Abstract:The main purpose of morphology analysis is to find out the geometric configuration of the chord-supported dome in the zero state and the initial strain value required for calculation. Based on the different parameters in zero state, the problems of shape analysis are divided into three categories: force finding, form finding, force finding + form finding. These three types of problems basically cover all possible morphological analysis problems in the structure of chord-supported domes. Based on the more mature numerical analysis theory, the paper deduces the formula of force finding and form finding, and successfully solves the force finding + form finding problem through the combination of force finding and form finding. Finally, the calculation flow of solving these three problems is given. According to the calculation process, the force-finding and force-finding + form-finding analyses were carried out respectively for the same structural model. The results show that the internal forces derived from the initial strain applied in the zero state are quite different from those in the initial state after internal force redistribution, so the force-finding analysis of the chord-supported dome structure is necessary. There is little difference between the element cutting length of the structure in zero state after shape finding and that of the structure in known geometry configuration, but there is a big difference between the coordinate values of some nodes in the two states. It is suggested that the structure can be cut directly according to the known geometry configuration during construction, but the lofting installation should be carried out according to the calculation results after shape finding.

Abstract:The influence of the prestressed implementation process on the optimization design result is analyzed, and the whole process optimization design concept of prestressed steel structure is discussed. Based on the unified description of the prestressing process, the mathematical model of the whole process optimization design of the prestressed steel structure is established, and from the Angle of the initial deformation of the cable, based on the construction mechanics analysis theory of the prestressed steel structure, the calculation method of the optimization model constraint conditions of the whole process analysis is discussed. Finally, according to the hierarchical optimization idea, the design variables in the optimization model are divided into several levels, and a three-level optimization method is constructed to solve the optimization model. The numerical results show that the whole process optimization design method has high efficiency and good stability, and can consider the influence of different prestressing processes on the optimization results. If the sequence of tensioning batches of each prestressing stage is given, the corresponding tensioning control scheme of prestressing stage can be output at the same time, so as to realize the overall optimization of the structural design scheme and the prestressing implementation scheme.

Abstract:Anchor plate and spiral reinforcement are important embedment parts in prestressed anchorage area, they work together with structural concrete to bear the huge concentrated load from the anchor. Commercial and engineering official use of anchor plate and screw bar, should meet the approved standard test. The anchoring area of prestressed structures may have only one anchorage device, or there may be multiple anchorage devices distributed in various ways. The stress of concrete and anchor plate in this area is complex and varied, and it is difficult to provide a consistent calculation criterion in the structural design code. Prestressing technology originated in Western Europe, where the authorities have formulated technical approval standards, product producers and structural designers are strictly followed. The product design of anchor plate and screw bar cannot be completely separated from calculation, at least estimation is required. The finite element analysis method can discuss the stress distribution of anchor plate, which is helpful to draw up the design of anchor plate. Based on "Discussion on Safety of Prestressed anchoring Area Part III" published in "Prestressed Technology" No. 3, 2012, this paper draws up a series of dimensions of anchor cushion plate and spiral reinforcement under circular clip anchors, which can be used by product manufacturers for product design, and can also be used as a reference for engineering design and construction units. The estimation method in this paper refers to the calculation criteria of PTI standard used for ordinary steel plate processing anchor plate, and only uses simple structural mechanics and empirical parameters. In this paper, only the anchor fittings of the 1 ~ 37 hole anchorage of Phi 15 steel strand are formulated. Practical experience is very important for prestressing technology. This paper lists the dimensions of anchor plate, spiral bar and bellows of French Freyssinet system, Swiss VSL system, Chinese QM, OVM and QVM system for reference. This paper considers the relevant requirements of China's railway department.

Abstract:In bridge construction, due to the influence of the blocked time in the construction process, the general river management requires to minimize the blocked time, so higher requirements are put forward for the lifting speed, and the instantaneous speed reaches 30mm/s. In the past, the large end of the piston of the lifting jack is guided by the buckle copper ring, and the structure of both sides is sealed by the gray ring can not meet the requirements of high speed lifting. Taking the lifting jack used in cable-carried crane of Qingcaobei Yangtze River Bridge in Chongqing as an example, this paper introduces the sealing structure of 1 channel Glay ring seal + phenolic cloth guide belt to meet the requirements of high speed lifting.

Abstract:This paper focuses on the replacement of the suspender of Shitanxi Bridge. Because some arch Bridges built in the early stage did not take into account the replacement of the boom during the operation of the bridge, the inner diameter of the embedded pipe matching with the bridge boom is mostly too small, which can not meet the technical requirements of the installation of the new boom anchor. Through the reasonable design of the structure and construction technology of the new boom, the installation and construction of the new boom can achieve the effect of not destroying the original structure of the bridge and convenient construction, which provides a feasible solution for similar bridge cable replacement projects.

Abstract:This paper introduces the whole lifting and sliding installation technology of large tonnage steel structure module by using synchronous hydraulic control system technology, and focuses on the key design methods and construction points of the process, summarizes the aspects that need improvement and attention of the installation process, and provides a reference example for similar large tonnage integral installation projects.

Abstract:At present, the prefabricated parts tend to be the whole prefabricated parts in domestic port bridge prefabrication yard, and the prefabricated parts show diversified characteristics such as oversized, ultra-high and overweight, which puts forward higher requirements for the transportation of prefabricated parts. According to the structural characteristics of the prefabricated cap of Hong Kong-Zhuhai-Macao Bridge CB04 standard, the transportation scheme of the project is further studied.