This article highlights the importance of construction stages in studying frame structures with transfer beams. For this purpose, a result comparison between Advance Design construction stages and classical full model single run analysis are presented for a steel frame model with a transfer beam.
Keywords: Advance Design, Construction Stages, Transfer Beam.
In conventional structural analysis, all loadings are applied at once on the complete final structure before studying their effects in a single step calculation. In other words, no loading of any type is applied on the structure until the entire construction process is completed. However, in practice, structures are constructed in stages (story by story) and loadings such as self-weight, construction and finishing loads are present at each stage prior to structure completion. Therefore, at each construction stage, the distribution of displacements and internal forces in the completed parts of the structure (due to the existing loads) is not affected by elements of upper stories that do not exist yet.
Neglecting the construction stages effect in the classical analysis will sometimes yield wrong results. A good example where this effect should not be overlooked is in analyzing frame structures with transfer beams.
2.Frame structure with transfer beam
A steel frame structure with a transfer beam in story 1 is considered. This structure is subjected to its self-weight and finishing dead loads at each story (refer to Figure 1).
2.1. Construction stages
Construction stages are defined according to the actual story by story construction sequence (Refer to Figure 2).
2.2. Results comparison
To highlight the importance of conducting construction stages analysis, results comparison between the Advance Design classical analysis (all loads applied at once on the complete final structure) and construction stages will be presented (refer to Figures 3, 4 and 5).
The real structural behavior obtained by the construction stages analysis is very different from the results of the classical analysis. Neglecting the construction stages effect, will lead to a dangerous under dimensioning of the transfer beam and middle column.
In this article you will see how to define a support of limited capacity for example a foundation piles.
Keywords: #AdvanceDesign #Concrete #Piles #FEM
1. New advanced support in Advance Design 2023
In Advance Design you could easily define rigid, elastic and non-linear (tension/compression) supports. Starting with 2023 release of Advance Design the possibilities increase with new more advanced support type. This new type will allow you to define more complex non-linear functions.
The definition of new supports is as it was before. However the restraints are specified differently.
Right now for each direction a different function can be defined. There are 3 linear restraints (free, fixed or elastic) and 5 non-linear where user specify a specific function.
2. Support with limited capacity
One of the example of non-linear support type is ‘Hardening’. For this support user specify a limit in force after which supports reaches it capacity.
Above you can see a support that is rigid until reaching the limit in force of 500kN. After reaching it capacity the support weakens and has reduced stiffness – its not rigid anymore. The restraint become free or elastic if any stiffness is defined.
Please see this simple example below of a foundation slab supported by piles of capacity 500kN.
When external loads are of low value piles do not reach the capacity limit. All works with the same rigidity.
But with increasing the loads some of supports reach the limit. Deformation changes because 2 middle piles can’t take any more load. The forces are distributed to neighboring supports.
With further increasing of loads more and more piles reach 500kN support force, until point of the slab being unstable.
As you can see this new support type will allow you to perform more advanced and complex analysis, and cover a bigger spectrum of design needs.
Note that limit in force is only one of the possibilities. Thanks to non-linear diagram definition user can reflect any behavior of structure support.
In Advance Design, we can quickly and efficiently perform the entire design process of a building structure, from modelling to analysis and structural optimization. And an integral part of the design process is the review, evaluation, and documentation of the calculation results. Today we will look at one aspect of this – methods for viewing results from FEM calculations using values in tables.
Available methods of presenting results with using tables
Results in tabular form can be generated in two ways – by generating tables during report generation, or using a new mechanism introduced in the latest 2023 version, by generating tables with results directly on the screen. Let’s look at the two methods in turn.
One of the main components of calculation reports are tables with results. The selection of the template tables that are to be included in the report is made on the Table tab of the report generator. In case of FEM analysis results, the number and type of available table templates depends on the model, including the type of calculations performed. For example, if no surface elements have been defined in the model, then no templates with results tables for surface elements will be found in the list
However, before we start to generate a report with a table, especially in case of results from FEA results, it is crucial to properly narrow down the range of results to be viewed. The reason is very simple – the number of results can be huge, especially when we have a larger model and a large number of combinations. In addition, most tables, such as the internal forces table for linear elements, present results at each node by default. With a relatively dense division into finite elements, this can result in a table that is many pages long for a single beam. So how do I filter the report tables?
Let’s start by selecting load cases / combinations. This can be done directly in the generator window using the load cases / combinations filter window. Thanks to the convenient selection options, we can easily set the range of interest. The selection made in this way is common for all tables for which you are generating the report.
However, if you want to select a different case range for some tables, then you can filter using the properties dialog box for each such table.
This way is also used for selecting points in which the results are presented. We can increase or decrease the result point density by selecting one of the options from the list. For example, in the table of internal forces of linear elements, by default the results are displayed in nodes of finite elements. We can change this setting so that the results are presented at 3 points – at the beginning, middle and end of the member, for example.
To have the table contain results for only selected objects, we can also use the table properties dialog box to generate a table for only the items in the selected systems. But we can also easily generate a table for any range of objects, even for a single element. To do so, before generating a table, you should simply select the elements for which you want to generate a report.
Another important functionality is the ability to create your own table templates. It means that we can decide what information and results should be placed in particular rows and columns of the table. We can put different types of data and results in the same table, of course within the same element type (for example, a linear element). Such templates can then be used to generate tables in exactly the same way as the default templates.
Tables with results
In Advance Design 2023, we have the ability to filter and check FEM calculation results even faster. This is all thanks to the new “Results Tables” functionality which allows us to quickly display the results in tabular form directly on the screen. This feature is available after the FE calculation has been completed and can be accessed directly from the ribbon.
We can generate tables using default template list, and if we want to narrow the number of displayed columns, we can easily hide the unnecessary.
But we can also create our own template with specific result columns and settings. For this purpose, a similar mechanism and dialog box is used as when defining report table templates. Saved table templates will be able to be used in all projects or deleted when no longer needed.
Similar to the report tables, you can narrow the table content to show results for only selected objects as well as for only selected load cases/combinations.
The tables also have useful features that make it easier to find interesting results in the already generated table. For example in an easy way we can sort values on columns, just by double clicking on headers. And we can filter the results using special fields below column headers. We can use text filters but also different types of single and multiple value ranges. And what is great is that we can easily use multiple filters at the same time.
Finally, another great feature of the tables is the ability to export of the contents of the table to an Excel spreadsheet. To do this, just use the export button and the whole process will run automatically. This allows us different scenarios for further external work with results.
Graphical presentation of results for surface elements
Advance Design can generate and calculate various types of three-dimensional structures, including those containing flat surface elements (such as slabs or walls), as well as shell elements (e.g. curved roofs or circular tanks). In addition to the preparation of the model and the execution of the calculations, an integral part of the design process is the review, evaluation, and documentation of the calculation results. Today we will look at one aspect of this – the ways in which results for surface elements are presented graphically in Advance Design.
The available methods will be presented on the example of one slab of a very simple spatial model of a concrete structure.
For the selected load case, we will check the graphical presentation of the displacement results, but the same methods as presented below can be used to display other types of results, ranging from internal forces and stresses to outputs related to the design of reinforcement (for example reinforcement areas or crack values).
How to change display settings for results
With the model calculated, displacements for all or selected part of the model can be displayed directly using the commands available on the ribbon. The results are then presented using a default display mode – in the case of displacements this is called ‘Deformed’. To change the mode, use the window with the setting of graphic results (opened, for example, using the keyboard shortcut Alt+Z). Note that the list of available display modes depends on the type of element and the type of result. In the case of surface elements, a list as shown in the image below will be available.
Available display modes
Let’s now take a look at the display modes available. The default one is called ‘Deformed’ which presents the results as color maps on the deformed structure. This mode is available also to linear elements, which allows showing results for a whole structure using common color scale.
There is a twin mode, called ‘Iso regions’, which also shows the results as maps but only for surface elements. The iso-value regions represent colored polygons on the planar elements corresponding to certain results on displacements, forces, stresses. Thus it is possible to view the highest stress areas on the planar element within a single glance. The values of these regions can be smoothed or not; for this purpose you can use the option “Smooth results on planar elements” from the Results dialog box – Options tab.
The next display mode is called ‘Iso lines’. The color of iso lines correspond to the results color scale. Note that regardless of the selected style, additional presentation options can be set, such as visibility of the finite element mesh, display of extreme values or values corresponding to particular iso lines.
The next display mode is called ‘Iso maps’, which combines the display of isolines and solid color maps.
As mentioned earlier, we can control additional graphical settings. In the example below, we have the same display mode but with isolines turned off and values displayed in finite element centers.
The next two similar display modes are called ‘X Diagram’ and ‘Y Diagram’. These are diagrams in the X or Y direction of the local system respectively, displayed in a plane perpendicular to the surface element. As these diagrams pass through the centers of the finite elements the resulting effect depends on the density and shape of the mesh.
The next display mode available is called ‘Values’. And as the name suggests, it displays values in finite element centers. Depending on the settings the values can be displayed in scale colors or in solid color.
As the values can be difficult to read (too small or overlapping) in the case of a dense or irregular finite element mesh or at lower magnification, we can display the values using another style called ‘Values on grid’. This display mode comes in three variations – for presenting minimum, maximum or average values in a grid. The results grid is a virtual mesh of regularly arranged rectangles used only for the presentation of results. The setting of the mesh size is available individually in the properties of each surface element.
In addition to the presentation display modes, Advance Design offers various additional options for setting the presentation of the results. Firstly, we can control the color scale. For example, we can set a reduced number of ranges with defined limit values.
Another possibility is the presentation of results using Dynamic Contouring command. This allows you to filter the displayed values to a selected range.
Another way of presenting results for surface elements is to display intersection diagrams. These are created using linear Section cut objects. You may create section cuts in the modeling step and in the analysis step, and like all elements of the model, the section cuts may be selected, resized, moved using CAD tools. Diagrams on section cuts may be generated in the element plane or in a perpendicular plane.
Finally, it is still worth mentioning that for planar elements it is possible to view the forces and stresses results expressed in the main axes. For this we use dedicated display mode called ‘Main axes’. The two main axes are represented graphically by their color, the sign is represented graphically by the arrowhead direction (inward for negative values and outward for positive values) while the angle of axis orientation is given by the alpha values.
Masonry can effectively carry compressive forces but this material only has moderate capacity when it comes to shear.
Yet, masonry walls may be exposed to wind forces that could cause shear failure mechanisms, especially on the top levels, where the compressive forces are moderate.
Therefore, shear resistance of masonry walls must be properly assessed.
Eurocode 6 provides a method in that regard.
2. Sliding shear resistance of an unreinforced masonry wall
Unreinforced masonry walls subjected to shear loading are covered in section 6.2 from EN1996-1-1.
As usual with the Eurocodes, a design force (VEd, design shear force) is compared to a resisting force (VRd, shear resistance).
Assume the following wall:
Initial shear strength: fvk0 = 0,20 MPa
Compressive strength: fk = 5,00 MPa
Partial factor for material: γM = 2,2
2.2. Shear resistance VRd
Shear resistance VRd is defined in eq. (6.13).
First of all, we need to estimate the compressed length of the wall (lc).
The VEd lateral force is indeed creating an in-plane moment that can cause tension at the bottom part of the wall, especially if the compressive forces are low.
Moment at the bottom of the wall
Compressed length lc
The eccentricity exceeds 1/6 of wall length.
Assuming a linear distribution and based on the equilibrium of force and moment:
We can assess the length of the compressed part of the wall:
Shear strength fvd
Assuming all joints (vertical and horizontal) are filled with mortar, we compute the characteristic shear strength fvk with eq.(3.5).
The design compressive stress σd can slightly increase fvk.
fvk does not exceed
The design shear strength is then given by:
Shear resistance VRd
We can finally compute shear resistance VRd from eq. (6.13):
Sliding shear verification:
The sliding shear verification is passed.
This verification can prevent some of the shear failure mechanisms that may occur in masonry buildings.
Of course, hand calculation might be tedious.
Fortunately, our upcoming Advance Design module, dedicated to masonry wall design, will perform this verification, among others, in a matter of seconds and provide a detailed calculation report, with intermediate values and reference to the EN1996-1-1.
In this article you will see how to define a multi-span concrete beam in Advance Design in order to design and detail it using RC Modules.
Keywords: #AdvanceDesign #Concrete #Reinforcement
1. Defining beams in Advance Design
In Advance Design you can model very different types of objects including planar and linear elements, which will represent our structural elements such as beams, columns, walls and slabs. With defining right section and material we can simulate behavior of our structure using FEM analysis.
If it comes to concrete beams we always could provide linear element stretching from one support to another. If we defined also intermediate supports like columns or walls our beam would be treated as multi-span.
2. Super-element concept for RC design
Even though we could easily design a beam shown on figure 1 above this approach has some limitations. Because it’s a single element we can for example specify only one section height for all spans. However, sometimes we need for a different spans to have different sections due to capacity requirements or some technical aspects (such as need of clear height of a story, leaving some space for ducts and so on).
Starting with Advance Design 2022 it is possible to use super element concept also for RC design. Initially it was implemented for steel structures, however using this workflow was found effective also for other materials.
2.1. Creating a super element in Advance Design
To create a super element we model each span of a beam as a single element. Remember to always define them from support to support. If possible, try keep local axes in the same direction and orientation.
Last thing to do is to convert these 3 single linear elements into one super element. We can do that using context menu at right mouse button or finding these exact options on Objects ribbon.
Note that now you can pick whole super element by selecting any part of it. However if you need to select only a single span for example to change its section you need to toggle pick mode from super elements to elements. You can do it by pressing ALT+E or again find it at right mouse button context menu.
After defining a super element you can see it has now new own identifier, a list of elements which you can always edit if needed and also each element included in this group gets a postscript to its name informing user it’s a super element. Remember you can always cancel super element similar way you created one.
2.1. Design of multi-span beam defined as super element
When you are done preparing super elements, rest is as usual. We need to perform a FEM analysis calculations to obtain static results. Now we are ready to open a super element using RC Beam Module.
Notice that super element shown below has 3 spans of 3 different sections height.
Right now we need to specify requested reinforcement and design assumptions. Element will be designed as it was continuous multi-span beam. Reinforcement drawings and schedules also can be provided for whole element at once.
In this article, you will learn how to start modifying and defining your own drawing style template in Advance Design modules.
Keywords: Drawings, Advance Design Modules, Bar schedules, Templates
Modifying Drawings in Advance Design Modules
The reinforcement drawings generated by Advance Design modules are highly customizable. The range of possibilities is very large and can be divided into two groups – the current modifications that can be done to the generated drawing and the modifications to the templates used for generating the drawings
Current modifications to the drawing are mainly done graphically or using a series of simple commands available from the properties list. Among these are ability to modify the scale, change the position of views on the sheet, add/remove views (as new sections), rename views, add dimension lines, move descriptions or symbols.
The second group of modifications relates to the templates used for the generation of the drawings. There are many different types of templates available, starting from the most general Drawing Style, which is a template collecting all settings and layouts of views, through templates controlling the settings of colors, lines and symbols used, templates for title blocks and templates for rebar lists.
Today we will look at modifying the general drawing template – the Drawing Style.
Drawing Style – general information
The style template is the most general template and contains a complete description of the drawing, i.e. the orientation of the paper, how many and which views you see, their scale and position on the sheet, used drawing templates, title blocks and bar schedules.
Each module (e.g. RC Beam, RC Forting, …) has its own set of style templates and their number and content is different depending on the regional settings of the program. So drawings may look different according to the default templates for France and the UK for example. However, anyone can easily modify existing templates or add their own.
Changing Drawing Style
Let’s start with how to apply a style other than the default template. The easiest method is to right-click on the first item in the tree (Drawings) and select one of the styles from the available list – Apply Style.
The list shows the styles available in the default styles folder for the given element type and for regional settings (country). By selecting ‘Select styles’ you can preview the contents of the folder and select a file from another location. This command menu also includes a Save Style command that saves all current drawing settings to a new Style template file.
Layout of views
Most of the changes to the settings in the property list (including the sheet format or the type of reinforcement list) as well as the number and type of views are written directly to the template. However, the placement of views and their scale depend on the Layout of views settings. So it is usually not enough to move the contents of a view (for example, a beam cross-section) to a new location on the sheet, but to move its associated rectangular outline, which is presented as a blue frame. Namely, modify the layout of the views on the sheet
To check and modify the layout of the views in the current drawing, right-click and select Edit Layout command.
We will then see the layout of the views, which we can freely arrange on the sheet by moving the corners of the outlines (using grips). This will allow us to ‘anchor’ a given view on the sheet, also in relation to the other views.
By default, the views are generated according to the position of the layout frame as well as their scale is automatically adjusted to its size. But we can change these settings using two options from the view properties.
The ‘Views fit layout’ option is responsible for automatically scaling the view so that it fits optimally in the frame area. If you disable this option, the scale will not be automatically modified when regenerating the drawing.
The ‘Views follow layout’ option is responsible for the location of the view relative to the frame area. If you disable this option, the view will not automatically follow the frame area when the drawing is regenerated, i.e. the last position of the view after it was manually modified will be preserved.
The above description, of course, only briefly introduces the subject of template customization, so I recommend exploring the available options on your own. At the end, one more note – remember that the final effect, i.e. finally generated drawings, can also be saved directly in DWG format, allowing further changes or assembling drawings in CAD if necessary.
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:
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:
3.1 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: (..).
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).
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).
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.
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
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.
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.
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.
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.
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.
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 selectingEnvelopes 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 theLoad 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.
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.
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
When creating a design model for a structure, one of the steps is to prepare combinations for defined load cases. Most often we use the mechanism of automatic generation of combinations, according to the rules of the standard set in the project configuration. If necessary, we can modify the rules and relations between cases or case families using the available mechanisms in the Concomitance between load cases dialog window (available for Eurocode combinations).
However, while working on many projects there are situations when we want to define a set of our own combinations. Of course, in the case of a small number of load cases and a small number of required combinations, this can be done directly in the combination dialog. Nevertheless, in this article we will take a look at more effective methods, which will work especially well in case of a larger number of cases/combinations and when we want to use our own combination definition in other projects. These will be two solutions: using the mechanism to export and import combination definitions using an Excel spreadsheet and the mechanism to import combination definitions as a CBN text file.
Using an Excel spreadsheet
Starting with version 2020.1 Advance Design allows for easy and quick exchange of combination definitions between the current project and an Excel spreadsheet. For this purpose, there are two dedicated buttons available in the Combinations window.
The Export button exports definitions of all existing in the project load combinations to a new Microsoft Excel spreadsheet. For this a dedicated xlsx file is created on the path selected by the user. The Import button reads definitions of load combinations from the selected spreadsheet and adds them to existing definitions on the current project.
Let’s look at the data structure in the spreadsheet. The first row contains the column names, while the following rows contain the definitions of the subsequent combinations.
This column contains the identification numbers of the successive load combinations.
CODE and TYPE columns
These columns contain the combination type text code (CODE) as well as the name of the combination type (TYPE). The names and type codes depend on the settings of the project location – working language and standard for the load combinations. Below is an example of codes and types for the Eurocode settings:
It is important that when editing or creating a worksheet, the combination types in the TYPE column are consistent with the types available for the current standard. Therefore, in the TYPE column, the cell values are selected from the list.
CAS and COEFF columns
These columns are always defined in pairs and specify the load case ID number (CAS) and the corresponding coefficient (COEFF). The number of pairs of these columns’ headers should be equal to the maximum number of load cases in the most extended combination. Of course we can reduce or increase the number of pairs of headers if necessary. The number of pairs of values in a given row with the definition of the combination depends only on the given combination, but at least one value pair should be defined.
When you import load combination definitions from a selected spreadsheet, these combinations are added to the list of existing combinations in the current project. If combinations with the same ID number already exist in the project, then the ID number of the imported combinations is changed to the first free number. If the combination definition in the Excel file is incorrect (e.g. contains case numbers that do not exist in the model), then the combination is omitted during import. In these cases a warning appears.
Using the possibilities of a spreadsheet, including the possibility of using complex formulas, macros or cooperation with other programs, we have almost unlimited possibilities to prepare and automate the creation of our own load combinations.
Using CBN files
CBN files are text documents containing combination definitions. Generation of the predefined load combination with using the CBN file is based on loading the file from the disk using the Loads CBN button, located in the Combinations window. We can also preview the contents of the file without the generation of combination by using the View button.
To define your own file with the definition of a combination, you need to create a text file similar in structure to the predefined .cbn files. Lines starting with # or // are used to enter comments / notes and are optional. The remaining lines are treated as definitions of subsequent combinations and consist of case codes and coefficients separated by spaces. Additionally, at the end of each line there is space for the combination code and for the comment. Let’s look through the contents of the sample file:
In this example there are 3 lines of combinations, so 3 combinations will be generated. CASE1, CASE2, CASE3 are the type codes for 3 different load cases. Next to each code there are coefficients given with a character. Codes such as ECELUSTR are codes for the generated combinations. They can be arbitrary texts, in which case they will be used as an additional description, or they can be created in the naming convention for a given standard, so that they are automatically recognized as suitable combinations for design calculations. The text at the end of each line of a combination is optional and is not used during combination generation. It can be our additional description visible only during file preview. Note that in the last combination, in the second and third case coefficients equal to zero appear, which means that this combination will only contain the first load case. Exactly the same effect you get if there are no codes and coefficients for these two last load cases in this line. In the picture below you can see the effect of combination generation for the above example.
When loading the file, combinations are generated according to custom definitions, and the combination code is assigned to combinations accordingly. The combination name is generated based on the combination definition.
Note that when using an Excel file, to identify load cases their ID number is used. This allows you to precisely determine the relationship, regardless of the type of load case. However, in this solution we need to know the ID numbers of these cases before the combination is generated.
In case of CBN files, load case codes are used. Thanks to the codes it is easier to prepare a universal combination definition, which can then be used for many projects, but at the same time we have to be careful about the compatibility of the codes in the CBN file and in the project.
In every new project the load case codes are the same for all load cases. They can then either be modified manually by us or updated automatically by the program during combination generation (the program asks for this during combination generation).
Manual modification of the codes is useful when we have prepared the combination definitions in the CBN file using our own codes. In such a case, we can mark each case explicitly in a given project, making sure that they match the codes in the CBN file.
If you allow the program to automatically complete the codes during combination definition, remember that the same codes are assigned to all cases of a given type. This means that all fixed load cases will have the same code, similarly all snow load cases etc. This solution is convenient when there is no need to combine cases inside the same type.
Let’s see the effect of one exemplary row defining the combination in the CBM file:
CASE1 +1.10 CASE2 +1.20 CASE3 +1.30 CombA
Example 1. There are 3 different load cases with names and codes respectively: A – CASE1, B – CASE2 and C – CASE3. The result will be one combination with all cases:
A*1.1 + B*1.2 + C*1.3
Example 2. There are 2 different load cases with names and codes respectively: A – CASE1 and B – CASE2. The result will be one combination:
A*1.1 + B*1.2
Example 3. There are 3 different load cases with names and codes in the project: A – CASE1, B – CASE1 and C – CASE3. Note that the first two cases have the same code. The result will be two combinations:
A*1.1 + C*1.3
B*1.1 + C*1.3
As you can see both mechanisms, either using an Excel spreadsheet or using CNB text files, allow you to easily and quickly create your own sets of load case combinations in Advance Design. I encourage you to get closer to these solutions and use them while working with your own projects.
All modern design applications require a solid testing mechanism in order to detect any regression regarding the quality of the results but also to cover all areas of the application (GUI, CAD, correct workflows, …).
Advance Design has a mechanism based on a script that works like a batch session. This mechanism was mainly designed as a system for automatic tests to offer access to almost all areas in the application. In this way we can reproduce various scenarios.
Since it’s quite extensive and very cryptic, the main idea to use this mechanism is to start from a base script and adjusted or completed with the other commands. A base script can be generated by Advance Design. Usually an automatic test in our QA system consist in a model and a script. Both are passed to Advance Design in command line and the application executes the script.
In the following points we will go into details for such scenarios.
The base model creation
The first step consists in creating a model using your preferred localization and norms. The creation of load cases and their configuration is also recommended.
The analysis hypothesis, options for concrete analysis, steel analysis, etc. can also be configured at this step. Then, after saving the model, a back-up is recommended because it will be needed at a later step.
Until now we could say we have a complete environment. From this point we can start generating the structure elements (linear elements, planar elements, footings….).
2. The elements creation through scripting
2.1. Commands syntax and script composition
The syntax of a command that creates an element with geometry is composed by:
the_name_of_the_command+space+(x_coordinate;y_coordinate;z_coordinate)[and repeat the ’+ space+(x_coordinate;y_coordinate;z_coordinate)’ for all the points in geometry]
’.’ is the coordinate decimal separator, and ‘enter’ is the separator between different commands, so each command is on a different line in a script.
A script contains multiples commands and the last command has to be ’end_auto_script‘.
You can generate a list of commands as bellow in Excel with macros, Dynamo or with another familiar program or tool.
This script will generate the elements in the model like in the picture bellow:
In order to create elements using commands as the ones above, when running one of them or the script the following snap modes have to be disabled: extension, tracking, ortho, relative and length on element.
All the commands executed by the user are recorded in the history of the console which is accessible in the input console line (E.G.: selecting an element, calling a ribbon or menu command like creating an element, etc. …).
For checking any executed command syntax, scrolling through the commands history is possible by clicking the input console and pressing left arrow key for each command (using right arrow will walk you back to the last executed command, opposite to the left arrow key, but only after starting to use left arrow). To copy it the recommended way is by selecting the text with the mouse, right clicking it and selecting copy from the contextual menu.
2.2. Script saving, recording and playing
If the script is generated with Excel/Dynamo/etc. then make sure the generated file has the extension set as .ads.
For manual script creation a text file with ads extension is needed. It can be created with Notepad or any other text file editor. After the creation of file copy the script described above at point 2.A. in the empty file and save it as your_script_file_name.ads .
For script recording in AD, right clicking in the input line of the console and choosing ‘start recording’ from the contextual menu starts the recording. After the user interaction with the program (E.G.: selecting an element, calling a ribbon or menu command like creating an element, modifying options in a dialog, etc…), right clicking in the input line of the console and choosing ‘stop recording’ a dialog is launched for choosing the name and the location of the script. There are some limitations that are listed at the end of the document.
To play the script for scenario 2.1, right click in the input line of the console and choosing ‘Load script’ from the contextual menu starts a dialog to choose the script file. After choosing it AD start playing the commands from the script one by one with a delay between them. The user should not move the mouse or press any key while playback is in progress. At the end a message will be printed in the console that notifies the end of the operation.
3. Model calculation and reports generation
At this step start recording a new script as described above. The automatic wind, snow, traffic loads, etc… and combination must be generated if needed. Then the analysis model should be created, maybe also the concrete analysis, steel analysis, etc…. Then in the report generation dialog add the needed reports and optionally change the report type: (Doc, docx, xls, xlsx(for the these first 4 extensions Office suite is required), rtf, txt). In the gif sample, the selected type is xls but in the script rtf type is selected in case Office is not installed. The report is generated in the document folder of the model and it is not automatically opened.
In the end you need to stop the recording. The resulting script can be used as a template script and should be modified/adapted to include the creating elements commands (from the point 2.1.). They should be added right after the last set_unit command:
4. Running the script in batch mode.
At this step you should use a copy of the backup model from the 1st point. Running a batch mode can be achieved by running a bat in which the command is having the following syntax:
“X:\Path to AD\Bin\AdvanceDesign.exe” /s “Y:\path to script\script name.ads” /m “Z:\path to model\model name.fto”
“C:\Program Files\Graitec\Advance Design\2021\Bin\AdvanceDesign.exe” /s “d:\AutoTests\models for new tests\newtest\combined script.ads” /m “d:\AutoTests\models for new tests\newtest\FTDoc15.fto”
A bat file can be created in Notepad and saved as ‘file_name.bat’ when selecting all types as the extension in the save as dialog.
5. Scripting recording and playback limitations
Double-click in pilot; instead, used right click or other commands
Combos in toolbars.
The Data Grid dialog (different technology, in work).
Buttons that open dialogs in Property list and the recording of the GUI operations in that dialogs.
Changing properties in property list commands might have to be updated at each version/subversion of AD because the commands are depending on the identifiers of the properties which are changed almost each version.
Changing the sections and materials for elements from property list.
Changing height for level in Property list
Double-click on result curves in order to save them as *.jpg
Only basic modifications in tables are supported
The measurement units must be the same as the ones installed by the kit
When creating a circle, the radius will be specified in console, not by clicking on the screen.
Modifications of snapping are to be done using the toolbar/ribbon.
Creating loads on selection.
All needed section cuts will be created before starting to register the script.
Mesh preview for planar elements.
Selecting the work plane.
When creating the analysis model, the script should compute a new analysis. When automatically running, if an analysis was computed for the current model, the check boxes for analysis types are disabled, therefore the test will try to open an existent analysis (which does not exist since we should run on a clean model). Therefore, when registering the script, even if the model is a new one and the option to create a new analysis is already selected, select “Create new analysis” and then the analysis type(s).
Do not use right click in reports window. Use instead left click and the existing buttons.
In order to change the cases/combinations for the report, do not use the Cases/Combinations window. Instead, use the Report properties window (select report and click Properties button) select advanced options to expand the dialog and check the specific case/combination and use the analysis type combo from the below of the extended window:
When adding more family cases or loads, do not use the keyboard to insert the number. Use instead the arrow buttons.
The two slides for size from the display options window (Alt+x): or from the ribbon
The window for pressure generation.
6. The power of automation
This tool is very efficient for our QA system but can be very useful also for anyone who wants to automatize repetitive scenarios but also to feed Advance Design with entire building structures extracted from another application. Just do the scenario inside the application, save the script, adapt it if you need it and run it.
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Modeling and defining the values of all climatic loads is a time-consuming process and a source of possible errors. The amount of time spent for the calculation of climatic effects can be significantly reduced, while assuring more accurate results. You can obtain in no time the climatic loads intensity and distribution on your structure using a fast and easy-to-use Advance Design function: the 3D Climatic loads generator.
Implemented Eurocode 1 and National specific standards
Advance Design provides several climatic standards such as NV 2009 (France), NP082-04 / CR1-1-3-2005 (Romania), Eurocode 1, Canadian (NBC2010 or 2015) and US (ASCE 7-10) codes, with different national appendixes:
The choice is done in the global project’s settings.
The structure and roof shape is taken into account, therefore you can create loads on portal frames, parapet walls, lattice structures, scaffolding elements, buildings with dominant face, panels, horizontal roofs, two slopes roofs, isolated roofs, protruding roofs, roofs with awning, etc.
Examples of automatic generation of climatic loads on various structures
Wind loads on multiple roofs
Snow loads on multiple roofs
Wind loads on awning
Snow accumulation on portal frames with a negative slope
Snow accumulation on portal frames with a negative slope
You can automatically generate all the climatic loads on a structure in an efficient way, which saves a great amount of time:
Select the appropriate climatic standard.
Generate windwalls on 3D structures.
Create load case families for snow or / and wind and configure the advanced properties (if necessary).
Access the snow and wind loads values map to define the structure location. With a single click, the values of the wind speed, wind pressure, snow load and exceptional snow loads on the structure faces and roof are automatically defined according to the selected region:
Launch the climatic generator
The climatic load cases and loads are automatically displayed in the graphic area and also, in the Pilot, in the corresponding loads family, providing access to an efficient management:
Accurate and prompt update
If the structure or the loads properties are modified after generating the climatic loads, a single click is enough to update the loads, according to the new conditions.
If you’re a structural engineer looking for powerful steel connection design software, then make sure you tune into our free Advance Design Connection week.
Boost your knowledge and skills with Advance Design Connection free webinars! Advance Design Connection Week is a series of webinars dedicated to BIM Workflow based on Graitec products!
About Advance Design Connection
Advance Design Connection is a powerful analysis solution for 3D Steel connection, fully integrated with Advance Design which is a global structural analysis software including a powerful 3D climatic generator, advanced stability checks and steel members design and optimization. Advance Design Connection can design all types of 3D connections using internal forces on members coming from Advance Design. It provides precise checks, results of strength, stiffness and buckling analysis of a steel joint. Joints are checked according to Eurocodes and North American codes (EC & AISC). Templates for most-used connections are available as well as wide range of predefined hot rolled and sheet welded members.
Join Advance Design Connection Week – free webinars which will be held in English and French.
During the webinars we will cover the following areas:
The workflow from Advance Design to Advance Design Connection –
In this webinar we will demonstrate how to export several connections of a steel structure which is modelled and analyzed in Graitec Advance Design (AD), to Graitec Advance Design Connection (ADC) software. You will see the automatic mapping procedure of sections and as well imported internal forces from AD. In the next step, we will create the connection geometry in ADC and run the analysis and code check process. Finally, we will go through the results of the analysis and status of the connection in ADC.
The workflow from Melody to Advance Design Connection –
We will show the export of a real building attachment calculated with Advance Design to Advance Design Connection (ADC). Then the export of tubular structures from Melody portal to Advance Design Connection. In Advance Design Connection where we will automatically retrieve the profiles and the efforts of Advance Design or Melody, we will build the fasteners in a few minutes and exploit the results.
The workflow Advance Design +Advance Steel to Advance Design Connection –
This webinar will cover the full workflow of steel connection design using Graitec Advance Design (AD), Autodesk Advance Steel (AS) and Graitec Advance Design Connection (ADC). First, we will export the structural node from AD to AS to transfer the sections, the geometry of the connection will be modelled in AS and exported to ADC. Then we will demonstrate how to import internal forces directly from AD into ADC.
The new version of Graitec Advance Design connection (ADC 20.1) –
The new version of Graitec Advance Design connection (ADC 20.1) will be released soon. In this presentation we will focus on new features and functionalities of the new version. Some of the highlights are: Cost estimation / Pre-design tool / Check of missing welds