> ## Documentation Index
> Fetch the complete documentation index at: https://calcs.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Calcs.com Release Notes — June 1–15, 2026

> Variable stirrup spacing for Concrete Beam, expanded Internal Double Gusset coverage, two-sided HSS beam moment analysis, and a CSA S16:19 weld resistance factor correction.

## Engineering Calculators

### 🛠️ Improvements & Fixes

* [**Concrete Beam (ACI 318-19)**](https://calcs.com/calculators/concreteBeamRectangularUSAACI318-19) 🇺🇸: Added support for varying stirrup spacing with separate support and mid-span zones based on support locations, replacing the single-value stirrup approach for more accurate shear reinforcement design.
* [**Combined Footing (IBC 2024)**](https://calcs.com/calculators/foundationsCombinedFootingUSAIBC2024) 🇺🇸: Added separate bar size inputs for top and bottom reinforcement in both X and Y axes, replacing the shared bar size input for more precise development length calculations.

***

## Atlas Tube Connection Hub

### 🛠️ Improvements & Fixes

* [**Steel Connection Column Bracing (AISC 360-22) — Internal Double Gusset**](https://www.atlastube.com/hss-connections-hub/) 🇺🇸: Extended Internal Double Gusset coverage to beam-to-gusset, beam capacity, and transverse shear limit states with per-gusset demand calculations.
* [**HSS Beam-to-HSS Moment Connections (AISC 360-22)**](https://www.atlastube.com/hss-connections-hub/) 🇺🇸: Added two-sided beam input support with dual beam analysis paths and combined demand calculations.
* [**HSS-to-HSS Splice Connections**](https://www.atlastube.com/hss-connections-hub/) 🇺🇸: Fixed weld axial stress calculations to properly account for compression and combined loading conditions.
* [**HSS Connections (CSA S16:19)**](https://www.atlastube.com/hss-connections-hub/) 🇨🇦: Corrected the weld resistance factor from 0.75 to 0.67 per code requirements, affecting 24 presets.
* [**Concrete-Filled Moment Connections**](https://www.atlastube.com/hss-connections-hub/) 🇺🇸: Enhanced end plate thickness checks and added weld force loading diagrams for HSS-to-HSS and HSS-to-WF connection configurations.
* [**Steel Connection Templates**](https://www.atlastube.com/hss-connections-hub/) 🇺🇸 🇨🇦: Fixed upgrade mappings to prevent load data corruption when upgrading existing calculators to new versions.
* [**WF-to-HSS Moment Connections — 3D Diagrams**](https://www.atlastube.com/hss-connections-hub/) 🇺🇸: Refreshed 3D diagrams with grouped bolt labels, improved angle plate information, and enhanced weld visibility based on Atlas Tube feedback.

***

## Platform Improvements

### 🛠️ Improvements & Fixes

* **Combine Mode Analytics:** Added comprehensive instrumentation across Editor, Review, and Combine workflows to track navigation funnels, widget actions, and edit patterns, giving the team better visibility into how Combine Mode is used.