International Concrete Abstracts Portal

International Concrete Abstracts Portal

The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

Showing 1-5 of 73 Abstracts search results

Document: 

SP275-49

Date: 

March 1, 2011

Author(s):

Luke Bisby, Tim Stratford, Joanna Smith and Sarah Halpin

Publication:

Symposium Papers

Volume:

275

Abstract:

Fiber reinforced cementitious mortar (FRCM) systems present a novel means of strengthening deficient concrete structures. They present a number of advantages over conventional externally bonded fiber reinforced polymer (FRP) systems. FRCM systems consist of open-weave polybenzoxozole (PBO) fabrics which are applied to structural elements, walls, domes, tunnels, or shells using cementitious mortars. They are breathable, non-combustible and non-flaming, and their performance in elevated service temperature environments is superior to common FRP systems. However, additional research on FRCM is needed, most importantly on their high temperature performance and their long term durability, before they can be widely applied with confidence. This paper reports on an ongoing experimental study into the performance of a specific FRCM system for concrete. Comparative tests on FRCM and FRP strengthened concrete prisms are presented. The superior performance of FRCM strengthening systems at temperatures between 50ºC (122ºF) and 80ºC (176ºF) is demonstrated. The effects of elevated service temperature environments on the bond between FRP strengthening systems and concrete are discussed.

DOI:

10.14359/51682459


Document: 

SP275-50

Date: 

March 1, 2011

Author(s):

E. Nigro, G. Cefarelli, A. Bilotta, G. Manfredi, and E. Cosenza

Publication:

Symposium Papers

Volume:

275

Abstract:

Three fire tests were carried out on slabs reinforced with Glass Fiber Reinforced Polymer (GFRP) bars bent at the ends of the member and the results were compared to those of six tests conducted previously. The anchoring of the FRP bars in the zone of slab not directly exposed to fire at the end of the members, provided by bending the bar ends, revealed essential to ensures slab resistance once in the fire exposed zone of slab the glass transition temperature was attained and the resin softening reduced the adhesion at the FRP-concrete interface. Therefore similar good performances of some of the six concrete slabs previously tested were later obtained even if a shorter length of the anchoring zone not directly exposed to fire was adopted. The production process allowing the bar to be bent is easily implemented by FRP bars manufacturers owing technologically advanced systems.

DOI:

10.14359/51682460


Document: 

SP275-51

Date: 

March 1, 2011

Author(s):

A. Palmieri, S. Matthys and L. Taerwe

Publication:

Symposium Papers

Volume:

275

Abstract:

The weak performance of fibre reinforced polymer (FRP) strengthened members in fire is a primary factor hindering the widespread implementation of FRP strengthening technology in the construction industry. An investigation was undertaken to examine and document the performance of NSM FRP strengthened concrete beams under fire conditions. Six reinforced concrete beams were strengthened in flexure with NSM FRP bars and insulated with different insulation systems. The specimens were subsequently exposed to a standard fire under service load. The testing parameters of these elements include the use of different thermal protections (including different materials and geometric layouts of the protection) of the glued reinforcement. Member deflections and temperatures throughout the section were measured during fire testing. Tests results indicated that insulated NSM FRP strengthened beams can achieve a fire endurance of at least of two hours.

DOI:

10.14359/51682461


Document: 

SP275-46

Date: 

March 1, 2011

Author(s):

J. Gustavo Tumialan, William J. Gold, Nestore Galati, and Andrea Prota

Publication:

Symposium Papers

Volume:

275

Abstract:

The American Concrete Institute (ACI) Committee 440 has recently published a design guide for strengthening of masonry with FRP systems. This paper summarizes and provides comments on the design protocols recommended by ACI 440 for flexural and shear strengthening with FRP systems of unreinforced masonry wall (URM). The development of the design protocols were based on calibration of bond reduction factors derived by a database of test results. This paper presents the rationale behind this approach, the calibration procedure, and its implementation in design protocols for flexural and shear strengthening of URM walls.

DOI:

10.14359/51682456


Document: 

SP275-47

Date: 

March 1, 2011

Author(s):

S. Rocca, M. Ekenel, N. Galati, B. Gerber and T. Alkhrdaji

Publication:

Symposium Papers

Volume:

275

Abstract:

Although the International Building Code (IBC) refers to the American Concrete Institute - ACI 318 Building Code for reinforced concrete design and to the Masonry Standards Joint Committee Building Code for Masonry Structures (TMS 402/ACI 530/ASCE 5) for masonry building design, neither ACI 318 nor TMS 402/ACI 530/ASCE 5 contain provisions for externally bonded FRP applications. To address this limitation, the International Code Council – Evaluation Services (ICC-ES) published in 1997 the acceptance criteria (AC125) to provide minimum requirements for externally bonded FRP strengthening systems, while meeting the main objectives of the building code, including strength, serviceability, fire safety, and durability. This paper provides the background for the latest revisions to the design criteria section of AC125 to reflect recent FRP knowledge regarding strength and serviceability requirements. These changes align AC125 with ACI 440.2R-08 and ACI 440.7R-10 guidelines, which would provide consistency in evaluation and design requirements of externally bonded FRP composites.

DOI:

10.14359/51682457


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