# 2D to 1D improvements

2012.0

## Brief introduction

In SCIA Engineer 2010.1 there exists a feature that can be used to export the internal forces by means of integration from a 2D plate into an empty new 1D beam.

The main idea is that from a 2D plate the user can export the internal forces into a 1D beam element.

This export will simplify the work for the user. Also with this feature we support 3D prestressing.

Another use case is bridge design. The user can start with e.g. an orthotropic 2D slab and end up with a simple 1D beam for in depth analysis (including stages & tda) and checks.

## Detailed Technical information

In SCIA Engineer 2011 and 2011.1 this feature is improved. For 2011.1 following is done:

- Parametric length of beam
- Division for 2D-1D upgrade
- Excel check
- Torsion
- Enabling of 2D-1D upgrade for integration strips

### 2D-1D upgrade for integration strips

Before 2D-1D upgrade was only available for 2D members and prefab slabs. This solution has now also been extended to integration strips.

In the basic analysis environment of SCIA Engineer, there is the possibility to introduce so-called integration strips on plate elements. They allow the user to draw arbitrary lines or polylines in a plate where the software will integrate internal forces from a given effective width parameter. The geometry can be changed graphically while the definition of the effective width is set in a similar way as ribs.

The same method for 2D to 1D upgrade is used as for 2D members and prefab slabs. This means under “Results > 2D/1D upgrade”. Selecting this option in the results menu shows an adapted command in the command line:

Afterwards the user has the possibility to select the integration strip.

After selecting the integration strip the 2D-1D upgrade dialogue appears with all parameters needed to export the integration strip to a 1D project.

A new option in this dialogue is the combobox 'Switch location'. This combobox has three functions (Automatically, Switch, No switch). It enables the possibility to switch direction of internal forces and also the orientation of cross-sections. These improvements were necessary for the correct function of the concrete check.

Description of the combobox 'Switch of location':

- Automatically: SCIA Engineer searches automatically for the main direction of load and position of the integration strip (horizontal or vertical) and selects the correct method for switching of internal forces or cross-section
- Switch: internal forces and cross-section will be switched
- No switch: nothing will be switched

Note that this combobox is not available for ribs or prefab slabs.

### Parametric length of beam

Previous solution of the length definition is based on the export of the real length from the 2D model to the 1D template. For the use of the user defined overhangs a new functionality was added for the definition of length parameters.

The new solution is available under “Results”> “2D/1D upgrade”

Three new comboboxes have been added: “Overhang parameter - beginning”, “Overhang parameter - end” and “Length parameter” (=length from 2D project). These comboboxes are activated when “Type of export” is set to “Template”.

If the user selects a template file, SCIA Engineer uploads all user defined parameters (type length and only values, no formulas) and fills the comboboxes “Overhang parameter - beginning”, “Overhang parameter - end” and “Length parameter”. The default value will be set to No parameter (current solution => length of the member in 1D template will be changed to the value of the length from 2D project).

Simple example for the use of parameters during 2D/1D export:

The selected parameters are a, b, L1.

a - Overhang parameter – beginning

b - Overhang parameter – end

L1 - Inner length parameter (=length from 2D project)

In the 1D template the parameter L1 will be changed to the value of the real length from the 2D project. The picture below shows the definition of the length parameters.

### Division for 2D-1D upgrade

The previous solution was based on the preview of internal forces on the beam only in the five points. This solution could be misleading in some cases. The shape and value of the internal forces can be interpreted incorrectly.

The new solution is based on the possibility to input the value “Division for 2D-1D upgrade” (in this way, the shape of internal forces will be interpreted more correctly). This is used for integration strips and for ribbed or prefab slabs (for the preview of internal forces and for export of not calculated internal forces).

This new solution is available under “Calculation mesh”, item “Mesh setup”.

Principle of 2D/1D upgrade:

With this new parameter, the shape of the internal forces will be drawn more correctly.

### Improvement Excel check

Previous solution of Excel check didn't enable the export of some user defined or other useful parameters. The new solution allows the user to export more useful parameters.

Following parameters have been added:

- b
_{w}- total width of girder (precast + topping) - x
_{u,max}– height of compressive zone when construction fails - A
_{b.max}– area of compressive zone) - user defined parameters (e.g. type length)

### Torsion

Torsion parameters have been added to the orthotropy input dialogue. These are needed to the calculate the torsion moment for the 1D beam when doing the 2D to 1D upgrade.

Extra stiffness coefficient (Kxy, Kyx) have been added which represent the stiffness in torsion in the X or Y direction.

The torsion moment along the main span of the 1D beam is calculated by the following formula:

These new stiffness coefficients are only used for the result of 2D/1D upgrade (Internal forces on beam, export to the new project and export to the template).

Astrid Bastiaens

03/06/2012