Advanced Materials Research Vols. 1065-1069

Abstract: The common problem of continuous rigid frame bridge is excessive mid-span deflection. The three factors of excessive deflection including vehicle loads, structural rigidity and prestressed loss are discussed on the case of a three spans continuous rigid frame bridge. Midas Civil is applied to analyze the sensitivity of mid-span deflection for these factors. The results indicate that the deflection is increasing with the increase of vehicle loads or the decrease of structural rigidity or the increase of prestressed loss. Furthermore, mid-span deflection is the most sensitive to the change of prestressed loss.

Abstract: Targeted at key technological difficulties of pre-stressed concrete bridge with precast segment assembling in short-line matching method, combined with the as-built projects and those under construction, this essay introduces systematic segmental precast assembly externally prestressed concrete construction technology in short-line matching method, and the developed serial complete equipments set, thus realizing development trend of factory-orientation, large-scale, mechanization, standardization of modern bridge construction.

Abstract: It is very important for the deformation control of the bridge pile foundation in the design of bridge with high piers. Using the Three Dimensions Numerical Simulation, the stabilizing project about anchor reinforced pile foundation which is based on the geological characteristics of the 405 federal highways is simulated analyzed. According to the stimulant result, we can see that anchor reinforced pile foundation can control the dimensions effectively and reduce investment compared with the general pile foundation.

Abstract: With the span of CFST (Concrete Filled Steel Tube) arch bridges getting much longer, the dynamic performance of them is becoming more and more advanced. In order to evaluate the structure of CFST arch bridges in a comprehensive way, it is necessary to take the dynamic performance of this kind of bridges into consideration. Methods of doing the dynamic analysis can be divided into two kinds: one is traditional theoretical analytical method, which is only suitable for simple arch bridge models; the other is FEM (Finite Element Methods), which is able to simulate the real structure and lead to more precise results. This paper attempts to study the calculation theory of free vibration characteristic of arch bridges through theoretical analytical method, and then it will do an empirical study on the dynamic performance of a CFST arch bridge by FEM to test the conclusion of theoretical study.

Abstract: Bridge is the most modern transportation systems more see the composition of the form, the construction of bridge engineering helps to relieve the pressure on the ground transportation, realize the efficiency of regional traffic comprehensive improvement. Domestic vehicle number has doubled in recent years, frequent traffic activities make bridge is facing serious gravity load, and a variety of diseases, threatening the safety of the bridge deck vehicle. Construction units in construction phase, should pay attention to the maintenance of bridge structure disease treatment, put forward a practical and reliable solutions. Half through bridge were examined in this paper, based on an engineering example, analyzed the common deterioration problems of concrete filled steel tube arch bridge, the corresponding protective measures are put forward.

Abstract: There are many bridge in our country, the new bridge has been built and numerous. Accurately and efficiently assess the bridge state to determine its carrying capacity and reliability level of great social and economic significance. Bridge load test can be directly measured structural properties of the bridge to provide a basis for the evaluation index maintenance of the bridge structure. Currently, the basic architecture using load bearing capacity performance test results assessed the bridge has been established, but many details are still unresolved issues still need to be further expanded research to accurately determine the fine actual carrying capacity of the bridge.

Abstract: A cable-strut tensile structure model with the diameter of 5.0m was designed and made to study the prestress and static behavior on the base of theory analysis. New schemes of the boundary compression ring, the cables and struts with the adjustable length, the connection nodes were designed and the least square method to fit the element force and strain curve was proposed. The initial prestress distribution and the responses of the model under full-span node load, half-span node load and 1/4-span node load were investigated. The experimental results indicate the cable-strut tensile structure will achieve the designed initial prestress while every element was tensioned to designed length. The outer planar stiffness of the structure is poor and easy to lost stability when subjected to asymmetric loads. The measured values and computed ones are almost consistent, which indicates the validity of the model design and the accuracy of the proposed methods.

Abstract: The effects of pile diameter, the property of pile end bearing stratum, the material parameters of pile shaft and the changes of pile length on the bearing performance of extra-long and large-diameter single pile were examined with the finite element software ABAQUS to make the numerical simulation analysis, by establishing the overall axial symmetry model, which was based on the data of static load test of single pile at the Yellow River Bridge site. The results show that the ultimate bearing capacity of single pile, the stiffness and the end resistance ratio would increase gradually, whereas the compression settlement ratio decreases slowly; the pile end grouting can significantly increase the ultimate loads, and therefore, improve the bearing performance of piles, but it has little effect on the stiffness of pile when loading was smaller; the elastic modulus of pile shaft has no effect on the ultimate bearing capacity of friction piles, little on the end resistance ratio, while the pile compression settlement ratio would gradually decrease and the stiffness would increased with the increase of the elastic modulus of pile shaft, and this increase of stiffness would slow down with the increase of elastic modulus of pile shaft; it is unreasonable to improve the ultimate bearing capacity of extra-long single pile only by means of increasing the pile length.

Abstract: This article relies projects, from derrick to replace the principle and derrick replacement order and step and important aspects of the construction derrick and the derrick to replace anti-corrosion treatment in half-through arch bridge construction derrick temporary replacement were discussed. Expect to be able to provide reference for similar projects draw on the research of this projects.

Abstract: Under the impact of environment, climate, conservation conditions and other factors, forms of bridge disease vary in different areas. This paper has researched on concrete bridges for middle and short span in Nantong. Through the investigation of bridges disease in Nantong and statistical analysis of the main structure type and related diseases, what can be seen is that the bridge diseases have a strong correlation with the region.Considering the characteristics in this area, by analyzing the common damage of bridges of different forms, the maintaining methods which are suitable for different forms have been put forward.