Lateral Stiffness of Masonry Infilled Reinforced Concrete (RC) Frames with Central Opening

Abstract

Window and door openings are inevitable parts of infill walls for functional reasons. Currently, publications like FEMA-273 and ATC-40 contain provisions for the calculation of stiffness of solid infilled frames mainly by modeling infill as a "diagonal strut." However, such provisions are not provided for infilled frames with openings. The present study proposes a reduction factor for effective width of diagonal strut over that of the solid reinforced concrete (RC) infilled frame to calculate its initial lateral stiffness when a central window opening is present. The study is based on initial lateral stiffness which is taken at 10% of the lateral strength of the infilled frames.

Rotations of RC Members of Infilled Frames at Yielding and Ultimate

“…According to the above adverse local effect, failure or heavy damage of an infill panel may dislodge part of it, exerting a concentrated force on the adjacent column. The stronger the infill, the larger is the magnitude of this force and the higher the likelihood of column shear failure in spite of the presence of openings, as presented in reference [13]. Nevertheless, experimental results that have been reported by Kakaletsis and Karayannis 2007 show the significance of various forms of openings on the reduction of strength, stiffness and energy dissipation capability for the examined cases of infilled frames.…”

Untitled

“…Banyak model RDP berlubang (RDPB) yang telah diusulkan sebagai idealisasi dari perilakunya, salah satunya metode strat diagonal yang direduksi lebarnya (Mondal andJain, 2008, Asteris et al, 2012). Metode lain yang dapat digunakan adalah model elemen shell dengan memperhitungkan bidang kontak dinding dengan struktur (Dorji and Thambiratnam, 2009).…”

Utjecaj otvora na krutost ispunjenih okvira

“…Objašnjenje nekih od značajnih parametara usmjerilo je istraživače prema detaljnoj analizi ponašanja. Mondal i Jain [28] analiziraju horizontalnu krutost okvira sa zidanom ispunom i središnjim otvorima. Parametarsko ispitivanje jednokatnog okvira s jednim rasponom obavljeno je pomoću metode MKE.…”

“…Iako na faktor redukcije krutosti (l) utječe koeficijent otvora (a), lokacija otvora i dimenzije zida (L/h), ustanovljeno je da detalji armiranja stupa i grede ne utječu značajno na faktor redukcije krutosti (slika 11.). Jednadžba predložena za "faktor redukcije krutosti", dobivena pomoću višestruke regresije u obliku jednadžbe (7) da bi se dobila najbolja usklađenost rezultata, uspoređena je s analizama metode konačnih elemenata (slika 12. za armaturu iz skupine 1) te s izrazima koje su ranije predložili razni istraživači [28,30] (slika 13. ):…”