Development of a displacement based design method for steel frame-RC wall buildings

Student: MReyes Garcia Lopez
Supervisors: PrDr Timothy J. Sullivan, Gaetano Della Corte


In the last years, performance-based seismic design has become an attractive and innovative approach for design of structures. Most of the research, however, has been focused to reinforced concrete (RC) systems and steel systems working independently under seismic attack. By several reasons that will be discussed in subsequent chapters, dual frame-wall systems represent an attractive solution to withstand seismic forces. Additionally, new construction practices that involve the use of RC and steel in a same structural system are emerging as an alternative to the traditional structures. Consequently, dual structures that combine frames steel and RC walls.

A new direct displacement based (DBD) seismic design procedure for steel frame-RC wall buildings was investigated. The general frame of the DBD seismic design is firstly introduced, to continue with a detailed explanation of the proposed methodology. Within the method, an important step is the estimation of the likely yield drift of the steel frame. A simplified expression that provides an approximate value of the yield drift of steel frames was presented and used due to its simplicity. In order to verify the proposed methodology, a set of five regular buildings with 4, 8, 12, 16 and 20 storeys were designed for a PGA of 0.5g using the design spectrum included in the EC8.

The five cases study were modelled and subsequently analysed using non-linear time-history analyses. In the analyses, seven artificial records compatible with the displacement design spectrum were used. Maximum displacements and maximum drift demands were obtained and compared with the design values considered at the start of the design process. For the assumptions made in this research, the new DBD method for frame-wall structures has demonstrated to perform reasonably well for the cases study used in the design and evaluation process.

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