Advanced Materials Research Vol. 663

Abstract: In order to find the distribution rules on the shear nails on the steel-concrete composite segment of arch foot of an oblique cross steel box arch bridge, it established a space finite element model through the engineering of Wenzhou Weiwulu oblique cross steel box arch bridge, analyzing the maximum shear stress of the shear nails under normal using stage. The result shows that the welding nails in different position have a great difference in their shear stress. The welding nails which welded in a place that has a greater stiffness bear a bigger shear stress. So their mechanical performance of steel-concrete segment is better. In addition, the maximum shear stress becomes bigger from the bottom up to the top of the steel box.

Abstract: This paper represents a Least-Square Support Vector Machine (LS-SVM) model based on the phase space reconstruction for forecasting nonlinear time series of dam deformation. Before training the LS-SVM, a time-delay reconstruction of phase space was made to view the dynamics of the monitoring data by using C-C method. And then the LS-SVM, which is a nonlinear, black-box regression method, was used for prediction. And the accuracy of this employed approach was examined by comparing it with multiple regression method. The experimental results indicate that the forecasting performance of the proposed method is significantly superior to that of the traditional multiple regression method.

Abstract: Based on massive concrete block in practical engineering, the effect of new pouring precooling concrete on lower layer concrete in different seasons was simulated by using three-dimensional finite element simulation program of non-steady temperature field, and the temperature changes near the surface of lower layer concrete have been analyzed detailedly. It is indicated that, there is obvious “cold strike” effect of new pouring precooling concrete on lower layer concrete in summer, the effect in autumn followed by, and there is also the effect in spring but not obvious. In winter, as ambient air temperature is very low, there is not “cold strike” effect and the lower layer concrete temperature gradually recovery after pouring new concrete. Because actual concrete pouring deck surface maintenance is often not in place, the surface temperature of the pouring deck, which is greatly influenced by ambient air temperature and solar radiation, is very high in high temperature seasons. At the moment, the “cold strike” effect of new pouring precooling concrete on lower layer concrete is very obvious and likely to lead to the crack of the concrete. Hence, it is suggested that, after finish pouring of concrete and final set of concrete, sprinkling water or flowing water maintenance should be carried out in high temperature seasons, such as summer and autumn; before pouring the concrete, it is better to take measures, like spray and sprinkling water, to reduce the surface temperature of lower layer concrete, and try to avoid starting pouring concrete at midday.

Abstract: In order to ensure the enough fracture toughness for the thickness steel structure, based on DNV-OS-C401, using three point bending specimen with a center crack, the test of the typical bridge steel materials were carried out at 20°C. The CTOD value of base metal, heat affect zone and welded seam were obtained. The results show that the plastic displacement of the fracture toughness of the material plays a decisive role.

Abstract: The explicit statistical model of concrete temperature variation is difficult to reasonably reflect the nonlinear relationship between the historical information and future information. This article is based on neural network intelligence tools and uses the neural network model to describe the concrete temperature variation during the construction. The relationships between the concrete temperature and initial temperature (pouring temperature), environmental temperature, the cement hydration heat temperature increase, water cooling effect and other factors are nonlinear. Establishing the neural network model of concrete temperature variation, exploring the historical temperature information could predict the future temperature information. Applying the intelligent prediction model to a construction project shows that when compared with the traditional explicit temperature statistical model, the temperature neural network prediction model established in this paper has obvious simplicity and superiority.

Abstract: This thesis makes an analysis of seismic performance of the frame-supported shear wall structure with high transfer floor. It focuses on the structural effect from the changes in the location of the conversion layer. Besides, rational distribution of layer stiffness of the high conversion layer structure has been mainly discussed.

Abstract: A mixture method based on exponential curve and ANN is presented according to settlement prediction of roadbed with measured data. Based on this method, the rule of roadbed settlement is classified into sure part and uncertain part. Exponential curve is used to model the sure part, and ANN to model the uncertain part, thus the mixture settlement model can be obtained. Prediction results show that the mixture model has advantages of high precision and small network scale; it provides a new method for settlement prediction of roadbed.

Abstract: More and more irregular structure appears in people's lives, while the theoretical research and disaster experience show that the irregular structure in the earthquake will produce translation and torsion coupled spatial vibration, and sometimes it will cause very serious consequences. Being based on the practical engineering -the Castle Hotel of Dalian, this text makes use of finite element analysis software--- ANSYS. By analyzing the dynamic characteristics and seismic response, we get the self-vibration characteristics of the structure and the time history curve of top level displacement and acceleration of the structure under the effect of earthquake forces. The calculation results indicate that it is effective and reasonable to set up three-dimensional finite element model used for the analyzing of seismic response by ANSYS.

Abstract: As an effective way of passive damping, isolation technology has been widely used in all types of building structures. Currently, for its theoretical analysis, it usually follows the rigid foundation assumption and ignores soil-structure interaction, which results in calculation results distortion in conducting seismic response analysis. In this paper, three-dimensional finite element method is used to establish finite element analysis model of large chassis single-tower base isolation structure which considers and do not consider soil-structure interaction. The calculation results show that: after considering soil-structure interaction, the dynamic characteristics of the isolation structure, and seismic response are subject to varying degrees of impact.

Abstract: Combining with the construction of Wusong Road Passenger Station, the paper explores the calculation method and construction technology of high-formwork support system, proposes the construction measure requirements of formwork, introduces the technical process, accumulates the experience of high-formwork design and construction, and popularizes the application of high-formwork technology in projects, which decreases the security accidents of high formwork and provides reference for the construction of similar projects in future.