Advanced Materials Research Vols. 163-167

Abstract: A series of mechanical properties tests on the supporting body of anchorage cable of late model were carried out, with the forms of the supporting body structure in the anchorage segment of pressure-type anchorage cable, and the strength of surrounding rock in the anchorage segment varied. Those were aimed to study the transfer mechanism of acting forces between the supporting body in the anchorage segment of anchorage cable with pressure uniform and the bearing mortar. Those could be used to gain the distribution and magnitude of axial stress and shear stress of the supporting body, as well as the resisting shear performance of the bearing mortar. The reasonable structure of supporting body of anchorage cable with the pressure uniform could be determined by the tests results. The research showed that the axial stress is distributed with uniform linear form along the steel pipe radius of supporting body with the pressure uniform. The rib—like structure on the surface of the supporting body could improve the resisting shear properties of the bearing mortar and raise the anchorage force 0f the anchorage cable with the pressure uniform. The tests results could be used to optimize the length of the anchorage segment.

Abstract: According to the analysis of existing experimental data, it is well known that the behavior of FRP-confined rectangular concrete column were mainly related to the cross section coefficient of concrete, the confinement effect coefficient and the strength of concrete. Based on experimental study and theoretical analysis, the formula for bearing capacity and ultimate axial strain of FRP-confined rectangular concrete column were proposed, and the stress-strain model with strain-hardening components or strain-softening components. The effects of every parameter on the stress-strain relationship were carefully considered. The predictions of the model agree well with test data.

Abstract: For the sustained and healthy development of colleges architectural design company, on the basis of the analysis of strengths and weaknesses of such enterprises, we should combine the development of colleges architectural design enterprise, put forward the developing strategy of colleges architectural design enterprise, which upholds the characteristics of revitalizing the enterprise, creates the project of a joint large-scale enterprises, the role played by the students, combining production, learning and research. In this paper, the strategic plan has important guiding significance for promoting the development of architectural design company.

Abstract: This research is to study the effect of deteriorated level on the ions migration in inhibiting the concrete damaged by ASR using electrochemical technique. Cylindrical concrete specimens made by reactive sandstone with 10 cm diameter and 5 cm height were prepared at the ages of 7, 14, 28, 90, and 180 days curing in a 38°C and 100% R.H. storage environment. The accelerated lithium migration technique (ALMT) was performed using LiOH H2O and Ca(OH)2 as electrolytes for anode and cathode, respectively. 9 A/m2 current density was used to drive lithium ion into and remove sodium ion out of the concrete. The results show that the rates of ions migration increase with increasing the deteriorated level of specimen. Furthermore, a linear relationship exists between the non-steady state migration coefficient of Li+ and the deteriorated level of specimen.

Abstract: The most common form of rehabilitation for a deteriorated structure is to remove the deteriorated concrete and replace it with a new material, thus increasing the design life of the structure. Good adhesion of a repair material to concrete is of vital importance in the application and performance of concrete repairs. A major factor that influences the durability of the repair is the bond strength between the new material and the substrate. In this investigation, the most common repair materials, produced by international reputed manufactures, available in the local market were selected from cementitious repair mortars and cementitious polymer modified mortars. The performance of these materials were evaluated in terms of compressive strength, tensile strength, bond strength in tension and bond strength in modulus of rupture.

Abstract: FRP-confined concrete filled steel tube may fully use the character of FRP-confined concrete and concrete filled steel tube. Based on the analysis of existing experimental data, the formula of ultimate bearing capacity of FRP-confined concrete filled steel tube is proposed. The mechanical behavior of FRP-confined concrete filled steel tube is mainly related to the equivalent confinement effect coefficient before the rupture of FRP. Based on the static equilibrium condition, the equivalent conversion section is adopted; taking as main parameter, the simplified stress-strain model of FRP-confined concrete filled steel tube is established. The predictions of the model agree well with test data.

Abstract: Twenty-nine circular specimens in four groups were tested to investigate the effect of short-term preloading on axial compressive behavior of CFRP-confined concrete. The results indicate that short-term preloading generally put a slight positive effect on the axial resistance of pure axial compressive members. As the preloading stress level index increases, the elastic segments of the load-strain curves of confined plain specimens, with or without preloading, firstly increase and then decrease. The influence of short-term preloading on the load-strain responses of confined reinforced concrete specimens is found to be insignificant. The elastic stiffness of all confined specimens does not seem to be affected by the index, but it would be increased by the introduction of longitudinal reinforcement. The results also indicate that the ultimate expansion ratio of a confined concrete column is related to the index and confinement ratio. As the ratio of the index to confinement ratio increases, the ultimate expansion ratio firstly decreases slightly and then increases rapidly. The regressive expression has also revealed that the influence of short-term preloading could be ignored if a column is extremely heavily confined with CFRP materials.

Abstract: This paper reports the experimental studies on the local stiffening of steel I-beams by using Carbon Fiber Reinforced Polymer (CFRP) strips. One of the problems which frequently occur for steel section is the large local deformation under point loads. To study the effects of applying CFRP for local stiffening, four steel I-beams were selected and tested to failure. The first beam had no steel stiffeners below the point loads and used as the control beam. The second beam had steel stiffeners and was not enhanced by using CFRP strip. The third and fourth beams had no steel stiffeners below the point loads and were strengthened on the compressive flanges by using two longitudinal CFRP strips. Also, the third and fourth specimens were strengthened on the web by using the latitudinal CFRP strips in the discrete and continual types, respectively. The results show that applying CFRP on the compressive flange and web increased the load bearing capacity and decreased the local and overall deformations appropriately. Also, the full-covering of the web seems to be the best type of web strengthening.

Abstract: Structural strengthening of beams subjected to flexure can be done by more than one method, both the CFRP laminates and the Light Gauge Galvanized Steel Plat methods are tested to compare the ductility of members designed using ACI-440 to reach the same strength.

Abstract: Through testing it is obtained that force and the damage that 1 root structure of prestressed concrete beams strengthened and 3 different layers CFRP reinforced stickup prestressed concrete beams under cyclic loading. This test results show that CFRP reinforcement effect of prestressed concrete beams is obvious, and at the same time the cracking of prestressed concrete beam has also has certain reinforcement effect; But the CFRP reinforcement effect is proportional to the number of layers.