Showing papers by "Edoardo Cosenza published in 2002"

Fiber-Reinforced Polymer Composites for Construction—State-of-the-Art Review

Abstract: A concise state-of-the-art survey of fiber-reinforced polymer (also known as fiber-reinforced plastic) composites for construction applications in civil engineering is presented. The paper is organized into separate sections on structural shapes, bridge decks, internal reinforcements, externally bonded reinforcements, and standards and codes. Each section includes a historical review, the current state of the art, and future challenges.

Development length of FRP straight rebars

Abstract: In recent years, some attempts have been performed to extend general design rules reported in the codes for steel reinforced concrete to Fiber Reinforced Polymer (FRP) materials; this is the case of relationships adopted in the evaluation of the development length clearly derived by extension of the formulations used for steel rebars. However, such relationships seem to be inappropriate for FRP reinforcing bars: in fact, experimental test results have shown that bond behaviour of FRP bars is different from that observed in case of deformed steel ones. As a consequence, a new procedure for the evaluation of development length based on an analytical approach is needed in order to directly account for the actual bond-slip constitutive law as obtained by experimental tests on different types of FRP reinforcing bars. An analytical solution of the problem of a FRP rebar embedded in a concrete block and pulled-out by means of a tensile force applied on the free end is presented herein. Such solution leads to an exact evaluation of the development length when splitting failure is prevented. Finally, based on the analytical approach, a limit state design procedure is suggested to evaluate the development length.

Seismic assessment of gravity load designed r.c. frames: critical issues in structural modelling

Abstract: Reinforced concrete frames designed according to early seismic provisions or, sometimes, without any seismic provision, have usually low strength and, in most cases, show limited ductility. Very often details are poor and, consequently, the critical zones do not behave in a ductile way, showing brittle mechanisms of failure. Because of these problems, the assessment of existing reinforced concrete (RC) structures requires a refined procedure. A summary of models that permit the analysis of the non-linear behaviour of RC structures is discussed. An innovative numerical model is presented wich takes into account the most important mechanical phenomena affecting the non-linear behaviour of the RC frames. In conclusion, the influence of different strength and deformation sources on the global behaviour of existing buildings is studied and the needed capabilities of the numerical models are underlined.

Research Needs and Unresolved Issues of Composites for Built Infrastructure

Abstract: This special issue of the Journal of Composites for Construction is part of the activities related to the international workshop Composites in Construction: A Reality held in Anacapri ~island of Capri, Italy! July 20 and 21, 2001. The meeting was a collaborative activity between the Department of Structural Analysis and Design of the University of Naples Federico II and the Center for Infrastructure Engineering Studies of the University of MissouriRolla; it was hosted in Villa Orlandi, International Center for Scientific Culture of the University of Naples. In the last few years, the great interest in fiber reinforced polymer ~FRP! composites for use in construction and the worldwide expectation that such advanced materials could significantly improve the performance and durability of new or deteriorated constructed facilities has induced many researchers to promote meetings and stimulate discussion on this topic. Along with the attention of the scientific community, significant efforts are continuously made by manufacturers and producers in order to develop innovative manufacturing technologies and propose more stable and stronger constituent materials. After the latest ‘‘Fiber Reinforced Plastics for Reinforced Concrete Structures ~FRPRCS!’’ conference was held at the University of Cambridge on July 16–18, 2001, the workshop organizers felt that a specialty two-day gathering, intended as a follow-up to the latest Cambridge event and opened to some invited participants, could be a unique opportunity to rethink and reflect on the state-of-the-art, look at an agenda for research in the new century, and possibly set the course for future initiatives. In this spirit, 30 leaders in FRP technology ~academics, contractors, engineers, and manufacturers! were invited to attend the workshop and were associated to a specific subtopic within a given matrix; each participant presented their contribution in a general session. All the papers were collected in the ASCE volume Composites in Construction: A Reality edited by E. Cosenza, G. Manfredi, and A. Nanni. Attendees were then split into break-up sessions before coming back into a general session where controversial aspects, unresolved issues, and needs of research were finally discussed and prioritized according to participants’ votes and opinions. Considerations were drawn on the present situation of composites for the built infrastructure, and a working plan was formulated for the international scientific community in terms of opportunities, barriers, and needed research, as well as action items that the participants themselves would commit to carry out or start in the near future. The main research needs summarizing the records of the different sessions are outlined below; for simplicity, they are re-

Non-Linear Behaviour of Continuous Steel-Concrete Composite Beams

Abstract: Continuous composite beams are affected by negative bending moments at the internal supports; thus tensile stresses arise in the concrete slab. Cracks in the concrete slab and slippage between concrete and steel component make the structural response very complex in the hogging moment regions. Thus behaviour results from many non linear phenomena involving the reinforced concrete and the steel components, and also very localised effects due to bond of the reinforcing bars and shear connection. Recent developments in the field of modelling of such beams are presented and a theoretical model able to take account of partial interaction and tension stiffening effect is discussed.