Limeng Zhu

To efficiently enhance the seismic performance of structures under multi-level earthquakes, one type of novel resilient energy dissipation damper for multi-level earthquakes (REDD) is proposed in this paper, and the mechanical models suitable for the proposed damper are suggested. Such dampers could obtain triple yielding points by employing different energy dissipation units, exhibiting different states in different earthquake intensities. Numerical simulation investigation of seismic performance was carried out on nine REDD models in software of ABAQUS. The influence of different parameters, such as the width-to-thickness ratio (b/t) of shear steel plate, the buckling-restrained devices, section forms and area of yielding portions in round steel bars on the bearing capacity and hysteretic energy dissipation performance of dampers were studied. The results show that the dampers could possess stable energy dissipation behavior and effectively achieve graded yielding energy dissipation under multi-level earthquakes. And the first and second yielding points exhibit a negative correlation with b/t of the shear plate, while the significant influence of the buckling-restrained device, section form and area of the round steel bar on the tensile and compressive bearing capacities. Furthermore, recommending that the diameter difference between the buckling-restrained device and the round steel bar be 6 mm. This bolt connected damper could be easily replace the energy dissipation units, which greatly reduce the repair cost and highly enhance the post-earthquake recovery ability of structure systems.

Under the blast loads, the energy-absorbing structure significantly influences the anti-explosion performance of the concrete-filled bilateral steel plate composite shear walls with the replaceable protective structure (RPS-SCS). This paper employs finite element numerical simulation methods to investigate the impact of the replaceable polyurethane foam energy-absorbing structure (PUF) on the anti-explosion performance of composite shear walls. The numerical models were established based on LS-DYNA. The arbitrary Lagrange Euler (ALE) algorithm is adopted to analyze the models under blast loads, and the accuracy of the models is verified based on existing experiments. The structural response and failure modes of concrete-filled bilateral steel plate composite shear walls with the replaceable energy absorbing and protective structure (PUF-RPS-SCS) are obtained from the numerical results. The displacement histories and energy absorption capacity of composite shear walls are obtained and discussed by conducting numerical calculations on parameters such as the thickness of concrete protection structure, the axial load rate, the thickness of the replaceable PUF energy-absorbing structure, and the mass of explosive charges. Numerical results indicate that the blast resistance performance of the shear wall increases with the increase of the replaceable protective structure thickness. The replaceable PUF energy-absorbing structure could effectively absorb the energy generated by blast loads. The set of the replaceable PUF energy-absorbing structure could greatly decrease the deformation of steel plates and core concrete, enhance the structure’s integrity after the explosion and effectively improve the blast resistance performance of the shear wall.

In this research, a protective concrete-filled steel plate composite wall (PSC) is developed, consisting of a core concrete-filled bilateral steel plate composite shear wall and two lateral replaceable surface steel plates with energy-absorbing layers. The PSC wall is characterised by high in-plane seismic performance as well as out-of-plane impact performance. Therefore, it could be employed primarily in high-rise constructions, civil defence initiatives, and buildings with stringent structural safety criteria. To investigate the out-of-plane low-velocity impact behaviour of the PSC wall, fine finite element models are validated and developed. Then, the influence of geometrical and dynamic loading parameters on its impact behaviour is investigated. The results show that the replaceable energy-absorbing layer could significantly decrease the out-of-plane displacement and plastic displacement of the PSC wall due to its large plastic deformation, which could absorb a significantly large amount of impact energy. Meanwhile, the PSC wall could maintain high in-plane seismic performance when subjected to impact load. The plastic yield-line theoretical model is proposed and utilised to predict the out-of-plane displacement of the PSC wall, and the calculated results agree very well with the simulated results.

This study proposed a developed horizontal-connection and energy-dissipation structure (HES), which could be employed for horizontal connection of prefabricated shear wall structural system. The HES consists of an external replaceable energy dissipation (ED) zone mainly for energy dissipation and an internal stiffness lifting (SL) zone for enhancing the load-bearing capacity. By the predicted displacement threshold control device, the ED zone made in bolted low-yielding steel plates could firstly dissipate the energy and can be replaced after damage, the SL zone could delay the load-bearing and the load-displacement curves of the HES would exhibit “double-step” characteristics. Detailed finite element models are established and validated in software ABAQUS. parametric analysis including aspect ratio, the shape of the steel plate in the ED zone and the displacement threshold in the SL zone, is conducted. It is found that the HES depicts high energy dissipation ability and its bearing capacity could be obtained again after the yielding of the ED zone. The optimized X-shaped steel plate in the ED zone exhibit better performance. The “double-step” design of the HES is a potential way of improving the seismic and anti-collapsing performance of prefabricated shear wall structures against large and super-large earthquakes.

This paper presents a novel steel-damping-concrete (SDC) composite wall as a vertical element for high-rise buildings and nuclear power plants etc. In an SDC composite wall, a damping layer is sandwiched between the concrete core and steel plates to reduce structural response based on its damping characteristics under axial and seismic loads. To ensure that an SDC composite wall exhibits a comparable compressive resistance as a steel-concrete-steel (SCS) composite wall, two types of reinforcing approaches including steel sheets and sleeves are utilized to enhance the weakness of the damping layer on the concrete core. The compressive performance of the reinforced SDC composite wall is numerically and analytically investigated using finite element (FE) simulations by ABAQUS. The influences of several key parameters including the type of reinforcement, the thickness of the damping layer, steel plates, and concrete core, the binding bar spacing as well as the diameter of steel sheets on the compressive performance of the composite walls are investigated through numerical analyses. The results show that while only embedding the rubber interlayer in the composite wall leads to the decrease of compressive resistance of the composite wall, the steel sheets and sleeves can provide the confinement effect on concrete core efficiently and improve the compressive resistance and ductility of walls. Based on the available methods in the current design codes such as Eurocode 4, AISC-360, a theoretical model is developed to predict the ultimate compressive resistance of SDC walls. The predictions show a reasonable correlation when compared with the numerical results.