Our Structural Design and Engineering Approach

A cable-suspended 3D truss system was used for the main structural steel roof of the stadium. The top chords were designed as double circular hollow sections, while the bottom chords were designed as single circular hollow sections, with each truss spanning 60 meters.

Structural analyses were performed using SAP2000 software, modeled in accordance with Eurocode 3 standards. Wind loads were determined based on data obtained from specially conducted wind tunnel tests. The primary structural system used S355 grade steel, and grade 1.9 geomet-coated bolts were selected for the connections.

Due to the complexity of assembling welded joints at a height of 40 meters, all initially designed welded connections were reevaluated and redesigned as bolted connections to enhance site applicability. Optimal designs were made by considering installation speed, crane capacity, and site conditions.

Component dimensions were revised to allow for containerized shipping, and all new connection details were developed by our team accordingly. The primary structural members were resized, while secondary steel structures (catwalks and cladding supports) were designed based on procurement lead times and material availability.

The cladding system features a circular outer form and connects to the main structural system at a 45° angle on the inner face. Cladding connection details were optimized to accelerate post-main steel assembly applications. UV-resistant polycarbonate panels in green and white, with widths of 980 mm and 1200 mm and thicknesses of 16 mm and 32 mm, were used. The layout plan was designed for the most efficient use of aluminum profiles.

Following all structural design revisions, detailed fabrication models for each block were produced using Tekla Structures software, and shop drawings were prepared in coordination with our fabrication department.

Fabrication Process

The originally specified hot-rolled steel tube profiles were redesigned as spiral welded tubes to shorten procurement times. In this project, where welded connections were not permitted, all pipe and box sections were specially sourced in required grades, lengths, and diameters. All holes were precisely processed using CNC drilling machines.

To facilitate on-site assembly of truss and column members of varying diameters, numerous face-plated and bolted connection solutions were developed. This project, in that sense, required advanced precision and expertise in fabrication techniques.

All welds were applied as full penetration, partial penetration, or fillet welds in accordance with connection calculations, and ultrasonic, magnetic particle, and dye penetrant tests were carried out in full compliance with the quality specifications.

Truss elements prepared in advance according to the erection sequence were preassembled in the workshop along selected axes and shipped accordingly. The system was protected with a three-coat painting system, and friction surfaces were treated with special masking and coatings.

Our Installation Approach

To ensure a smooth installation process, separate on-site stock areas were designated for each block. Special kits were designed for preassembly of the 3D trusses on the ground, and the trusses were installed in place without temporary supports using crawler and rubber-tired cranes.

The 35-meter-long cables were installed in a single step using special apparatus. Elevation and sag were measured during installation, and final adjustments were made via bolt tensioning. Reinforced concrete support anchors were executed as post-tensioned in accordance with the project requirements.

As ATAK Engineering, we provided continuous and effective communication throughout the site installation process—essentially operating as a 24/7 engineering support hotline. By responding to all needs accurately and on time, we ensured uninterrupted progress in the assembly process.

As of July 2017, 5 blocks were completed, and with the installation of the remaining 7 blocks, the steel roof assembly is planned to be completed by the end of the year.