SEISMIC PERFORMANCE EVALUATION OF CODE-DESIGNED GRANDSTAND STRUCTURE OF A ROOFLESS SPORT STADIUM

Nowadays, special structures such as sports stadiums have become part of the megacity’s engineering symbols. Given the significant investments made by the public or private sectors for construction and operation of these specific structures, it is essential to develop appropriate approaches for facilitating decision making in risk management of building financial sectors, especially in the seismic prone areas. Currently, stadiums have considered in the category of buildings with high importance according to the Iranian code of practice for seismic resistant design of buildings (2015). Therefore, no major damages maybe expected for these buildings under the seismic hazard level of 10% probability of exceedance in 50 years and they can be repaired quickly for reusing during the design level earthquake events. However, the adequacy of simplified seismic code design procedures when applied to this type of buildings is questionable in terms of seismic performance by considering randomness and uncertainty in both the seismic loading and building resistance. In this approach, a performance based assessment approach to the design of grandstand structure of sport stadiums can provide greater insight of designers into the unique characteristics of these structures, such as the crowd-structure interaction, the circular or oval geometrical configuration of frames, the high potential of vertical irregularities’ formation along the height of the structure and also, the arrangement of slopping beams under the sitting platform of spectators (Gkologiannis et al., 2010). In this paper, the probabilistic framework is used for the seismic performance evaluation of grandstand structure of a roofless football stadium by using the incremental dynamic analysis (IDA) method (Vamvatsikos and Cornell, 2002), and the interaction effects of various scenarios of population gravity distribution (i.e., living load) on the seismic performance of structure are assessed during different intensity levels of probable earthquakes. The stadium has a symmetric oval shape plan view and will have the ability to host approximately 20,000 spectators (Figure 1). The structure is designed for a very high seismic zone with a site-specific earthquake acceleration of 0.35 g according to the 4th edition of Iranian seismic code (2015). The lateral force resisting system in all structural directions is a special concrete moment resisting frame. The structure are designed based on the linear response spectrum analysis method by applying the orthogonal combination procedure.

Keywords:

Probabilistic seismic performance , Crowd-Structure interaction , Grandstand structure , Sport stadium , Incremental dynamic analysis