Applied Mechanics and Materials Vols. 423-426

Abstract: Starting from the thermodynamics, model of frozen soil is studied by energy dissipation theory and the inside and outside the state variables is given under isothermal conditions. Damage of frozen soil is re-flecked by effective stress and damage tensor in Damage Mechanics. Dissipation function is in form of plastic dissipation function (DP yield criterion) and the damage dissipation function. And plastic dissipation function is coupled of the damage variable. Through the elastic-plastic and damage evolution, frozen soil incremental elastic-plastic damage constitutive model is made. And finite element scheme is given.

Abstract: As more and more large-span prestressed concrete continuous rigid frame bridges have been constructed, different types of cracks have appeared on box girder, which not only spoils the beauty, but also reduces the safety and durability of these bridges. This paper sees one rigid frame bridge on the highway as the research background, and then detects and analyzes the cracks appeared on the web plates of the long-span prestressed concrete rigid frame bridge in construction phase. In the last, it discusses the major causes of the cracks on the web plates with ANSYS simulation analysis results.

Abstract: Through indoor tests, the influence of compactness and the water content on the CBR and resilient modulus was analyzed. The experiment results indicate that double indexes of degree of compaction and percent air voids designed, or single index of field percent air voids should be applied in construction.

Abstract: PsdVoigt2 function was used to fit SGW function and a series of bar beam elements based on the theory of SGW and wavelet finite element were constructed. Traditional finite element polynomial interpolation was replaced by the SGW scaling function and transformation matrix was utilized to transform wavelet interpolation coefficients to physical space. Thereby the shape function and element were constructed. The precision of a series of bar beam elements constructed with the SGW scale function as the interpolation function were verified by the calculation cases. The calculation results showed that the precision of the SGW-based element constructed was higher in calculating the deformation and strain. And the SGW-based bar beam element constructed enriched the element library of wavelet-finite element method.

Abstract: To avoid the fatigue fracture of casing inside slips, the plastic extension of casing cracks near slips under inner pressure after taking RTTS packer out should be analyzed. The plastic zone size of instability extension of two/three-dimensional cracks on casing was derived based on the theory of fracture mechanics. Analysis results show that hoop stress caused by inner pressure of casing is a key factor to lead to the instability extension of casing radial cracks after testing. The plastic extension zone size of cracks on casing near slips increases with the inner pressure or hoop stress. And, the plastic extension of cracks on casing near slips reduces the burst strength of casing significantly. The materials of casing materials and the inner pressure should be appropriately controlled to control the propagation of cracks.

Abstract: Concrete has been used as one of the major building materials for nuclear power plant (NPP) structures. While NPP structures of conventional concrete mixtures are considered to provide sufficient shielding capacities in terms of both structural containment and radiation barrier, further demands have been added to ensure and enhance the structural safety with considerations of aircraft impacts and/or earthquakes. To improve the impact resistance of the concrete itself, this paper presents the potential application of steel fibers as additives with no variation of the concrete mixture proportions that are currently used for NPP structures in Korea. Different types of steel fibers with variations of addition volumes were applied to the concrete mixtures and various kinds of mechanical properties such as strength, toughness, and fracture energy were evaluated. From the experimental results, a practical addition proportion and a type of steel fiber were chosen for the potential application to NPP structures. .

Abstract: Considering local sleepers supported invalidly, the dynamic analysis is presented for ballastless railway track system subjected to moving loads. The track is modeled as an infinitely Euler-Bernoulli beam with Kelvin viscoelastic foundation. The restrain conditions of system change suddenly at unsupported sleepers. Numerical simulating was carried out by the finite element discrete and Newmarks-method. Dynamic responses of system were analyzed in the case of single or multi-sleeper to be not working properly. Results show that the maximum value of displacement of track is going up 50% approximately due to an invalid sleeper occurring. The amplitude of vibration is two times increase when three sleepers to be hung up. Hence, there would be a bad effect on the vibration control of ballastless railway track system as some sleepers lose efficacy continuously.

Abstract: Lightweight concrete blocks, when under the affection of earthquake, will cause negative affection on the performance of the frame structure[1], but many designers will only take the calculation method into consideration with the neglect of the design of the block structure. This article, which summarizes some previous studies, has designed a new type earthquake-resistant and crack-resistant Block, which is formed by the base block and rubber integrated earthquake-resistant block. This kind of block filled wall, which is similar to viscous damper,will reduce the negative affection on the performance of the frame structure and enhance the frame structure of the earthquake-resistant capacity. By the coordinating of earthquakereducing convex block and earthquake reducing trench on the base, interact links between the block will be strengthened, so that to strengthen the crack-resistant capacity of the wall.

Abstract: From the basic theory of structural optimization design and shape control factors, the characteristics and control requirements for control factors of high-rise frame shear wall structure optimization have been introduced in this paper. The research and analysis showed that: the structure system and building height, length-width ratio of building plane, and the vertical height-width ratio play an important role on structural optimization.

Abstract: In recent years, high-rise buildings have developed very rapidly in our country. Because of the particularity of the high-rise building, more strictly technical measures should be taken in seismic design to ensure security. Three level fortifications, two stage design method have been used for seismic design in our country. Combined with the practical, the key points of response spectrum, time history analysis and performance design which related to seismic design of high-rise buildings were analyzed.