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Software features list

PT3D is an analytical tool in the form of a software package for 3D modelling, analysis and design of prestressed concrete floor systems. The loading can be a made up of a combination of vertical loading, including dead load, live load and tendon uplift, supported by walls, beams and columns.

The software package is based on an unique approach, which allows the user to create a mathematical model of the entire floor, including all tendons in all directions, taking advantage of two-way action.  This approach will result in a more economical and more accurate design, whilst cutting down drastically the design time, allowing the engineer to examine several alternative designs.

PT3D software follows AS 3600 design provisions.

Once a model contains all the necessary elements and input data, the model can be successfully solved. PT3D offers comprehensive results and reports which are presented in either an interactive form (user can simply click on a location in a model to extract results) or a complete detailed report.

The following set of results and reports are available in this version of PT3D;

- Tendon Losses (see details below)
- Vertical Deflections Shape (slabs)
- Mx-x & My-y Bending Moments in Slabs
- Moment Envelope
- Principle Stresses
- Reinforcement in the slab
- Tension Cracks
- Punching Shear
- Reactions - Columns and Walls (internal forces by static analysis)
- Reactions by Floor Area (contributory area)
- Structural Summary Report
- Gravity Load Summary Report
- Reaction Report (Static Analysis)
- Reaction Report (Floor Area)
- Beams Report

There are also a complete set of tools that report errors or warnings regarding the overall geometry; e.g two tendons intersecting at a common point, any part of a tendon that is positioned outside the slab area, double elements etc.

Project Gallery

Dee Why - Australian Consulting Engineer, NSW
Transfer Slab in the UK - J.C. Lind & Associates, NSW
BG Group - Brisbane, QLD
Jones Nicholson - Wollongong, NSW
Transfer Slab - J.C. Engineers, QLD
Light Transfer Slab - ATB Engineers, Wollongong, NSW
House Slab - Optima Consulting, NSW
Simple  Model, 4-Span Beam

How Does it Work?

The first step is to generate a PT3D model, which can be done in a number of ways. The most efficient method is either by directly importing data from an existing R/C Building model or by creating the complete model using AutoCAD files.

PT3D contains "Smart DXF Import" which utilizes the original AutoCAD drawing to generate all the elements in the model. When the slab panels are represented as "closed polylines" in the AutoCAD drawing, all the slab panels can be created in one single importing step.

Import from CAD drawing

Learn PT Design With Us

Come for 2 or 3 days in our Sydney office learn how to use PT3D software, get extended help with all aspects of PT design, including concept design, tendon layout, details, and finish the project.  Call INDUCTA for details.

User Interface - An opened PT model

Above: PT3D model showing the slab outline, columns and all tendons

AutoCAD file exported from PT3D

Final Shop Drawing- PT3D exports to AutoCAD Tendon Drape (Underside of Duct)

IntelliMESH - Finite Element Meshing

The capability and intelligence of the meshing procedure in PT3D now gives much more freedom to the user. As the meshing distributes the nodes by a distance (rather than number of sub-divisions), the effects of irregular slab panel shapes do not have to be considered. Placing large slab panels adjacent to much smaller panels is also not an issue regarding the mesh distribution.  PT3D will automatically adjust the nodes to fit all tendons in the model, allowing total flexibility on the position of each tendon, and also eliminating the requirement for tendons to be placed along slab edges.

Before IntelliMesh

Note that the tendon ends and columns can be placed inside slab panels (see figures above). The meshing will place a finite element node at each column and tendon end. (see figure below)  This will drastically reduce the modelling time, and provide greater freedom in placing the tendons.

After IntelliMesh

Tendon Profiles (automatic or manual)

Grouping the tendons according to the profile is the easiest and most efficient way to create the model. At the time of creating the tendons, PT3D will automatically offer a profile for each tendon or group of tendons according to the geometry profile the tendons are positioned through. The user can manually calibrate each profile by adjusting the profile that was automatically generated by the software or by inserting additional points along the tendon.  (more...)

Tendons that are grouped will automatically take on any changes made to the profile of any one of the tendons contained in the same group.

Tendon profile module

Tendon Losses (short and long term)

All tendon loses are evaluated automatically, following the AS 3600 design rules:

Instant Losses:
Anchorage losses
Friction losses
Draw-in losses
Concrete Elastic Shortening losses
Prestress after instant losses
Long-term Losses:
Shrinkage losses
Creep losses
Tendon relaxation losses
Effective prestress after long-term losses

Tendon Uplifts (service and working)

Tendon uplifts are evaluated for two stages:  Transfer and Working.

R/C BUILDING Import

R/C BUILDING software can be used to create and analyse the structural system of a complete building in 3D, and then one floor can be exported to PT3D for a detailed design.  Floor geometry and all loading from all floors above will be exported.  In PT3D only the tendons need to be entered, and the floor can be designed.   This is especially useful for transfer slabs.

Model in 3D view

There are also a complete set of tools that report errors or warnings regarding the overall geometry; e.g two tendons intersecting at a common point, any part of a tendon that is positioned outside the slab area, double elements etc.

Static Analysis (bending and in-plane)

During the static analysis, PT3D will determine the slab bending moments in both orthogonal directions, Mx, My due to the vertical loading including the tendon uplifts at Transfer and at Work.

In-plane analysis is performed in order to determine P/A due to tendon jacking forces.  The tendon forces are applied at the nodal points along each tendon, considering force variation due to losses. 

Simple Models

PT3D can be used very efficiently for simple 1-way continuous beams. (mode...)

Design Reinforcing Steel in Tendon Sections

After the static analysis the software will evaluate a number of detailed points along each tendon.  At each detailed point, a design section will be evaluated.

Each tendon section will be designed for the envelope bending moment, as defined in the Load Combinations.  The software will design the section for +ve and/or -ve bending moments, adopting compression reinforcement if required to prevent brittle failure, by limiting the Ku factor to 0.40.

Each tendon section contains one tendon, with the overall complexity of the section depending on the slab panel thickness and offsets.

The secondary moment (M2) is included in the Analysis and Design via the Load Factors.

PT3D will check the crack criteria AS 3600, 9.4.2(b).

Transfer Slab Design by John Matheson & Associates Pty Ltd,  (PT3D model and construction)

Design of R/C Sections Outside Tendons Influence Zone

Some areas of the slab will not be included in the tendon section design.  PT3D will automatically identify these zones and will design them as ordinary reinforced concrete, following the AS 3600 rules for ordinary reinforced concrete.  At an identical point in a slab, a section parallel to a tendon line will be designed as a PT section (considering the tendon steel, and prestressing force), while the same point the section in the perpendicular direction may not be included in any tendon sections, therefore being designed as ordinary reinforced concrete.

Show all Concrete Steps and Export to AutoCAD

PT3D showing the step viewed from the bottom

Color Contouring for Results

Evaluating of the deflections using Ieff

Based on the adopted reinforcement, PT3D will evaluate Ieff in each point, in both orthogonal directions and will calculate the short-term deflections based on the reduced section properties.  The long term deflections are evaluate using Kcs factor, and increased load factors.

What about Support and Services?

Like with all major INDUCTA software packages, FREE upgrades and technical support with modelling is included for one year after the purchase date. We are more than happy to work closely on the first 1 or 2 projects with new customers that incorporate PT3D in the design, allowing the users to gain confidence in using the software.

INDUCTA Engineering currently offers the service of building models for clients using the R/C Building software package, and this service will extend into the area of building PT3D models. For more information regarding this service, please contact: goce@inducta.com.au