Eurocode-Compliant Seismic Analysis and Design of R/C Buildings

This chapter provides a concise qualitative overview of the philosophy for earthquake resistant design of ordinary structures adopted by relevant international codes of practice, including Eurocode 8. The aim is to facilitate practicing engineers with the interpretation of the code-prescribed design objectives and requirements for the seismic design of ordinary reinforced concrete (r/c) building structures which allow for structural damage to occur for a nominal design seismic action specified in a probabilistic manner. In this regard, the structural properties of stiffness, strength, and ductility are introduced along with the standard capacity design rules and requirements. Further, the role of these structural properties in the seismic design of r/c building structures following a force-based approach in conjunction with equivalent linear analysis methods is explained. Emphasis is placed on delineating the concept of the behaviour factor, or force reduction factor, which regulates the intensity of the seismic design loads and ductility demands. Moreover, the development and current trends in the emerging performance-based design approach for earthquake resistance are briefly reviewed. Lastly, practical recommendations to achieve higher-than-the-minimum-required by current codes of practice structural performance within the force-based design approach are provided.

This chapter provides practical recommendations for the preliminary seismic design and the finite element modeling of reinforced concrete (r/c) building structures assumed to behave linearly. It also discusses and provides commentary on structural seismic analysis methods adopted by Eurocode 8 (EC8). Specifically, the main principles of conceptual design for achieving well-qualified lateral load-resisting structural systems for earthquake resistance are briefly reviewed. Further, capacity design rules and local detailing practices for enhanced ductility capacity in r/c buildings are presented. Different types of structural analysis methods commonly employed in code-compliant seismic design of structures are outlined and focus is given to the EC8-prescribed equivalent linear analysis methods for forced-based seismic design, namely, the lateral force method and the modal response spectrum method. In this context, the EC8-compatible seismic design loading combinations and the EC8 design spectrum for elastic analysis are also presented. Moreover, the most commonly used finite element modeling practices for linear analysis of r/c multi-storey buildings are detailed, including the modeling of floor slabs, frames, planar walls, cores, and footings resting on compliant soil. Finally, brief comments are included on the proper use and quality verification of commercial seismic design software using benchmark structural analysis and design example problems.

This chapter delineates all the required computational and logical steps involved in the analysis stage of seismic design of ordinary reinforced concrete (r/c) buildings according to Eurocode 8 (EC8) by means of detailed self-contained flowcharts and pertinent comments. Special focus is given to verification checks for structural regularity in plan and elevation, on the classification of building structures based on torsional sensitivity, on the determination of the maximum allowed behavior factor by EC8, and on the selection and implementation of the two equivalent linear methods of analysis considered by EC8, namely the lateral force method and the modal response spectrum method. Furthermore, additional flowcharts and comments are included for the implementation of EC8-prescribed post-analysis verification checks based on deformations, that is, verification check of second-order effects via the interstorey drift sensitivity coefficient and verification check for maximum interstorey drift to ensure that damage limitation requirements of EC8 are met. Practical recommendations expediting the implementation of EC8-compliant analysis of ordinary r/c buildings are provided. Finally, the required detailing and verification checks for the design of r/c structural members according to Eurocode 2 and Eurocode 8 are presented in the form of self-explanatory flowcharts, along with the special requirements for the determination of seismic design bending moment and shear force diagrams.

This chapter presents three numerical benchmark example problems considering three different structures to illustrate the implementation of various clauses of Eurocode 8 (EC8) for the seismic design of ordinary reinforced concrete (r/c) buildings. Pertinent numerical input data and selected output data are reported in tabular form to facilitate the use of these example problems as tutorials for commercial seismic structural analysis and design software packages according to EC8. In particular, the first example problem involves undertaking EC8-compliant seismic analysis and deformation-based verification checks using both the lateral force and the modal response spectrum methods for a 5-storey dual r/c building with a single in-plan symmetry and with fixed support conditions. The outcomes from each analysis method are juxtaposed and compared. Further, the second example problem considers a 5-storey dual torsionally sensitive r/c building with fixed support conditions to perform seismic analysis using the modal response spectrum method along with post-analysis deformation-based verification checks. Finally, the third example considers a 4-storey dual r/c building with an r/c core and one underground storey (basement) resting on compliant soil. Emphasis is placed on the modelling of the box-type foundation, including pad and strip footings, and of the supporting ground using linear translational and rotational springs. The modal response spectrum method of analysis is used for the EC8-compliant design of the structure. Complete detailing and design verification checks according to Eurocode 2 and Eurocode 8, including capacity design rules, are presented in detail for selected r/c structural members, namely, for two beams, one column and a wall.