A Restoring Force Model for Prefabricated Concrete Shear Walls with Built-In Steel Sections

Prefabricated shear walls have been widely used in engineering structures. Vertical connection joints of the walls are the key to ensure the safety of the structures. Steel–concrete composite structures have been proved to have a good bearing capacity and ductility. In this paper, a new type of prefabricated structure is proposed, in which vertical wall members are connected together through built-in steel sections and cast-in-place concrete. This paper studies the seismic performance of the proposed prefabricated concrete shear wall structure. Hysteretic curves and skeleton curves of the shear wall are obtained based on experimental analyses. A dimensionless skeleton curve model is developed using the theory of material mechanics and the method of regression analysis. A stiffness calculation method for different loading stages is obtained and a restoring force model is proposed. The proposed innovative prefabricated shear wall structure provides good resistance to seismic performance and the related analysis provides a fundamental reference for studies of prefabricated shear wall structures.

Hysteretic Behavior of Specimens of Circular Concrete-Filled CFRP-Steel Tubular Beam-Column

To study the difference in hysteretic behavior of specimens of circular concrete-filled CFRP-steel tube under different influencing factors, 12 specimens were designed, and their failure modes and P-Δ curves were studied. ABAQUS was used to simulate the specimens’ P-Δ curves and deformation mode. Based upon the simulation results, the stress distribution of all of the specimens’ component materials and the interaction between the steel tube and concrete was analyzed throughout the entire loading process, and the trilinear model, the restoring force model of circular concrete-filled CFRP-steel tube, was proposed. All of the specimens’ P-Δ curves were full and demonstrated excellent hysteretic behavior. The specimens’ P-Δ curves, the skeleton curves, and deformation mode were simulated by the ABAQUS, and the simulation results agreed well with the experimental results. Further, the results of the restoring force model built based upon the trilinear model agreed well with the finite element simulation results.

Restoring Force Model For A New Type of Bolted Prefabricated Beam-To-Column Joint

The wet prefabricated beam-to-column joint (PBCJ) has a densely reinforced panel zone and is difficult to construct, leading to poor connection reliability. To address this problem, we propose a dry PBCJ, where the concrete column is encased with steel plates at the connection and the beams and the column are connected by high-strength bolts. The method for constructing the joint is described herein. A total of six full-scale PBCJs were designed and subjected to quasi-static loading tests with different stirrup ratios, reinforcement strengths, and joint strengthening methods. Based on the test loading process, the joint failure mode is summarised, and a trilinear backbone curve model is proposed. According to the characteristics of the hysteresis curve and the backbone curve, the stiffness degradation law and hysteresis rule are analysed; then, the restoring force model for the new type of PBCJ is established, and the model results are compared with the test results. The data show that the new bolted PBCJ undergoes the cracking, yielding, ultimate, and failure stages; the trilinear backbone curve, which is composed of an elastic section, an elastoplastic section, and a plastic section, well describes the load-carrying characteristics of the joint. The backbone curve calculated by the established restoring force model is consistent with that obtained from the tests, indicating that the model can accurately describe the energy dissipation performance of the new PBCJ and thus provide a theoretical basis for the seismic performance analysis of this type of joint.

Investigation of the restoring force model of through-tenon and half-tenon of timber with a certain level of universality

A restoring force model of through-tenon and half-tenon joints was studied with a certain level of universality. To address the differences among data collected under different test conditions, test data collected via through-tenon and half-tenon joints were counted and fitted, and their similarities were then generalized. To better simulate the gap and stiffness degradation between the through-tenon and half-tenon joints, the skeleton curves frameworks were simplified into four phases, namely sliding, elastic, yielding, and failure. The normalized control parameters collected through the characteristics of the framework of through-tenon and half-tenon joints, as well as the different coefficients of strength degradation and stiffness degradation were calculated. The hysteretic rules of the restoring force model of through-tenon and half-tenon joints were developed. Through case study, the results show that the MAPE (mean absolute percentage error) and R2 (coefficient of determination) of experimental data in the references and simulated data of through-tenon are respectively 12.570% and 0.735, while those of half-tenon are respectively 11.763% and 0.772; and the restoring force model of through-tenon and half-tenon joints being constructed had a certain level of universality. The results demonstrated that the construction of refined finite element analysis model of Chinese ancient timber architectures can be simplified to a certain extent to meet the pressing time for seismic performance analysis of many ancient timber architectures. It provides researchers with an innovative pathway to enhance the efficiency of seismic performance analysis of ancient timber architectures.