Application of Section Steel-Concrete Combination Strengthening Method and External Bracing Method in Seismic Strengthening

摘要

At present, structure members can be strengthened by enlarging section, externally bonded steel frame, FRP, and so on. Structural system can be strengthened by many methods such as by shear walls, wing walls, and external braces. In addition, in recently years, the strengthening methods begin including seismic isolation and energy dissipation technique. Due to the merits and demerits of these methods, seismic strengthening design, in essence, should rationally integrate these methods. The paper, based on an engineering example, introduces the design methods of section steel-concrete combination strengthening method and external bracing method, discusses their details of seismic design, and illustrates the importance of reasonable selection of strengthening methods in seismic strengthening design.By example, we think that to determine the strengthening design should be based on security, economic, and applicable principles. Section steel-concrete combination strengthening method has significant effect on frame column with high axial compression ratio. Especially when increasing section method is limited by foundation size, the new method can avoid the basis of treatment. But structure strengthening with brace will change the way of force transmission of the original structure, and the columns and nodes attached with brace will produce internal force redistribution. In this paper, the phenomenon has been considered. Structure strengthening with brace is an economic and efficient strengthening method that can avoid the basis of treatment, increase lateral stiffness and torsional rigidity, and has multiple seismic fortification lines. Besides, the connect part requires reasonable design, to ensure brace and original structure work together further to satisfy the "strong column weak beam, strong nodes and weak brace" concept of the earthquake.