Concrete slab thickness OWSJ
January 24, 2026
Interview with the Inventor of NIAZIT Open Web Steel Joists – Eng. Mohammad Niazi
Introduction
I am Mohammad Niazi, a structural engineer and the inventor of the NIAZIT Open Web Steel Joist (OWSJ) Roof System, and a graduate of the University of Tehran and universities in the United States. Throughout my professional career, structural safety, construction-stage stability, and seismic performance of floor systems have been the core focus of my research and engineering activities.
Field Studies on Major Iranian Earthquakes
As part of these studies, I conducted extensive field investigations and analytical research on major earthquakes in Iran, including Buin-Zahra, Avaj, and Bam. The published results clearly demonstrated that:
Floor systems utilizing open web steel joists with no concrete in the web zone, i.e. truss-based systems, showed the lowest level of seismic damage compared to conventional slab and joist systems.
Development of the NIAZIT Steel Joist System
These findings, combined with years of engineering experience, led to the design and invention of the NIAZIT steel joist system. This system is applicable to:
Reinforced concrete structures
Steel structures
Industrial and commercial halls
Various types of building projects
Key Advantages of the NIAZIT Roof System
🔷 High Seismic Safety and Performance
The NIAZIT system is specifically designed to enhance earthquake resistance and to reduce structural damage, contributing to improved life safety and economic resilience.
🔷 Optimized Material Consumption
By eliminating concrete within the joist web and optimizing steel geometry:
Approximately 15–20% reduction in steel and concrete consumption
Reduced dead load of the structure
Lower construction costs and environmental impact
🔷 Economic Efficiency and Extended Service Life
Compared to traditional floor systems, NIAZIT offers:
More cost-effective execution
Longer service life
Reduced long-term maintenance costs
Global Background of Open Web Steel Joist Systems
Open web steel joist systems have been used and continuously developed in Europe and North America for over 70 years.
The NIAZIT system represents a new generation by:
Addressing the weaknesses of earlier systems
Achieving superior seismic performance
Maximizing efficiency with minimum material usage
As a result, it has been officially registered in Iran as a novel patented structural system.
Official Approvals and Honors
Patent Registration No. 27755 – Iran
Approval from the Ministry of Housing and Urban Development
Technical certification from the Building and Housing Research Center
National Standard Mark – Tehran Province
Approval by multiple provincial Engineering Organizations
Appreciation Award from Tehran Ironworkers Union (Shahriar)
Recognition by Tehran Governorate
Recognition by Kurdistan Provincial Standard Office
National Award as a Distinguished Figure in Iran’s Industry and Trade awarded to Eng. Mohammad Niazi
