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PLPAK (product description)


PLPAK (product description) 
The PLPAK is special purpose software package for structural analysis of building slabs and foundations. The PLAPK uses the boundary element method as numerical method. It also uses the shear-deformable plate bending theory according to Reissner. The structural modeling is carried out according to the philosophy presented by Prof Youssef F. Rashed, the technical director of ( in:
-          Rashed, Y.F., Boundary element modelling of flat plate floors under vertical loading, Int. J. Numerical Methods in Engineering, 62, 1606-1635, (2005).
-          Rashed, Y.F., A boundary/domain element method for analysis of building raft foundations, Engineering Analysis with Boundary Elements, 29, 859-877, (2005).
 The PLPAK solves single floor at the time; each floor consists of single slab with several openings. The boundary element theory, on which the PLPAK is based, is published in several international journal publications as listed on this website. Results of the PLPAK are also validated through several examples published in several journal publications. The PLPAK philosophy is based on:
-          Using the accuracy of the “boundary element method” together with its capabilities in modeling the real geometry to achieve a solution as close to reality as possible.
-          Easy model preparation or model adjustments as well as fast processing.
-          The PLPAK is written in modular form so engineers, researchers, and computational modelers can add their own module and integrate it within the PLPAK. Therefore the PLPAK has no ceiling and its capabilities is open to your thinking and personal inventions.
The PLPAK development is kept to ensure the easy learning (matter of few hours) to any new engineer or numerical modeler. Learning the PLPAK does not require previous knowledge of boundary elements of even finite elements.
The main components of the PLPAK are:
-          The preprocessor – the PLGen module 
-          The numerical model (or the boundary element model) viewer – the PLView module
-          The Core manager – the PLCOREMan module
-          The command line solver – the PL.EXE
-          The post-processing – the PLPost module

The PLPAK has other add-ons: EHSPAK (Advanced soil modeling), PLDesign (Structural design module) and PTPAK (Post-tensioning modeling module).

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What is the Boundary Element Method (BEM)?
 The boundary element method (more accurately known as the boundary integral equation method) is a numerical method to solve challenges in computational mechanics. It actually could be regarded as semi-analytical semi-numerical method rather than being fully numerical method. This guarantees the high precision result. Our main interest is the application of the boundary elements in structural engineering and in particular to plate bending problems. In doing so, Rashed [1,2] had presented two imperative papers in modeling building slabs and foundation plates using the boundary element method. The PLPAK is mainly based on these two publications.
In the boundary element method, the analyzed slab boundary (floor slab or foundation plate) is the only discretized element; i.e., no internal meshing is required. This ensures that the slab is treated as an actual single slab. Moreover, easy placement of internal elements is available: such as columns, piles, openings, drops, beam, etc. Re-analysis due to architecture changes is very simple (no need for re-meshing).
The PLPAK also considers internal supports with their actual geometric shapes. This guarantees no peaking of bending moments over supports and accurate deflection calculations (especially; if we kept in mind the analyzed slab remains a single structure without discretization). Another vital feature in the PLPAK (or in fact the boundary element method) is all results generated in the post-processing stage are generated in the real-time; i.e. with no interpolation (for including results along strips, or contour maps). This enables achieving results along even the most diminutive of possible areas (1 cm X 1 cm or even less!). 
These papers are available in the Technical Documantation section.
1-Rashed, Y.F., Boundary element modelling of flat plate floors under vertical loading, Int. J. Numerical Methods in Engineering, 62, 1606-1635, (2005).
2-Rashed, Y.F., A boundary/domain element method for analysis of building raft foundations, Engineering Analysis with Boundary Elements, 29, 859-877, (2005). 
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Why using the PLPAK? 
We use the PLPAK for the following reasons:
-          Real time post-processing
-          Accuracy of the boundary element method and the shear deformable plate bending theory
-          Easy input in forms of:
o   Multiple exporting from DXF to the virtual model in the PLGen, makes life easy for engineers to account for any modification in design, change of column places, adding duct openings, etc. This is done without re-meshing or re-building the numerical model (please recall: the boundary element method requires boundary only-discretizations).
o   Multiple post-tensioned cables input, leading to make engineers work as groups and in parallel; this increases the work efficiency especially in large projects.
o   Multiple level of “undo” in the PLPAK preprocessor (the PLGen).
-          Capable of modeling fine details such as small duct openings.
-          Easy and accurate processing.
-          Easy and very accurate post processing and computation of design values.
-          Results are produced fast and are mailable in terms of size.
-          The PLPAK is very light on your computer system (the installation file, without the documentations, is just about 2.5 MB)
The followings are some unique capabilities offered by the PLPAK:
-          The PLPAK provide a possible way to check the obtained finite element results in companies.
-          The easy drawing capabilities of the PLPAK makes life simple for practical engineers; especially in case of having changes. Moreover the boundary only discretization will minimize errors generated by engineer in the numerical models.
-          The PLPAK multiple DXF import and the multiple pre-stressing cable imports will allow engineers to work in parallel in a single project.
-          The PLPAK has the capability of zooming in for local result details
-          The PLPAK can generate soil stress map to check the bearing capacity violation under rafts.
-          The PLPAK models beams with its actual interaction area to the slab with make it unique in case of modelling slab with irregular beams supported not on the full beam width.
-          Unlike the centre-line modelling of finite elements, the PLPAK considers the actual slab geometry. This makes the PLPAK more suitable for design and detailing software. Moreover it will be a perfect numerical environment for what is called the Building Information Modelling (such as REVIT) . 
-          The PLPAK uses the so called boundary domain method to model the soil support. The well-known Winkler model is build-in inside the package. However, advanced models, such as the multi-layered elastic half-space could be used. Whatever the soil model, the soil springs are considered as continuous spring patches underneath the continuum foundation plate. The allows:
o   The capability of considering non-homogeneous soil pattern
o   The capability of obtaining pressure map for soil reactions.
-          The PLPAK models supports with their actual shapes, for example piles are considered as circular sections. Unlike finite elements, no peaking values is obtained for straining actions (such as bending moments) over columns or in vicinity of stress concentrations.
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What you can do with the PLPAK? 
The PLPAK applications are:
-          Flat slabs (columns are considered with the real cross section)
-          Slab with beams (beams can be considered with its actual area connection to the slab)
-          Raft foundation (with beams, on non-homogeneous soil)
-          Piled raft and piled foundations (piles are considered as circular area)
-          Post-tensioned flat slabs or rafts
The PLPAK has the following capabilities:
-          More accurate and realistic structural modeling
-          More accurate punching calculations
-          Solution for multiple load cases and load combinations
-          Multiple DXF import to suit any changes in the structural drawing or in the as-built drawings
-          Multiple Post-tensioned cable importing, to allow engineers work in parallel
-          Produce results in forms of distribution along strips, contour maps , local rectangular and quadrilateral contour maps, max/min arrows for principal moments
-          Results are obtained in forms of deflections, rotations, bending & torsional moments, shear forces. Also design moments according to Wood and Armur equations are produced.
-          Export results to text files or Excel files 
On the other hand, the PLPAK can be considered as:
-          Practical check or validation for your finite element results.
-          Numerical tool to carry out “value engineering” process to minimize cost of materials.
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PLPAK user categories 
          Practical structural engineers: they can model practical building with almost no knowledge of BEM (daily structural engineering work)
          Boundary element modelers: they can be able to write input files and uses advanced BEM capabilities (research level)  
          Expert programmers: they can add/change a feature or linking the PLPAK to other packages, such as REVIT or FEM solvers or MATLAB optimizer or …

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