Keywords: performance-based design, masonry infill walls, life-cycle cost analysis, reinforced concrete buildings, structural optimization, evolutionary algorithms.

The majority of the reinforced concrete (RC) buildings are infilled with masonry walls. However, in most of the contemporary design procedures the combination of masonry infills with the framed structure is neglected, assuming that the influence of the infill walls on the structural performance is always positive. Such an assumption may lead to inaccurate prediction of the lateral stiffness, strength and ductility of the structure, and thus obtain unacceptable designs. In the past, a number of studies have been performed on the seismic behaviour of RC buildings with masonry infill walls and a number of analytical models for the masonry infills have been developed for a rational design of RC framed structures [1,2,3].

In the last decade the concept of performance-based design (PBD) for structures subjected to seismic loading conditions was introduced. ATC-40 [4] and FEMA-273 [5] were the first guidelines for performance-based seismic rehabilitation of existing buildings while in the report Vision 2000 [6] these ideas were extended to the design of new buildings. The main objective of these kinds of design procedures is to achieve predictable and reliable levels of safety and operability against natural hazards.

The present study examins the influence of the masonry infill walls in the framework of performance-based optimum design of reinforced concrete buildings. The construction practices that are examined are the bare frame, the fully infilled frame and the weak ground storey case (Pilotis). Nonlinear static and nonlinear dynamic procedures are implemented into the framework of performance-based structural design optimization in order to define an automatic seismic design methodology for taking into account the influence of infill walls. The designs obtained through this methodology are assessed performing life-cycle cost analysis where it was found that ignoring the influence of infill walls lead to designs that exhibits poor performance in future earthquakes.

1

A. Madan, A.M. Reinhorn, J.B. Mander, R.E. Valles, "Modeling of masonry infill panels for structural analysis", Journal of Structural Engineering, 123(10): 1295-1302, 1997. doi:10.1061/(ASCE)0733-9445(1997)123:10(1295)

2

R. Perera, S. Gomez, E. Alarcon, "Experimental and analytical study of masonry infill reinforced concrete frames retrofitted with steel braces", Journal of Structural Engineering, 130(12): 2032-2039, 2004. doi:10.1061/(ASCE)0733-9445(2004)130:12(2032)

3

M. Dolsek, P. Fajfar, "Simplified non-linear seismic analysis of infilled reinforced concrete frames", Earthquake Engineering and Structural Dynamics, 34: 49-66, 2005. doi:10.1002/eqe.411

4

ATC-40, Applied Technology Council, "Seismic Evaluation and Retrofit of Concrete Buildings", California Seismic Safety Commission, (Report No. SSC 96-01), Redwood City, California, USA, 1996.

5

FEMA-273, "NEHRP Guidelines for the Seismic Rehabilitation of Buildings", Building Seismic Safety Council for the Federal Emergency Management Agency, (FEMA Publication No. 273), Washington D.C., USA, 1997.

6

SEAOC Vision 2000, "A framework of performance-based seismic engineering of buildings", Structural Engineers Association of California, Vision 2000 Committee, Sacramento, California, USA, 1995.

purchase the full-text of this paper (price £20)

go to the previous paper
go to the next paper
return to the table of contents
return to the book description
purchase this book (price £145 +P&P)