Kajian Numerik terhadap Perilaku Seismik Link Panjang dengan Pemasangan Pengaku Diagonal Badan pada Sistem Struktur Rangka Baja Tahan Gempa Tipe Eccentrically Brace Frames (EBF)

Makalah ini merupakan hasil studi numerik yang meneliti perilaku seismik terhadap link panjang dengan menggunakan pengaku diagonal pada bagian badan untuk meningkatkan kinerjanya, pada sistem struktur baja berpengaku eksentrik (EBF). Perilaku seismik ini mencakup kekuatan (strength), kekakuan (stiffeness), daktilitas (ductility) dan dissipasi energi (energy of dissipation). Penelitian ini bertujuan untuk meneliti perilaku link panjang dengan menggunakan pengaku diagonal pada bagian badan dibawah pembebanan statik monotonik dan siklik dengan kontrol perpindahan (displacement control), riwayat pembebanan yang diberikan dalam pengujian ini sesuai dengan standar pembebanan AISC 2010. Analisis dilakukan dengan pendekatan elemen hingga Non-Linier dengan menggunakan perangkat lunak komputer MSC/NASTRAN. Link dimodelkan sebagai elemen shell CQUAD yang ditumpu pada kedua ujungnya sedangkan beberapa nodal pada posisi pembebanan diperbolehkan untuk bertranslasi dalam satu arah saja (arah sumbu-y). Panjang link yang digunakan dalam analisa ini adalah 1555 mm penampang link profil WF 150.75. Perilaku link panjang dengan pengaku diagonal badan dibandingkan dengan perilaku link panjang standard yang direncanakan sesuai dengan ketentuan AISC 2010. Hasil analisis menunjukkan bahwa pengaku diagonal badan dapat meningkatkan kinerja link panjang dalam hal : kekuatan kekakuan dan dissipasi energi dalam menahan beban lateral. Namun, perbedaan perilaku antara link panjang dengan pengaku diagonal badan dan link panjang yang direncanakan sesuai standar AISC tidak begitu signifikan.

PERKUATAN SEISMIK STRUKTUR RANGKA BETON BERTULANG MENGGUNAKAN BREISING BAJA TIPE X DAN V TERBALIK

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%.

PERKUATAN SEISMIK STRUKTUR RANGKA BETON BERTULANG MENGGUNAKAN BREISING BAJA TIPE X DAN V TERBALIK

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%.

Inelastic behavior of smart recentering buckling-restrained braced frames with superelastic shape memory alloy bracing systems

Buckling-restrained braced frames are steadily replacing concentrically braced frames because buckling-restrained brace can yield without buckling when subjected to both tension and compression. Though buckling-restrained brace frames are being widely used as framing structures for construction in high seismicity areas, it is shown that at large strains, a considerable amount of permanent deformation is produced at the support connector between the brace and the frame. This drawback can be overcome by providing recentering capabilities to the braced frame system. By applying the concept of a recentering system to the design of buckling-restrained brace frames, we developed braced frames that incorporate buckling-restrained braces with superelastic shape memory alloy end-support connectors. Owing to the recentering capability, shape memory alloy materials have been used in the place where large deformation may feasibly occur. The primary advantages of the innovative braced frames proposed herein are verified through nonlinear pushover analyses. Analytical frame models are developed to estimate theultimate and residual inter-story drifts. The analysis results suggest that buckling-restrained brace frames with superelastic shape memory alloy bracing systems are more effective in controlling residual inter-story drifts than those with conventional steel bracing systems owing to the inherent self-healing characteristics of superelastic shape memory alloys.

Research on Application of BRBs in Steel Frame Structures

This paper presents an analysis on the seismic behavior of buckling-restrained brace frames（BRBFs）with different rigidity ratios by the finite element analysis software ANSYS. Based on the elastic-plastic time-history analysis, the relationships of maximum story drift ratio and the uniformity of maximum story drift ratio with different rigidity ratios are established for BRBFs subjected to large earthquakes, a reasonable range of rigidity ratio is recommended, which is the reference for the design of BRBFs.

The Damping Energy Dissipation Study on Buckling Restrained Brace in Multilayer Steel Frame

The buckling-restrained brace has stable energy dissipation capability. It has been widely used in recent years. This paper uses finite element software ANSYS to do non-linear time history analysis for Center Braced Steel Frame, Eccentrically Braced Steel Frame, Buckling-restrained Braced Steel Frame under the earthquake. The results show that: (1) The peak acceleration, residual displacement and top floor displacement of buckling-restrained braced steel frame is smaller than the other two brace frames, provide support for the structure stability. (2) The damping energy and bracing energy dissipation capability of buckling-restrained braces and eccentrically braced are strong, so it can avoid the collapse of the main structure under the large or medium earthquake.