CSI SAFE 23.3.1 for Windows is a professional structural analysis and design software package developed by Computers and Structures, Inc. (CSI) for the analysis and design of concrete floor systems, slabs, foundations, and related structural components. It is widely used by structural engineers, civil engineers, consultants, and building-design professionals for modeling reinforced-concrete and post-tensioned floor systems, evaluating structural behavior, and producing design information for engineering documentation.

SAFE provides an integrated environment for creating floor-system models, defining materials and section properties, assigning loads and load combinations, generating finite-element meshes, performing structural analysis, and reviewing forces, stresses, displacements, reactions, and design results. The software is particularly suited to two-way slabs, flat plates, ribbed slabs, post-tensioned slabs, mats, and foundation systems, with tools for modeling tendons, supports, springs, openings, columns, walls, and other structural components.

The program supports reinforced-concrete and post-tensioned slab design using multiple international design standards. SAFE 23.3.1 specifically adds concrete and post-tensioned slab design according to CSA A23.3:2024, expanding the code options available within the SAFE 23 product line.

SAFE also provides database-table and API capabilities for engineering workflows and interoperability. Model and results information can be reviewed through tabular output, while API functions support automated model and data operations. The software can therefore be incorporated into larger structural-engineering workflows alongside other CSI products and external analysis, documentation, and data-processing tools.

Key Features

• Finite-element analysis of concrete floor systems

• Reinforced-concrete slab design

• Post-tensioned slab design

• Flat plate and flat slab analysis

• Two-way slab analysis and design

• Foundation and mat analysis

• Column, wall, opening, and support modeling

• Tendon and post-tensioning modeling

• Load patterns and load combinations

• Static and dynamic structural analysis

• Finite-element mesh generation

• Deflection and displacement analysis

• Punching shear analysis and design

• Reinforcement design and detailing information

• Multiple international concrete design codes

• CSA A23.3:2024 concrete and PT slab design

• ACI-based concrete and PT slab design

• Eurocode-based design options

• Korean KDS design support

• Database tables for model and analysis data

• Import and export capabilities

• API support for automation and integration

• Graphical model visualization

• Detailed analysis and design results

• Engineering reports and tabular output

• Integration with broader CSI structural-analysis workflows

What’s New

SAFE 23.3.1

• Added reinforced-concrete slab design according to CSA A23.3:2024

• Added post-tensioned slab design according to CSA A23.3:2024

• Expanded Canadian code support for concrete floor-system design

• SAFE 23.3.1 is part of the SAFE 23.3 release family. CSI’s current enhancement information lists the 23.3.0/23.3.1 release family with the CSA A23.3:2024 design enhancement.

Earlier SAFE 23 releases

• SAFE 23.0 introduced reinforced-concrete and post-tensioned slab design according to ACI 318-25.

• SAFE 23.2 added reinforced-concrete and PT slab design according to KDS 14 20 00:2022.

Professional Applications

• Structural engineering and building design

• Reinforced-concrete floor-system design

• Post-tensioned slab design

• Flat-slab and flat-plate design

• Foundation and mat design

• Commercial building projects

• Residential and high-rise buildings

• Industrial structures

• Institutional buildings

• Parking structures

• Structural consulting

• Concrete design verification

• Structural analysis and engineering documentation

• Building-code compliance studies

System Requirements

Minimum Requirements

• OS: 64-bit Windows; SAFE 23.x is designed for modern 64-bit Windows environments.
• CPU: Modern Intel or AMD 64-bit processor
• RAM: 4 GB minimum practical starting point
• Storage: Approximately 5 GB or more of free disk space
• GPU: DirectX-compatible graphics hardware
• Display: 1280 × 800 or higher recommended
• Input: Keyboard and mouse
• Internet: Required where applicable for cloud-sign-in licensing, software activation, updates, or online services. CSI provides cloud sign-in licensing for its software.