Cable Stayed and Suspended Post Tensioned Solutions for Precast Concrete Frames the Brooklyn System

Sergio Zambelli

Architect and Principal, B.S. Italia s.r.l., Styl-Comp Group, Zanica, Bergamo, Italy

Claudio Pagani

Chief Engineer, B.S. Italia s.r.l., Styl-Comp Group, Zanica, Bergamo, Italy

Stefano Pampanin

Senior Lecturer, Department of Civil Engineering, University of Canterbury, Christchurch, New Zealand

Alternative solutions for precast concrete buildings have been recently developed under the U.S. PRESSS (PREcast Seismic Structural System) program and successfully adopted with practical applications in seismic regions worldwide. Jointed ductile “dry” connections, obtained through unbonded post-tensioning techniques, have been proved to provide extremely efficient and damage-resistant systems for the next generation of buildings.

In this contribution, an extension of these emerging solutions for gravity-load-dominated frame buildings is presented, being named “Brooklyn” system for the peculiarity of incorporating the structural efficiency of a cable-stayed or suspended bridge systems within a multi-storey buildings. An overview of the conceptual definition, development, experimental validations on six full-scale one-storey frame systems will be given, including a description of the up-to-date practical applications on a series of buildings in regions of low seismicity. Proper modifications and validations are under development to accommodate high seismic demand.

Recent Developments in Precast Connections and Systems

The use and development of precast concrete for multi-storey building structures have typically suffered, when compared to their cast-in-situ concrete counterparts, an intrinsic lack of redundancy in the main structural scheme, consisting of statically determined systems with beam simply supported on, or hinged to, cantilever columns. As a result, excessive dimensions of, or reinforcement ratio in, the structural members (both beam and columns) are adopted. Additional and architecturally invasive lateral load resisting solutions (i.e. typically braces) should thus be adopted.

References

Stanton, J.F., Stone, W.C., and Cheok, G.S., 1997. A hybrid reinforced precast frame for seismic regions, PCI Journal, Vol. 42, No.2, pp.20-32.

ACI Comiitee 318 Building Code Requirement for Structural Concrete (ACI 318-99 mad 318-02) and commentary, American Concrete Institute, Farmington Hills, Mich, 1999 (2002).

Pagani, C., 2001 Four is better than two – The principle of cable-stayed bridges applied to building beams, Elite Journal, Vol.4, pp. 50-69, Vol.5, pp 42-57.

ACI T1.2-03 ACI Innovation Task group 1 and collaborators, 2003 Special Hybrid moment frames composed of discretely jointed precast and posttensioned concrete members (ACI T1.2-03) and commentary (ACI T1.2R-03) American Concrete Institute Farmington Hills, MI.

International Federation for Structural Concrete, 2003, Seismic design of precast concrete building structures, Bulletin 27, Lausanne, 254 pp.

Pampanin, S., Priestley, M.J.N, Sritharan, S., 2001. Analytical modelling of the seismic behaviour of precast concrete frames designed with ductile connections, Journal of Earthquake Engineering, Vol.5, No. 3, pp.329-367.

Watanabe F., 2000 Seismic Design for Prefabricated and Prestressed Concrete Moment Resisting Frames Proceedings of the 46^th PCI Annual Convention, Orlando, Florida.

Sanpaolesi, L., 1995 Sperimentazione su Prototipi di Strutture Prefabbricate per Edilizia Civile in Zona Sismica, C.N.R. Progetto finalizzato Edilizia.

Park, 2002 Seismic Design and Construction of Precast Concrete Buildings in New Zealand PCI Journal, Vol. 47, No. 5, pp. 60-75.

Priestley, M.J.N., Sritharan, S., Conley, J.R. and Pampanin, S., 1999 Preliminary Results and Conclusions From the PRESSS Five-Storey Precast Concrete Test Building, PCI Journal, Vol. 44, No.6, pp. 42-67.

Priestley, M.J.N. 1991. Overview of the PRESSS Research Programme PCI Journal, Vol.36, No. 4, pp.50-57.

Christopoulos, C. Pampanin S., 2004, Towards performance-based design of MDOF structures with explicit consideration of residual deformations, ISET Journal of Structural Engineering, Special Issue on “Performance Based Seismic Design” (Guest Editor M.J.N. Priestley) Vol. 41, No.1, paper 440.