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 17 Abstracts search results

Document: 

SP133-04

Date: 

September 1, 1992

Author(s):

R.S. Fling

Publication:

Symposium Papers

Volume:

133

Abstract:

This paper reviews the development of deflection calculation procedures and comments on the risk of computational errors. It then discusses practical considerations affecting deflection and their limitations. It assesses the effect of nine parameters on the variability of deflection by reference to two example beams. Finally, the paper recommends further laboratory and analytical research and makes suggestions on how design engineers may improve the accuracy of their deflection computations.

DOI:

10.14359/10031


Document: 

SP133-16

Date: 

September 1, 1992

Author(s):

Howard H. M. Hwang and Hui-Mi Hsu

Publication:

Symposium Papers

Volume:

133

Abstract:

This paper presents the evaluation of seismic performance of a special moment-resisting (SMR) frame building and an intermediate moment-resisting (IMR) frame building designed in accordance with the NEHRP provisions and ACI Code 318-83. The annual limit-state probabilities for both SMR and IMR frames are determined by integrating the seismic hazard curve and structural fragility curve. From the comparison between the calculated annual limit-state probability and the specified acceptable risk levels, the seismic performance of a structure can be evaluated. In the NEHRP provision, if reinforced concrete frames are used to resist earthquake forces, the SMR frame is required for buildings belonging to higher seismic performance categories such as Categories D and E. Even though the SMR frame has a higher ductility than the IMR frame, the SMR frame is only designed for 50 percent of the strength required for the IMR frame. As demonstrated in this study, the IMR frame may perform better than the SMR frame in the event of an earthquake. Thus, the concept employed in the NEHRP provisions to protect high-risk and essential buildings needs careful reexamination.

DOI:

10.14359/3062


Document: 

SP133-07

Date: 

September 1, 1992

Author(s):

Stephen J. Sopko

Publication:

Symposium Papers

Volume:

133

Abstract:

Reinforced concrete floor systems must be analyzed for deflections to minimize serviceability problems such as excessive deflections. Member depths should be based on serviceability requirements as well as stress, especially when long-term deflection must be considered. The ACI equations for member depth may not always be adequate to prevent excessive long-term deflections of reinforced concrete floor members where heavy sustained loads are present. Two case studies are presented focusing on floor systems which have exhibited excessive deflections. From this investigation and analysis, proper design, detailing, and construction practices will be discussed to minimize serviceability problems. Care must be taken in analyzing and designing floor systems which support heavy sustained loadings or masonry.

DOI:

10.14359/3159


Document: 

SP133-12

Date: 

September 1, 1992

Author(s):

Dan M. Frangopol

Publication:

Symposium Papers

Volume:

133

Abstract:

A formulation is presented for extending structural system design concepts from safety and serviceability to damage tolerability. The assumptions necessary to implement damage tolerability concepts in structural system design are explained using both deterministic and probabilistic approaches. A particular emphasis is placed upon redundancy measures and their use in system damage-tolerant optimum design. Examples of solutions for optimum system design for safety, serviceability, and damage tolerability are presented.

DOI:

10.14359/3163


Document: 

SP133-14

Date: 

September 1, 1992

Author(s):

W. B. Cranst

Publication:

Symposium Papers

Volume:

133

Abstract:

The introduction of limit state design into the UK code for structural concrete in the 1960s is reviewed. The objections and controversies aroused are described. A selection of probability studies carried out in the interim is discussed and a possible way forward is outlined.

DOI:

10.14359/3168


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