Application And Seismic Behaviors Of Partially Prestressed Concrete Frames With Unbonded Tendons

The development of design, research and application of the effective prestressed concrete structure, the development of the option of partially prestressed concrete and the technology of prestressed concrete with posted tendons, make the application of partially prestressed concrete structure go into a new stage. The development of the technology of the prestressed concrete with unbonded tendons has promoted the development of new materials, new structure, new technology, new craftwork. Since 1980 the application has ranged from single member to a whole structure such as flat floor, frame, high-story structure, portal rigid frame, special structure and special structure.In earthquake area, many engineers used concrete structure with unbonded tendons. But people still has lots of different opinions about its seismic behaviors. However, for it's late that the unbonded prestressed structures are applied in Fujian, so the level is low and the range of appliance is narrow. Previous research showed that the unbonded prestressed concrete member has the similar ductility to the commom reinforced concrete member, while the energy-dissipating capacity is worse that can be found from the narrow hysteretic characteristic. But it is seldom reported how is the behavior of the partially prestressed concrete frames with unbonded tendons under the low-cyclic loading. The common view of seismic behaviors of prestressed structures is generated in this article. The amending coefficient of designed action spectrum of prestressed structures is calculated. The main construct design methods of prestressed structures are provided for the engineers. I compare the fatigue mode of the common partially concrete frames with unbonded tendons under low-cyclic loading with that of the flat-beam ones. I also compare the fatigue modes of these two kinds of joints to state the course of the force of the flat-beam joints and use the action of the concrete tilted sprint mode and the reinforced concrete joist mode to analyze the mechanism. This article provides the reference forthe application of partially prestressed concrete frames with unbonded tendons in earthquake area.