A key feature to the design process for two-way slabs, either RC or PT, in ADAPT-Builder is the necessity to model support lines for creation of design strips. The software generates design cuts at customized or defaulted-to intervals along a support line for evaluation and design. Nodal Integration is used on the design cuts to calculate resultant actions for calculations of stresses, flexural reinforcement, shear reinforcement, cracking, etc. Design strips are vital to proper and successful use of the software.
One tool that enables the user to efficiently create and edit support lines and design strips is the Support line Dynamic Editor. Of critical importance is the ability for auto-generating middle and column strips and allowance for allocation of tributary width to each strip type. This feature has been reintroduced and improved for ADAPT-Builder. Note that the editor contains many other new features related to strip generation. These features are highlighted in the video linked above as well as new feature documentation.
As part of the design process, the user will typically first draw in manually or through use of a “wizard” the column strips along column or wall supports. This can be thought of as a spline along a frame line if one to break out a two-way slab into equivalent frames.
The column strip support line can be specified to carry a specific maximum width to each side of the support line (each side of the frame line) to define the total strip width. Another option new to ADAPT-Builder 2020 is to allocate the % of the distance to adjacent column strips for the total design strip width.
These new settings used to create middle strip support lines based on the column strips support lines previously created either through wizard or manual input. This option generates all middle strip support lines rapidly and at once with removal of the support lines once the design sections are generated and then discarded by the user.
Create Middle Strips: This option will automatically generate middle strip support lines between already-defined column strip support lines. These are colored in blue while active in the Dynamic Support Line Editor
Delete Middle Strips: This deletes the auto-generated middle strip support lines.
Min Span Distance: This threshold is used to set the minimum span distance for a column strip support line that the program uses to generate the middle strip.
Auto Trim Middle Strip to Slab Edge: When this is selected, the program will auto trim/extend the ends of middle strips to the slab edge located within the tolerance setting.
An example of using the new column and middle strip options is shown below. In this condition the support line representing the middle strip support line fills in the gap relative to the rule set for the column strip support line. For this case, the column strip is set to a percent between of 15%. This leads to the column strip width being set as 4.5’ each side of the support line and the middle strip filling in the gap at 21’.
For more information on this topic, check out the video below: