Experimental evaluation of slab reinforcement contribution to negative moment capacity in beam-column joints to prevent storey mechanism in RC frames

Doğan O., Genç Y., ÖZTÜRK B., Odacıoğlu O. G., KOPRAMAN Y., Sevim O.

Engineering Structures, cilt.345, 2025 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 345
  • Basım Tarihi: 2025
  • Doi Numarası: 10.1016/j.engstruct.2025.121569
  • Dergi Adı: Engineering Structures
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aerospace Database, Aquatic Science & Fisheries Abstracts (ASFA), Communication Abstracts, Compendex, Geobase, ICONDA Bibliographic, INSPEC, Metadex, DIALNET, Civil Engineering Abstracts
  • Anahtar Kelimeler: Beam–column joints, Effective slab width, Flexural strength, Reinforced concrete frames, Slab reinforcement, Storey mechanism, Strong column–weak beam design
  • Gazi Üniversitesi Adresli: Evet

Özet

Türkiye, located in a high seismic risk zone, has experienced the collapse of many reinforced concrete (RC) buildings due to the strong beam–weak column problem, largely caused by neglecting the contribution of adjacent slab reinforcement in joint design. While Turkish standards and Eurocode disregard this contribution in negative moment regions, international codes such as ACI 318 partially or fully consider it. This study presents an experimental investigation on the flexural contribution of slab reinforcement placed parallel to beams in joint regions. Eighteen half-scale RC beams, including T-section beams with slabs and rectangular beams without slabs, were tested under static three-point loading. The results show that slab reinforcements significantly enhance the negative moment capacity, with their effectiveness decreasing parabolically as the distance from the beam web increases. Approximately 35 % of the reinforcement within the effective slab width was found to contribute as effectively as beam reinforcement. Based on these findings, an equation was proposed to determine the effective slab width and the contribution rate of slab reinforcement. Recognizing this effect can help maintain ductile strong column–weak beam behavior, reduce reinforcement congestion at joints, and improve seismic performance.