RAM Concept CONNECT Edition V8 Update 2

The Structural Products development team is pleased to announce the availability of RAM Concept CONNECT Edition V8 Update 2 (08.02.00.146) is an analysis and design program that uses the finite element method for elevated concrete floor systems, or mat foundations.

RAM Concept CONNECT Edition V8 Update 2 Release Notes - Date: January 2021

Enhancements
RAM Concept CONNECT Edition V8 Update 2 includes the enhancements discussed below.

Python Scripting API
A Python scripting API, with limited access to the data and functionality in RAM Concept, is now available. This feature allows you to automate routine tasks such as creating models, running analyses, and accessing results. Over time, we expect to expose almost all of the data and functionality in RAM Concept through the scripting API. Examples of workflows that are supported in this release include: exporting column reactions for load takedown, exporting elevations and coordinates at increments along tendon profiles, and importing point loads from spreadsheets.
The scripting API permits RAM Concept to be run “headless” (from a command line, without the graphical interface). RAM Concept and/or RAM Concept Post Tension licenses are consumed when running the program in this mode. Normal license rules and restrictions still apply.
New Creep and Shrinkage Models for Load History Deflections
The ACI 209.2R-08/GL 2000, AS 3600-2018, and Eurocode 2-2004 creep and shrinkage models are now implemented for use in the load history deflection calculations. The ACI 209R-92 model remains and will be the selected code when models created in earlier versions are opened in this or future versions.
The options in Load History / ECR tab of the Calc Options dialog have been reorganized, as shown in the image below, to accommodate the new creep/shrinkage models. The General Parameters marked in the image apply to all creep/shrinkage models. The Model Specific Parameters are used to automatically calculate basic creep and shrinkage coefficients and adjustment factors that are defined in the selected creep/shrinkage model. Code Specific parameters that do not apply to the selected creep/shrinkage model are automatically disabled when that model is selected for use. The creep factor and shrinkage strain defined in the ECR box and marked in the image are used for the ACI 209R-92 model only.


Meshed Rigid Support Regions
An option to mesh a rigid support region is now available in the column and wall property dialogs. When utilized, the rigid support region option forces the program to mesh elements within the plan area of the column elements and walls. The flexural and torsional stiffness of these elements is then modified using the specified “Slab Support Region Stiffness Factor” in the same dialog. The default stiffness factor is 10, which represents the maximum factor permitted by RAM Concept and attempts to create a rigid zone over the supports. This feature may help predict more accurate floor deflections, especially for floors with large columns.


Table for Load History Deflection Analysis Results
A table for load history analysis results is now available on the Load History Deflections Layer. The tables include results and parameters that are directly used by the program to calculate the load history deflections and parameters that are not directly used but are useful for understanding the relative importance of different behaviors, like internal and external shrinkage restraint. A separate table is available for each load history step. Each table includes information for all sections defined in the model.


Precompression Checks for Post-Tensioned Sections
A maximum and minimum precompression check for post-tensioned sections has been added to the User Minimum Rule Set. The minimum and maximum precompression limits are defined by the user and are a property of the span segment or design section.
The average precompression in the section can be calculated using the Balance Loading, which includes the effects of diversion of prestress (e.g. into rigid supports) or FpsAse/Ac, which uses the vector component of the effective tendon force perpendicular to the cross section and excludes restraint. When the average precompression stress in the section is less than the defined minimum value or greater than the defined maximum value, a design criteria failure is reported.
These checks are also included in the PT Optimization feature. When the precompression calculations are activated, the user can save time preparing models for optimization by using a wide max/min range (for example, min number of strands = 0, max number of strands = 100) and use the Optimizer to find a solution with the specified precompression range.


Other Changes
RAM Concept CONNECT Edition V8 Update 2 also includes the changes discussed below.

Load History Tension Stiffening Model
RAM Concept uses the Eurocode 2 tension stiffening model for all load history calculations regardless of the selected creep/shrinkage model. This tension stiffening model utilizes a Beta parameter, which Eurocode 2 states should be taken as 1 for short-term loading and 0.5 for long-term loading. Previous versions of RAM Concept used Beta = 0.5 when using that code equation. Some experts have concluded that Beta = 0.5 is equivalent to reducing the cracking moment by about 30 percent and is an approximate way to account for shrinkage induced cracking (i.e. internal and external shrinkage restraint). Since RAM Concept always rigorously calculates the effects of internal restraint and uses the Shrinkage Restraint % parameter to account for the effects of external restraint, RAM Concept now always uses Beta =1 to avoid double counting those effects.
Load History Shrinkage Restraint %
In the Load History Calc Options dialog, the user now has the option of entering a specific percentage for external shrinkage restraint or selecting one of the pre-set options. The pre-set options are mapped to assumed percentages as tabulated below.


In prior versions, a default shrinkage restraint percentage that was used in new RAM Concept models was 20%. The default has now been changed to None, which results in a shrinkage restraint of 0%. This percentage may be appropriate for a typical, intermediate floor in a multi-story structure. However, a larger percentage may be more appropriate for other conditions (podium slab, transfer plate, basement slab, etc.).

Load History Calculations - Strength Adjustments for Time of Loading ACI209R-92 Creep/Shrinkage Model
The ACI 209R-92 model calculates creep strain based upon the modulus of the mean concrete strength at time of loading. Since RAM Concept calculates curvatures based upon the concrete modulus value at 28 days, an adjustment is needed to convert creep strains to the code model values. RAM Concept now accounts for this adjustment by modifying all creep strains by the ratio of the mean elastic modulus at 28 days (Ecmt28) to the mean elastic modulus at the time of loading (Ecmt0).
A similar adjustment is applied to the modulus of rupture, which is used for the concrete flexural tension strength in the tension stiffening equation. In previous versions, the rupture strength was valued using the 28-day design concrete strength that was defined in the Materials window. RAM Concept now converts the modulus of rupture from 28 days to the actual time of loading to account for the reduced concrete strength at early age loading (before 28 days).
Punching Shear Sections - Exclude Acute Angles
In rare cases, the punching shear check in previous versions may have been governed by sections with acute angles like the one shown in the image below. A change was made to limit the angle between adjacent edges of the punching shear section to 45 degrees. This change will eliminate unrealistic sections from consideration, which will typically improve the reinforcement design of affected punching shear checks.


Resolved Issues
RAM Concept CONNECT Edition V8 Update 2 includes fixes for the issues discussed below.

APolyLine2D and ABoundaryShape2D Errors When Generating Design Strips
In some models, snap issues with span segment ends or other geometry issues caused an ApolyLine2D or AboundaryShape2D error to occur when design strips were generated. The errors prevented the analysis from completing. Additional details can be found here.

File Compatibility Warning
RAM Concept CONNECT Edition V8 Update 2 can read all previous file formats, but writes files in a format that cannot be read by previous versions.


RAM Concept is a software application for the structural analysis and design of conventionally reinforced and post-tensioned concrete floors, mats, and rafts. RAM Concept contains an advanced feature set that allows for the design of a wide variety of floor systems including post-tensioned, reinforced concrete and hybrid systems, elevated slabs and mat/raft foundations, one-way slabs, two-way slabs, beams, and joist systems.

Historically, the vast majority of concrete floors have been analyzed by approximating a region of a slab as a frame (or design strip), and then analyzing the frame/strip using variations of conventional frame or moment distribution analysis techniques. There are two limitations to this approach. First, in irregular structures, the approximation of the real structure into a frame model could be grossly inaccurate and designing with the analysis results might not even satisfy equilibrium requirements in the real structure. The second limitation is that even in regular structures with regular loadings, the frame analysis approximates the slab/column interaction and provides no information regarding the distribution of forces across the design strip.

RAM Concept enables the engineer to design post-tensioned and reinforced concrete slabs by using a finite element model of the entire slab. RAM Concept can predict the elastic behavior of a slab much more accurately than frame models. In addition, the finite element method guarantees that the analysis satisfies all equilibrium.

In this RAM Concept training video, we introduce you to the new post-tension optimization workflow.


Bentley Systems, Incorporated is the global leader dedicated to providing architects, engineers, constructors, and owner-operators with comprehensive architecture and engineering software solutions for sustaining infrastructure. Founded in 1984, Bentley has nearly 3,000 colleagues in more than 45 countries, $500 million in annual revenues, and, since 2001, has invested more than $1 billion in research, development, and acquisitions.

Product: RAM Concept
Version: CONNECT Edition V8 Update 2 (08.02.00.146)
Supported Architectures: x64
Website Home Page : www.bentley.com
Languages Supported: english
System Requirements: PC *
Size: 1.3 Gb