•The eigenvalue of the dispersion relation for periodic materials is derived and solved.•The isolation effectiveness of frequency band gap is validated by shaking table tests.•The floor response ...spectra of FEM and experiment are provided to validate the effectiveness.•The FRF is defined to quantificationally evaluate the impact of the 1D periodic foundation.•The effects of number of unit cells of 1D periodic foundation are parametrically analyzed.
Periodic material possesses distinct characteristics that can block some certain frequency waves propagate through the structure, which can be used to reduce the unwanted seismic waves in civil engineering. Base on the Bloch-Floquet theory, the certain frequencies, terms frequency band gaps, are theoretically presented and derived. A numerical model of 1D periodic foundation is established to investigate the filtering effects of elastic waves. The dynamic response and filtering effects of a three-storey steel frame with a 1D periodic foundation and concrete foundation are performed and compared through the numerical method and shaking table tests. Ambient vibration, earthquake ground motions, and sine waves are applied as the input waves. The results show that the seismic waves cannot propagate in the 1D periodic foundation when the frequencies of the waves fall into the frequency band gaps of the foundation. Simultaneously, a single unit cell has proven to possess the same frequency band gaps as those with an infinite number of unit cells and has enough response reduction inside the frequency band gaps of the periodic foundation. Consequently, the proposed periodic foundation can be used to apply in isolating environmental vibration or seismic waves in civil engineering through adjusting the frequency band gaps enveloping the exciting frequencies of the waves.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Integrating the concepts of frictional energy dissipation and low-damage mechanism, this paper proposes a built-in continuous-column (BCC) steel moment frame structure with low-damage cover plate ...slip-friction connections (CPSFCs) at the column bases. The slip-friction connections can convert the buckling energy dissipation of the column into frictional energy dissipation, and the continuous column can improve the lateral deformation mode of the structure under seismic action. The strength and stiffness deterioration characteristics of the material were considered in the simulation of the seismic performance of the structure, and the simplified numerical models of CPSFCs and continuous columns were established in OpenSees. Comparative analyses were carried on a seven-story steel frame, steel moment frame (SMF) with CPSFCs at the column bases (CPSFC–SMF), and a built-in continuous column steel frame (BCCF) with CPSFC at the column bases (CPSFC–BCCF). The results showed that CPSFC slightly reduced the bearing capacity of the steel moment frame but minished the structural stiffness degradation and increased the ductility of the structure. The setting of CPSFC changed the plasticity hinge sequence of the structure, resulting in a homogeneous deformation between stories. The CPSFC–BCCF had the best damage pattern and the most uniform inter-story energy dissipation.
•A damping system consisting of a spring viscous damper linked with a preloaded tendon was proposed.•The seismic performance of the spring viscous damper is evaluated by pseudo-dynamic tests.•Shaking ...table tests of a frame installed with the damping system are conducted using five earthquakes.•The results from the tests are verified by numerical simulation of the retrofitted structure.
This research proposes a self-centering passive damping system consisting of a spring viscous damper linked with a preloaded tendon. The seismic performance of the spring viscous damper is evaluated by cyclic loading tests, and the results are used for the formulation of an analytical model of the retrofit system in the structural analysis program. The shaking table tests of a two-story steel frame installed with the proposed damping system are carried out using five different earthquake records. The results from the shaking table tests are verified by numerical simulation of the retrofitted structure. The results obtained from the experiments and numerical simulations demonstrate that the proposed damping system with added stiffness and self-centering capability is effective in reducing earthquake-induced displacement and member forces.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The width‐thickness requirement for highly ductile built‐up box columns in AISC 341‐22 is conservative when comparing the hysteretic responses of highly ductile box columns and I‐shaped columns. This ...study aimed to assess the seismic performance of moderately ductile box columns in a 3‐story steel dual frame with a buckling‐restrained braced frame (BRBF) and a special moment frame (SMF). The frame specimen was configured in phase 1 testing to allow the slabs to slide relative to the steel frame; Teflon pads were provided between the slabs and steel beams, and horizontal buckling‐restrained braces (BRBs) were installed between the slabs and steel beams. In phase 2, the horizontal BRBs were replaced by rigid links such that the frame specimen simulated a conventional construction. Two phases with 17 shake table tests were conducted on the frame specimen. A near‐fault motion record, obtained from the 2022 Chihshang earthquake, was used as an input motion. In phase 1, test results showed that the slab sliding system was effective in reducing the floor acceleration by 25% when compared to the rigid slab frame system. In phase 2, the base of moderately ductile built‐up box columns still performed well without local buckling even when the interstory drift angle reached 0.045 rad. Postearthquake tests were conducted on the all‐steel, first‐story BRB that was removed from the building specimen after all shake table tests. A higher‐mode buckling of the core plate was observed at both ends of the core, causing a minor strength increase at the end of the test.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Recent destructive seismic events have underlined the need for increasing research efforts devoted to the development of innovative seismic‐resilient structures able to reduce seismic‐induced direct ...and indirect losses. Regarding steel Moment Resisting Frames (MRFs), the inclusion of Friction Devices (FDs) in Beam‐to‐Column Joints (BCJs) has emerged as an effective solution to dissipate the seismic input energy while ensuring a damage‐free behavior. Additionally, recent studies have demonstrated the benefits of implementing similar damage‐free solutions for Column Bases (CBs). In this context, the authors have recently experimentally investigated a Self‐Centering CB (SC‐CB) aimed at residual drift reduction. Previous experimental tests only focused on the response of isolated SC‐CBs under cyclic loads. Conversely, the present paper advances the research through an experimental campaign on a large‐scale steel structure equipped with the proposed SC‐CBs, providing valuable insights into the global structural response and improved repairability. A set of eight Pseudo‐Dynamic (PsD) tests were conducted considering different records and configurations of the structure. The experimental results highlighted the effectiveness of the SC‐CBs in minimizing the residual interstory drifts and protecting the first‐story columns from damage, thus enhancing the structure's resilience. Moreover, the consecutive PsD tests allowed investigating the effectiveness of the reparation process in restoring the seismic performance of the ‘undamaged’ structure. An advanced numerical model was developed in OpenSees and validated against the global and component‐level experimental results. Incremental Dynamic Analyses were finally performed to investigate the influence of the SC‐CBs on the structure's seismic response while accounting for the record‐to‐record variability.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Supplemental rotational inertia devices provide an efficient means of suppressing ground-induced vibrations over a large range of structural periods. The beneficial effects of the inerter can be ...further enhanced by coupling it with a clutch system that prevents it from driving the structural response and ensures that its supplemental rotational inertia is only employed to resist the motion. In this paper, we examine the behaviour of single-degree-of-freedom and multi-degree-of-freedom structures equipped with twin inerter-clutch devices subjected to strong ground-motion. The influence of the clutch stiffness, gears play, viscous damping and dry friction, on the non-linear dynamics of the system are explored first, by analysing the stable periodic solutions of a structure with inerters under harmonic-sweeps. We demonstrate that, for the range of parameters typically expected in earthquake engineering practice, the influence of dry-friction and clutch damping are limited, although the clutch stiffness and gear play may need to be accounted for when large inertances or defective clutches are considered. Based on these findings, we propose a simplified numerical modelling strategy suitable for implementation in conventional Finite Element simulations. Small scale experiments on bare elastic structures as well as structures equipped with 3D-printed inerter and inerter-clutch twins are presented and employed for concept demonstration and for the validation of the numerical model proposed. Finally, a series of studies on detailed numerical models of multi-storey steel frames under idealized and real pulse-like ground-motions are used to demonstrate the vibration absorbing capabilities brought about by the twin inerter-clutch system and to highlight practical aspects related to their structural implementation.
•The influence of non-linearities on structures equipped with inerters and twin inerter-clutch devices is explored.•A Finite Element model of the inerter and clutch is proposed and validated.•Experimental results on structures equipped with rack-pinion-flywheel inerters and twin inerterclutches are presented.The outstanding seismic vibration control capabilities of supplemental inertia are demonstrated experimentally and numerically.•Multi-storey steel frames with parallel inerters largely outperform their un-controlled counterparts.•Non-linear response history analyses with real records confirm the benefits of using inerters to reduce seismic deformations and forces.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•The steel frame connection with replaceable LYP cover plates was developed.•Cyclic tests on original and repaired SF-LYCP specimens were conducted.•The seismic behavior and resilience performance of ...SF-LYCP were explored.
In order to avoid the brittle failure of welded region at the beam-column connection of steel frame under strong earthquake action and achieve resilient objective, the steel frame connection with replaceable low-yield-point steel cover plates (SF-LYCP) was developed. Cyclic tests were conducted on original and repaired full-scale specimens to explore the mechanical behavior and quick recovery performance. The various materials and configurations of cover plates were focused on. The failure modes, strain development, global and local hysteresis curves, energy dissipation behavior and the replacement performance of the damaged fuses were comprehensively compared. The results showed that the cover plates of specimens with the same weakening degree (C-LY100, C-LY160, C-Q235B and C-Q345B) all played the role of structural fuses through concentrating the damage and protecting the primary frame members. The SF-LYCPs had plumper hysteresis curves, more accumulated energy dissipation and superior ductility. The damaged low-yield-point steel cover plates of C-LY100 and C-LY160 were replaced within only 50 mins to form the repaired specimens under laboratory conditions, proving the possibility of recovery. The performance of the structures with replaced cover plates basically coincided with the one of the original structures, which satisfied the design objective of resilience.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A steel-concrete composite frame is typically used for building construction. Earthquake action and progressive collapse event caused by accidental local failures are the primary threats affecting ...the safety of steel-concrete composite frames. Currently, multi-hazard resistance and building resilience have garnered much research attention from the international civil engineering community. Based on the previously proposed first-generation seismic and progressive collapse resistant composite frame (SPCRCF), an improved second-generation seismic and progressive collapse resilient steel-concrete composite frame (SPCRCF-2) is proposed. The performance of SPCRCF-2 is compared with that of SPCRCF as well as a conventional steel-concrete composite frame (CSCCF) through seismic and progressive collapse experiments. Compared with CSCCF and SPCRCF, SPCRCF-2 is proven to be able to localize the damage to the replaceable energy-dissipating (ED) components under both seismic and progressive collapse conditions, whilst maintaining the other key components (beams and columns) damage-free. This special feature facilitates rapid repair of the structure thereby achieving multi-hazard resilience. Finally, theoretical models are proposed to calculate the initial stiffness and flexural yield strength of the beam-column joint connection in SPCRCF-2. The models are further validated by the experimental results.
•A seismic and progressive collapse resilient composite frame is proposed.•Seismic and progressive collapse experiments of the proposed frame are conducted.•Seismic and progressive collapse resilience of the frame system is discussed.•Analytical models for initial stiffness and yield moment of the joint are proposed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The design of joints of steel frames is often simplified, assuming that they have a fully rigid or ideally pinned behaviour. This wrong assumption is sometimes acquiesced by national technical codes, ...which mainly focus on the behaviour of simple connections and neglect the role of the joints in terms of global structural behaviour, particularly under lateral loads. In this paper, a numerical study about the evaluation of the influence of partial‐strength/semi‐rigid joints on the seismic performance of one‐storey steel buildings is presented. For this purpose, a population of real steel buildings has been considered, for which column bases and/or beam‐to‐column joints were originally designed as infinitely resistant/rigid restraints, but that, after the application of the component method, were found to be characterized by a partial‐strength/semi‐rigid behaviour. Finite element models of the examined buildings were developed, assuming both the theoretical and the actual joint behaviour. Fragility curves were constructed through nonlinear dynamic analyses, so to evaluate the seismic vulnerability of the structures and assess whether they need joint reinforcement, or, otherwise, if they already ensure adequate seismic safety.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
This paper examines the response of steel‐timber hybrid (STH) lateral stability systems for medium‐rise buildings. A ten‐storey baseline STH structure was designed to codified procedures and compared ...with a steel‐concrete composite structure. Detailed numerical models were constructed in which specific constitutive representations were assigned to steel‐timber and timber‐timber connections. Parametric investigations on the STH structure were carried out in which the cross laminated timber panel layups, timber shear wall length, and connection characteristics were modified. The study indicated that the STH structure had larger lateral deformations compared to the steel‐concrete structure, both within code limits. For the same design loads, the reduction in self‐weight from the steel‐concrete structure to the STH structure was 73.1%, whilst the floor depth was reduced by 17.2%, respectively. Parametric studies showed that the lateral response of STHs is generally improved with the effective thickness of the timber infill panel and is influenced by the panel layup. Increasing the shear wall length generally enhances the lateral stiffness, yet the overall performance is reduced with the increase of panel connections. The reduction in self‐weight, member sizes and replacement of the concrete with timber led to a reduction in embodied carbon of more than 32.7% whilst achieving similar structural performance.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
