Design And Construction Technology Research On Approach Pavements Of Jointless Bridges

The total jointless bridge cancels the expansion joints of the whole bridge deck, thus, the temperature deformation of the main beam is absorbed by CRCP approach pavement that behind the approach slab. Commonly, CRCP approach pavement is comprised by subbase course, lean concrete base course, asphalt macadam seal coat, continuously reinforced concrete layer and asphalt concrete upper layer. The approach pavement is in the worst stress state when the temperature drops. The mechanical performance of CRCP approach pavements is influenced by following three: contraction distortion of the main beam, shrinkage and dry shrinkage of CRCP itself. Through checking the crack width and reinforcement stresses that are generated under these three aspects, the approach pavement length and reinforcement design could be achieved. This paper is combined with a real construction project, and simply introduced a jointless bridge which is a demonstration project in Guangxi Province, and the CRCP approach pavement length, reinforcement and structure design of which are introduced in this paper; also, the correctness and rationality of the CRCP approach pavement design are verified through monitoring this real CRCP approach pavement project.This paper taking the CRCP approach pavement for the main research object, the main research works are done as follow:(1)Under the premise of studing the development and current research status that concern jointless bridge and CRCP pavement from domestic to overseas, this paper introducing the construction features of the total jointless bridge which was proposed by Hunan University Bridge Engineering Institute, aslo the CRCP approach pavement structural system in this jointless bridge is adopted.(2)This paper analyzes the mechanical performance of CRCP approach pavements which under effect of the contraction distortion of the main beam, shrinkage and dry shrinkage of CRCP itself, from which the calculation formula of CRCP approach pavements crack width and reinforcement stresses under the effect of temperature dropping is derived, also theoretically calculates the deformation of CRCP approach pavements, meanwhile the approach pavements structural composition design method and the technique of active controlling crack through CRCP are proposed. Also, according to the mechanical characteristics of CRCP approach pavements, the corresponding calculation program and formula is compiled, and the CRCP approach pavements length and reinforced design is done by this paper.(3)The total jointless bridge adopt CRCP approach pavement as a new type of pavement structure, and the mechanical performance of it is more complicated than the normal pavements, therefore, the structure and construction technique of CRCP approach pavement demand a higher request. According to the practical experience and the theoretical research, this paper summarizes the key points of the structure requirements and construction techniques.(4)Taking the western traffic construction projects as a background and the theory research for the premise, the real project of CRCP approach pavements design is done. Through one year monitoring of the CRCP approach pavements with summarizing and analyzing the measured data, the correctness and rationality of the CRCP approach pavement design are verified, which provides a criteria for CRCP approach pavements design.