ABOUT THE 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.

International Concrete Abstracts Portal

Showing 1-5 of 278 Abstracts search results

Document: 

SP343

Date: 

November 3, 2020

Author(s):

fib and ACI

Publication:

Symposium Papers

Volume:

343

Abstract:

The first international FRC workshop supported by RILEM and ACI was held in Bergamo (Italy) in 2004. At that time, a lack of specific building codes and standards was identified as the main inhibitor to the application of this technology in engineering practice. The workshop aim was placed on the identification of applications, guidelines, and research needs in order for this advanced technology to be transferred to professional practice. The second international FRC workshop, held in Montreal (Canada) in 2014, was the first ACI-fib joint technical event. Many of the objectives identified in 2004 had been achieved by various groups of researchers who shared a common interest in extending the application of FRC materials into the realm of structural engineering and design. The aim of the workshop was to provide the State-of-the-Art on the recent progress that had been made in term of specifications and actual applications for buildings, underground structures, and bridge projects worldwide. The rapid development of codes, the introduction of new materials and the growing interest of the construction industry suggested presenting this forum at closer intervals. In this context, the third international FRC workshop was held in Desenzano (Italy), four years after Montreal. In this first ACI-fib-RILEM joint technical event, the maturity gained through the recent technological developments and large-scale applications were used to show the acceptability of the concrete design using various fibre compositions. The growing interests of civil infrastructure owners in ultra-high-performance fibre-reinforced concrete (UHPFRC) and synthetic fibres in structural applications bring new challenges in terms of concrete technology and design recommendations. In such a short period of time, we have witnessed the proliferation of the use of fibres as structural reinforcement in various applications such as industrial floors, elevated slabs, precast tunnel lining sections, foundations, as well as bridge decks. We are now moving towards addressing many durability-based design requirements by the use of fibres, as well as the general serviceability-based design. However, the possibility of having a residual tensile strength after cracking of the concrete matrix requires a new conceptual approach for a proper design of FRC structural elements. With such a perspective in mind, the aim of FRC2018 workshop was to provide the State-of-the-Art on the recent progress in terms of specifications development, actual applications, and to expose users and researchers to the challenges in the design and construction of a wide variety of structural applications. Considering that at the time of the first workshop, in 2004, no structural codes were available on FRC, we have to recognize the enormous work done by researchers all over the world, who have presented at many FRC events, and convinced code bodies to include FRC among the reliable alternatives for structural applications. This will allow engineers to increasingly utilize FRC with confidence for designing safe and durable structures. Many presentations also clearly showed that FRC is a promising material for efficient rehabilitation of existing infrastructure in a broad spectrum of repair applications. These cases range from sustained gravity loads to harsh environmental conditions and seismic applications, which are some of the broadest ranges of applications in Civil Engineering. The workshop was attended by researchers, designers, owner and government representatives as well as participants from the construction and fibre industries. The presence of people with different expertise provided a unique opportunity to share knowledge and promote collaborative efforts. These interactions are essential for the common goal of making better and sustainable constructions in the near future. The workshop was attended by about 150 participants coming from 30 countries. Researchers from all the continents participated in the workshop, including 24 Ph.D. students, who brought their enthusiasm in FRC structural applications. For this reason, the workshop Co-chairs sincerely thank all the enterprises that sponsored this event. They also extend their appreciation for the support provided by the industry over the last 30 years which allowed research centers to study FRC materials and their properties, and develop applications to making its use more routine and accepted throughout the world. Their important contribution has been essential for moving the knowledge base forward. Finally, we appreciate the enormous support received from all three sponsoring organizations of ACI, fib and Rilem and look forward to paving the path for future collaborations in various areas of common interest so that the developmental work and implementation of new specifications and design procedures can be expedited internationally. June 2018 Bruno Massicotte, Fausto Minelli, Barzin Mobasher, Giovanni Plizzari


Document: 

SP344

Date: 

October 21, 2020

Publication:

Symposium Papers

Volume:

344

Abstract:

The design and analysis of structural concrete elements is a topic of practical interest. While sometimes the effect of torsion is only addressed based on simple examples, practicing engineers are faced with the need to include the effects of torsion in their designs of a variety of structures and load arrangements. This Special Publication (SP) contains papers about the design of reinforced and prestressed concrete elements for torsion. The focus of the SP is on practical design examples according to different concrete bridge and building codes. In addition to the design examples, papers dealing with the current state of the art on torsion in structural concrete, as well as recent advances in the analysis and design of concrete elements failing in torsion, are added. The objectives of this SP are to provide practicing engineers with the tools necessary to better understand and design concrete elements for torsion. The need for this SP arose after the development of the State-of-the-Art Report on Torsion of Joint ACI-ASCE Committee 445 “Shear and Torsion” and Subcommittee 445-E “Torsion”. Usually, the attention that is paid to torsion in engineering education is limited to simplified textbook examples. The examples in this SP show applications in bridges and buildings, where the torsion design is combined with the design for flexure and shear. Additionally, the examples in this SP give insight on the different outcomes when using different bridge and building codes. Finally, the papers that include theoretical considerations give practicing engineers a deeper understanding and background on torsion in structural concrete. The views from an international group of authors are included in this SP, subsequently representing a variety of building and bridge codes the engineer may encounter in practice. In particular, authors from the United States, Canada, Ecuador, the Netherlands, Italy, Greece, and the Czech Republic contributed to the papers in this SP. Views from academia and the industry are included. To exchange experience in the design of torsion-critical structures as well as new research insights on torsion, Joint ACI-ASCE Committee 445 and Subcommittee 445-E organized two sessions titled “Examples for the Design of Reinforced and Prestressed Concrete Members under Torsion” at the ACI Fall Convention 2020. This SP contains several technical papers from experts who presented their work at these sessions, in addition to papers submitted for publication only. In summary, this SP addresses numerous practical examples of structural elements under torsion in bridges and buildings, as well as insights from recent research applied to practical cases of elements under torsion. The co-editors of this SP are grateful for the contributions of the authors and sincerely value the time and effort they invested in preparing the papers in this volume, as well as the contributions of the reviewers of the manuscripts.


Document: 

SP-344_09

Date: 

October 1, 2020

Author(s):

Camilo Granda Valencia and Eva Lantsoght

Publication:

Symposium Papers

Volume:

344

Abstract:

This paper provides a practical example of the torsion design of an inverted tee bent cap of a three-span bridge. A full torsional design following the guidelines of the ACI 318-19 building code is carried out and the results are compared with the outcomes from CSA-A23.3-04, AASHTO-LRFD-17, and EN 1992-1-1:2004 codes. Then, a summary of the detailing of the cross-section considering the reinforcement requirements is presented. The objective of this paper is to illustrate the application of ACI 318-19 when designing a structural element subjected to large torsional moments.


Document: 

SP-344_08

Date: 

October 1, 2020

Author(s):

Kevin S. Benítez C. and Eva O. L. Lantsoght

Publication:

Symposium Papers

Volume:

344

Abstract:

The design of a cast-in-place, post-tensioned concrete, multi-cell box girder bridge under combined torsion, shear, and flexure is presented in this example. The bridge covers three spans of different lengths, supported by two abutments and two bents; its cross-section consists of three 12 ft (3.7 m) lanes, two 10 ft (3.0 m) shoulders, and two concrete barriers. The detailed procedure for the design based on ACI 318-14 is presented, and a comparison is done with the design results for: AASHTO LRFD 2017, EN 1992-1-1:2004, and MC-2010. With this example, the authors illustrate the differences between provisions of the aforementioned codes for design of torsional effects, outlining the different theories and approaches used for each of these.


Document: 

SP-344_04

Date: 

October 1, 2020

Author(s):

Allan Kuan, Edvard P.G. Bruun, Evan C. Bentz, and Michael P. Collins

Publication:

Symposium Papers

Volume:

344

Abstract:

Although the torsion design procedures in ACI 318-19 are simple and broadly applicable, the resulting designs tend to be conservative. To address this, clause 9.5.4.6 in ACI 318-19 permits the use of an alternative design procedure when designing members with an aspect ratio ≥ 3 for torsion, provided that the alternative procedure has been shown to agree with the results of comprehensive tests. This paper evaluates and compares the torsion design procedures in CSA A23.3:19 and the PCI Design Handbook 8th edition with those in ACI 318-19. Each of the three methods are found to show good agreement with 282 tests found in the literature. A comparison of the three concludes that the designs obtained using the ACI method generally require the most reinforcement. More economical designs for members subjected to relatively low and high torques can be obtained by using the PCI and CSA methods respectively. A design example of a spandrel beam using the three methods is presented, and then further conclusions are stated to guide practicing engineers on the relative strengths and weaknesses of each procedure.


12345...>>

Results Per Page 




Please enter this 5 digit unlock code on the web page.