Applied Mechanics and Materials Vols. 226-228

Abstract: With the rapid development of economy and the civil engineering discipline, the seismic performance of existing masonry wall can't satisfy the codes and regional seismic requirements. As a result, strengthening the earthquake resistance of it is put on the agenda. Using large-scale finite element software-abaqus, this paper analyzes different methods of strengthening masonry walls by constructional columns. Under the premise of the cross area of the columns used to reinforce is identical, it shows that the wall strengthened by bilateral constructional columns has a better seismic performance than by unilateral constructional column. The ductility coefficient of the former increases 49.4% than the original masonry, while the latter increases 26.3%. The bilateral constructional column could significantly improve the integrity and ductility of the masonry wall, so does the seismic performance. It has engineering sense for the strengthening work.

Abstract: The dynamic characteristics of the building could comprehensively reflect the seismic performance of the building. To make use of high sensitivity vibratory sensor picks up response of the external excitation of the structure. And then the dynamic characteristics of the structural could be obtained. According to it, the relevant judgment of the structural health status might be made. Based on the modal characteristics of the structure, the structure of the overall seismic performance is analyzed. Taking targeted reinforcement measures for seismic system optimization based on dynamic characteristics test results. It may effectively improve the overall seismic performance of the existing structure, avoid the blindness of reinforcement, and reduce the reinforcement costs. This paper takes a teaching building as an example to introduce seismic reinforcement design method that is based on dynamic characteristics of the test.

Abstract: The paper, based on analyzing original monitoring data, employs forward and backward cloud algorithm in studying determining safety-monitoring index for concrete dam ,which integrates randomness and fuzziness into of qualitative concept of digital features. By means of above monitoring data, its digital characteristics can be easily transformed to the “quantitative-qualitative- quantitative” change. The final generated quantitative value constitutes the cloud diagram where each droplet demonstrates the characterization of raw monitoring data. At the same time, it also shows the randomness and fuzziness of monitored value. we can study out the safety monitoring indexes according to different remarkable levels by using the probability density function and deterministic function which completed by cloud algorithm. In the end, it is obtained with practice that this method is more suitable and reliability.

Abstract: In the view of the actual project, this paper analyses the credit problems of the foundation treatment, from the three aspects of the location, the shallow blow fill and the pile’s negative firctio- n. Then this paper especially studies the field testing scheme about the dynamic compaction method with precipitation, based on the analysis of the percussive compaction method with precipitation, the dynamic compaction method with precipitation and packless vibroflotation method. Meanwhile, the operated steps and the attention of the construction have been enucleated.

Abstract: Performance levels in performance-based seismic design are affected by many factors. In this paper, based on the unclear division of the performance levels, finite element models of masonry buildings with windows of different sizes and different structural measures, according to damage constitutive equation of masonry in strain space and damage evolution equation [1], are built, which are analysed by the pushover analysis method. Stiffness change and damage evolution of masonry buildings under earthquake action are quantitatively described by the basic damage index and holistic damage index. In order to show their joint action on seismic performance of masonry buildings, the comprehensive evaluation coefficient is suggested to divide and evaluate performance levels of masonry buildings, which can evaluate overall seismic behavior of masonry buildings.

Abstract: The research about base isolation in building construction in the region of medium risk seismicity has now received great attention. Seismic behavior of base-isolated structures is highly dependent on the nonlinear properties of the rubber-bearing isolated system. Thus, it’s very necessary and significant to identify the nonlinear properties of the rubber-bearing exactly with suitable method. In this paper, a data-based method solely using the time series of structural dynamic response and excitation measurements is proposed to identify the nonlinear parameters of rubber-bearing isolated system. The method is based on the sequential application of extended Kalman estimator for the nonlinear structural parameters. A numerical simulation results demonstrate that the proposed method is capable of identifying the nonlinear parameters of rubber-bearing isolated system with good accuracy.

Abstract: The Submerged Floating Tunnels are one new type of infrastructure, representing a challenge in structural engineering, both on the theoretical and operational fields. In this paper, a 3D finite element analysis procedure is developed accounting for material and geometrical nonlinearities, soil-structure interaction and multiple-support seismic excitation. A comparison between dynamic response in case of elastic and inelastic material behavior of the anchor bars is given, which shows the beneficial effect of this source of energy dissipation. Furthermore, the effects of introducing dissipation devices for restraining the tunnel axial motion have been investigated as well. Besides this, the earthquake transmission through water (seaquake) is here introduced as an additional hydrodynamic loading on the tunnel. The ensuing increase of loading in the tunnel indicates that a significant role is played by this loading source and highlights the need of further investigations on seaquake effects.

Abstract: Bond-slip performance between section steel and concrete has influence on deformation of steel reinforced concrete beams based on results of experimental studies. Current standards on steel reinforced concrete structures do not involve bond-slip effects when calculating the deflection of steel reinforced concrete beams and this is not valid exactly. This paper describes a new method of deflection calculation for steel reinforced concrete beams, which considering the bond-slip effects on deformation. Deflection of steel reinforced concrete beams are divided into two parts: deflection of steel reinforced concrete beams under loads considering the fully bond between steel and concrete, and the additional deflection caused by the bond-slip. The sum of the two parts is the total deflection. Results show that the proposed method in this paper fits with experimental results.

Abstract: In the practical engineer, the infilled-wall frame structure is widely used by its economy and applicability. Under the project research, the paper establishes a finite element model for infilled-brick-wall structure based on the infilled-wall frame structure performance and after Pushover's analyses,it obtains the inter-story displacement angle, which is anti-seismic performance index to the point each floor of the infilled-wall structure under the different earthquake action . The paper analysis and assesses the infilled-wall frame structure anti-seismic performance based on the anti-seismic performance index and it provides a reference and basis for anti-seismic standard's development towards based-performance direction.

Abstract: Ascertaining existing buildings of seismic capacity deficiency is the precondition of strengthening them, which is very important to reduce earthquake disaster in the future. So it is necessary to predict the seismic damage of buildings. This article is the results of earthquake disaster prediction in urban area of Langfang, which is expected to provide a theoretical basis for the buildings in Langfang to defense the earthquake disaster.