Numerical Study of Alternative Seismic-Resisting Systems for CLT Buildings

Abstract

Changes to building codes that enable use of materials such as cross-laminated timber (CLT) in mid- and high-rise construction are facilitating sustainable urban development in various parts of the world. Keys to this are the transition to multi-performance-based design approaches along with fewer limitations on heights or the number of storeys in superstructures constructed from combustible materials. Architects and engineers have increased freedom to apply new design and construction concepts and methods, as well as to combine timber with other structural materials. They also have started to develop wall arrangements that optimise interior space layouts and take advantage of the unique characteristics of CLT. This paper discusses the seismic response of multi-story buildings braced with a CLT core and perimeter shear walls anchored to foundations and floor platforms using modern high-capacity angle brackets and hold-downs, or X-Rad connectors. Linear dynamic finite element (FE) models of seismic responses of superstructures of various heights are presented, based on experimentally determined characteristics of wall anchor connections. Particular attention is given to fundamental vibration periods, base shear and uplift forces on walls, as well as inter-story drift. Discussion of FE model results focuses on structural engineering implications and advantages of using CLT to create shear walls, with emphasis on how choice of wall anchoring connections impacts the possible number of storeys and configurations of superstructures. Employing CLT shear walls with X-Rad or other types of high capacity anchoring connections makes possible the creation of building superstructures having eight and potentially more storeys even in high seismicity regions. However, it is important to emphasise that proper selection of suitable arrangements of shear walls for CLT buildings depends on accurate representation of the semi-rigid behaviors of anchoring connections. The linear dynamic analyses presented here demonstrates the need during engineering seismic design practices to avoid use of FE or other design models which do not explicitly incorporate connection flexibilities while estimating parameters like fundamental periods, base shear and uplift forces, as well as inter-story drift.

From Trees to Skyscrapers: Holistic Review of the Advances and Limitations of Multi-Storey Timber Buildings

“…In addition, as part of the findings, methods to facilitate the modeling of multi-storey timber buildings are described [47,105,[110][111][112][113][114]116,117,119,123,124,132,133,136,139,140,142], along with simulations based on experimental test results [21,31,[120][121][122]125,127,130,134,135].…”

Seismic Design of Timber Buildings: Highlighted Challenges and Future Trends

“…In addition to seismic actions, also wind-induced vibrations shall be furtherly addressed in tall timber buildings [72][73][74][75]; • Numerical modeling of tall timber buildings-addressing problems such as determination of vibration periods and damping [76], modeling ductility in the joints [77][78][79], selection of appropriate seismic design assumptions and procedures [80], proper simplification assumptions in FEM models of tall timber buildings and hybrid timber buildings [81], etc.…”

“…Acoustic insulation requirements (tendency towards physical separation of structural elements in order to prevent sound transmission [63,64]) vs. seismic design principles requirements (tendency towards connection of structural elements in order to achieve necessary strength and stiffness) should be addressed, as some studies and technical documents show the reduction in strength and stiffness of acoustically-isolated connections in timber structures [65,66]; in addition, improved acoustic performance of timber wall and floor elements can also be achieved with additional high-density layers [67,68] Numerical modeling of tall timber buildings-addressing problems such as determination of vibration periods and damping [76], modeling ductility in the joints [77][78][79], selection of appropriate seismic design assumptions and procedures [80], proper simplification assumptions in FEM models of tall timber buildings and hybrid timber buildings [81], etc.…”

Ensaios para avaliação do comportamento sísmico de paredes de Cisalhamento e Paredes Oscilantes de CLT: revisão sistemática da literatura

“…Com isso, a consideração da força lateral devido a terremotos em projetos é fundamental em países localizados em zonas sísmicas como no Japão, Indonésia e ao longo da costa oeste da América. Essas cargas laterais são resistidas pelo Sistema Resistente a Forças Laterais (LFRS) do edifício, referido como Sistema de Resistência à Força Sísmica (SFRS) em edifícios concebidos para resistir a sismos (LOSS et al, 2018), nos quais o CLT pode ser usado como componente primário (MA;DAI, 2023). Dentre as paredes de cisalhamento CLT, as paredes oscilantes, do inglês rocking walls, destacam-se, oferecendo um desempenho sísmico superior em comparação com as estruturas convencionais de madeira leve e as paredes de cisalhamento de CLT (ASSADI; HASHEMI; QUENNEVILLE, 2023).…”