STRIAN 2.0 is a free online structural analysis tool designed for students and teachers. This program can analyze both a) statically indeterminate and b) determinate structures. It builds upon the 2015 software STRIAN, created by Miroslav Stibor and Petr Frantík, and utilizes the Matrix Stiffness Method, originally from MaFoDeM, another free structural analysis software.

Tutorial

• J STRIAN 2.0 Structural analysis software – Beam calculator
• J STRIAN 2.0 Structural analysis software – Frame calculator
• J STRIAN 2.0 Structural analysis software – Truss calculator

Known bugs

Currently, there are no known bugs. Chrome web browser is recommended. STRIAN is tested on MS Windows, Android and macOS.

Results

You can evaluate beams, frames and trusses for internal forces. If your model is successfully solved, the following diagrams can be drawn:

• Reactions at the supports,
• Bending moment diagram (BMD),
• Shear force diagram (SFD),
• Normal/axial force diagram (NFD/AFD),
• Deflected shape.

Creating spans

Bars and beams begin and terminate at nodes, which are automatically generated. Hinges and supports can only be placed within these nodes. When bars intersect, they do not interact.

• You can drag a node to change its position (on the desktop version).
• The mouse pointer adheres to grid lines; grid spacing is based on the zoom level.
• You can edit nodes' coordinates in the Node Table at a later time.
• Cross sections can be assigned to bars and beams later.

You can also press ESC to finish.

Creating supports and hinges

Supports and hinges must be positioned at nodes. Additional support types can be accessed and applied from the Node Table.

Truss solver

To use STRIAN as a truss solver, you must place hinges on the bars. You're solving for normal forces in a truss; thus, there will be no bending moments or shear forces on the members.

Inclined roller support

Inclined roller support is not implemented. However, a workaround can be achieved by using an auxiliary stiff bar connected via a hinge.

Loads

Loads are generated by pointing to the beam. If they're not placed precisely where you intended, you can click on the load to adjust its position. Alternatively, you can open the Load Table to modify the loads. For continuous loads spanning multiple sections, you'll need to repeat the load for each span.

Distributed load on inclined beams

The distributed load is specified per meter of the beam (not per the length as projected into the coordinate system). Example: if the beam is projected onto the horizontal axis as 1 meter long, but its actual length is 1.41421 meters, the total force would be 1.41421 kN.

Load cases

For most users, this function may not be needed. To create and switch among load cases, use the drop-down box next to the last tab.

Sections

For simple beams, creating cross-sections is unnecessary. Simple structures will be solved correctly without defining material and cross-section properties. However, deflection data depends on these specifications. When you assign a cross section to a bar, it will be displayed in the graphical view in parentheses next to the beam ID

For frames, it's crucial to assign appropriate sections to the beams and bars to achieve accurate results. Beams often have different stiffness compared to columns, and these differences significantly affect the results.

In structural analysis, it's typical not to consider the impact of shear when assessing reactions or deflections, hence the A_sh (shear area) is optional. The shear area varies depending on the section type, such as solid section, I-beam, or hollow section. For clarification, refer to other sources if uncertain.

After modifying a section, when you save, you will be prompted to specify whether you intend to create a new section or simply modify the current one.

Tables

Your structure can be described using nodes, beams, loads, sections, and settlements. Each category is displayed in its respective table, and you can edit parameters directly from these tables. You cannot add a new row directly from within a table.

Node table

Nodes are generated automatically when creating new beams. Incorrect coordinates can be corrected within this section. The first column displays the Node ID, which is also marked graphically next to the nodes. The last column indicates the support type at the node (if any).

Beam table

The first column shows the Beam ID, which is also graphically marked near the midpoint of the beams. The second column displays the ID of the cross-section, visually indicated in parentheses after the beam ID. Next, there are fields for the start node and end node. Lastly, the smaller fields indicate the presence of a hinge

Load table

The tables display both the Node ID and the Beam ID, with the Node ID being crucial as it indicates the starting point of the beam. The distances where the loads are applied are measured on the beam from its starting point.

Load cases

This is an advanced feature used by a few. You can define multiple load cases on the same structure. For instance, 1: self-weight, 2: snow, 3: wind. When you switch to another case, you are working with a different set of loads. This allows you to analyze independent sets of loads and their respective results.

Section table

Sections that have been created will be listed in this table, and they can be edited here. The first column is Section ID, which can be used to assign a section directly to beam(s) from the Beam Table.

Settlements table

Some problems may involve support settlement due to factors like soil erosion or consolidation. Settlement can only be defined at the supports.

Table of settlements displays all nodes that have supports. If settlement is assigned to a node, it will be displayed here.

Files (Load and Save)

Your projects are saved on a server and cannot be stored on your local computer. When you use STRIAN for the first time, the program receives a unique User ID from the server, which acts as your dedicated folder on the server. If you run STRIAN on another device (or even on the same device with a different account or browser), another folder will be created on the server. To share files across your devices, use the same User ID from one device on all of them.

Only the structure is saved; results and settings are not included in the file.

Results

The solver runs in your browser and doesn't rely on the internet. Initially, only reactions are displayed, but you can enable diagrams (SFD, BMD, NFD and Deflected shape) from the Settings dialog. If you require more detailed diagrams, create additional nodes within the specific area of interest.

Settings

You control what and how is displayed. In some cases, graphical representations may cause entities to overlap.

1. Use '-' and '+' to zoom the structure in and out.
2. The 'Zoom' feature in Settings is designed to enhance the readability of model descriptions and marks.
3. You can switch object layers to temporarily hide them.
4. For optimal performance and improved user-friendliness, keep the paper size minimal for your structures.

STRIAN operates internally in SI units, and coordinates are ultimately rounded to 1/100 of a millimeter precision. When switching to imperial units, you can input measurements in feet and inches, such as 2' 3", which is equivalent to 2.25 inches.

Credit

• Authors: Miroslav Stibor, Petr Frantík, info {at} structural-analyser.com
• Wout Fierens for svg.js,
• Joshua Gatcke for HTML KickStart,
• Výměníky tepla for hosting this domain,
• Dave Furfero for jQuery UI Touch Punch,
• Glyphter.com for vector icons.