International Concrete Abstracts Portal

Showing 1-5 of 19 Abstracts search results

Document: 

SP72-06

Date: 

December 1, 1981

Author(s):

William L. Gamble and Ned H. Burns

Publication:

Symposium Papers

Volume:

72

Abstract:

This paper presents a historic review of the development of reinforced and prestressed concrete floor slabs. There has been an emphasis on tests of prototype and scale model structures in the past, and much current design practice is related to the results of these tests. It is also noted that design and construction of slab structures have often been ahead of the develop-ment of coherent analyses of these complex structures. While reinforced concrete slabs have been built since the earliest days of the 20th century, prestressed slabs have been developed and built only in the second half of the present century. In spite of the many advances in the analysis and design of slabs, a number of questions remain. Reinforcement detailing is important to the satisfactory behavior of slabs, and this may be particularly true at edge columns, and in edge beams. The shear capacity of beamless slabs, especially when moments are also to be transferred, is an area in which many uncertainties still exist. Effects of concentrated loads and of holes on moment distributions have not been extensively studied.

DOI:

10.14359/6758


Document: 

SP72-07

Date: 

December 1, 1981

Author(s):

Neil M. Hawkins

Publication:

Symposium Papers

Volume:

72

Abstract:

The history of prestressed concrete specifications in the U.S.A. is correlated with the personal philosophies of key individuals at the time the first specifications were developed, with the nature of interactions between research, codes and practice and with the human factors involved in the regulatory process. It is concluded that if regulatory authorities are to fulfill their professional obligation of encouraging new developments and applications, then they must in turn develop and publish generic guidelines that can be used to assess whether changes in specifications are justified.

DOI:

10.14359/6759


Document: 

SP72-08

Date: 

December 1, 1981

Author(s):

J. 0. Jirsa

Publication:

Symposium Papers

Volume:

72

Abstract:

A number of approaches are available for design of beam-column joints. The joint details resulting from the application of each approach differ considerably. In most cases the transverse reinforcement required in the joint is substantial and makes fabrication difficult. The requirements for transverse reinforcement can be traced to the research which forms the basis for design rules. In many cases the loading histories used in test programs produce very large deformations which may be in excess of the deformation realized in actual structures. Research on beam-column joints is reviewed and suggestions are made for determining loading histories and test specimens which may be more rational in terms of structural performance requirements.

DOI:

10.14359/6760


Document: 

SP72-09

Date: 

December 1, 1981

Author(s):

J. G. MacGregor

Publication:

Symposium Papers

Volume:

72

Abstract:

The ACI Building Code has become more and more complex as engineers and plan checkers have insisted that every eventuality be covered in the code. Three possible ways of simplifying codes are discussed. These include: (a) rearrangement of the code by components rather than stress states, (b) use of a performance code format plus a recommended practice and (c) use of a two-tiered code. The paper suggests that (a) and (c) are most likely to be successful at this time.

DOI:

10.14359/6761


Document: 

SP72-10

Date: 

December 1, 1981

Author(s):

M. Daniel Vanderbilt

Publication:

Symposium Papers

Volume:

72

Abstract:

A reinforced concrete building may be approximately analyzed as a series of crossing plane frames. The beam-column connections can be modeled using either the lateral-torsional member or equivalent beam width techniques. The lateral-torsion-almember definition and associated frame and member modeling rules which comprise the equivalent frame method of ACI 318-77 were calibrated against tests of real structures while methods of computing effective beam widths are based largely on theoretical analyses of elastic plates. Comparisons of the two methods in analyzing a test building for lateral loads are given. Both methods can be forced to produce computed deflections which agree favorably with test data. However, compatibility of lateral de-flections of separately analyzed parallel frames at the same floor level is not assured. Two methods for forcing compatibility of lateral deflections at each floor level of a building are described and shown to produce computed deflections which compare favorably with test data. Limitations of both equivalent frame and equivalent beam width methods are discussed.

DOI:

10.14359/6762


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