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Parametric study of multi-story buildings incorporating buckling-restrained braces
Published in Alka Mahajan, B.A. Modi, Parul Patel, Technology Drivers: Engine for Growth, 2018
Kushal Parikh, Paresh V. Patel, Sharadkumar P. Purohit
A Buckling-Restrained Brace (BRB) is a structural element in a building that is designed to allow the building to withstand cyclical lateral loadings, typically induced by earthquake. It consists of a slender steel core in a concrete casing to support the core and prevent its buckling under axial compression. BRBs have improved energy dissipative behavior compared to Concentrically Braced Frames (CBFs). Bai and Ou (2016) developed a performance-based plastic design method for a dual system of reinforced concrete moment-resisting frames using BRBs. Sabelli and López (2004) discussed the methodology for design of buckling-restrained braced elements. Amiri et al. (2013) compared three steel frame structures of three, five and eight stories, retrofitted separately using tube-in-tube metal dampers and buckling-restrained braces, in order to compare their performance before and after the retrofitting. The current paper presents analysis of a multistoried frame structure with BRBs to investigate the effectiveness of BRBs in controlling seismic response. A parametric study of five-storied and ten-storied reinforced concrete frame buildings incorporating BRBs at various locations with different configurations is carried out. Modal time period and various seismic parameters are compared for all buildings. Based on analysis of the results, the optimal location and configuration of BRBs are suggested.
Synthesis of structural self-repairing and health monitoring
Published in You-Lin Xu, Jia He, Smart Civil Structures, 2017
The SC braces that combine PT elements and energy dissipating components have an outlook similar to that of a conventional steel brace or a specialised damping device. This bracing member exhibits a repeatable flag-shaped hysteretic response with full SC capabilities, thereby eliminating residual deformations. The mechanics of this new type of brace was first explained by Christopoulos et al. (2008), and the equations governing its design and response were outlined as well. A comparison of the seismic responses of steel frame buildings with two types of bracing members, SC braces and buckling-restrained braces (BRBs), was numerically conducted by Tremblay et al. (2008). It was found that the SC bracing frames generally experienced smaller peak story drifts, less damage concentration over the building height and smaller residual lateral deformations compared with the BRB system. Shaking table tests on a three-story SC-braced frame were then conducted to validate the efficiency of the SC brace (Erochko et al. 2013). Moreover, a new enhanced-elongation telescoping SC brace was recently developed, which allows for an SC response over two times the range achieved with the original SC bracing system (Erochko et al. 2014).
Metallic Dampers
Published in Suhasini Madhekar, Vasant Matsagar, Passive Vibration Control of Structures, 2022
Suhasini Madhekar, Vasant Matsagar
Inelastic deformation of metals is an effective mechanism for energy dissipation. Traditionally, seismic-resistant design of structures depends on the ductility of structural members to dissipate energy imparted to the structure due to the dynamic excitations. To increase the seismic capabilities of concentrically braced frames, uniquely designed buckling restrained braces (BRB) are employed. However, the core of BRB, which extends beyond its sleeve, is likely to buckle and eventually fracture at its ends, as seen in Photo 7.3. This could lead to the failure of the connection. Hence, the ductility and energy dissipating capacities of BRB are not fully utilized.
Seismic Retrofit of Pilotis Buildings by Novel Aluminium Buckling-Restrained Braces (Al-BRBs). Application to a Modernist Architecture Building in Lisbon
Published in International Journal of Architectural Heritage, 2023
Jorge M. Proença, Ricardo Ferreira, António Sousa Gago
One of the most effective ways of strengthening existing building structures is that of adding, locally (at a given storey) or globally (uniformly along the height of the building), buckling-restrained braces (BRBs) to the lateral load-resisting system. These braces provide additional lateral stiffness and strength to the existing structure, unaffected by the sign of the axial force (tension or compression) since the braces are prevented from buckling. The BRBs also provide additional damping through the hysteretic dissipative behaviour of the core component. These braces are typically composed of an internal core brace (through which the axial force of the brace is transmitted), an external casing/restraining unit (providing for the flexural strength and stiffness to prevent global buckling of the BRBs and also indirectly providing for buckling restraint of the core brace), and, sometimes, an infill material between the former components.
Cyclic Behavior of All-steel BRBs with Bolted Angle Restrainers: Testing and Numerical Analysis
Published in Journal of Earthquake Engineering, 2023
Ahmad Fayeq Ghowsi, Dipti Ranjan Sahoo
Buckling-restrained braces (BRBs) are widely adopted as either lateral force-resisting systems or energy dissipation devices in structures located in the high-seismic regions. The main characteristics of BRBs are the higher energy dissipation capacity, better displacement ductility, and nearly symmetrical hysteretic behavior. Typically, a BRB consists of two elements, namely, an axial load-resisting element having a central yielding core segment with transition and elastic connection segments at both ends, and a restraining unit to prevent the buckling of the central core element under compression loading. A debonding material is used between the yielding core segment and the restraining unit to eliminate the load-sharing and to minimize the frictional resistance between them (Fahnestock, Ricles, and Sause 2007; Xie 2005). A clearance (i.e., air gap) is provided between the core segment and the restraining element to allow the core expansion due to Poisson’s effect at the elastic stage and to accommodate the higher mode buckling of core plates under axial compressive loading (Chen et al. 2016). The main goal is to absorb the input energy demand within the BRBs by plasticizing central core segments while keeping the beams and columns of a buckling-restrained braced frame (BRBF) in the nearly elastic stage when subjected to a seismic event (ASCE 7-16 2017).
Displacement Spectra Damping Factors for Preliminary Design of Structures with Hysteretic Energy-Dissipation Devices
Published in Journal of Earthquake Engineering, 2022
Miguel A. Orellana, Sonia E. Ruiz, Ali Rodríguez-Castellanos
Regarding this topic, the new philosophies of seismic design aim to have more resilient structures (quick recovery capacity). As an alternative, the inclusion of seismic protection systems in structures through the use of energy dissipaters has been promoted over the last few decades. Examples of such devices are the classical steel dampers whose energy dissipation depends on the displacement between its ends (Merritt, Uang, and Benzoni 2003) as well as new replaceable dampers that reduce architectural invasiveness, such as Dissipative Columns (DC) consisting of two or more adjacent steel vertical elements connected with continuous mild/low strength steel X-shaped plates (Palazzo, Castaldo, and Marino 2015). The objective of such damping systems is to absorb most of the seismic energy through its non-linear inelastic structural behavior (hysteretic). In addition, hysteretic dampers such as buckling restrained braces (BRBs) represent one of the best solutions for retrofitting or upgrading the numerous existing buildings in areas with a high seismic hazard (Castaldo et al. 2021; Ruiz et al. 2021). Currently, there are multiple buildings equipped with hysteretic dampers around the world (Domínguez and López-Almansa 2017; Symans et al. 2008; Takeuchi 2018).