The Mass Concrete Temperature Field Of Hydration And Temperature Effect Study On Continuous Rigid Frame Bridge

Because of the bad heat conduction of the concrete material, prestressed concrete bridges are subject to varied temperature actions, which can make notable influence on the transformation and stress of bridge structures, sometimes even engender cracks. With the rapid development of transportation, the strength of concrete becomes higher and higher, the span of the prestressed concrete continuous rigid frame bridges constructed by cantilever method becomes larger and larger. At the same time, the volume of the box girders near piers are much bigger than before, and the temperature actions which were aroused by heat of cement hydration are extremely notable. Thus, it is important to make attention to the temperature problem caused by heat of cement hydration and to solve the problem in order to reduce the cracks brought by temperature in cement during the placement of the large volume of box girders—the zero-block and first-block.After consulting lots of professional theories and academic articles, the temperature field and stress field during the placement of the zero-block and first-block is this paper. All the following analysis is on the basis of a four-span continuous rigid frame bridge whose main span is 185m. The paper's work and research results are as follows:(1) Through on-site temperature monitoring and observation of large amounts of data, it researches and analyzes the hydration heat temperature field and the rule with time varying of the zero-block and first-block.(2) According to the thermal conduction theory and finite element method, the model of zero-block and first-block is built to simulate the cement hydration, then, sums up its temperature development process and the distribution. Then, compare with the temperature monitoring data and the result of compute, it studies the method of analysis of the accuracy and feasibility. At last, it puts forward the corresponding temperature control principles and applies to engineering practice.(3) Use of finite element analysis software MIDAS to calculate box girder temperature stress and get the stress distribution of zero-block and first-block. Then, it analyzes and seeks the action of the response to temperature about prestressed concrete continuous rigid frame bridges. At last, it puts forward the measures to control the cracks of concrete box-girder, and provides reference information to similar bridges.