Applied Mechanics and Materials Vols. 94-96

Abstract: Bohai Bay is an semi-closed bay, the storm surge disaster is very serious in past. Now more and more large ocean engineering are built here, To study changes of storm surge induced by the construction of large-scale coastal engineering in Bohai Bay in present, 2D numerical storm surge model is established with large - medium - small model nested approach. The three most typical storms surges: 9216, 9711 and by cold wave in October 2003 are simulated in the condition of before and after implementation of planning projects in Bohai Bay. Changes of storm surge water level due to implementation of artificial projects are analysis in this paper.

Abstract: Tall buildings play an important role in the modern urban city, where only a few lands are available for the increasing population. In this study a hybrid genetic algorithm (GA) and optimality criteria (OC) method is presented for the optimum design of tall buildings under multi-load cases based on the current Chinese design codes. The entire optimum design procedure is divided into two parts: strength optimum design and stiffness optimum design. Member depths are treated as design variables. A GA with the strategy of adaptive feasible region is proposed to perform the discrete optimization of tall buildings under the strength constraints with the results of the stiffness optimum design as the lower bounds of the member size. The optimum stiffness design is conducted using OC method with the results of the strength optimum design as the lower bounds of the member size. This procedure is repeated until convergence is obtained. A design example is optimized to demonstrate the practicability and effectiveness of the proposed method

Abstract: This paper based on the unified strength theory, analyzed the ultimate bearing capacity of the reinforced concrete columns combined with FRP under axial loads. First, analyzed the mechanical property of the RC columns combined with FRP. Second, based on the unified strength theory, deduced the three-direction compressive stress of the core concrete and got the unified formula for calculating the ultimate bearing capacity of RC columns combined with FRP. Last, compared the analytical results obtained in this paper with the relevant experimental data, good agreement can be found and it proved the good applicability of the formula. Comparing with other methods in calculating the ultimate bearing capacity of RC columns combined with FRP，this method is well-founded, so it has a significant value in analysis of RC columns combined with FRP.

Abstract: The foundation of slope stability analysis is the data acquisition of the deformation. How to obtain the data detection point directly and efficiently is the access to achieve real-time predict method to slope stability. By introducing the Trimble GX 3D laser scanning data acquisition method, road slope detection method is put forward. According to the scanner system and working principle of the implementation steps, the slope detection and data processing procedures are developed and present references to the slope detection. With specific engineering application analysis, the feasibility of such acquisition is verified.

Abstract: In this paper, the effect of the non-uniformity settlement of ground foundation on the upper frame structure is studied. It takes a four-story space frame structure with two spans as an example. The different pedestals are installed at the joint of column footing, which respectively form the fixed supported model and the elastic supported model. Basin shaped settlement is applied in each model. The result shows that the beams are principally suffered with the bending moment and the columns principally suffered with axial force, shear force and bending moment, and that the elastic support model has certain economy.

Abstract: Deterioration of structures due to aging, cumulative crack growth or excessive response significantly affects the performance and safety of structures during their service life. Recently, signal-based methods have received many attentions for structural health monitoring and damage detection. These methods examine changes in the features derived directly from the measured time histories or their corresponding spectra through proper signal processing methods and algorithms to detect damage. Based on different signal processing techniques for feature extraction, these methods are classified into time-domain methods, frequency-domain methods, and time-frequency (or time-scale)-domain methods. As an enhancement for feature extraction, selection and classification, pattern recognition techniques are deeply integrated into signal-based damage detection. This paper provided an overview of these methods based on two aspects: (1) feature extraction and selection, and (2) pattern recognition. Signal-based methods are particularly more effective for structures with complicated nonlinear behavior and the incomplete, incoherent, and noise-contaminated measurements of structural response.

Abstract: The works is relied on the mass prestressed sewage tank, the tendon loss of prestress is calculated. Value of equivalent load of tensions applied on the pool wall is gained using elastic mechanics. The stress of the concrete section is tested when prestressing tendon is stretching and during the process of feeding water. To verify the accuracy of the measurement, calculating results are compared with the measured values by using FEM model analysis software, both are relatively approach. The paper specifically gives the differences between the measured data and theoretical data and analyzes the cause. The aim is accumulating relevant test data and providing reference for the similar project.

Abstract: Concrete admixture is a kind of addition agents, which can improve the performance of concrete. Adding a certain amount of concrete admixture can enhance the early strength, the age strength, and the anti-permeability strength of concrete. Also, concrete admixtures can improve the workability and adjust the setting time of concrete, so as to reduce the dosage of concrete and save the cost of concrete. This paper describes the types of concrete admixture and their functions, studies the functions of water reducers, and analyzes their effects to concrete, so as to improve the concrete performance and save materials in actual operation.

Abstract: In this paper a simple statically determinate and indeterminate truss structure is chosen as the model for the design of the stadium stand. The design simplifies the canopy structure, considering actual handling of the connection of nodes; fewer nodes would be chosen for the convenience of installation. The supporting frame is put slantwise between the roof and vertical walls to improve the safety and reliability of the cantilevered structure. The roof truss adopts bidirectional and orthogonal divisions, adding up inclined trusses in divisions of upper and lower surfaces, thus increasing space stiffness. Schematic drawings, internal forces and material processing lists are put forward in this paper, aiming at less material, simple construction, saving manual labor and financial resources and satisfying the masses on the basis of enough intensity and stiffness.

Abstract: Studies on the static stability and the ultimate bearing capacity of vierendeel latticed shells have been carried out. The buckling modal and the whole course of instability are shown using the Finite Element Method. The ultimate bearing capacity is compared with that of the single-layer latticed shell structure. The results show that the ultimate bearing capacity of the vierendeel latticed shells is 2.87 times more than that of the single-layer lattice shell in the condition of consuming the same steel. The vierendeel latticed shell structure not only has the advantages of concision and transparency like the single layer latticed shell structure, but also has the stability and carrying capacity like double-layer latticed shell structure.