The objective of this study was to determine the collapse risk of failsafe reinforced concrete (RC) frames due to earthquakes by newly developed fragility curves. The curves were constructed based on the collapse mechanism, instead of measures of lateral drift as customarily adopted. The procedure was applied to RC open frames that were seismic resistant. A fail-safe mechanism was imposed by allowing plastic hinges to be formed mainly in the beams. This automatically satisfied the stronger column-weaker beam requirement; shear failure was neither tolerated anywhere in the columns nor in the beams. Two kinds of fail-safe RC frames were investigated: special moment resisting frames (SMF) and ordinary moment resisting frames (OMF). Their earthquake collapse risk was computed and compared. Inelastic time history (NLTH) and the nonlinear static procedure (NSP) were conducted to assess their structural performance. The results showed among others that the fail-safe OMF had lower collapse risk than the fail-safe SMF. The collapse prevention performance level in NLTH could only be achieved for the fail-safe frames. The non-linear time history analysis should be the only method used for seismic reevaluation/safety checking of building frame structures.

Analysis of reinforced concrete frame with steel braces has been done to compare the behavior of the open frame structure with reinforced concrete structure with steel braces. Three models of 2D open frame structure with 3, 4 and 5 floors were made and analyzed in SAP2000 v17 with intermediate detailing according to Indonesian Codes for Seismic Load (SNI 1726: 2002). 3-span frame structure with a span length of 6 m and level height of 3,5 m were designed according to SNI 1726: 2002, and then re-analyzed with special detailing according to New Indonesian Codes for Seismic Load (SNI 1726: 2012). After that, it was added with braces as seismic retrofitting. Two types of braces (X and concentric inverted V) were used in this study and analyzed with conventional analysis and stage construction analysis according to their stages of implementation. From the analysis results, several structure components that analyzed according to SNI 1726:2012 provitions were experience over-stressed. After retrofitted with steel braces, those components fulfill strength provition according to SNI 2847:2013 about structural concrete regulations for buildings. In addition to that, displacements that occurs on braced frame are smaller than displacements of the open frame structure with ratio of 0.08, 0.12, and 0.18 for X-brace frames with 3,4, and 5 storey and 0.07, 0.11, and 0.16 for inverted-V brace. With staged construction analysis, displacements of  X-braced frame structure increased by 14.38%, 13.62%, and 9.98% from the conventional analysis results for structure with 3, 4,and 5 storey. For structure with inverted-V brace, displacements increased by 15.83%, 14.29%, and 10.09%.

Analysis of reinforced concrete frame with steel braces has been done to compare the behavior of the open frame structure with reinforced concrete structure with steel braces. Three models of 2D open frame structure with 3, 4 and 5 floors were made and analyzed in SAP2000 v17 with intermediate detailing according to Indonesian Codes for Seismic Load (SNI 1726: 2002). 3-span frame structure with a span length of 6 m and level height of 3,5 m were designed according to SNI 1726: 2002, and then re-analyzed with special detailing according to New Indonesian Codes for Seismic Load (SNI 1726: 2012). After that, it was added with braces as seismic retrofitting. Two types of braces (X and concentric inverted V) were used in this study and analyzed with conventional analysis and stage construction analysis according to their stages of implementation. From the analysis results, several structure components that analyzed according to SNI 1726:2012 provitions were experience over-stressed. After retrofitted with steel braces, those components fulfill strength provition according to SNI 2847:2013 about structural concrete regulations for buildings. In addition to that, displacements that occurs on braced frame are smaller than displacements of the open frame structure with ratio of 0.08, 0.12, and 0.18 for X-brace frames with 3,4, and 5 storey and 0.07, 0.11, and 0.16 for inverted-V brace. With staged construction analysis, displacements of  X-braced frame structure increased by 14.38%, 13.62%, and 9.98% from the conventional analysis results for structure with 3, 4,and 5 storey. For structure with inverted-V brace, displacements increased by 15.83%, 14.29%, and 10.09%.

Sejak akhir abad ke-19, rangka baja terbreis (BF) menjadi pilihan dalam desain gedung tinggi karena adanya bresing yang sangat efisien dalam menahan gaya lateral yang diterima struktur. Namun demikian, bresing tetap memiliki kekurangan utama yakni kurang estetiknya tampilan fasad gedung akibat penggunaan bresing yang juga dapat menghalangi area untuk bukaan pintu ataupun jendela serta kolom eksternal yang membuat struktur terkesan kaku.  Struktur diagrid (DIA) muncul sebagai alternatif yang unggul secara estetik karena dengan penggunaan batang diagonal pada perimeter struktur membuat kolom vertikal tidak lagi diperlukan dan tampilan gedung menjadi lebih futuristik. Pada penelitian ini, kinerja struktur DIA dibandingkan dengan BF tipe-X (BFX) pada gedung 15 lantai di program SAP2000 dengan analisis statik non-linier pushover. Hasil analisis menunjukkan struktur DIA mampu menahan gaya geser dasar 14 -17% lebih besar dengan simpangan yang relatif lebih kecil dari struktur BFX yang menunjukkan bahwa DIA lebih kuat dalam menahan beban lateral akibat gempa. Dari hasil perbandingan taraf kinerja, struktur BFX dan DIA memiliki taraf kinerja IO (Immediate Occupancy) dengan sendi plastis pertama pada BFX terbentuk di bresing dan DIA di batang diagonalnya. Perbandingan berat kedua struktur menunjukkan rasio 1 : 2,176 (DIA : BFX) yang membuktikan bahwa DIA lebih ringan dari BFX. Berdasarkan hasil tersebut, DIA merupakan alternatif BFX yang tepat karena lebih efisien serta dapat menahan gaya geser dasar yang lebih besar.