Design, Safety Monitoring And Its Applicability Of Movable Scaffolding System

In the construction of large span concrete bridge, Movable Scaffolding System (MSS) compared with other methods of construction possess following overt merit: process is simple; linear of girder is easy to control; construction cycle is short; it doesn't require fundamental dispose, so the applicability is expand; construction traffic impact small, and security advantages. Meanwhile in urban viaduct, high-sea bridge and Pier Road bridge construction, MSS is widely used. But our country has not a comprehensive set of MSS on the design, construction and maintenance work order to guide or practical guidance at present. This article takes Guangzhou Zhujiang Huangpu large bridge for the construction of the concrete bridge engineering background, and carries out a series of research on MSS around the design, construction and maintenance and other aspects. Through research, this article obtained some valuable conclusions and Innovation.1) In statistics and reorganization at present existing MSS and practice and other construction method practices foundations, This article studied the style, characteristic and serviceability of MSS, and suggested an integrated design and structure and material request, deflection control value.2) In view of the main beam of MSS is the main bearing structure, this article analyzed the influence of the box beam structure girder-web plate resisting force, the ratio of web-thick and so on the parameter of MSS, and this article has calculated the horizontal stiffening rib spacing and stability of the local web; meanwhile it has discussed the scissors and bent characteristic of wave form steel plates (folding steel plate) and the feasibility of wave form steel plates which has been treated as a web girder structure of MSS system. The results showed that: when the main beam web of the high aspect ratio greater than a certain value, should configuration horizontal stiffening rib compression and the longitudinal stiffening rib, but should be calculated stiffening rib spacing or webs of local stability.3) Associated with the design theory of steel structure and relevant norms, this article has given some recommendations about calculation load and calculation load mode (planar patterns and spatial patterns) and load combination of MSS; also it has given the steps of the design elements, design principles and strength, stiffness, stability, fatigue, wind, weld connecting the calculation criteria of MSS. And it applied ANSYS to have simulated analysis about Huangpu bridge MSS62.5 which across Guangzhou Zhujiang River. The results show that MSS near the main beam bearing several webs opening comer reinforced vertical flange plate and reinforced plate connecting the obvious stress conc- entration. Von Mises stress has been over Q345 plate girder design stress and yield strength. These sites indicate plate in the most disadvantaged under the load of plastic may enter plastic. Pre main girder beams in the process of MSS component of the Von Mises stress value is less than the design of stress, so the results show strength compo- nent to meet the design requirements the design requirements.4) This article has been also analyzed the construction handicraft and key technology of concrete bridge being under MSS construction such as the assembly, debugging and testing surcharging of MSS, pre-camber settings, concrete pouring sequence, concrete conservation, pre-stressed tension, grouting holes and so on. This article has proposed cast-in-place post-tensioned box girder quality control indicators and old and new concrete bridge construction with the department of dislocation control measures of-MSS construction.5) Also control theory of MSS has been discussed detailedly, that in which the strain and stress control have been well studied. And this article has given a configuration of pre-camber and a pouting concrete stress treatment. MSS in the beam of concrete pouring and MSS moving ahead of the status of the process control and control in various key positions of stress and deformation values compared with the theoretical values calculated; Judging MSS in the actual structure of the state work safety reserve; Evaluating MSS in the design load performance; That's for MSS the normal use of providing security and MSS of the box girder construction setting pre-camber to provide the basis.6) To ensure that a safety construction of MSS, this paper in the final also set up a security management system, and suggest safety measures that guarantee safe in the MSS construction process and organizations. The daily general provisions and content about maintenance and repair, testing, evaluation and assessment conservation measures of MSS are given, that offer basis for MSS use of conservation and maintenance.