Seismic Behavior of Shear Wall–Dominant Tunnel Form Buildings With Continuous Slab–Wall Connections During the Kahramanmaras Earthquakes of February 6, 2023, in Turkey

Tunnel form buildings dominated by shear walls are often built in countries with a high earthquake risk, as they can be erected quickly and cheaply. Since there are no beams and columns, the connections between the floor and wall are continuous and important for seismic behavior. This is the most important observation on site during the severe earthquakes on February 6, 2023, in Kahramanmaras, Turkey. There are no reports of the collapse of buildings constructed in tunnel form and no fatalities, although more than 300,000 buildings collapsed or were severely damaged and more than 50,000 people died. This seismic performance was mainly enhanced by the continuous slab–wall connections, shear walls, redistribution of lateral seismic forces at the edges, and 3D behavior due to T‐C coupling. This paper also discusses the distribution of lateral forces and the strengthening strategies that affect the seismic behavior of buildings in tunnel form. Two‐story slab–wall interaction models with openings that may be relevant to the effect of continuous slab–wall interaction are analyzed. During the field observation, some buildings in tunnel form are damaged due to their low torsional stiffness. To remove the tunnel formwork to the outside, most of the perimeter, which is very effective for torsional stiffness, is open. In most cases, the first dynamic period is the torsion, which leads to a lower torsional stiffness. To improve the torsional stiffness, X‐bracing was used at the corners of the building. Three‐story, 1:3 scaled, existing, and reinforced test models of tunnel form buildings with X‐bracing are tested under pushover loads. By analyzing experimental studies and finite element analysis, valuable insights are gained to improve the seismic resistance of existing and future tunnel form buildings against seismic hazards. The seismic capacity of the strengthened model is increased by 22.6%, and the first period is changed from torsional to flexural mode.