R/C BUILDING

3D Modelling and Analysis of Building Structures on Gravity and Lateral Loading, Including Vertical Load Transfer, Global Torsion, Columns Slenderness, Soil-Structure Interaction and Construction Stages Analysis

l SLABS l R/C COLUMN l R/C BEAM l FOOTING l STRESS 2D l BEAM l SPAN l SUPPORT l

What is This?

R/C BUILDING is a new software product for 3D modelling and analysis of building structures on gravity and lateral loading, including vertical load transfer, global torsion and columns slenderness. The software can be used to analyse reinforced concrete and masonry building structures. The software will consider slenderness of braced and unbraced columns and it will magnify the bending moment automatically.

After many years of software development, we have identified a growing need for a simple, but efficient 3D building analysis and design software. R/C BUILDING is a response to this demand.

<<< From Concept to Design in No Time >>>

The software is an ideal tool for assessment of the minimum lateral load resistance, which is now compulsory for any structure, according to AS 1170.0 – 2002, clause 6.2.2, and to evaluate inter-storey drift according to AS 3600, clause 2.4.3.

The software will consider the secondary moment due to column slenderness and it will magnify the bending moments automatically.  Consequently, all the columns can be designed as "braced", since the P-Delta effect is considered during the analysis. This procedure is much simple to implement, but yet more precise than the simplified method suggested in AS 3600. This is especially important for unbraced multi-storey frame structures.

The software graphical editor is based on a unique approach, which allows the user to create each floor separately, taking advantage of a simple 2D modelling environment, while building a complex 3D model.

floor + floor + floor = building

Model Courtesy of K.F. Williams & Associates, Wollongong, NSW

What Does it Do?

The current version of the software can be use to model and analyse (1st and 2nd order) a reinforced concrete building on horizontal and vertical loading, and to design all walls and columns.  The software can be used to evaluate the internal forces in the columns and in the walls, and the vertical and the horizontal deflections due to vertical and horizontal loading.

Gallery of Projects - Small and Tall

·         2-Storey Residential House

·         2-Floor U-Shape Residential Building

·         3-Storey Residential House, Sydney

·         3-Storey House, Pretoria, South Africa

·         4-Storey Building in Wollongong

·         4-Storey Residential Building in Darwin

·         5-Storey Building, Van der Meer Bonser - Sydney

·         5-Storey Typical Residential Building - Nelson Bay

·         5-Storey Residential Building, Campsie, NSW

·         5-Storey Light Frame

·         6-Storey Residential Building with Carpark

·         7-Storey, Building, H & H Consulting

·         7-Storey Shopping Centre, Parramatta, MPN - Sydney

·         9-Storey, Apartment Building, Covey & Assoc. - QLD

·         9-Storey, Apartment Building, John Romanous + Assoc. - NSW

·         9-Storey, Residential Building, BG & E Pty Limited - Sydney, NSW

·         10-Storey Building, K.F. Williams & Assocoates - Wollongong

·         10-Storey Precast Panel Building

·         10-Storey L-Shape Building

·         11-Storey Building QLD (Sky Garden)

·         11-Storey, Apartment Building, Charlestown

·         11-Storey Apartment Development in Darwin, NT

·         11-Storey, Box Tower, China, CSCEC Design - China

·         12-Storey Massive Triangular Atrium Building, BMD Consulting QLD

·         13-Storey Slender Tower

·         13-Storey, M1 Re-Development, Maroochydore - QLD

·         14-Storey, Detailed Model of an Existing Building, NSW

·         16-Storey, Auburn Central - Tower Building

·         17-Storey Tower, Jones Nicholson, Sutherland NSW

·         19-Storey Building

·         27-Storey Tower, Progress Consultants - Cairns

·         27-Storey, Parramatta Apartments, D'Amici Colombo Pty Ltd - Sydney, NSW

·         33-Storey Building, BG Group - Brisbane 

·         32-Storey Tower, Alliance Design Group, QLD

·         32-Storey Crystal Tower

·         38-Storey Building, MPN - Sydney

·         39-The Tallest Building in East Malaysia

·         44-Storey, Malaysia

·         49-Storey, Birzulis Associates

·         50-Storey Tower - Malaysia, Alliance Design Group QLD

Modelling

A structural system of a building is treated as an assemblage of floors composed of slabs and beams supported by columns and walls.  Each floor is modelled independently as a 2D architectural floor plan.  On each floor the user can define any number of slab panels, beams, columns and walls.  The beams, columns and walls can be integral part of the slab or they can be free standing, forming a frame structure.  Once all floors are entered the building model is automatically assembled.  This is a very efficient way to model a complicated geometry of a building in a simple manner, concentrating on one floor at the time.  Each, structural element type of the "working" floor and the "transparent" floor can be switched on or off, for better clarity.

In order to ensure the correct position and continuity of the vertical structural member, the user can switch On any other floor as a transparent layer.

The software can load one BMP (Bitmap) image on each floor.  Each Bitmap image can be manipulated independently (scaled, shifted, unloaded and loaded again).  The Bitmap image can be generated by any CAD software, or scanned from a paper drawing. 

The interactive graphical editor allows generating and editing one floor at the time, called "working floor".  While the "working floor" is generated, any other floor can be shown as a background image, the "transparent floor".  The structural elements in the "transparent floor" can be used as reference point to create the structural members in the "working floor".  At the same time the Bitmap image can be shown as another layer.  The "transparent floor" and the Bitmap image can be switched On and Off an any time.   Any floor can be selected as "working floor" for making some modification.

SLABS import utility can be used to import any SLABS data file.  A building model can be created by importing several SLABS data files, to create a complete building.  If the data files in SLABS are prepared in such way to preserve the continuity of the vertical element, the imported model is ready for analysis.    If a building has several identical floors, the same SLABS data file can be imported several times to create several floor in the R/C BUILDING model.

Also, each floor of a building model created by the R/C BUILDING software can be exported to SLABS, for a detailed analysis and design of a particular floor on vertical loading.  All the columns and walls below the floor will be exported as supports in SLABS, and all the reactions from the columns and walls above the floor will be exported as point and line loads.  The exported SLABS model will be ready for analysis without any modifications.

This is considered as very efficient approach, taking advantage of a simple 2D modelling environment, while building a complex 3D model.

At any time the building model can be viewed in 3D to check the geometry,

Editing

Once the model is prepared the editing of the element can be done in a standard Windows fashion.  One or more structural elements can be selected, and the common properties can be changed on all of them.

Also, all structural elements, and their properties can be edited in a convenient table, similar to MS Excel.

Analysis with Construction Stages

Once the model is finished a linear static analysis, 1st or 2nd Order, can be performed for vertical and horizontal loading.  Each floor is automatically subdivided in smaller finite elements, and the model is analysed as 3D structure, considering global torsion and influence of the slabs and beams on the lateral stiffness.  

The horizontal loading can be applied in the mass centroid of the floor for earthquakes, or in the geometrical centroid of the storey profile for wind loading.

2nd Order Analysis

The 2nd Order analysis will consider the slenderness of braced and unbraced columns and it will magnify the bending moments automatically. The software will consider the reduction of the column stiffness due to the effect of the axial load. This will cause larger lateral floor deflections, and it will increase the columns and walls bending moments. This type of analysis is recommended for unbraced frame structures without shear walls.

In genera, the 2nd Order analysis will provide more accurate deflection and internal forces results, since the P-Delta effects are automatically considered during the analysis. This procedure is much simple to implement, but yet much more precise than the simplified column design method suggested in AS 3600. This is especially important for unbraced multi-storey frame structures.

For areas with very low seismicty, such as Australia, this type of analysis, in some cases might eliminate the need for shear walls, or it can reduce their size or number, which will lead to more economical design. The 2nd Order analysis can be used to prove that an unbraced multi-storey frame structure (columns only), might provide sufficient lateral robustness (AS 1170.0, clause 6.22), and inter-storey lateral drifts below 1/500 (AS 3600, clause 2.4.3), and that the column can take the increase moment due to slenderness.

The 2nd Order analysis considers only the columns, since the walls are not prone to potential buckling. Out-of-plane stiffness of the walls should be neglected, and in-plane stiffness is very large and any buckling is very unlikely.

The internal forces in the columns obtained by the 2nd Order analysis can be used to design all the column treading them as "short " columns, since the moment magnification is already done during the analysis. This is much more accurate and yet simple procedure for the column design. There is no need to make a decision whether the columns are braced or unbraced, or to estimate the effective length. The internal forces (N, M and S) produced by the 2nd Order analysis can be taken directly, and the column can be designed a "short" column.

Construction Stages Analysis

In any Structural Analysis it is assumed that the entire loading is applied on the complete structure instantaneously.  However, building structures are constructed and loaded gradually, sever floor at the time. Typically, in a building structure the construction loading is about 80% to 90% of the service loading. The loading of the 1st stage is supported only by the structure which is constructed up to that moment. The additional loading from the 2nd stage is supported by the structure which is constructed up to that moment (stage 1 and 2). The 2nd stage is constructed on already realized deflections from the 1st stage. This will influence the distribution of the internal forces in all structural elements, especially the reaction of the transfer floor.

In the Constriction Stages Analysis the structure and the loading is applied gradually, as it is constructed. For instance, at the end of the first stage all the deflections due to the self weight are released, and the upper levels will be constructed on already realized deflections. R/C BUILDING software can perform this type of analysis in stages. The deflections and the internal forces are incrementally accumulated as the structure is constructed. This will provide the most accurate estimate of the reactions on the transfer slabs.

Soil-Structure Interaction

Normally, when a 3D model of a building is created, we need to constrain the vertical movement at all footings.  In R/C BUILDING software we can assign the "Footing" property to some walls and columns.  Usually, we need to assign the "Footing" property to all columns and walls at the lowest level.   This approach is suitable for very stiff foundation soils, such as rock or compacted sands and gravel.  But, when the soils is "softer", we need to consider the influence of the footing settlements on the internal forces on all structural elements.

In the figure above, it is illustrated the influence of the footing settlements on the bending moments in the structural elements.  For instance, "soft" soil can reduce the negative moments in the mid-supports, and increase the positive moment in the mid span.  This effect can spread over many floors in a multi-storey building.  A thicker raft slabs will reduce but not eliminate this effect. 

The best approach is to analyse the structure and the foundation soil as a combined system, which will include soil-structure-interaction.  R/C BUILDING software allows you to include complete soil-structure-interaction.  We just need to enter material properties of the soil layers, and remove all "Footings" in the model, then the software will evaluate the Influence Factors under each nodal point of the slab panels, and analyse the building and the soil as one integral structural system. (A Nodal Point is a corner of each Finite Element triangle.)  In this case the software will assume that all slab panels at the lowest level are in contact with soil.

The Influence Factors for the soil are based on Boussinesq formula, assuming homogeneous liner elastic isotropic material.  The Modulus of Elasticity and thickness of each soil layer is taken into account.  The size of the corresponding area under each Nodal Point, and the influence to all Other Nodal points are included in the analysis.

This is considered to be the most superior analytical approach available for evaluation of foundation settlements and the effect on the structure.

For example, if a building structure consists of a raft and a transfer slabs, supporting several floors of masonry (see figure below). R/C BUILDING software will consider the contribution of all structural elements in evaluation of the settlements, not just the raft slab. If only the rafts slab is considered, it might results in over-design of the raft itself, by the effect of the settlement will be ignored on all other structural elements, which might cause development of some cracks in the upper levels.

Columns and Walls Design

This feature will design hundreds of columns and walls, virtually in several seconds, in bending and shear.  The secondary moments are already included, which allows to treat all the columns as braced.  Also, the bending moments are magnified for slenderness. The software will consider a number of load cases, and select appropriate number of bars. The result is provided in a report as number of bars per column. Also, the bars are shown on the floor plan, which can be exported in CAD, and placed on top of the formwork plan.

Smart CAD Import - DXF and DWG Files

This new feature can be used to import the location and dimensions of all columns and walls directly from a CAD file without any preparation. Once the columns and walls are imported, they can be used as reference points to generate slab panels. This is the fastest and most accurate way to import the geometry.

Compare CAD with Structural Model

After the preliminary location and dimensions of the columns are imported into the building model, the architects might supply a modified floor layout. The software has a special feature to compare the columns in the model with the new CAD drawing. The software will compare the location, dimensions and orientation of all columns. The detailed report will list all differences.

Special Features

Steel Cross Bracing:  The steel bracings can be used to restrain the lateral movement.  These elements can span one, two or three floors. 

Joint / Corbels:  A slip-joint or shear-dowels joint can be easily modelled.  When a slip-joint is used, the bending moments along the joint will be zero, while there is a full transfer of the shear force. (more...)

Simplified 2D Dynamic Spectral Analysis:  Dynamic response analysis for a given spectral curve. (more...)

3D Frequency Analysis:  R/C BUILDING software can perform a complete 3D frequency analysis and  evaluate translation and rotational model shapes and associated frequencies. (more...)

3D Earthquake Spectral Analysis:  This features is used to perform a complete 3D dynamic analysis, including global torsion, due to earthquake action using mode superposition spectral method.  AS 1170.4-2007, Section 7.

Inclined Columns:  Normally, the column are defined as vertical elements, however R/C BUILDING software can accept inclined column to accommodate for special architectural requirements.

Initial Settlements:  Each column and wall can be prescribed with a different initial settlement.  This feature may be used in mine subsidence analysis.

Wall / Deep Beams Analysis and Design:  The software can be used to analyse the walls with internal finite element mesh considering simultaneously in-plane (membrane) and out-of-plane (bending) action to evaluate the stresses in the deep beam, and to deign the steel in the beep beams. (more...)

Soil-structure-interaction:  State-of-art analysis of slabs-on-grade, where the entire structure and the soil are analysed together, in order to obtain most reliable soil pressure and settlement results.

Very Large Models:  The software implements "our-of-core" solution for very larger buildings.  For instance, a larger shopping complex composed of several buildings connected by expansion joints, can be analysed as a single model.  (more...)

Construction Stages Analysis:  The loading is applied as the structure is built.  More realistic reaction evaluation on a transfer floor.

In-plane slab stresses due to shrinkage and temperature change. This feature can be used to evaluate very accurately the stresses in the slab and the internal forces in the walls and columns due to concrete shrinkage and temperature change.  This feature is especially useful for larger size floors.

Walls Group Detailed Results:  This feature can be used to extract lift core results in many different formats.   (more...)

Friction Piles

Special Structural Elements: Inclined Columns ad Bracing

Results

In this version of the software the following sets of results and reports are available:

Vertical Deflections Shape (slabs)
Horizontal Displacements (floors)
Reactions - Columns and Walls (internal forces by static analysis)
Mode Shapes and Natural Periods
Reactions by Floor Area (contributory area)
Mx-x & My-y, Bending Moments in Slab
Structural Summary Report
Gravity Load Summary Report
Quantities Summary Table
Horizontal Displacements Report (floors)
Reaction Report (Static Analysis)
Axial Load Stresses in Columns and Walls
Reaction Report (Floor Area)
Beams Report
Shear Walls (Masonry)
Log file

Beam Bending Moment Diagram Display

The lateral deflections are given for each floor as absolute value, and as inter-storey-drift (relative displacements between consecutive two floor).

The internal forces in all columns and wall, for each load case, are given in a text file, which can be saved under any name and opened by MS Excel for further usage.

DXF Export in Combination with SLABS Import

The software can export each floor independently in a DXF file, which can be opened by any CAD software.  It is worthed to consider purchasing the software, for this feature alone.  This feature can be used to import your existing SLABS data files, and create a DXF file, which will show structural members of your choice.  For instance the DXF file can contain one floor geometry with all the columns and walls above and below.  (more...)

How Does it Compare With Other Frame Analysis Software?

R/C BUILDING seems to be similar to a frame analysis software, but there are several major differences.  R/C BUILDING software is especially designed for building structures, and all the editing features and analytical capabilities are devised for this particular design task. 

For instance, a general purpose frame analysis program can be used to model and analyse a multi-storey building, but if the software has no plate elements to model the walls and the floor slabs, it may not be suitable for analysis of building structures.  R/C BUILDING software will distribute the horizontal load on the walls and columns taking into account the stiffness contribution of the floor slabs.  The floor slabs will link together all vertical elements in one floor, which will include 3D effects, such as global torsion, without any need for a master-slave links.    The slab elements will distribute the vertical load automatically on the walls and columns, without any need for manual distribution of the vertical load on the equivalent beam strips. 

Even if we compare R/C BUILDING software with some comprehensive general purpose finite element packages, it will be more suitable for analysis of building structures, since there are many features which make the modelling and review of the results much easier, without compromising the quality of the results.  For instance, there are special features to control the role of the shear walls in the lateral response of the building.

However, we must say that R/C BUILDING cannot be used for a general frame analysis.  Basically R/C BUILDING complements your existing frame analysis package.

3D Frequency Analysis

What are the Benefits?

R/C BUILDING software will help you to perform a 3D analysis of building structures, which will result in a better design.  The software can save you countles hours of design time.  Especially, when some modification has to be made.   Not to mentioned, that the structural model is built only once for horizontal loading, and design of the slab on vertical loading.  The geometry is exported in DXF format, which is directly imported in any CAD program to speed up the drafting.

·         Better and More Accurate Design (including column slenderness)

·         Save Design Time

·         Easy Modifications

·         Build Only One Model for all Analytical Needs

·         DXF Export Helps the Drafting

Can I Have a Demo?

No, there is no demo.  The prices is so low, and it does not justify distribution of a trial version.  But, if the software does not perform any of the advertised features, the money will be fully refunded.

Some more details on the R/C BUILDING software are avaliable in the on-line manual. (600 kB)

Model Courtesy of Australian Consulting Engineers, Concord NSW

What About Support?

The software is fully supported, vial telephone or e-mail.  Actually, we want to hear more suggestions, comments and constructive critics to include more useful features and improve the existing features.

What I Can Expect?

If the building model is generated correctly, the analysis will be performed without any problems, and the results will be reliable.  But, like any other new software, some difficulties my be expected.  We will try to fix any potential problem as soon as we are aware about it.

What Will Happen in the Future?

Although the software is fully functional for the defined task, gradually many new features will be included.  The plan is to include more analytical features and to include all necessary reinforced concrete design modules to make a comprehensive analytical and design software package.

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l SLABS l R/C COLUMN l R/C BEAM l FOOTING l STRESS 2D l BEAM l SPAN l SUPPORT l