The hybrid simulation (HS) testing method combines physical test and numerical simulation, and provides a viable alternative to evaluate the structural seismic performance. Most studies focused on the accuracy, stability and reliability of the HS method in the small-scale tests. It is a challenge to evaluate the seismic performance of a twelve-story pre-cast reinforced concrete shear-wall structure using this HS method which takes the full-scale bottom three-story structural model as the physical substructure and the elastic non-linear model as the numerical substructure. This paper employs an equivalent force control (EFC) method with implicit integration algorithm to deal with the numerical integration of the equation of motion (EOM) and the control of the loading device. Because of the arrangement of the test model, an elastic non-linear numerical model is used to simulate the numerical substructure. And non-subdivision strategy for the displacement inflection point of numerical substructure is used to easily realize the simulation of the numerical substructure and thus reduce the measured error. The parameters of the EFC method are calculated basing on analytical and numerical studies and used to the actual full-scale HS test. Finally, the accuracy and feasibility of the EFC-based HS method is verified experimentally through the substructure HS tests of the pre-cast reinforced concrete shear-wall structure model. And the testing results of the descending stage can be conveniently obtained from the EFC-based HS method.

The flexural performance of prestressed steel-reinforced ultra-high-performance concrete (UHPC) beams was investigated through finite element (FE) modeling and nonlinear numerical analysis. Two FE models were established for prestressed steel-reinforced concrete beams and prestressed UHPC beams, respectively, and the accuracy was validated by comparing with the experimental results. On this basis, a comprehensive analysis of load–deflection behavior, load–strain relationships, and failure modes was conducted under varying parameters, including reinforcement ratio, prestress level, steel web thickness, and steel flange thickness. The results indicate that an increase in reinforcement ratio from 1.17% to 1.90% enhanced the ultimate load by 12.05%, while increasing the prestress level from 0.61 to 0.76 improved the cracking load by 114.88% and the ultimate load by 53.73%. Moreover, the beams exhibited superior ductility and cracking resistance compared to conventional concrete structures. A formula for predicting the flexural capacity of prestressed steel-reinforced UHPC beams was derived, showing an average error of less than 3% when compared with FE simulations. This formula provides a reliable basis for the structural design and optimization of high-performance composite beams in engineering practice.

Ultra-high-performance concrete (UHPC) exhibits significantly higher tensile strength compared to normal concrete (NC). In this paper, the application of UHPC to the precast base plate of composite slabs was proposed, leading to the development of a reinforced truss UHPC-NC composite slab. This approach effectively enhanced the crack resistance of the slab. A finite element model (FEM) for the reinforced truss UHPC-NC composite slab was developed based on the ABAQUS (2016) platform, using appropriate material constitutive relationships for UHPC, NC, and steel reinforcement. The validity of the model was verified through comparison with relevant test results. Subsequently, the effects of parameters such as the cross-sectional area of the upper and lower truss chords, the reinforcement ratio of the precast base plate, the strength grade of the UHPC base plate, and the thickness of the UHPC base plate on the flexural capacity of the UHPC-NC composite slab were investigated. Finally, the equations for calculating the flexural capacity of the UHPC-NC composite slab were proposed. It was found that increasing the cross-sectional area of the lower truss chord improved the flexural capacity and stiffness of such slabs to some extent, though ductility was slightly reduced. On the other hand, increasing the upper chord cross-sectional area had limited impact on the flexural performance. Increasing the reinforcement ratio of the longitudinal reinforcement in the precast base plate significantly enhanced the load-bearing capacity and stiffness but similarly reduced ductility. As the UHPC grade of the precast base plate increased, the cracking load, yield load, and ultimate load of the slab also increased. However, when the UHPC grade exceeded C120, the improvement in flexural capacity became less significant. With an increase in thickness of the precast UHPC base plate, cracking, yield, and ultimate loads also rose, but ductility decreased. When the thickness of UHPC exceeded 60 mm, the increase in flexural capacity became modest. The proposed equations for calculating the flexural capacity of the reinforced truss UHPC-NC composite slab in the normal section agreed well with simulation results, providing theoretical and numerical support for the design and analysis of UHPC-NC composite slabs.