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This paper deals with the shear strength of prestressed concrete box girders having corrugated steel webs (PCBGCSW), with particular emphasis on the shear lag and the stochastic variation of material properties. First, the shear strength curve of corrugated steel web is proposed based on experimental and analytical results obtained for simply supported beams composed of corrugated steel web without and with concrete flanges. In order to evaluate the shear strength of PCBGCSW based on the shear strength curve of corrugated steel web, it is important to know the distribution of shearing force between the corrugated steel web and the concrete flanges. The effect of the concrete flanges, therefore, on the distribution of shearing force is investigated considering the shear lag behavior. Finally the stochastic variation of material properties for the evaluation of the shear strength of corrugated steel webs is discussed from the design viewpoint.

The horizontal press performance of column is deteriorated because of its special-shaped section. Moreover, because the antiseismic performance of column is worse, special-shaped column is only used in regions where seismic intensity is lower. So the main problem is to enhance the ductility and shear capacity. This test study on mechanical performance has been carried out through 14 SRCLSSC and 2 RCLSSC. The study focuses on the impacts of test axial load ratio (n_t), hooped reinforcement ratio (ρ_v), shear span ratio (λ) and steel ratio (ρ_ss) on the shear strength and the antiseismic performance of SRCLSSC. It can be concluded that the shear strength of SRCLSSC is increasing with the increasing of n_t and ρ_ss, but the degree of increasing is small when n_t is a certainty value, and that the shear strength of SRCLSSC is decreasing with increasing of λ; The shear resistance formula of L-shaped column is derived through tests, the calculated results are in correspondence with those of the tests. It also can be concluded that the hysteretic loops of the SRCLSSC are full and the hysteretic behaviors are improved; the displacement ductility is increasing with increasing of ρ_ν and ρ_ss, but decreasing with the increasing of n_t; the degree of variety in high axial load ratio is larger than that in low axial load ratio. If steel bars are added, the shear strength and displacement ductility of SRCLSSC are increased in a large degree.

In this paper, Kalman filter technology which originally came from the field of signal control is introduced as an inverse analysis to identify some important material parameters. By performing detailed FEM simulation and using the experimental data of the force and displacement curve of the fiber pull-out test, the Kalman filter recursive process is successfully carried out to identify the values of the shear strength τ and the fracture energy G for the SiC (SCS-6) / Ti material interface. The great advantage of this inverse technology is that the influence of experimental noise can be taken into account. The calculation results show that the rate of convergence to the correct solution depends on the number and the initial estimation of unknown parameters to be identified and the accuracy of the measured data. Our analysis demonstrates that the proposed approach is suitable and capable in the identification of material parameters of the composite interface.

In order to reduce the brittleness of soil stabilized by lime only, a recent study of a newly proposed mixture of fiber wastes and lime – rice hush ash mixtures for ground improvement is described in this paper. The research was conducted to investigate the influence of the mixture of wastes fibers on the mechanical properties of the stabilized clay soil with lime-rice husk mixtures. The amount of lime and rice husk ash was used 12% by dry weight of soil specimen. The fiber content and length are 0.4% (by weight of the parent soil) and 2 mm respectively. The specimens were subjected to triaxial tests under unconsolidated – undrained condition (UU) condition which is tested after 3, 7, 14 and 21 days of curing. Stress and strain relationship shows the post-peak stress which indicating ductility behavior of the treated soil. It was found that the addition of fibers contributed significantly on the shear strength parameters of the treated soil and the shear strength increased with increasing the curing time.

The shear strength of unsaturated soil is one of the important engineering properties. On the basis of referring to the Chinese and foreign literatures, mainly from the theories and formulas, instruments as well as the specific aspects of the experimental research results to summarize, the paper outlines the advance in research on shear strength of unsaturated soil. Although different scholars have carried out extensive studies and obtained certain research results, also, the view of the difference between shear strength of unsaturated soil and shear strength of saturated soil is the matrix suction's contribution to the strength is approved by academia now. There are still some problems that the scope of shear strength formulas of unsaturated soil, the difficulty of measuring matrix suction and the experimental conditions can't reflect the real stress state of unsaturated soil. Therefore, the further researches are needed to improve the shear strength theory system of unsaturated soil.

In this study, Cu nanoparticles were dispersed into Sn-58Bi solder paste to prepare Sn-58Bi-xCu solders in order to inhibit the disadvantages of undesirable Bi segregation and microstructure coarsening of Sn-58Bi solder in electronic industry. The content of Cu ranged from 0 to 2.0wt.% in the solders. The effects of Cu nanoparticles on microstructure, hardness and ball shear strength of Sn-Bi lead-free solder were investigated. The results indicated that small amount of Cu addition in Sn-58Bi solder enhanced not only the shear strength but also to some extent the hardness of the composite solder, which may be attributed to the uniform distribution of the formed Cu₆Sn₅ IMCs and the refined microstructure of composite solder. However, further increase of Cu additions decreased the shear strength, which may be attribute to the relatively more primary β-Sn grains, the gathered Cu₆Sn₅ IMCs and the coarse eutectic structure. The Cu nanoparticles addition of 1.0% in Sn-58Bi is the optimal addition ratio to get well dispersed microstructure.