Experimentally Designde Of The Technology On The Combination Of Internal And External Prestressed And Light Aggregate Concrete In Continous Rigid Frame

Concrete continuous rigid-frame bridge is widely used in the highway and city bridge which has such advantages as beam continuous without expansion joints and comfort driving as continuous bridge, no bearing, no respond system as T-frame bridge. In recent years, excessive mid—span deflection and cracks in box girder appear in the long-span continuous rigid frame bridge in use, which affect load bearing and serviceability and greatly reduced durability of continuous rigid frame bridge. On the other hand, with the rapid development of transport, there are some development directions such as long-span, lighter-the upper structure and the abolition of the closure sector on side span floor support in the development of the continuous rigid frame bridge. as so, it is essential to find the technical measures to control the existing diseases of the continuous rigid frame bridge and adapt to future development .The application of lightweight aggregate concrete make continuous rigid frame bridge adapt to the future development ,but the disadvantage of lightweight aggregate concrete such as low elastic modulus and large shrinkage and creep have an adverse impact on the long-term use of construction. The external prestressed technique can reduce the disease and weight of the upper structure of Continuous Rigid Frame bridge and make up the impact of the disadvantage of the lightweight aggregate concrete. It is excellent to take advantage of the internal and external prestressed technique and the material performance advantages of the lightweight aggregate concrete. As so, ShuiTuJiaLingJiang bridge as a model, this paper study on the design of the Continuous Rigid Frame bridge with the Midas Civil software.The Research results show that the use of the combination technology make that the High-span ratio of the root section become 1/17.52 from 1/16.6, the backplane thick-span ratio of the mid span of the box beam reach 1/977 and that of the root of the box beam attain 1/211.7, box web thickness become 35,40,45cm from 50,65,80cm, and the thickness of the 0# web become 110cm from 150cm . Prestressed steel beam on apical plate OptimizedΦs15.2-22 andΦs15.2-17 fromΦs15.2-25 andΦs15.2-19.The mid span of ShuiTuJiaLingJiang bridge increase 9m with the entire span unchanged . Construction of continuous rigid-frame bridge without supports become a reality with the reasonable selection of segment length of lightweight aggregate concrete in the side and mid of the cross-section (The proportion of lightweight aggregate concrete segment in the side span is 0.475 while that in the main mid span is 0.472.)It can effectively improve the impact of web inclined cracks and large deflection in mid span on the security and the use of bridge in the latter part of bridge structures。Amount of concrete used in the continuous rigid frame bridge designed in this paper save3915m3compared with original ShuiTuJiaLingJiang bridge. With the economic benefits for the cancel of the floor stand and the reduce of the prestressed beam, it will become the future trends of PC continuous rigid frame construction to use the technology of the internal and external prestressed.