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Showing 1-5 of 13 Abstracts search results

Document: 

SP88

Date: 

November 1, 1985

Author(s):

Editor: Tony C. Liu

Publication:

Symposium Papers

Volume:

88

Abstract:

SP-88 This volume covers a wide range of subjects of strength evaluation of existing concrete bridge structures: including condition survey, analytical investigation methods such as finite element analysis and modified compression field theory, in situ load testing, laboratory modeling and testing, deflection measurement methods, remote sensing techniques, and strategy for rating older concrete bridges. Case histories are also included.

DOI:

10.14359/14045


Document: 

SP88-04

Date: 

November 1, 1985

Author(s):

M. Ladner

Publication:

Symposium Papers

Volume:

88

Abstract:

After a short survey on the development of static load tests on structures, the standard test procedure used by the Swiss Federal Laboratories for Materials Testing and Research (EMPA) is presented . From the static load tests basically the following results can be gained: the elastic behavior of a structure under the applied loads as asign for the good quality of the execution the accordance of the measured deformations withthose obtained independently on a theoretic always a sign for the good quality of the design the measured spring constant of a bridge offers the possibility to qualify the bending stiffness. This qualification is based on the results of some 330 static load testing facilities.To illustrate this, three different case histories are descreibed and discussed in this paper.

DOI:

10.14359/6260


Document: 

SP88-03

Date: 

November 1, 1985

Author(s):

Takeshi Oshiro and Sumio Hamada

Publication:

Symposium Papers

Volume:

88

Abstract:

Recently, significant deterioration of concrete surface and corrosion of reinforcing bars have been observed, and the necessity for the structural evaluation of such bridges becomes urgent for safety considerations. The primary objective of this study is to investigate the structural performance of two deteriorated reinforced concrete bridges and isolated test beams cut out of the same bridges at the time of replacement. Field and bending tests were conducted from which the strength of existing bridges and isolated beams was observed. Correlations of the values of strength obtained from these two tests give important data to be used for evaluation of existing deteriorated bridges. From the results of general investigations, field tests and bending tests, the following conclusions are drawn; (1) From the results of field tests of Nakama Bridge, strains of reinforcing bars and deflections are rather close to Theory II uncracked gross section), whereas those of Yaka Bridge are located between Theories I (cracked section) and II. This indicates the varying effects of deterioration on main beams. (2) Beams in bending tests yield larger strains and deflections compared with those from tests; this shows that the rigidity of a beam that is part of an existing bridge is much higher than that expected from an isolated beam. (3) According to general investigations, these two bridges were highly deteriorated in appearance. However, ultimate strength of test beams is higher than that computed by ACI Code, indicating no significant losses of strength.

DOI:

10.14359/6259


Document: 

SP88-02

Date: 

November 1, 1985

Author(s):

J. Kirkpatrick, A. E. Long, W. M. C. Stevenson, and A. Thompson

Publication:

Symposium Papers

Volume:

88

Abstract:

`The results of load tests on four prestressed concrete multi-girder bridge decks are presented. The girders have been used to form both tee and pseudo box decks each of which has its own distribution characteristics. The measured distribution of beam soffit stresses are compared with predictions using a grillage analysis. For the beam construction good correlation was obtained but for the pseudo box deck measured stresses were less than those predicted. In the latter case good correlation was obtained by substantially increasing the torsional stiffness of the transverse grillage members.

DOI:

10.14359/6258


Document: 

SP88-01

Date: 

November 1, 1985

Author(s):

Gilbert A. Hartley, Gerhard T. Suter, Heinz Keller, and David C . Marett

Publication:

Symposium Papers

Volume:

88

Abstract:

A structural investigation of a bridge pier using the finite element method is presented. For the pier, supported on three caissons with loads applied at the top, the structural action is similar to that of a deep beam. The purpose of this investiga-tion is to examine possible causes of existing cracks in the pier. The simplicity of the application and the accessibility of the computer program are emphasized. Once the finite element model is prepared, experimentation is possible with the effects of various loading conditions, all feasible support conditions and the appli-cation of external posttensioning to prevent further cracking and to relieve internal tension stresses during remedial work.

DOI:

10.14359/6257


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