External Prestressing Continuous Rigid Frame Technology

Continuous rigid frame bridge widely used in the engineering field, but due to the design,inadequate understanding of the role of shrinkage and creep, the longitudinal prestressingcause excessive loss of prestress due to creep, the primary beam deflection, the constructionquality controllax, the pore pressure grouting is sometimes not full, prestressed beam, theoccurrence of corrosion, resulting in reduction of the effective prestressing steel beam,causing the flexible beam, the flexural vertical cracks. Plus live load, the role of long-termgauge. The bridge key parts of the deformation and cracks can not be restored. Continuousrigid frame bridge operators after a few years with varying degrees of disease, these diseasesaffect the carrying capacity of the structure, endangering the safe operation of the bridge.With the development of external prestressing computing theory and application oftechnology, making bridges with external prestressing reinforcement has been very widelyused increasingly in the project. Externally prestressed structures for traditional body clothPrestressed structure: cross-section of small size, light weight, the tendon replacement,maintenance and management, little loss of prestress, shorten the construction period, anddurability advantages. This paper describes the development of the use of externallyprestressed structures, composition, mechanical properties and combined with a strengtheningworks examples of externally prestressed continuous rigid frame reinforcement on designideas, construction process and the reinforcing effect analysis.The main research work and the results obtained are as follows:â‘ T he analysis summarizes the disease situation and the causes of the active-dutylong-span bridges.â‘¡Instance of a large span continuous rigid frame reinforcement on the calculation ofreinforcement design principles and ideas, pointed out that early in the design, the correctassessment of the simulation of structural reinforcement before, providing reinforcementdesign and simulation of state and calculation, targeted reinforcementthe importance of design.As reference for the reinforcement of the same type of bridge design.â‘¢Through the introduction of the construction of process units, process, control points,and summarizes the construction experience and recommendations.â‘£E mphasizes the real-time monitoring, compliance, load test and other means to verifythe design structure of the simulation and the actual reinforcement project status to ensure thatthe reinforcement effect.