Applied Mechanics and Materials Vols. 193-194

Abstract: The Falling Weight Deflectometer (FWD) is designed to impart a load pulse to the pavement surface which simulates the load produced by a rolling vehicle wheel, wildly used in back-calculating pavement structure modulus. In this paper, a new form of Genetic Algorithm based on database searching theory is introduced. This method is not sensitive to initial values and it could identify the modulus effectively with establishing simple databases. By using a project measured data as an example, the result shows that this method is stable, convergent and practical. This method is better than the traditional method. It will be one of useful tools for the highway assessment.

Abstract: The assembly building is sought after by people For its speed, subject to the constraints of climate conditions, seismic energy saving and environmental protection, construction of low cost, flexible and diverse housing. However, in the assembly building maintenance, scrap processing and recycling of how to improve the efficiency of demolition is a new issue to be resolved. In this paper, based on the components of the demolition wave optional disassembly planning algorithm, by the definition of prefabricated building demolition wave is a topological relationship of certain components in the assembly building to reflect the components of the demolition order. The calculation of the algorithm is small, easy to use it to carry out efficient search, optional optimal component disassembly sequence, and thus improve the efficiency of disassembly.

Abstract: Against the characteristic of the concrete bridge suffered from the fire, with an engineering example, some methods of detecting and estimating the damaged bridges are introduced in the paper, and the treatment plans for reinforcement are put forward, a useful reference for dealing with the concrete bridge with similar diseases.

Abstract: Fire models using Computational Fluid Dynamics (CFD) are now popular design or evaluation tools as the computer’s development sharply. By those tools the thermal fire environment can be predicted in a ‘microscopic’ picture with air flow pattern, pressure and temperature contours. However, most of the fire models are only validated by some experiments not specially designed for such purpose, especially for large rooms. In this paper, an existing fire test was used to justify a fire model - FDS4.07 on predicting fires in large room. Smoke layer height and air temperatures inside the room were taken as the parameters. Functional analysis was applied to justify the predictions by the CFD model.

Abstract: Taking a 5-story reinforced concrete frame structure on the transformed 3-layer steel frames for an example, use finite element software ANSYS to reformation as a whole building model under static wind load changes for comparative analysis of internal force and displacement of the corresponding node. Analysis results show that in the transformation of steel on reinforced concrete frame structure, should fully take into account the structural stiffness change on construction of the overall effect of wind resistance, so that the transformation of the steel concrete frame structure more reasonable.

Abstract: Cable-stayed bridges can be recognized as a suitable solution for connecting wide-span crossings. More than 600 cable bridges are constructed in the world till now while this process is in progress and this number is increasing. The span of cable bridges is between 100m to 500m wide usually while length of widest cable bridges has increased up to 1000m during this decade. Construction of such bridges still is so profitable and according to this point studying these bridges seems so important. Cable-stayed bridges are studied from many aspects such as number of spans, number of towers, number of cables and girder types. Among this process, this paper has gathered more than 100 cable stayed bridges around the world in a table and has assessed them based on different parameters and has categorized these bridges in 3 categories of harp, fan and radial. This categorizing has been based on a relationship between the pattern of cables and the width of spans. Fundamentals of this categorizing have been defined in the first step of this paper. In continue the results have been represented. At the end the relationship between the width of span of these bridges and the category will be analyzed and the final conclusion will be presented.

Abstract: As a high-efficiency and clean fuel, natural gas has been used intensively by the world, its contribution to environment protect has been received more and more attention. The gas source structure of city gas is changing greatly, and natural gas will be the dominant gas instead of artificial coal gas and liquefied petroleum. Many coastal cities are working actively on use planning and feasibility of city natural gas now, so the use planning study is important. This paper presents the key problems in city natural gas planning, and analysis the gas source plan, gas amount predict, and pressure level selection of pipe network, some advices and suggestions are given.

Abstract: On April fifteenth, 2007, the 4 vertical and 2 horizontal railway lines were increased the sixth time by the Chinese Ministry of Railways. The electrical multiple unit (EMU) was running at speed of 200km/h in these sections. In some sections, the EMU maximum speed has reached 250km/h. Dynamic behaviors of bridges and piers under the loads of the train were analyzed with different spans and types in existing speed-raising trunk lines. The critical parameters, such as lateral and vertical natural frequency, dynamic factor, lateral amplitude, lateral natural frequency and lateral amplitude of pier and so on, which play important roles in dynamic behaviors of bridge, are analyzed by experimental data. The lateral rigidity and dynamic behaviors of bridge including beams and piers are the most obvious problems in existing speed-raising lines. Based on years of research, especially lots of dynamic behavior tests of concrete bridge in recent year, the dynamic behaviors of bridges are analyzed comprehensively considering the vibration of bridge and train characteristics. Many results are got and used in the relevant codes.

Abstract: SRC-RC transfer columns are commonly designed as a transition floor for high-rising buildings to transfer from lower SRC columns to upper RC columns. The mechanical performances are studied in the paper using the finite element software of ABAQUS. Nonlinear numerical analyses are made for SRC-RC transfer columns firstly to obtain the relationship between force and displacement at top of the columns. By comparing the analytical results with experimental ones, it is found that the results from finite element analysis coincide well with experimental ones. So ABAQUS software could be used as a supplementary means to simulate SRC-RC transfer columns mechanical behavior. Then the factors such as steel ratio and axial compression ratio are contrastively analyzed. The results show that axial compression ratio has a greater influence on the bearing capacity and hysteretic performance of the structure, but the steel ratio has less influence. Finally, comparisons between SRC-RC and RC columns are also made to demonstrate the mechanical performance of SRC-RC columns further. Conclusions drawn in the study might be useful in practical engineering design.

Abstract: The smoke control is of great importance for the life safety of the occupants in the building fire. Many analytical models have been studied for the design of smoke control. The objective of the article is to bring several numerical simulation models about building fire and smoke movement. There are generally three kinds of different models, which are net model, zone model and field model. The characteristics and weak points of each category are discussed, indicating that each model might be applicable to different building fire scenarios.