PSI - Issue 78

Yavuz Yadim et al. / Procedia Structural Integrity 78 (2026) 1895–1902

1898

proper engineering oversight and seismic considerations, significantly worsening the extent of damage in 2023. While politically expedient, this policy undermined structural resilience and contributed to human and material loss.

(a) (b) Fig. 2. (a) Buildings overturned owing to the ground liquefaction. (b) The urban fabric of these cities in Turkey and Syria is often composed of 8– 10 storey RC structures built in close proximity. Pounding effects are frequent during seismic events. Need for a Holistic Design Approach: The 2023 disaster underscores the need for a design paradigm that prioritizes seismic resilience, redundancy, adaptability, and strict inspection integrity from planning to maintenance. Mere code compliance is insufficient without a robust earthquake engineering framework, which is lacking in Turkey. Structural design is often performed by civil engineers with limited expertise in earthquake and geotechnical engineering. Though titles like “chartered structural engineer” exist, they are awarded without formal examinations or rigorous professional assessment (The Guardian, 2023), raising concerns over designer qualifications. Previous efforts to introduce stricter licensing have received little attention. Cantilevered Overhangs and Disrupted Load Paths: A popular architectural feature in Turkey, cantilevered balconies, often enclosed over time, introduce significant structural weaknesses. To accommodate these features, beams intended to connect columns directly were removed, disrupting the load path and weakening the global frame action. This reduced the building's ability to redistribute seismic energy, increasing the risk of instability and collapse, particularly in structures built between the 1960s and the early 2000s. Low lateral stiffness is a key contributor to seismic vulnerability because it increases the building drift and deformation under lateral forces. Studies (Jalayer & Ebrahimian, 2015) have confirmed that enhancing the stiffness reduces seismic damage risks. Tunnel-form buildings, which are widely used in Turkish social housing, demonstrate high stiffness and perform well in major earthquakes, with no reported structural damage. Inadequate Foundation Design and Liquefaction: Shallow foundation failures and liquefaction were widespread during the February 2023 earthquakes. Poor soil–foundation interaction, combined with loose, water-saturated soils, led to differential settlement, tilting, and overturning. These failures highlight the urgent need to incorporate liquefaction risk into geotechnical design, particularly in susceptible regions. Soft-storey configurations, particularly at ground levels converted for commercial use, significantly weakened the seismic performance. The removal or reduction of structural elements, such as infill walls or columns, concentrated deformation at the base, leading to excessive drift and the formation of plastic hinges. Such mechanisms are among the most common and destructive failure modes in earthquake-prone regions. Shear Failures and Short Column Effects: Partial-height infill walls and architectural openings often create unintended short columns that exhibit elevated stiffness and attract disproportionate seismic forces. These elements are prone to brittle shear failure, which often stems from minor design oversights or post-construction modifications. Short-column effects disrupt uniform drift demands, creating critical points of failure within RC frames. Storey Failure Mechanisms in RC Buildings: One of the most devastating structural failures during the February 2023 earthquakes was storey failure, often leading to total or near-total collapse. While violation of the strong-column weak-beam (SCWB) principle remains a key concern—where columns fail before beams can yield—several other mechanisms also contributed. In many buildings, poor concrete quality and undersized columns led to axial failures at the first storey, causing a sudden loss of vertical load-bearing capacity. Inadequate detailing and poor construction often resulted in joint shear failures or sliding shear failures at the column tops, particularly under bidirectional seismic demands. Sliding shear cracks, forming at the beam-column interfaces, triggered rapid stiffness degradation and