Virtual Table
Table Exhibition #3
Ahmet Topbaş is a structural engineer and the founder of ATTEC, a structural design and engineering firm based in Istanbul and New York in 2008. He graduated from Istanbul Technical University with a degree in civil engineering in 1995. He furthered his education in the United States, earning an MBA from Georgia State University and an MSc in Structural Engineering from Columbia University in New York.
Throughout his career, Ahmet Topbaş has gained extensive experience both in Turkey and the USA, including significant roles in construction and project management at Navigant (SoundBuild) and as a structural designer and project engineer at Thornton Tomasetti. He holds a Professional Engineering (P.E.) license in the United States, which underscores his expertise and qualifications in the field.
Topbaş is recognized for his innovative approach to structural design, working with various materials such as steel, wood, masonry, and concrete. His projects often integrate and mix these materials in a hybrid manner, to create unique, aesthetically pleasing, and structurally sound buildings. Additionally, he is involved in academia, sharing his knowledge through lectures and workshops at engineering and architecture schools in Istanbul.
His firm, ATTEC, is known for tackling challenging projects and providing creative engineering solutions, contributing to numerous architectural, transportation, industrial, and infrastructure projects.
Masonry
Concrete
Wood
Steel
Wood
SideBySide, Venice
The necessity of constructing a foundationless structure on the Arsenale dock and the 2 ton/m2 maximum dock load limitations defined the boundaries of the design. This constraint led to the structural design criteria of using precast modular foundations, concrete, steel for structural finesse, and structural massive wood instead of cladding. Another design criterion was that the entire structure was produced in Turkey and transported by trucks. Thanks to these limitations, the dismantled system can now be reassembled in the Golden Horn in Turkey. We adapted the massive wood structural details applied in this project with the experience and inspiration we gained from different types of structures.
Odunpazarı Modern Museum (OMM), Eskişehir
The main design criterion that required us to reconsider the structural system was the incompatibility of the proposed structural framework with the desired spatial effect in the initial design stages of the project. Another important criterion was the optimization of the wooden sections of the facade. In these sketches, you can trace the efforts of this improvement: the Wood Sourcing Matrix Sketch answers the question of how a mathematical and intelligent solution can be made from a multi-component matrix, providing a visual for making informed decisions! The structural wood widths, which started at 240mm at the beginning of the project, were reduced to 200-100mm through engineering optimization in the section.
Steel
Arter, VKV Contemporary Art Museum, Istanbul
This project, realized through an international competition and coordinated by a multinational design team, is significant as it represents a successfully executed cultural building in these lands until the end. The greatest originality in the structural design was the use of steel trusses suspended from two major reinforced concrete cores, allowing the exhibition spaces and street entrance to remain transparent and free. Supporting the underground foyer and Black Box, as well as the multipurpose halls with delicate steel elements, was the biggest technical challenge, as these had to withstand soil pressure despite the large gaps in the floors.
The steel truss peripheral structure not only lightened the building but also maintained its delicacy with truss rods made from high-strength S460 material, ensuring a minimal presence within the envelope. The details also needed to be special. Large gussets would disrupt the delicacy. Specially welded 3D truss nodes guaranteed the envelope’s delicacy, freeing the gallery spaces with millimetric precision.
Another special solution implemented to maximize ceiling height and floor delicacy while staying within the envelope was to create openings in the floor beams 30% larger than those permitted by standards. This unique steel structure had to be isolated for seismic considerations due to its asymmetry and suspended nature. The columns on the first floor were kept slender to ensure transparency. All of this was achieved with special bridge sliding bearings. While the trusses were suspended from the cores, the bridge sliding bearings allowed horizontal freedom over the slender columns on the first floor. Thus, all seismic loads were carried by the cores, designed specifically for this purpose, through the movement of the trusses.
Kalyon PV Solar Power Plant Central Control Building, Karapınar Konya
A story of the integrity between engineer, architect, client, and implementation. The mullions to which we mounted the glass cladding also serve as the facade support and the columns for the green roof, which carries approximately 1 meter of soil load. Therefore, the elegance and delicacy within the interior make the “Structural = Architectural” approach visible. The holistic use of concrete and steel, employing the principles of a composite structural system, is emphasized in this project.
Masonry
Hatice ve Fehime Sultan Yalıları Restorasyonu, Ortaköy, İstanbul (Hamam)
In the domes, placing steel elements to absorb vertical shell thrust loads and horizontal seismic roof diaphragm loads was made possible by a special Mediterranean or Catalan vaulting technique. In this method, bricks are laid horizontally, almost like floor tiling, unlike the traditional Byzantine or Roman systems. The joints formed between the layers provide exceptional shear strength and cohesion.
In this vaulting technique, it is very difficult for shear cracks to form between the traditional vertical brick layers. Its shear strength is superior to that of the Byzantine technique. Additionally, the joints provide an excellent interface for inserting carbon, steel rods, or woven elements to counteract tensile stresses in the dome. Thus, this allows us to absorb seismic loads with a delicate and holistic masonry structure solution.
Creative solutions learned, interpreted, and adapted from the past make this structure very special to me. Thanks to these solutions and designs, there was no need for a secondary seismic load-bearing system, and thus, architectural details were automatically created by the structural systems.
Haydarpaşa Jewish Community School, Yeldeğirmeni Kadıköy Istanbul
The structural design concept is inspired by the mixed New York and English buildings from the Industrial Revolution. Drawing inspiration from history to create simple, honest, sustainable, and tectonic masonry structures in an earthquake zone, in accordance with new regulations: The Quetta Masonry system, a combination of masonry and iron continuity, is an adaptation of the old English technique to the seismic region's brick building systems. This includes the support provided by the late Ottoman period’s hybrid metal-brick building systems for vertical loads and floors, adapted for seismic and horizontal loads.
Concrete
Palanga 1888, Erzincan
The layered plate geometry provides high rigidity in both directions. It can easily span very large openings without intermediate columns through local detailing and variations in thickness. This ensures exceptional strength and lightness, especially in earthquake-prone areas. Columns and slabs transform into beams and braces, reinforcing each other's rigidity. With the correct support and element alignment, economical and lightweight structures with high strength can be achieved.
Its implementation was full of challenges! It was boldly constructed on-site by Paraf Engineering. For example, the slender but tall columns and beam slabs had to be cast with minimal segregation in the concrete, and the connections between vertical and horizontal angled plates had to be rigid enough to transfer moments. The joints in these areas could be made staggered thanks to the craftsmanship of the formwork.
The Korugan, also known as Han Dam, stands out with its special statics and method of application. Our GFRC (Glass Fiber Reinforced Concrete) shells, created on-site without formwork using a spray technique, are another example of adapting past learnings to contemporary architectural technologies.
Moloz Beton
A joint invention by İTÜ and Ahmet Topbaş, this concrete formula is essentially over 2000 years old! Inspired by the ancient world, Vitruvius, Rome, and its reflections in these lands, the idea was born: using concrete rubble as fill material like rubble masonry. Vitruvius’s description in Book 2, Chapter 8, is the ancestor of today’s cast-in-place concrete. Moloz Beton uses recycled concrete pieces instead of stone/aggregate. A special and environmentally friendly plasticizer additive, high-dose cement, slag, and sand create a self-compacting concrete mortar that completely fills the gaps between the rubble. This method yields a minimum C20 quality concrete with 85% recycled content.
