Rubber bearings are widely used to protect civil structures from destructive earthquakes. The mechanical properties of the bearings are the key technical parameters that determine the seismic isolation performance of isolated structures. To estimate the probability distribution of the mechanical properties related to rubber bearings (including horizontal stiffness, vertical stiffness, post-yield stiffness and yield force) under seismic events. Typical natural rubber bearings (NRBs) and lead-core rubber bearings (LRBs) were designed and fabricated, and the bearings were subjected to repeated load tests using a compression-shear testing machine. The test results of the horizontal and vertical mechanical properties of the bearings in the tests were basically consistent with the design values, and the rubber bearings showed stable mechanical behavior under repeated cyclic loading. The statistical analysis of the test results revealed that the relevant mechanical properties of the NRB and LRB specimens followed a lognormal or general extreme distribution with coefficients of variation mainly ranging from 0.86% to 5.6%. The dispersion of the yield force of LRB was the largest in the repeated tests of many mechanical parameters of typical rubber bearings.

A physical conceptual model for water retention in fractured rocks is derived while taking into account the effect of pore size distribution and tortuosity of capillaries. The formula of calculating relative hydraulic conductivity of fractured rock is given based on fractal theory. It is an issue to choose an appropriate capillary pressure‐saturation curve in the research of unsaturated fractured mass. The geometric pattern of the fracture bulk is described based on the fractal distribution of tortuosity. The resulting water content expression is then used to estimate the unsaturated hydraulic conductivity of the fractured medium based on the well‐known model of Burdine. It is found that for large enough ranges of fracture apertures the new constitutive model converges to the empirical Brooks‐Corey model.

This paper presents shock Hugoniot compression data for several concrete materials obtained from flat plate impact experiments. The manganin pressure gauge was used to measure the pressure-time curves of the samples. The physical quantities were all obtained by the Lagrange method. Moreover, it is observed from the measured pressure-time curves that the rate sensitivity of the dynamic response to the concrete is not negligible. Based on the polynomial Grüneisen equation, the parameters of the equation of state of concrete were obtained. The steel fiber reinforcement effect was analyzed.

A new type of connection node filled with steel tubular column is proposed for the frame structure of concrete. In this paper, the mechanical properties and failure mechanism are studied. As shown by the finite element analysis results, the hysteresis curve attains the full standard, indicating that the joints possess good deformation performance, as well as good bearing capacity, ductility and energy dissipation capacity. Based on the results of the finite element analysis, the experimental study of this type of node is carried out. Meanwhile, a series of experiments are conducted to enhance the length of the steel plate, the effectiveness of the steel plate and the thickness of the protective layer of the steel plate.