Advanced Materials Research Vols. 368-373

Abstract: Aiming at the complexity and uncertainty of rock and soil body, the paper the paper introducing a new global intelligent optimization arithmetic – Difference Evolution (DE) and combined with stress return mapping nonlinear elastic-plastic Finite Element Method(FEM), realizing rapid elastic plastic parameters identification of surrounding rock. The analytical theory and method are introduced in detail, analyzes the tunnel of Dalian Metro by the proposed method, and gets satisfied results.

Abstract: As defined in optimization ideas, economical efficiency is the objective function, while the volume of sealing concrete and ballast, two independent variables, exerts impacts on the objective function value through economic parameters respectively. Constraints are founded according to the strength and stability requirements of sealing concrete and steel box, in the most unfavorable condition. At the last, Matlab is used to achieve optimal solution. This paper combined Xiangjiang River Grand Bridge Project in Changxiang express way and achieved good practical results.

Abstract: 3-D Numerical simulation on the directional pressure relief partition side of blast hole isolation material though LS-DYNA software. The result shows: the semicircle isolation material can put off the time that the explosion stress wave arrived at the hole-wall and reduce the peak of stress wave. Meanwhile, it proves that the explosion in the material substance is more powerful than that in the air. So it has certain directive significance on rock blasting on the slope.

Abstract: We named the Prehistoric and primitive times by materials--- the Stone Age, Bronze Age and Iron Age are just the vivid description of the importance of the material. Some experts called the present “Synthetic material times”, the future “Allergenic material times”. In product design, new materials, as an important element of component performance, plays an important role in improving the product's features and enriching the product’s content. In this paper, I will make a reasonable description on the performance of new materials and functional requirements of products, providing designers with a selection of ideas.

Abstract: Brief description of the basic idea of semi-rigid joints is given. Several types of joints are showed combined with the development of the study in recent years. The classification and design methods of semi-rigid joints in steel structure design specifications of the USA , Europe , Canada , Hong Kong are introduced and discussed. Several problems to be studies and the way of further research directions are given.

Abstract: To study axial compressive strength of high strength concrete-filled steel tube composite columns, tests of 18 specimens were carried out. Parameters of the specimens were the confinement index of concrete-filled steel tube, the cubic strength and the stirrup characteristic value of concrete outer of steel tube. Test results show that the concrete-filled steel tube and the reinforced concrete deformed simultaneously in the axial direction before and at the peak value of axial compressive force; after failure of the reinforced concrete, the concrete-filled steel tube can still bear the axial load and deformation; the main influential factors of axial compressive capacity are confinement index, the cubic strength and the stirrup characteristic value of concrete outer of steel tube. The accuracy of the formula of axial compressive strength of composite columns provided by CECS 188:2005 is proved by the test results of this paper.

Abstract: The deterioration mechanism of sulfate attack on cement- based materials under partial soaking condition is very complex. This paper investigated the surface morphology, microstructure and corrosion products in different zones of cement mortar under 5% sulfate solution partial soaking condition at 360 d by methods of SEM, EDS and XRD, respectively. Results show that under partial soaking condition, cement mortar are distinguished four zones – soaking zone, wet zone, crystallization zone and dry zone. Corrosion products in soaking zone and wet zone are predominantly ettringite, showing chemical corrosion take place in those zones. Corrosion products in crystallization zone are gypsum and crystals of Na2SO4 and Na₂SO₄.10H₂O, showing both sulfate chemical corrosion in high concentration and physical crystallization attack occur in this zone. However, there is no any corrosion product founded in dry zone.

Abstract: Based on the fiber bridging model and constant frictional interface stress, this paper derived the P-δ relation for the X-type fiber pulled out of cementitious matrix. By considering the random distributions of the bridging fibers and supposing that rupture of fiber never occurs, it derived the σ_B-δ relation of a single macro-crack, from which the fracture energy equation was deduced by integral. The derived toughening equations have continuous and explicit forms and are convenient for the approximate estimate of the fracture toughness of the composite. The fracture energy expression suggests that increasing fiber volume fraction, utilizing longer fibers or slender fibers and improving interface bonding are effective methods for improving the composite fracture toughness, while adopting fibers with higher elastic modulus is not a preferred suggestion. It is also found that when using X-type fibers to replace cylindrical fibers with same section area, one can obtain 3~8 times of fracture energy (corresponding leg length-width ratio of the X-type fiber cross section is 5~50).

Abstract: The new building wall material solid composite sandwich panel consists of panel and inserted layer material-steel wire nets of composite light bar, and it is called ALC ( Autoclaved Lightweight Concrete) wallboard. The transportation, installation of ALC wallboard is required to meet certain strength requirement, and the wallboard can carry the aseismatic behavior and the bending capacity when it is laid into the wall. Therefore, in order to ensure the ALC wallboard can be better applied in practical engineering, the experimental research need to be done on the wallboard mechanical properties, such as impact resistance, hanging force, bending resistance, etc.

Abstract: This article study the connecting performance of the corrosion high-strength bolts. According to the experiment of anti-slippery,the essay investigate anti-slippery coefficient, sliding load and ultimate load affected by the the extent of corrosion.The articl aslo study about the load-displacement cure of high-strength bolts connecting,which study The difference of the relation between load and displacement in each stages,cause by the whether the high-strength is corrosion.