respect to the local coordinate system, the Y axis is the strong axis and the Z axis is the weak axis analogous to the Eurocode. (See below.) In all checks, all beam forces are transformed to this coordinate system.

Check deflection

Setting if deflection has to be checked.

Type

This influences the requirement of additional deflection.

Additional deflection

Requirement of additional deflection.

Final deflection

Requirements of final deflection.

Pre-camber

The size of pre-camber in mm.

Beamproperties: Dummy

Specifically for plates, it is possible to enter dummy beams. Arithmetically, a dummy beam is taken into account with small bending stiffness.

Line Loads: With dummy beams, any line loads on a plate can be taken into account.

Line supports: Dummy beams can be supported by.

Beam number

The number of the beam.

Length

The length of the beam in mm.

From node no.

The number of the begin node.

To node no.

The number of the end node.

flip

By the use of this function, you can turn around the beam orientation. The begin- and end node will be switched.

Angle x-axis

The angle in which the local coordinate system can rotate around the x-axis.

The clockwise direction is positive.

Layer

Beams can optionally be drawn in layers. This corresponds to the functionality of AutoCAD. The layers can be set visible or invisible. (on/off). You can adapt the names of the layers. See Display options

Orientation node

The number of the orientation node. This is a node in the local x-y plane or in the x-z plane.

Line supports

Indication/ Description

' ' free - no limitation

'A' Fully limited (Absolute)

'P' Limited for a Positive reaction force; free for a negative reaction force

'N' Limited for a Negative reaction force; free for a positive reaction force

'S' Springer (Spring); spring value needs to be inserted

Local to the plate

Setting whether the supports are to be introduced in relation to the local axle system of the plate.

Supports / Restraints

Here you enter how the beam is supported. There are many possibilities.

You can use the most common / standard supports:

• Fully fixed Tx=A(Absolute), Ty=A, Tz=A, Rx=A, Ry=A, Rz=A. (That is the default setting)
• Hinged Tx=A, Ty=A, Tz=A. No moments can be transmitted, only transverse and normal forces.

Spring support

You can also enter a spring support. Tx=S(Spring), Ry=S and/or Rz=S. You also give the spring value Kx, Cy and/or Cz in kN/m or kNm/rad.

Local x-axis see XFEM4U Design Arrangements

Input per beam

This gives you the possibility to adapt the input for every new beam.

Profiles

The first time you draw a beam, a profile needs to be chosen / inserted. There is asked what kind of profile you want to add. Also if you want to enter a new profile, there is asked what kind of profile you want to insert.