基于抗规和隔规的RC框架隔震结构设计对比

未来我国隔震设计将存在两个依据，包括抗规（《建筑抗震设计规范》）和隔规（《建筑隔震设计标准》），两种规范的设计方法和关键设计指标存在显著差别，而关于两种规范的设计对比研究还相对较少。该文以RC框架隔震结构为基本研究对象，基于两种规范设计了具有不同结构高度的3组6个案例，明确了基于隔规设计的控制因素，对比分析了基于两种规范设计的结构的地震响应和经济性差别。该文研究结果表明基于隔规设计的控制因素为底部剪力比。相比于抗规，基于隔规设计时上部结构可采用更柔的设计方案，上部结构地震作用存在15%~20%左右的降低，但由于上部结构刚度降低程度大于地震作用降低程度，导致上部结构最大层间位移角增大。随着结构高度的增加，最大层间位移角增大程度显著增加。在材料用量方面，基于隔规设计时混凝土用量存在7.7%~12.1%的减小，钢筋用量则存在11.02%~26.29%的增加；随着结构高度的增加，混凝土用量减少程度逐渐增大，而钢筋用量增大程度逐渐减小。该文的研究成果可为RC框架隔震结构的设计提供重要参考。

COMPARISON ON THE SEISMIC DEISGN OF BASE-ISOLATED RC FRAMES USING TWO CHINESE CODES

There will be two seismic design codes for the base-isolated structures in the near future in China, including Code for Seismic Design of Buildings and Code of Design for Seismic Isolated Buildings. It is notable that significant differences exist in terms of design methods and critical design indexes between these two codes. However, comparisons on the seismic design of base-isolated structures using these two codes are rarely reported. The seismically isolated reinforced concrete(RC) frame structure is herein selected as the study subject. Using three pairs of structure cases with different heights which were designed according to the two codes, the controlling factor for the seismic design of such structures using Code of Design for Seismic Isolated Buildings was identified. In addition, the seismic responses and economic investment of such structures designed according to the two codes were compared and analyzed. The results indicate that the abovementioned controlling factor is base shear ratio. For the superstructure, a smaller stiffness is selected if Code of Design for Seismic Isolated Buildings is adopted, and the corresponding seismic load reduces by approximately 15%~20% in comparison with that designed following Code for Seismic Design of Buildings. However, because the degree of stiffness reduction of superstructure is greater than that of seismic load reduction, a significant increase of maximum inter-story drift ratio(i.e.,θmax) of superstructure is observed. Furthermore, the increment of θmax basically increases with the increase of total height of structure. As for the material consumption, the concrete consumption is reduced by 7.7%~12.1% while the reinforcement consumption is increases by 11.02%~26.29% if Code of Design for Seismic Isolated Buildings is adopted. With the increase of total height of structure, the reduction of concrete consumption increases, while the increment in reinforcement consumption decreases. The research outcome will assist in providing a useful reference for seismic design of base-isolated RC frame structures.