PHX Skytrain RCC

PHX Skytrain

Location: Phoenix, Arizona
Client: Able Steel
Project Type: Infrastructure – Transit & Transportation Facility
Scope: Steel Detailing for Curved Roof Framing, Stair Systems, Splice Connections, and Column Bases

Project Overview

The PHX Sky Train is a key transportation infrastructure project in Phoenix, Arizona, designed to support efficient passenger movement and connectivity within the airport transit system. The structure incorporates architecturally expressive curved roof framing and integrated access systems, requiring a high level of precision in steel detailing and fabrication coordination.

Structures Online (SOL) provided comprehensive steel detailing services for the project, focusing on complex curved geometry, connection accuracy, and constructability. Advanced 3D modeling was essential to ensure seamless integration between roof framing, vertical supports, and access components.

Scope of Work

Curved Roof Beam Framing
The roof structure consists of a series of curved primary and secondary beams, fully modeled to maintain precise curvature and alignment along the roof profile. Each curved member was coordinated with supporting columns and adjacent framing to ensure structural continuity. Connection detailing—including end plates, splice locations, and bracing ties—was developed to suit fabrication constraints and enable accurate field assembly.

Curved Roof Beam-to-Column Connection
This roof beam connection was detailed using a combination of end plates and vertical shear tabs to accommodate varying beam angles. Bolt spacing, plate sizing, and weld access were carefully coordinated to maintain fit-up accuracy while supporting fabrication of curved profiles.

Multi-Flight Staircase System
A multi-flight staircase system was fully modeled to ensure accurate alignment across all levels. The detailing included stringers, treads, landings, and handrail assemblies, coordinated with surrounding structural framing to maintain uniform riser heights and compliant walking geometry. Special care was taken to avoid clashes with adjacent beams and columns while enabling fabrication-friendly segmentation for transport and erection.

Beam-to-Beam Splice with Column Interface
This segment features a detailed beam-to-beam splice connection integrated with a column support interface. The splice assembly included precisely modeled end plates, bolt arrangements, and alignment tolerances to ensure accurate fit-up during erection.

Column Base and Anchor Bolt Assembly
A fully detailed column base connection was developed using a multi-plate base configuration and anchor bolt group. Leveling plates, grout thickness, and side plate interfaces were coordinated to ensure accurate positioning, stability, and accessibility during installation and inspection.

Key Deliverables

• Detailed 3D models for curved roof framing, stair      systems, and base connections.

• Shop and fabrication drawings with      coordinated bolt layouts, splice details, and weld profiles.

• Anchor bolt and base plate drawings aligned with foundation      geometry.

• CNC-ready data supporting efficient fabrication and erection      sequencing.

Project Outcome

Through precision-driven detailing and advanced 3D coordination, Structures Online contributed to the successful execution of the PHX Sky Train project. The work demonstrates SOL’s expertise in curved steel geometry, infrastructure-scale detailing, and complex connection modeling, delivering a structure that meets both architectural intent and long-term performance requirements.