Temperature And Shrinkage Stress Analysis Of Over-long Concrete Frame Structure And Seamless Design Method

With the development of city modernization, all kinds of large-scale buildings appear frequently. The seamless design of over-long structure has been widely applied. The design of this kind of structure, China has not formed a unified methods and regulations, lead to the design of autonomy and discretion, this paper has researched the seamless design method of over-long concrete structure design, put forward reasonable suggestions, provides the reference for the design and construction. In this paper, the following work mainly.First of all, the over-long concrete structure need to stress and displacement quantitative consideration of temperature and shrinkage of concrete can be produced, using elastic finite element method, but the elasticity method the calculated stress values without considering concrete creep and stress relaxation, cannot be used directly, also need according to the linear creep theory to deduce the creep stress solution, the creep stress solution as a judge of concrete member is cracking and reinforcement calculation of standard.Secondly, the stiffness reduction method to consider the creep and stress relaxation, and based on the age-adjusted effective modulus method to derive the stiffness reduction factor, in order to study the stiffness reduction method is more convenient in engineering design, based on the stiffness reduction method is proposed on the temperature reduction.Again, analysis of the temperature and shrinkage effect of typical over-long frame structure using the temperature reduction method, the stress of beam slab structure is mainly composed of two parts, the first is the column as the external constraint beam stop beam deformation stress, and deformation of beam, plate is their differences lead to mutual restraint stress. Typically the beam, plate tension, the latter makes the beam compression and in tension. In the design of the principal tensile stress and focus on the plate boundary column side shift.Finally, according to the adverse effects of over-long structure under temperature shrinkage, put forward a series of countermeasures including design, reasonable arrangement of structural members, using the settings of prestressed technology, the beams and slabs of post-pouring belt, the use of expansive concrete. The overall aim is to "fight and release", not only to control cracks, and also want to control the end displacement.