How to determine the equivalent characteristics of a steel beam supporting a concrete floor?


Steel beams supporting a concrete slab are quite common in building practice.

Yet, one might need to determine the equivalent characteristics of the whole system (for quick assessment of dynamic behaviour for example).

This can be achieved manually or with a section editor program.

Let’s consider the system below:

The distance between the centres of gravity is 14cm + 4cm = 18cm:

Modelling in Advance Design

In Advance Design, this result could easily be achieved by using the Section Editor:

First, a rectangular contour is introduced, with concrete material, to account for the slab:

Then, the HEB280 profile is called from the library and positioned right below the slab:

In the calculation settings, we select the intended material for the equivalent member:

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Graitec PowerPack – Reinforcement layers


With Graitec PowerPack for Revit, a specific functionality has been introduced for assigning reinforcement to a layer (for example Top or Bottom) for easy and quick filtering of the reinforcement. 

The layer might refer to a geometrical location of reinforcement but also to another purpose, such as its function. 

The information about the assigned layer is stored using shared parameters: G.Rebar Location for Structural Reinforcement and G.Fabric Location for Structural Fabric Reinforcement.

The assignment is done automatically and manually. The automatic method is applied during reinforcement generation using calculation modules or reinforcement generators in PowerPack. For example, the top bars in the foundation have an automatically assigned value T (a default name for a top reinforcement). Automatic assignment is made to the selected rebars, for example in the case of a foundation to the lower and upper bars in the pad.

The manual assignment is done for selected reinforcement using the Assign Layers command, which is available in the PowerPack Detailing ribbon.

The Assign Layers command opens a special dialog with the list of default/predefined layers.

The content of the list is based on the configuration from the Reinforcement Layers Definition window, opened by the  Layers Definition command. The user can modify names for default layers, use the Active option to limit the list of layers that can be available during the assignment and add new positions/layers to the Other group.

The value of the layer parameter is mainly used in the new options of the tools for controlling the reinforcement visibility

In fact, in the Rebar Visibility functionality, there is a group of options for selecting by layers.

When the Top or Bottom option is selected, then an additional filtering for reinforcement is activated, respectively by the top and interior or the bottom and exterior layers. When the Selected option is active then the selection of layers for displaying is done through the dialog opened by the Select Layers button .

In addition, three new commands are available under the drop-down list under the Rebar Visibility: By layer, Hide All Reinforcement and Show All reinforcement.

Hide All Reinforcement and Show All Reinforcement allow you to quickly turn off or on the visibility of the entire reinforcement in a given view. By Layer allow you to quickly select the reinforcement to be displayed by using the Layer property.

This is particularly useful when generating drawings with separate views, e.g. for bottom/ top reinforcement for slabs or foundations.

Easy ways to create libraries of typical elements in GRAITEC Advance Design


Among the many features that make modeling in Advance Design easier, today we will look at two simple ways to create your own library of common elements.  These options can greatly speed up the modeling of upcoming projects, especially if you often use the same elements.

The first solution is to save element properties to file for assigning them to other elements in a current or new project. 

Let us see a simple example. Consider a steel structure that has already been designed and verified. Thus all the individual elements such as columns, purlins, lateral bracing etc. are not only correctly modeled but also have their design parameters set correctly.

 If in the next project some of the elements should be modeled and parameterized in a similar or identical way, we can create our own library easily. To do so, simply select an element (e.g. bracing) and use the ‘Save properties’ command located at the top of the properties window (Figure 1).

Figure 1

Importantly, all properties, both basic, such as section or material, as well as others, including release settings, system assignments, and dimensioning parameters, are included in such a saved template.

The template will be saved as a file in XML format, and you can decide on its name and location on the disk. In this way, you can create your own database of typical elements, both linear (steel, concrete or wood) and surface elements. Working with the next project, after modeling the geometry, we can select one or more elements of the same type (although not necessarily with the same properties) and load the properties using the ‘Load a properties file’ command (Figure 2).  

Figure 2

Let us now look at another solution. When we want to create a library containing many elements with information about their geometry, we can use a slightly different mechanism – saving selected elements to the library. To do this, we use the commands available on the BIM ribbon (Figure 3).

Figure 3

The procedure is also simple. Select the objects (it can be any selection of objects of different types, including linear elements, surface elements, supports, loads and others) and export to a file, specifying the insertion point (Figure 4). When inserting into a new project, simply select the file and specify the insertion point.

Figure 4

In this way, we can create a library of typical structural parts (for example, girders, frames, trusses, bracing systems) and, together with the geometry, all the properties of the elements are preserved, including the design parameters.  But this mechanism is more universal and allows you to write any object, for example a layout of selected loads, into the library. This functionality is also useful when one or more users separately model different parts of a structure. Then the element libraries export / import tool makes it possible to assembly these parts into one single project.

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EnergyPlus simulation with ArchiWIZARD


1.    EnergyPlus engine

The EnergyPlus module in ArchiWIZARD provides access to dynamic thermal simulation covering the building envelope, inertia phenomena, glazing, sun shading, and occupant comfort analysis, from the same energy model used for bioclimatic simulations and RT2012/RE2020 regulatory calculations.

Based on the American «EnergyPlus» engine, EnergyPlus is a powerful and comprehensive computing engine that allows to go further in the fineness of the simulated phenomena.
In ArchiWIZARD this EnergyPlus module allows, among other things, to guide architectural choices, optimize projects, energetically audit projects, with high accuracy.

2. Creation and verification of the EnergyPlus model in ArchiWIZARD

Compatible with all CAD solutions on the market, ArchiWIZARD translates the digital model into an energy model, which will be the basis of all energy and environmental calculations. As part of the thermal and dynamic simulations, an EnergyPlus energy model is generated from the ArchiWIZARD model. In other words, the ArchiWIZARD model data is translated to fit the EnergyPlus calculation engine.
The ArchiWIZARD model data that will be translated for dynamic simulation are:

  • Parameters from the building envelope and the model
  • Scenarios

In addition to the ArchiWIZARD model data, the management of the solar masks and the duration of the simulation must be configured in the EnergyPlus module :

Management of solar masks
Simulation time

To start a dynamic simulation, after setting the input data, the EnergyPlus model must be created:

Creation of the EnergyPlus model

After the EnergyPlus model has been created, it is possible to check its consistency directly in the ArchiWIZARD 3D interface.

Model verification interface

Color code :

  • Green : environment (solar masks)
  • Blue : Bay
  • Volume in purple : Temperature controlled areas
  • Volume in blue : Buffer space

3. Variant manager and results

The module is accompanied by a simulation and variant manager, as well as an integrated result viewer to exploit live simulations in the ArchiWZARD interface.

EnergyPlus results interface and 3D view

ArchiWIZARD produces all input (.idf, .epw) and output files for EnergyPlus simulations for an easy interoperability with third-party applications using EnergyPlus.

Learn more about ArchiWIZARD here

How is the anchorage length calculated?


For the Base Plate and Tubular Base Plate joints, designed with Advance Design Steel Connections, to determine the bond resistance of anchors subjected to tension, an anchorage length needs to be computed.

The anchorage length calculation has changed:
 for the French localization (French design annex), the anchorage length will be
computed according to both CNC2M and EC2 recommendations; the smallest
length will be used to compute the bond resistance.
 for the localizations, Eurocode 2 recommendations will be used to determine
the anchorage length.

The main steps which are implemented in the calculation, both for straight and hooked
anchors are the following:

1. The basic required anchorage length, lb,rqd (EN 1992-1-1, 8.4.3)

The calculation of the basic required anchorage length is done according to the EN 1992-1-1, 8.4.3:

The values for the ultimate bond stress fbd are given in 8.4.2, as follows

For simplification, 𝜎𝑆𝑑 = fyd = fyk/Ɣs (acc. to paragraph 3.2.7; fyd = design tensile stress of anchor – conservative assumption).
And:

Straight anchors – Extract from Chapter 3.5 from “Pratique de l’Eurocode 2”, J. Roux,
2009
Hooked anchors – Extract from Chapter 3.7 from “Pratique de l’Eurocode 2”, J. Roux,
2009

2. The design anchorage length (EN 1992-1-1, 8.4.4)


Since we deal with tensioned anchorage, 8.4.4 (2) allows for the use of an equivalent anchorage length (𝑙𝑏,𝑒𝑞), as a simplified alternative to the design anchorage length lbd given in 8.4.4 (1):

𝑙𝑏,𝑒𝑞 = 𝛼1 𝑙𝑏,𝑟𝑞𝑑, for shapes shown in Figure 8.1b to 8.1d
𝛼1 is computed according to Table 8.2 and fig. 8.3 (for hooked anchors):

Paragraph 8.4.4 (1) also provides a minimum anchorage length, if no other limitation is applied:

3. Warnings


3.1 Minimum anchorage length

The real anchorage length* must fulfill the minimum anchorage length condition:


𝑙𝑟𝑒𝑎𝑙 ≥ 𝑙𝑚𝑖𝑛

If the condition is not fulfilled, the anchor bond strength will be neglected.


• Warning message: Anchor bond strength is neglected! Minimum recommended anchorage length is not fulfilled – 8.4.4(1) (8.6), EN 1992-1-1. In this case, l real for hooked anchors is considered to be l = l1+r+l2 (see figure below

3.2 Equivalent anchorage length
The real anchorage length* must be bigger than the equivalent anchorage length (see Figure 8.1, EN1992-1-1):


𝑙𝑟𝑒𝑎𝑙 ≥ 𝑙𝑏,𝑒𝑞


Currently, users cannot define a custom anchor, so if this condition is not fulfilled, the bond resistance will be computed with the real anchorage length and a warning message about the inadequacy between anchorage lengths will appear in the report.


• Warning message: “Increase anchorage length! There is not enough length remained to match the equivalent anchorage length (8.4.4(2) & Fig. 8.1, EN 1992-1-1)”.


In this case, l real for hooked anchors is considered to be l = l1+r (see figure below)

3.3 Hooked anchors – Minimum hook extension
According to fig. 8.1., the hook extension must be bigger than 5 bar diameter:

If the condition is not met, a warning message will appear inside the report.


• Warning message: “The length past the end of the bend is smaller than 5 diameters of the anchor (Figure 8.1, EN 1992-1-1)! The Minimum recommended length is: (..).

Example of a report with warning messages

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Join GRAITEC Advance Design Award Winner’s Ceremony!


The GRAITEC ADVANCE DESIGN AWARD 2021 is an international contest organized by GRAITEC and dedicated to structural engineers and design offices. The award is for the best practical use of Advance Design in Steel / Timber / Concrete design projects. The submission process is now complete, the Jury has selected the winners and we are delighted to invite you to the Awards Ceremony!

Join our live broadcast and watch the Advance Design Award Winner’s Ceremony.
See live discussion of Jury members, Advance Design Award winnersi and Graitec representatives about the projects. Gain and share experience with this unique group of experts!

The ceremony will take place on 19 October at 3PM, in GRAITEC studio in Prague and we will host a live broadcast! During the ceremony you will get to know the winners and their projects, get behind the scenes stories and find out what the jury’s deliberations were like!

You can’t miss it!

Fill in the registration form and be part of the ceremony today

How to determine the rotational stiffness from sheeting to purlin at EN1993-1-3?


The following example shows how to estimate the rotational stiffness of a trapezoidal sheeting connected to the top flange of a purlin (CD,A) as per EN1993-1-3.

Note: Position of sheeting positive / negative

bT: Width of the sheeting flange through which it is fastened to the purlin (in mm)

bT,max: See Table 10.3

In Advanced Design, the rotational stiffness from sheeting to purlin can be considered when the Advanced Stability feature is enabled:

The CD,A rotational stiffness can then be specified in the bedding tab, as the KRx component:

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Importance of Performance Point calculation for Pushover Analysis in Advance Design


The Pushover is a static nonlinear analysis in which the structure is pushed gradually following a predefined load pattern distribution. Material nonlinearities in structural elements are usually modeled by concentrated plastic hinges and the option for including geometrical nonlinearities is available.

A control node, generally located at the top level of the structure, is considered to monitor the lateral displacement while the load is increased. The base shear is plotted Versus the control node lateral displacement and the resulting graph is called the Pushover curve.

The pushover curve represents the structural capacity to resist lateral loads and for this reason it is also called the capacity curve. On the other hand, the adequate seismic response spectrum represents the seismic demand and is also referred to as the demand curve.

The purpose of the pushover analysis is to determine the maximum structural nonlinear response to seismic loads. This extremum is provided in the form of maximum control node displacement. Then, based on its value, the location and plastic limit state of hinges are determined and the inter story drift is checked.

The sought maximum response is found at a point that balances between the structural capacity and the seismic demand. This point is called Performance Point and in Advance Design it can be calculated according to the Eurocode 8 N2 method or the ATC-40 Capacity Spectrum Method (CSM).

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Graitec PowerPack – Rebar Layer visibility


Graitec PowerPack propose a specific command for assigning reinforcement to a layer (for example Top or Bottom) for easy and quick filtering of the reinforcement. 

The layer might refer to a geometrical location of reinforcement but also to another purpose, such as its function. 

The information about the assigned layer is stored using shared parameters: G.Rebar Location for Structural Reinforcement and G.Fabric Location for Structural Fabric Reinforcement.

The assignment is done automatically and manually. The automatic method is applied during reinforcement generation using calculation modules or reinforcement generators in PowerPack. For example, the top bars in the foundation have an automatically assigned value T (a default name for a top reinforcement). This automatic assignment is made to the selected rebars, for example in the case of a foundation to the lower and upper bars in the pad.

The manual assignment is done for selected reinforcement using the Assign Layers command, which is available in the PowerPack Detailing ribbon.

The Assign Layers command opens a special dialog with the list of default/predefined layers.

The content of the list is based on the configuration from the Reinforcement Layers Definition window, opened by the Layers Definition command. The user can modify names for default layers, use the Active option to limit the list of layers that can be available during the assignment and add new positions/layers to the Other group.

The value of the layer parameter is mainly used in the new options of the tools for controlling the reinforcement visibility. Indeed, to the Rebar Visibility functionality, a new group of options for selecting by layers is added.

When the Top or Bottom option is selected, then an additional filtering for reinforcement is activated, respectively by the top and interior or the bottom and exterior layers. When the Selected option is active then the selection of layers for displaying is done through the dialog opened by the Select Layers button.

In addition, three commands are available under the drop-down list under the Rebar Visibility: By layer, Hide All Reinforcement and Show All reinforcement.

Hide All Reinforcement and Show All Reinforcement allow you to quickly turn off or on the visibility of the entire reinforcement in a given view. By Layer allow you to quickly select the reinforcement to be displayed by using the Layer property.

This is particularly useful when generating drawings with separate views, e.g. for bottom/ top reinforcement for slabs or foundations.

Article by Stevens Chemise / BIM Industry Manager / GRAITEC France

Selected reinforcement configuration options for reinforced concrete beams


During the last few years, the Advance Design reinforced concrete modules have been progressively getting more and more configurable for automatically generated reinforcement. New customer-specific settings are added in each version, making the modules for RC beams, RC columns, RC foundations as well as RC walls and RC slabs more and more configurable. This allows you to set the parameters in such a way that the reinforcement for the elements is generated according to your expectations. And of course the expectations on the reinforcement of an element can be different, depending on the user and sometimes on current needs. Sometimes in one project the focus is on the optimum use of the reinforcement and in another on the ease and speed of construction. 

Today, let’s look at a few selected reinforcement settings for reinforced concrete beams.

Common longitudinal reinforcement for the spans

Imagine that we have a reinforced concrete beam with several spans. We have modeled and calculated it as a continuous beam, and we want to generate the longitudinal reinforcement for each span separately. This is the default setting of the module.

But if we want to get the effect of continuous longitudinal reinforcement on all spans we can get it very simply. In the window Reinforcement Assumption on the Longitudinal Bars tab we have dedicated options ‘Bars on Multiple Spans’.

The option Top/Bottom bars extend across the entire beam can be enabled independently for longitudinal bottom and top reinforcement. Additionally, you can select whether you want to extend bars from the first layer only or also bars from all layers (if any).

Let’s take a look at the examples in the pictures below (only the main bars of the bottom reinforcement are shown for easier understanding).

Option for extending is disabled (default setting) – bottom bars are independent on both spans
The first layer is extended
All layers are extended

Linking of longitudinal members with transverse reinforcement

One of the settings for transverse reinforcement is the default shape type of these bars. In the Reinforcement Assumptions window on the Transversal Bars tab, we have a number of useful options for setting shapes. One of them is the possibility of deactivating the automatic selection of shape types and the possibility to choose from the list the type of transversal reinforcement – and actually the way of joining the longitudinal bars not located in the cross-section corners. We have 4 types available, as on the pictures below: A – None, B – Stirrups, C – Pins and D – Multiple links.

Note that multiple links for this case can have two solutions: with one large and one small stirrup or two identical ones. When we can have more longitudinal bars in a layer (than 4, as is the case on the above picture), the number of possible configurations for multiple links is larger. This can also be set according to our needs in the Multiple Links tab where we can graphically choose default settings for different number of longitudinal bars.

Maximum number of longitudinal bars

One of the reinforcement settings is the number of members of the longitudinal reinforcement to be generated due to the width of the beam cross-section.

These settings are available in the Reinforcement Assumption window on the Numbers of bars tab. We can set there the number of longitudinal bars in the span and in the support for different width ranges of the cross-section.

So for example if the cross-section is 300 mm wide, 4 longitudinal bars (in the span and in the support) are taken automatically. Depending on the required calculated theoretical reinforcement, the program will then select the diameters of these bars and if necessary, add additional layers of bars.
But among the options available in this configuration window we can also find a special option that changes the way of determining the number of longitudinal bars. It is called Consider number of bars and layers as maximum limits. When this option is not active, the entered number of bars is considered as imposed. When this option is active, then the number of bars is considered as maximum allowed value and the number of bars will be automatically determined based on required reinforcement area.

As the selection of this method for a given required reinforcement area can lead to a variety of possible solutions, e.g. fewer members with larger diameter or more members with smaller diameter, two options are additionally available for choosing the preferred solution:

  • Smallest reinforcement area – will assure the smallest difference between the real and the theoretical reinforcement area.
  • Minimum number of bars – will assure the minimum number of longitudinal bars and will eventually lead to bigger diameters.

Typically, both options produce fewer bars than the fixed number of columns method, especially when the second option is chosen, but the end result also depends heavily on other assumptions. We can see a simple example for a cross section having 300 mm with three different settings used: A – the number of columns of bars is fixed  (which gives 4 columns of bars for this width), B – the number of columns of bars is a maximum limit, and the first option “Smallest reinforcement area” is selected, C – as previously but the second option “Minimum number of bars” is selected.

Examples of different configuration of longitudinal bars in section for the same required theoretical reinforcement.

All these settings give different configurations for the number and diameters of longitudinal members, but they all satisfy the section verification requirements and give a larger area of real reinforcement than the required area of theoretical reinforcement.

The above settings are only a fragment of the possible settings. It’s worth to get to know all the settings, because thanks to the multitude of configuration options and the possibility to save them to templates, using design modules of Advance Design we can dramatically accelerate the daily work.

Article by Mateusz Budzinski / Technical Product Manager / GRAITEC

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Railing Lugs Feature for Graitec PowerPack


Recently introduced into the Graitec Stairs and Railings, deployed as part of the PowerPack for Advance Steel, is the New Lug feature for Railings.    This new feature allows user to split up the infill panels for site installation, making it easier to transport and install these items if difficult site workspaces, I speak from experience here when trying to transport and install Railings with solid bar infills, can be quite a challenge in the confined space of a Stairwell.

Behind this new feature there are essential settings that can allow the user different types of configurations for the user to allow for combinations needed for full and partial assembly.

Basics of Railings Lug Activation.

The railing lug option inside the Railing macro is available working with mid-rails to post connections, it is available under the Handrailing Connection Tab, as a sub tab Fixing lugs.

Important Setting 1

When you first go to the Fixing lugs tab you may see a dialog page that has a warning message about the availability of the lugs, this is default settings that is driven by the settings under the Middle Handrail to post Tab

The message shown above is driven by the setting in the Middle handrail to post, from the General Tab Connection properties, connection type, the combo box must be set to Aligned.

Middle handrail to post,>General Tab> Connection properties> connection type> combo box > Aligned.

Setting this and returning to the Fixing lugs, the user will then see the option to activate lugs for all or each post location.

On the Fixing lug page, the user will start with a combo box set to  ‘ No Lugs’,  changing this drop down will enable the fixing lugs, noting that the user has a choice to select which method of lugs they wish to use.

When selected the lugs are then active and the user can start changing the lugs arrangements.

Important setting 2

So, the user has set the lugs to horizontal, this means the lugs are positioned along the adjoining mid rail.  But when we set the mid rail Connection type to aligned, then the user must look down in that dialog to change the Check box for the ‘Use Bevel cut on Slope’, unchecking this box will make the mid rail ends change to a square cut end.

Unchecking the box will change the mid-rail ends as shown in in the next image

Lug Types (tip for full vertical closure type)

We saw in the initial drop down that the user can have both horizontal and vertical lugs, but there is another variation under Vertical type, that is a Full Vertical type.   This type can be used to create an end closure to a railing panel that is bolting through and adjacent post.  Useful for when railing panels are too long and need splitting into manageable sections for installation.

The user can change the basic lug type to Vertical from the initial combo box, see top of the dialog tab.  Then using the Type combo box, the user will see options for ‘Each middle rail’or Full Height’, Changing to full height will place a continuous vertical section at the panel end or start depending upon the location settings.

Also another nice feature of the Graitec Macro, is the dialog Tree Structure that allows the user to set the same parameters and types for all the posts in the railing panel, or for each posts, note the structure in the dialog and see that in this instance we have chosen to select Post 2 location, as we wish to split the Top rail at this location also. (split top rail is feature of the Graitec Railings.)

When this is applied you can also go back and change the mid rail ends to give a sloping cut and if required to vertical Flat Section, noting that we changed from Plate to Rolled Steel flat bar section, same as the handrail profile (Could also be different if required.)

There are many other features of the Graitec Railings macro that allow users to progress their designs efficiently and quickly and store settings that they commonly reuse within the product ranges.

Look out for more Tips of using the Graitec Railing tools in our blogs and Video postings.

Article by – John Bennet / Senior Product Specialist / GRAITEC

Provided reinforcement on supports in Advance Design RC Beam


This article explains how the Advance Design RC Beam program computes the provided reinforcement on support.

Assume the following beam with 5 Ha14 bars anchored on support.

These 5 Ha14 bars should make for a 7,70cm² reinforcement area.

In this case, how come the program only returns 4,95cm² on support?

Of course, if the user activates the ‘Fully anchored reinforcement’ option:

Bars will be extended after the bend to ensure full anchorage:

Learn more about Advance Design!

Graitec PowerPack – Edge reinforcement in Revit


Revit propose a various set of commands to distribute rebar within a structural host. It is also possible with Revit native tools to distribute a specific rebar shape along a path with the Path reinforcement command.

This workflow could be used for any polyline path globally.

Nevertheless, in term of possibilities, this tool is not allowing the placement of rebar parallel to the major path such as longitudinal rebar. Graitec PowerPack is proposing a dedicated command to speed up the process of placing a set of bars along a path.

The Edge Reinforcement command is used to quickly generate structural reinforcement along the edges of elements such as slabs or walls. It is available on the PowerPack Detailing ribbon:

This command works by selecting one (or more) edge face, so that the reinforcement can be generated for multiple configurations. 

The configuration window allows the setting of parameters for:

  • transverse reinforcement (open or closed)
  • and longitudinal bars, separately for vertical, top and bottom distributions.

The available settings allow for many different layout configurations, for example:

Adjustment of slab geometry for correct generation of reinforcement bars and drawings


With version 2022 of Advance Design, a module for the generation of the real reinforcement for concrete slabs has been introduced. One of the main tasks of this module is to prepare the reinforcement cage on the basis of the previously calculated theoretical reinforcement and then to prepare a drawing with the description of this reinforcement.

3D reinforcement cage (top bars) generated by the RC Slab module

In practice, the theoretical reinforcement is calculated on the basis of the results of the FEM (finite element) model. However, the FEM calculation model itself, by its nature, is usually a simplification of the real geometry of the structure.

Example of finite element calculation model

But for the real reinforcement and the drawing documentation we have to take into account the real geometry of slabs and supporting elements like beams, columns and walls. Of course, the extent to which the calculated and real models diverge depends on how the FEM model was created. So, how can we ensure that the real reinforcement and the drawings correct in case of model differences? Let’s take a closer look at the possibilities the new module for reinforced concrete slabs in Advance Design offers in this respect.


Consider the first case – the position of the axes of the supporting elements (beams, columns and walls) in the FEM model is consistent with their real position, while the outline of the slab is simplified – the edges of the slab are modelled along the outline of the support axis. This is a common case, especially when the model has been created based on construction axes.


After importing the slab model into the RC design slab module we’ll see the outlines of the supporting elements and the edges of the analytical slab model (green lines in the images below). While the analytical model cannot be modified at this point, we can automatically modify the external geometric contour of the slab.
In this case, we can automatically adjust the geometric contour of the slab using the option available in the geometry parameters window called ‘Slab physical contour’.

With this option we can decide whether:
->leave the geometric contour unchanged, as identical to the analytical contour;

-> extend the geometric contour to the outer contours of beams and walls;

-> extend the geometric contour to the outer contours of the columns;

-> extend the geometric contour to the outer contours of any supports (beams, walls and columns). For this corner example, the effect of this last option is the same as for the previous one.

Note that the change concerns the geometric contour of the plate, while the analytical contour remains unchanged. Therefore the values of the determined theoretical reinforcement do not change and the generated real reinforcement in the stretched area of the slab is assumed to be the same as on the edge of the analytical contour.

Theoretical reinforcement area and bar distribution of the top reinforcement

Let us now consider a different case – the position of the support elements in the FEM model is different from the real one. To illustrate this we will use the same corner from the model shown above. Let us therefore assume that in reality the column is aligned with the correctly modelled beams.

FEM model column positions (left) and true column position (right)

In this case we can use a graphical method to edit the geometric model. To do this, we select the appropriate icon and choose graphically the element that we want to modify.

The new position of the axis is then indicated graphically or the value of the displacement vector is entered from the keyboard.

In a similar way, we can move beams and walls. In addition, it is also possible to graphically modify the position of individual edges of the geometric model of the slab.

Of course, when the geometrical contour of the slab is changed, this affects the arrangement of the reinforcement bars, including their number and length. On the other hand, when the position of the supports is modified, in most cases only the reinforcement drawing is influenced.

Thanks to these easy-to-use methods of geometry modification, the final effect, i.e. automatically generated drawing, corresponds with the real geometry of the slab.

How is computed the average yield strength for a cold-formed member at the EN1993-1-3?


According to EN1993-1-3, formula (3.1), the average yield strength (fya) of a cold-formed member may be calculated as:

Let’s consider the Sigma section below:

In Advance Design 2022, this average yield strength will be used for several verifications, such as the ones where torsion is involved:

Graitec PowerPack – Reinforcement Openings


Revit propose a process to create reinforcement for most structural members, based mainly on two steps: first place the rebar shape in an appropriate section view and then distribute it in an elevation or the opposite, place the rebar shape in an elevation and then distribute it in a section (for longitudinal bars for example).

This manual and repetitive process therefore involve multiple manipulations and frequent switching between Revit views.

Whether for slabs or walls, the reinforcement of any kinds of openings is a recurring operation during projects. This technical aspect is addressed by one of the functions of the Graitec PowerPack, Reinforcement Openings.

This Openings command is used to quickly generate constructive reinforcement around openings. It is available on the PowerPack Detailing ribbon.

The command enables the generation of reinforcement around openings on slabs and walls. It allows as well rebars generation for multiple separate openings at once. For a selected opening , it opens the configuration window with parameters related to concrete cover and tabs for different reinforcement bar types.

The Cover section allows the manual control of the cover, the automatic cutting of bars in case of holes close to the edge and the option to automatically adjust the cover to the existing reinforcement, to keep the correct 3D arrangement of bars.

The remaining parameters are available on independent tabs separately for four optional reinforcement types: Main bars (longitudinal bars along edges), Diagonal bars (bars that are perpendicular to bisectors of corners), Edge bars (transverse bars along edges) and Lintel bars (longitudinal and transversal bars above openings on walls). Thanks to the wide range of settings, many different bar configurations are possible.

This new version 2022 has added a special option of opening rebar for door by the possibility to add or not the bottom diagonal rebar.

In the case of non-rectangular shapes of openings, the reinforcement is generated on its rectangular external perimeter

For beams, users may have to deal with several situations with openings such as placed within the beam, a depression … For all those situation, Graitec PowerPack provide some dedicated tools.

Firstly, the command Main bars or Constructive Dispositions can generate a 3D rebar cage on beam, even those one with custom shape including openings and depressions.

Then, it is also possible to add reinforcement around an opening in a beam with a dedicated command. This opening could be created by the native command By face.

For further information go to   https://www.graitec.com/

Look out for video and further blogs on the various Graitec sites in the coming weeks.

Steel Connection Design – What are the filtering criteria for envelopes and how to use them?


All connections available in the Steel Connection module can be designed using all combinations or envelopes created from those combinations.

The possibility to choose how to use the combinations in the design process is available in the Design Assumptions dialog.

By selecting Envelopes method, the calculation will be performed using only the combinations that provide Max/Min of the design forces using certain filtering criteria done in Advance Design Steel connection.

The envelopes that are considered now in calculation can be seen inside the new Combinations report or inside detailed or intermediate reports in the Load combinations chapter.

The Combinations report added to the available report list for each joint type will display only the Load combinations description chapter, which will provide an easier and faster way to access the envelope list.

As have been mentioned, there are two options possible: All and Envelopes.

Now let’s see how the selection affects the behavior during calculation process.

Combinations = All

For Combinations set on “All”, the Advance Design Steel Connection is using all the combinations generated to design the connection.

Example:

For the Base Plate connection for a tubular column as on the picture below, the number of combinations is 181, and all are used for design calculations. It influences the report (as a table listing all the combinations is long), but the most important is that due to the number of combinations, the calculation time is relatively long.

Combinations = Envelopes

For Combinations set as “Envelopes” the module will calculate the connection using just some of the combinations which are fulfilling certain criteria.  

The criteria used to select just a part of the combinations are the following:

Based on these criteria, Advance Design Steel Connection module is selecting the combinations that compliant with one or more criteria and does the design calculations based on the selected combinations.

The calculation time decreases, and the report is much more compact as only the selected combinations will be listed.

Example:

For the Base Plate connection for a tubular column as on the picture below (having more load cases that the previous example), the number of combinations is 482. But this time calculations are done with “Envelopes” of combinations.

Even there are 482 combinations, thanks to the envelopes, the calculation time is less than for the previous example. And in addition, the report does not have pages full of combination tables and it is generated much faster. The Load combinations description table on the report contains now only several combinations that are fulfilling one or more criteria. And the connection is verified using these combinations

Moving loads in Advance Design


As the 2022 version of GRAITEC Advance Design introduced the Crane Moving Loads feature, in this short article we will take a look at the moving loads available in Advance Design – the Traffic load and the new Crane load. As the traffic load generator has been available for a long time, I will present only brief information about it and focus mainly on crane loads.

Moving load panel on the ribbon

Let us start with the traffic load. The traffic load generator enables us to create traffic loads on road bridges according to EN1991-2 (Section 4). In order to create the appropriate traffic loads on the road bridge (on planar elements), we define graphically the elements composing the carriageway: one or several traffic lanes, remaining areas and footways or cycle-tracks.

Carriageway definition

The next step is to add a Traffic loads family and select the appropriate load model, according to the provisions of the Eurocode. Five load groups are available, containing respectively:

  • gr1a – combination of the concentrated loads (Tandem Systems) and the Uniformly Distributed Load (UDL System) with the uniformly distributed load on footways.
  • gr1b – a couple of concentrated loads that represent a single axle of a truck, for creating concentrated forces along the lane.
  • gr2 – combination of the concentrated loads (Tandem Systems) and the Uniformly Distributed Load (UDL System) with  braking and acceleration forces and centrifugal forces.
  • gr3 – uniformly distributed load on footways.
  • gr4 –  uniformly distributed load on footways and traffic panels.
Traffic load model selection

After automatically assigning the load parameters to the roadway, we are ready for load generation in the model.

Carriageway load parameters

Depending on the load model selected, this results in load cases that include uniform loads as well as a series of consecutive steps in the position of the concentrated forces from the vehicle wheels.

Uniform loads and moving loads from vehicle (all steps are shown)
Loads in section for one of the selected steps

For loads from cranes, the process is somewhat similar. The first stage consists in defining graphically the route of the crane forces – it can be a single polyline to model the forces moving along a single rail (for monorail crane modelling) or two parallel lines to model the route for the forces from two trucks on both sides of the bridge crane.

Runway for the bridge crane placed on two beams

The next step is to add a Crane object. It is used to describe the geometry, such as the number and spacing of the wheels, and to describe the forces from the wheels.

Basic crane geometrical data

In the simplest case, the forces on each wheel can be defined manually, separately for each wheel. But it is also possible to use three different automatic methods, so that the wheel forces are automatically determined according to the rules of the standard.

Choice of force generation method

We have three methods available for the automatic determination of forces:

  • By crane loads (EN 1991-3) – for defining wheel loads automatically on the basis of entered crane loads, by using Eurocode EN 1991-3 rules. In this method several loads of different origin (e.g. loads from crane self-weight, from the weight of the load, from braking forces, etc.) are separately entered for each wheel. These load components are combined with the dynamic factors and the final wheel forces are determined. As the result this method gives several groups of load sets (ULS Group 1 to 6), according to the EN 1991-3.
  • By crane parameters (EN 1991-3) – for defining wheel load automatically on the basis of entered crane parameters, by using the Eurocode EN 1991-3 rules. The main difference compared to the previous method is that the values for each wheel are not entered, but the crane parameters (like self-weight of the bridge, self-weight of the trolley and the crane capacity) are given. The output is the same as for the previous method – six groups with sets of forces for each wheel.
  • By crane parameters (ASCE/NBCC) – similar to the previous one, so we do not enter the forces on individual wheels, but such loads are calculated automatically on the basis of entered crane parameters. But this time the method of automatic load generation is based on the general method, related to US/CAN standards (especially ASCE). But it is worth to mention, that the load generation rules are generic and are essentially independent of any standard.
Groups of loads per wheel calculated acc. By crane parameters (ASCE/NBCC) method

With the crane runway and the crane with the forces on the wheel, we can proceed to the next step, which is the definition of the load family. Here we determine the range of crane movement and the number/length of moving load steps.

Definition of move parameters for crane load family

The generation of crane moving cases is done automatically after using a ‘Generate’ command available when right click on the Crane Load case family. After it is run a set of moving load cases are generated, separately for each crane and each step position. They contain the forces from all wheels in a given position. Depending on the definition of the crane, these are both vertical forces and horizontal transverse or longitudinal (from braking) forces.

Load cases for each wheel position with forces

Together with the load case generation, sets of force envelopes from all force positions are also generated.

Automatically created envelopes

Importantly, we can define more than one crane and place them on the same or different runways. In this case, the program will generate for each crane a series of all force positions and then, when the envelope is generated, only the possible combinations of crane positions are considered.

One of the combinations of positions of 2 bridge cranes on the same runway

The final load combinations are defied by using typical load cases (dead, live, wind…) and Crane Envelopes. This is particularly important when there are a large number of crane steps and especially many cranes, as the final combinations consider only a dozen or so envelopes instead of thousands of crane position combinations.

The static calculation and the results for the combination cases do not differ from other load types and you can check the results for each crane position as well as for the envelope of the crane forces. Specific to crane is a new type of graphical output – the influence line diagram. It shows graphically the value of the result at a given point for all successive positions of the crane.  Although in this version of the program the influence line diagram can only be displayed for displacements in structure nodes, it is one of the additional tools useful when analyzing the results.

Influence line diagram

Graitec product release – Hidden Gems for 2022 release.


June 1st we released our products for their 2022 versions, this covers the entire Graitec portfolio, well within that there are few things that stand out to me coming from the Steel detailing and design background, that sound a clear intention of Graitec in this area.

Advance Design 2022

The first one is within our analysis engine ‘Advance Design’, the New feature of Cold Formed Design to EC3. This is a Game changer for those engineers using portal frame constructions and trying to design the most efficient systems for those structures. 

Powerpack for Advance Steel

The next one is more in the link between our Advance Design platform and Autodesk Advance Steel for the transfer of model data, for this version we have a Newly design GUI and Mechanism for the Synchronization of Data using the Graitec GTCX file format.    This new interface allows form many options to optimise what you wish to transfer and sync,

Figure 1-Example of new Dialog

Within the file and the options available we have the ability to have a dedicated object ID,  object type, Status display for New/Modified/Deleted,   Material,  Geometry, Element Type.

Figure 2-example of column types

Having all these options, we now have also filter options available, to help you dig down and only see the data you require.

Figure 3- filter example.

Also, the file has now the option to contain the level of the element within the model space.   It has two options to show the host location and the allocated level in the GTCX itself.

Also, all important one for model Tolerance, this allows for the user to control during the Sync process the variation between the model elements is acceptable, based upon those numeric values.

Figure 4- tolerance example

 Concrete elements are now also considered for the GTCX file and the transfer, presently standard column, and beam shapes for this version, but sure other more complex shape definitions will be added to this new feature.

There are a lot more elements and options to the GTCX and the New Sync process, these are explained in depth in the what’s new, that is available to customers via the Graitec Advantage site.

Powerpack Premium Steel – Stairs and Railings

Within the premium model, particularly for Stairs and Railings we have a great new feature for those working with panelised balustrades/railings, that is the inclusion of ‘Lugs’ to the panels.

We can now add vertical and horizonal/incline lugs.

This may only look like a small feature but for those of us that have to detail these, this will be a real time saver.

Figure 5-Lugs dialog – perpendicular/incline to rail
Figure 6- Lugs – vertical to post.

Anther part of the railings in the actual placement of panels within the rail, previously there where some limits on what we could achieve, but again the development team have worked on this to improve this function to accommodate more complex arrangements.

Figure 7- complex panel shaping

This also works with the frames type panels as well.

Figure 8- framed types

A new option is to allow for the user to turn off the top rail and still have the panels,  this can be useful in the situation of external fencing panels and picket type fencing arrangements.

Figure 9- fencing arrangement/ Stairs/ pickets etc.

For further information go to   https://www.graitec.com/

Look out for video and further blogs on the various Graitec sites in the coming weeks.

The new rebar drawings generator



With the new release of the Powerpack for Revit 2022 we are launching the new rebar drawings generator.

In this post I am intending to explain the concept behind the tool, assumptions that were made in order to obtain the best results and at the end I will add some tips&tricks.

As you know, we already had a view generator in the Powerpack. There were 2 issues that were making the mechanism basically unusable:

  1. ​​​​​​​​​​​​​​The mechanism used an external Revit file that contained the drawing configurations. Therefore, there was no initial link between the user’s Revit project and our drawing template. Of course, our template could have been customized but it would had presumed some time.
  2. In order to work properly, the rebar cage needed to be generated with the Powerpack so that rebars could have roles. After the generation, the mechanism knew the roles of the bars and knew what to do with them.

We decided to stray from this approach and we established the main pillars the mechanism will be based on:

  1. The mechanism will be totally based on the user’s Revit Template.
  2. It will use the active project’s view templates, detail view types and rebar schedules. It will read the Multi-Rebar Annotation, Tags and Title blocks families.
  3. The rebar cage inside the element can be manually modelled or generated by the Powerpack.
  4. The section of the elements will not be an issue. The mechanism will work the same for cast-in-place or pre-cast elements.
  5. We will implement the mechanism is such a way that it will take account of the user’s browser organization sorting rules by inserting Revit’s View parameters also.
  6. We will be able to generate wall drawings also.

In a few words, this is how the mechanism works:

  1. Using the drawing manager, the user will make his own drawing configurations for each category of elements (Beams, Columns, Walls, Foundations)
  2. The user will run the command and he will select the elements.
  3. After the selection is made, the grouping algorithms will decide if the elements can be treated as a group or not.
  4. The configuration dialog will appear, and the user is able to change the configurations.
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The drawing manager
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Selection of elements
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Create views dialog

Using the user’s Revit Template

This part of the implementation was easy-to-do. However, during the development we ran into the issue of multiple projects. We decided to not put the user to make the drawings configurations each time he starts a new project (Assuming that users have the same revit template).

We decided to create an .xml file that will contain all the configurations made by the user. This way, the settings will always be there when the user starts a new project. Of course, modifying the Revit template to a completely different one means that you should do the configuration again.

The .xml file is placed here: C:\Users\<User>\AppData\Local\Graitec\Advance Design modules\2022\Templates\Revit\DrawingConfigs

Furthermore, with this approach, the .xml file can be shared across the office. This way only one person needs to make the configurations.

Supported elements and Rebar cages​​​​​​​

​​​​​​​The mechanism will work the same for any Revit Family. We are not using any mapping mechanism. Any Loadable family will be supported. Model-In-Place elements are not supported.

We established that we needed to perform the drawings regardless of the method the rebar cage was obtained (by hand or generated by the Powerpack). In order to achieve this, we needed to use the Style of the rebar shape family.

Quick recap: The style of the shape can be Standard or Stirrup/Tie. There are no geometrical differences between these two, any rebar shape can be set as either of them. The difference comes from Revit’s rebar constraints mechanism. When placing a stirrup/tie bar, it will search for the nearest host rebar cover. Standard bars will additionally search for the stirrup bars handles. Basically, the Stirrup knows that it needs to tie Standard bars. This is especially helpful when modelling rebars by hand.

Thus, we are using the style of the rebar as an input parameter in order to know on which bars we are placing Multi-Rebar Annotation or for which bars we are generating bending details.

This is probably the most important point in order to achieve proper drawings.

Example:

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Rebar shape styles

​​​​​​​Drawing manager dialog

We needed to let the user configure his drawings according to his Revit template and requirements. The dialog will manage the Annotations, Bending details (General page) and drawing configurations (Element category pages).

In the following I will explain all the options inside the dialog.

General page

  • Generate views only by default configuration – Checking this option will bypass the Create views dialog. The drawings will be generated according to the check at the left of the configuration in the left panel. It was intended to speed up the process.
  • Name – The name of the annotation configuration. It will be further used in the drawing configuration
  • Rebars – The rebars that the user wants to place Multi-Rebar Annotations on.
  • Rebar Presentation – How the users wants to show the rebars in the generated view. Examples: Central bar, three in the middle…
  • Multi-Rebar Annotation – The family that the user wants to use for this drawing. The list will contain all the MRA inside the project
  • Group MRA – If the elements has multiple distribution of the same rebar number you can group the MRA in order to obtain a single distribution symbol. Example: For a beam with stirrups distributed on 3 zones you can obtain 3 MRA or only 1 MRA.
  • Multiple Tag Family – On rebars that are not distributed, we are placing rebar tags using our own tag multiple bar command. The user needs to set what tag family he wants to use.
  • Bending detail family – What family the user wants for the generated bending details

Drawing configurations:

  • View type – what kind of drawing the users wants his configuration to contain. He can choose from a list that is different for each element category.
  • Revit view type – We used detail views for the drawings. The user can choose what detail type he wants for his drawings. We considered that this option might be used also for the browser organization. The list will contain all the detail view types in the model.
  • View Template – What view template the user wants to apply to the view. The list will contain all the view templates in the model.
  • View scale – At which scale the user wants to generate the drawing. If the view template has the scale included, the value in the dialog will be ignored.
  • Length ratio: Percentage of the length/height of the element at which the section/plan view/node detail will be generated.
  • Annotation – the annotation configuration that the user wants to use in the drawing. The list will contain the configurations from the General page
  • Bending detail – the bending detail configuration the user wants to apply to the view. The list will contain the configurations from the General page.
  • Rebar schedule category – what type of rebar schedule do you want to generate for the select element (Structural Rebar, Fabrics etc.)
  • Rebar schedule type – a template that will be used for the newly generated rebar schedules. The list will contain all the schedules inside the model according to the selected category.
  • Titleblock ​​​​​​​- A list of all the titleblocks in the model

Revit View parameters and Browser organization

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Browser Organization

Advanced Revit projects are using a different browser organization rule. They are doing this with a combination of Revit View Parameters. We decided that the drawings should not be randomly generated and should take advantage of the user’s browser organization.

In order to do this, we needed to read the project’s view parameters and include them in our drawing configurations.

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Add Revit View Parameters

First you need to add them into the drawing manager by clicking on the “Manage” button. Some parameters might be included in the view templates definition, so you do not need to include all of them. After adding them in the drawing manager, for each configuration, at the end of the table, new columns will be added.

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Revit View parameters added to the configuration table

If you want all your drawings to have the same value for a parameter, you should insert the value into the drawing manager. However, if your values differ for each element, you should insert them into the Create Views dialog.

Grouping algorithms

Users have different ways of modelling in Revit so we needed to develop some connection algorithms that will allow us to group elements. Each element category needed to have its own grouping algorithms. Also, the grouping was made accordingly to the desired drawings.

We also took account of the design groups made in the Powerpack. Thus, if there are Multi-Span Beams or groups of Walls the user will need to select only one element inside the group.

Beams

For individual beams to be treated as a group they need to fulfill these two conditions:

  1. They need to share a node.​​​​​​​
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Connected node in order to treat beams as a group
  1. Their axis need to be coplanar.
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Different examples for beam groups.

​​​​​​​Grouping will allow the user to generate a full-beam elevation of elevation per each span. Sections will be placed for each span.

Columns

There are users that model columns individually for each level or who model them throughout the full height of the building. We needed to be able to obtain full column elevation. We also support slanted columns.

To be treated as a group, columns need to fulfill these conditions:

  1. They need to be concurrent.
  2. They need to share the same X and Y global coordinates
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Column Groups

Walls

            Structural walls are usually complicated drawings. They contain a lot rebars and usually they need multiple types of drawings (plan views, node details, sections, elevations and so on)

            Wall groups are also different from the other element categories because they need to be grouped on 2 different planes. First they need to be grouped on the horizontal plane in order to obtain the plan view and then they need to be grouped on the Z direction in order to obtain the full elevation.

            The discussion regarding the manner of modeling walls is the same from the column. They can be modelled individually or through the full height of the building, so we needed to address this issue.

In order to treat them as a group they need to fulfill these conditions:

  • For proper plan views:
    1. They need to share the same Base Constraint, Base Offset, Top Constraint and Top Offset
    2. They need to share an edge
  • For proper elevation:
    1. They need to be concurrent
    2. They need to share an edge​​​​​​​
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Wall groups

Final results:

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Full beam elevation with sections
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Wall drawings

Final Tips&Tricks

  1. Pay attention to rebar styles (Standard and Stirrup/Tie)
  2. I recommend making dedicated View Templates to each element category. This way you can automatically hide unwanted rebars or sections
  3. You can use multiple bending details tags
  4. You can use this tool also for the initial views the user needs to have in order to place the rebars. Generating drawings without multi-rebar annotations and bending details will be instantly done. You can use this in your advantage.