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Showing 1-5 of 16 Abstracts search results

Document: 

SP160-09

Date: 

June 1, 1996

Author(s):

Azez Hindi

Publication:

Symposium Papers

Volume:

160

Abstract:

Reports tests of a three span reduced scale segmental box girder bridge model post-tensioned with external tendons. The objectives of this study included the determination of the effect of using external tendons discretely bonded at an intermediate diaphragm in each segment and/or using grouted internal tendons on the strength and ductility of external tendon bridges. The scope included experimentally determining and analytically predicting the external tendon maximum stress and the flexural capacity of the bridge. The flexural tests, performed on the three span model, were conducted in three phases. In the first phase, the external tendons were discretely bonded at only two or four intermediate diaphragms in each span. In the second phase, the external tendons were discretely bonded at all ten intermediate diaphragms in each span. In the third phase, supplementary ungrouted or grouted internal tendons were added. The test results indicated that discrete bonding of external tendons and/or using grouted internal tendons substantially improved the strength and ductility of this kind of construction.

DOI:

10.14359/1450


Document: 

SP160-06

Date: 

June 1, 1996

Author(s):

Zareh B. Gregorian and Garen B. Gregorian.

Publication:

Symposium Papers

Volume:

160

Abstract:

Prior to the upgrading the seismic zoning of Massachusetts, not much attention was given to new or existing structures in the east coast with regard to seismic design and strengthening. Strengthening existing structures undergoing renovations has become mandatory for all government owned and operated buildings. This paper is the result of strength evaluation of two VA hospital buildings which are planned to undergo major renovations. Various options were considered for seismic strengthening of the two existing reinforced concrete frame structures, built in the 1930s without any earthquake load design considerations. Adding interior shearwalls, exterior buttresses, steel cross bracings, and base isolation proved to be complex, costly, and undesirable for architectural reasons. Use of peripheral shearwalls, attached to existing concrete frames was considered as a final solution for strengthening.

DOI:

10.14359/1550


Document: 

SP160-01

Date: 

June 1, 1996

Author(s):

Jerome S. B. Iffland and Avanti C. Shroff

Publication:

Symposium Papers

Volume:

160

Abstract:

Summarizes the findings of a research project performed by the American Iron and Steel Institute entitled, "Technical Review of Current and Proposed Seismic Design Provisions." In the last several years, both New York City and the Building Officials and Code Administrators International (BOCA) have proposed and drafted seismic provisions for their respective building codes. The purpose of this study was to compare the pertinent provisions of these proposed provisions to each other and to existing building codes (UBC, SEAOC, NEHRP, and ASCE 7). In addition, the American Institute of Steel Construction has adapted seismic provisions in their Load and Resistance Factor Design Specifications. BOCA has proposed a method of adapting these LRFD seismic provisions into its building code. This study also reviewed these proposed revisions with respect to applicability to east coast earthquakes, especially in New York City. The impact of both the NYC and BOCA provisions on design and construction costs is also addressed.

DOI:

10.14359/1508


Document: 

SP160

Date: 

June 1, 1996

Author(s):

Editors: Gajanan M. Sabnis, Avanti C. Shroff, and Lawrence F. Kahn

Publication:

Symposium Papers

Volume:

160

Abstract:

SP160 This publication brings out a wide spectrum of the state research and practice in the rehabilitation of concrete structures for improved earthquake resistance. It also covers seismic rehabilitation with regard to elements of the structures as well as the whole structure.

DOI:

10.14359/14200


Document: 

SP160-04

Date: 

June 1, 1996

Author(s):

Kent A. Harries, William D. Cook, and Denis Mitchell

Publication:

Symposium Papers

Volume:

160

Abstract:

Existing beams coupling reinforced concrete walls are often found to be deficient. Common deficiencies include inadequate overall capacities, particularly shear capacities that are insufficient to develop flexural yielding of the beams. This research examines the use of steel plates to improve the shear resistance of reinforced concrete coupling beams in moderate seismic zones. Full-scale reversed cyclic loading tests of shear-deficient reinforced concrete coupling beams were carried out. The retrofit measures involved attaching thin steel plates on one side of the coupling beams to enhance their shear performance. A number of different ways of attaching the plate were investigated. Tests with the steel plate attached only with epoxy demonstrated a need for further connection to improve the hysteretic response. Additional specimens were constructed to investigate the influence of connecting the plate with both epoxy and bolting. The purpose of testing these retrofitted specimens was to develop a procedure for designing the plate connection details such that significant stresses are developed in the plate. The reversed cyclic loading responses of the retrofitted specimens are compared with a control specimen representing the deficient coupling beam before retrofit.

DOI:

10.14359/1548


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