Summaries

Location: Tizi-Ouzou, Algeria

Project Year: 2016 - 2017

Owner S.P.A MAPA Construction et Commerce –ETRHB Haddad

Architectural Design: DUNE Architecture

Structural Design: Proengel – ATAK Mühendislik

Steel Roof Fabrication and Installation: ATAK Mühendislik

Project Executives: Halit Levent Akbaş (M.Sc. CE), İssa Omar (M.Sc. CE), Gülce Akbaş (M.Sc. CE), Tuğçe Akbaş (Dr. M.Sc.CE)

Steel Roof Main Support System Total Weight: 5450 tonnes (6250 tonnes including catwalks and sheeting sections)

Steel Roof Area: 56.000 m2

Enveloping on Steel: 16 mm and 32 mm UV-resıstant polycarbonate

Capacity: 50.000 spectators

Tizi-Ouzou Football Stadium with 50.000 Capacity is being constructed in the capital of Algiers, Tizi-Ouzou, which is one of the biggest cities of Algiers and it is at a distance of approximately 1.5 hours to the capital. It is one of the first modern football stadiums of Algiers with large capacity and Algerian football fans are waiting for its completion with excitement. Steel roof fabrication, installation and structural design revisions of this project is performed by us, Atak Mühendislik.

 

Cable suspended truss system is used as steel roof main support system in Tizi-Ouzou Football Stadium. In 3D truss system, top caps are designed as double pipe section while bottom caps are designed as single pipe section. Each truss covers a span of 60 meters.

 

Steel roof design was performed pursuant to Eurocode 3 and finite element modelling was performed through utilization of SAP2000 software. Analyses were executed as per non-linear analysis principles for large deformation steel elements. Wind loads considered in steel roof design are obtained through wind tunnel tests. S355 grade steel is used in main supporting steel members pursuant to Employer’s request and 1.9 grade geomet covered bolts are used in bolted connections.

 

All truss cross-members in the preliminary design performed by Proengel were designed with welded joints. Considering that the roof installation is to be executed at 40 meters over the ground and difficulty of weld workmanship at site, it has been decided that welded joints are not appropriate fort his project. By taking into consideration of the tight time schedule of the project, site and local crane availability, installation workmanship and rate, all these connections are re-designed as bolted connections.

Dimensions of the elements to be delivered with containers were revised to allow means of delivery and installation above ground, and all additional connections required due to this revision were designed accordingly.

 

Members used in main supporting steel structure were re-dimensioned and design of secondary steel structure (catwalks and sheeting sections) were performed in accordance with material procurement durations and availability. All new designs and revisions were checked and approved by local consultants in the country.

 

Steel roof covering is circular in stadium outer surface and connects to main steel roof system with an angle of 45 degrees in the inner surface of the stadium. Wind forces obtained through wind tunnel test results are used in the design of covering support system. Since the installation of the covering support members will be performed after completion of the main steel roof installation, connection details of covering steel system with main supporting system are evaluated meticulously and designed to expedite installation. In steel roof covering system, 16 mm and 32 mm UV-resistant polycarbonate sheets in green and white colors are used. Width of the polycarbonate sheets vary as 980 mm and 1200 mm. Layout of polycarbonate sheets is designed to optimize the use of aluminum sections.

 

Fabrication modelling for each block forming the stadium after structural design revisions was performed through utilization of Tekla Structures software. Shop drawings are prepared in coordination with fabrication department to facilitate roof workmanship.

 

Pipe sections designed as rolled steel in main design are revised as spiral welded pipes in order to optimize material procurement durations. Since project fabrication specification did not allow welded joints, all pipe and box sections are especially procured in requested grade, length and diameter. All perforation works were performed with CNC peck drilling equipment.

 

Due to reasons such as main supporting members (trusses and masts) being selected with different diamters and wall thicknesses and optimization of transport and installation conditions, a high number of connections with face plates and bolts are used. Therefore, this is a top-class project in terms of difficulty and precision in fabrication techniques.

 

All weld connections were made as full penetration, partial penetration or fillet welds as per connection calculations and all ultrasonic, magnetic and/or penetrant test of welds were executed completely as required by the quality specification.

 

Fabrication was made in accordance with installation priority and truss elements were assembled before delivery for selected axis.

 

Three-layer paint is used in fabrication stage. Connection surfaces designed as slipcritical in design were painted with special paint with masking.

One of the most significant factors for installation to proceed as planned is stackpiling the delivered material in an orderly manner in the storage area. In this respect, separate storage areas were reserved for each block at site.

 

Installation kits were designed for rapid installation of 3D trusses on the ground. Trusses pre-assembled on the ground were installed above the ground by using crawling cranes and rubber-wheeled cranes without the requirement of any temporary support. Installation of cable connections having the length of 35 meters is performed at one try using the specifically designed installation apparatus. Truss levels and cable deflections were surveyed during installation and cables were brought to required dimension and pretension through tension bolts.

Anchorages in all concrete supports were post-tensioned as per the design.

 

Our design department preserved an effective communication with site during the project in order not to hamper installation similar to a call center working 24/7 and organized to respond to requests from site in complete and correct manner on time.

 

Installation of 5 blocks are completed as of end of July 2017 and steel roof installation of the stadium will be completed by the end of the year with the completion of installation of all 12 blocks.