A shield is a part of a thermal boundary. It has no supporting effect.
In this window you can describe how the surfaces of the concrete are covered during the hardening process. This way of doing should be identified by a model-name.
First you have to define your basic casting forms, insulation, plastic foils, tarpaulins etc.
Press the button:
and define an identification, the thickness and the thermal conductivity for the materials you want to "wrap" your structure into.
Alternatively it is possible to import "wrap"-data from libraries. Examples are delivered together with the software.
When a "wrap" has been defined it can be exported to a library for use in other jobs.
Afterwards you simply specify times for placing and removal for relevant shields in the schedule. Several shields can be placed at the same time.
When editing the schedule, you can use the INSERT-, DELETE- and ENTER-keys.
You can assign the same model to several surfaces just by selecting the surface by clicking the left mouse-button. Dragging the mouse over surfaces with Shift and left mouse button pressed, copies selection/deselection to the surfaces.
To position the structure in the right angle, you can turn it by means of the scrollbars, the arrow-keys or keep the left mouse-button pressed while you drag the mouse.
You can zoom in on a specific part of the structure by dragging the mouse with the left mouse button kept down, while the Ctrl-key is pressed. Zoom back out by clicking the right mouse button. Also, the mouse wheel can be used for zoom/unzoom.
By means of the keyboard all surfaces on a specific volume or on the entire structure can be selected, see Overview Mouse and Keyboard actions
The selected surfaces will be marked with red colour.
Surfaces with the same model as the one you are going to apply are shown with an orange colour.
When the actual surface is participating in a casting joint, the shield of the participating part will automatically be removed and the structure is considered monolithic.
If you apply a shield model to a surface you also have to apply models for convective temperature and wind-speed.
Instead of defining models for wind and shields a model describing the resulting transmission coefficient of convection can be specified directly, convective transmission coefficient. When using this model, it is possible to define time points relatively to the time where the concrete is placed.
Convective Transmission Coefficient
The convection transmission coefficient of a surface acted upon by wind is calculated as:
with
|
αk= 20 + 14 v |
v <= 5 m/s |
|
αk= 25.6 v0.78 |
v > 5 m/s |
where
|
e |
Thickness of formwork/insulation-material |
|
λ |
Thermal conductivity of material |
|
v |
Wind-speed |