Applied Mechanics and Materials Vols. 94-96

Abstract: Many Marine environment or other corrosion in the concrete structure under the condition of fatigue cycle usually bear, thus make these components of fatigue and corrosion under coupling effect, thus speeding up the process of structure component, killing structure degradation of corrosion fatigue. This paper using self-designed corrosion fatigue loading test device, studied in sodium solution of concrete under the action of erosion strength increasing regularity, results show that the concrete strength by corrosion fatigue than fatigue specimen attenuation extent.

Abstract: At present, green energy saving idea, aimed at protecting environment and saving energy, now has become the guiding philosophy of modern architecture. Based on this, recycled carpet waste fibers for textile mechanical properties of concrete were discussed in this paper. The application of polypropylene fiber concrete abroad has been widely used, which is becoming more and more popularly in China recent years. Meanwhile, research on the application of recycled polypropylene fiber concrete is still scarce. The experiment of this paper adopt waste polypropylene fibers as reinforcing fiber, and we make the standard specimen which size is . We use the specimen to do the research of mechanical properties of compressive strength and observing the variation of compressive strength of concrete specimen in different fiber volume. We discovered that when we add volume of 0.12% recycled polypropylene fiber and the length is 19mm, the compressive strength of concrete increases greatly. We draw the conclusion that the compressive strength of recycled fiber concrete is better than ordinary one from the experiment. In addition, if such concrete was used widely, we may reach the goals of conserving resources and protecting the environment.

Abstract: Different failure mechanism of dry scarf connection is decomposed into its end of the beam as a whole destruction of inclined cracks, R part of partial compression damage, destruction of inclined cracks, vertical shear damage and concave corner of the tensile damage in five forms, and describes the destruction of time corresponding to the six kinds of fracture morphology. This paper gives the R part constructed and reinforced concrete way. R part of the connection non-linear finite element analysis of level-load, compared to the relevant test results, verify the theoretical calculation method proposed in this paper. The proposed method of calculation for the corresponding FPC frame of dry scarf connection, designed to connect R to provide a useful reference.

Abstract: Differential equation of motion of energy-dissipation structure is established in the paper. In order to decouple the equation ,the equation is be reduced based on complex mode theory.Take a 10-storey shearing frame for an example ,selecting elcentro and taft wave as seismic motions ,structural roof displacements and relative storey displacements are be calculated and the effect of energy-dissipation dampers is evaluated.

Abstract: Earth Pressure Balance shield machines are used to construct metro tunnel in Shenzhen mixed ground. The ground condition is full of water and the diversity of two grounds in juncture is drastic. The risk mechanism of this ground is studied, and the main risks are found out. The main risks are assessed and classified employing the method of P=R×C, then the risk classification is determined. These studies ensure the projects in Shenzhen metro advance successfully.

Abstract: Aiming at the actuality which exist in construction parts that the setting-level of the safety of steel structural design codes between China and America is different in present, this paper use the reliability theory to compares the reliability of axial forced components from Chinese (Code for Design of Steel Structure)GB50017-2003 and American (Loads and Resistance Factor Design Specification for Structural Steel Buildings)LRFD-2001.From the result of comparing, some conclusions about the setting-level of the reliability of axial forced components from steel structural design codes between China and American are obtained, which can provide reference to the constructions.

Abstract: The mechanical behavior and ultimate bearing capacity of the circular bar-reinforced concrete filled steel tube (BRCFST) short columns under axial compression are analyzed in this paper based on the unified strength theory. Considering the restriction effect of steel tube and hoop bar on concrete, the calculation formula of bearing capacity of the column is deduced. Parametric studies are carried out to evaluate the effects of intermediate principal stresses, diameter-thickness ratio of steel tube and the stirrup ratio on the bearing capacity of the column. A good agreement is reached by comparing the results calculated by the formula with the test results. It is concluded that the unified strength theory is applicable in the theoretical analyses of the BRCFST columns.

Abstract: When the AR model is used to identify the structural damage, one problem is often met, that is the method can only make a decision whether the structure is damaged, however, the damage location can not be identified exactly. A structural damage localization method based on AR model in combination with BP neural network is proposed in this paper. The AR time series models are used to describe the acceleration responses. The changes of the first 3-order AR model parameters are extracted and composed as damage characteristic vectors which are put into BP neural network to identify the damage location. The effectiveness of the method is validated by the results of numerical simulation and experiment for a four-layer offshore platform. Only the acceleration responses can be used adequately to localize the structural damage, without the usage of modal parameter and excitation force. Thus the dependence on the modal parameter and excitation can be avoided in this method.

Abstract: This paper analysised the mechanical characteristics of precast reinforced concrete wall，introducing a fitting that can sliding along two directions and rotate round the last direction.It realized the flexible connection between the precast reinforced concrete composited wall and the structure beam，and make the hypothesis of wall not exposed to structural force come true。The paper analysised the mechanical characteristics of node fitting，sponsored design method，and explained the designation by an example.

Abstract: In this paper, a novel strain sensor based on chirped fiber grating with temperature compensation is presented. The proposed strain sensor uses double chirped fiber gratings. The temperature compensation exploit the principle that the wavelength shifts of these two chirped fiber gratings induced by temperature is consistent. This strain sensor is demodulated by the light intensity detection with low cost. Furthermore, the strain sensor is simulated in the end of this paper.