Even if numerous studies were dedicated to propose soil-structure interaction analysis methods, most of these methods introduce several assumptions to circumvent the difficulties encountered in modeling and reduce computational efforts. The complex spatial configuration of the soil-foundation interface or the distribution of the soil medium are often simplified using flat-layered soil profiles and, the nonlinearity of the soil medium is generally dealt through an equivalent linear model. However, real soil profiles are featured by complex shapes, inclusion of discontinuities and nonlinear characteristics of soil. Accordingly, this paper presents a soil-structure interaction analysis method considering the characteristics of the structure, soil-structure interface and complex nonlinear distribution of the soil that could not be accurately modeled in previous methods. The proposed method adopts unaligned mesh generation and nonlinear modeling approach to model complex soil profiles. The validity and applicability of the nonlinear soil-structure interaction analysis method are verified through a numerical example.

The necessity of assessing uncertainties to guarantee safety in structural design arises the potential of reliability-based design optimisation (RBDO), which is a methodology based on reliability analysis and design optimisation through probabilistic models. RBDO differs from conventional design optimisation by the presence of probabilistic constraints, which are evaluated using reliability index approach (RIA) or performance measure approach (PMA). It is generally known that PMA is more stable and efficient than RIA. Despite the advantages brought by PMA, RBDO still requires excessive computational cost for large scale structures involving complex finite element analysis. Accordingly, this paper presents a new scheme for RBDO achieving improved stability and efficiency by combining response surface method with PMA. The moving least squares (MLS) method is used to approximate the limit state function. Applications to a mathematical example, the 10-bar truss problem and the vehicle side impact problem verify that the proposed method shows better convergence and efficiency than other approaches.

Studies examined experimentally the flexural behavior of concrete beams reinforced with the hybrid FRP‐steel rebar but very few among them evaluated their fatigue performance. In this study, the fatigue test has been performed, and an analytical model for simulating the flexural fatigue behavior of the concrete beam reinforced with the hybrid bar considering its postyielding behavior is developed. A formula relating the postyielding fatigue strain of the rebar to the number of the fatigue cycle is suggested and used in the proposed procedure. The method simulating the low‐cycle behavior of the reinforced concrete beam is found to be satisfactory and can predict the number of cyclic loading to failure.

Crack healing has been studied extensively to protect reinforced concrete structures from the ingress of harmful ions. Research examining the regain in the mechanical properties of self-healing composites has focused mostly on the computation of the healing ratio based on the measurement of the tensile and compressive strengths but with poor regard for the flexural performance. However, the regain in the flexural performance should also be investigated for design purposes. The present study performs flexural testing on reinforced concrete members using crushed clinker binder and aggregates as well as crystalline admixtures as healing agents. Healing ratios of 100% for crack widths smaller than 200 μm and 85% to 90% for crack widths of 250 μm were observed according to the admixing of clinker binder and aggregates. Water flow test showed that the members replacing binder by 100% of clinker achieved the best crack healing performance. The crack healing property of concrete improved to some extent the rebar yield load, the members’ ultimate load and energy absorption capacity and ductility index. The crack distribution density from the observed crack patterns confirmed the crack healing effect provided by clinker powder. The fine grain size of clinker made it possible to replace fine aggregates and longer healing time increased the crack healing effect.