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Showing 1-5 of 65 Abstracts search results

Document: 

SP164-28

Date: 

November 1, 1996

Author(s):

Renzo Medeot

Publication:

Symposium Papers

Volume:

164

Abstract:

The seismic retrofit project of the Marquam Bridge in Portland, Oregon is the first example, in the United States, of the application of high dissipative capacity isolators in conjunction with shock transmitters. This technique was developed and has been vastly applied to the seismic engineering of bridges in Italy during the last twenty years. After a brief description of the structure, the paper lists the seismic requirements of the structure and illustrates the design approach adopted. It then describes the model used for the time history, step-by-step non-linear analysis and comments on the results obtained. The latter demonstrate that the utilization of the above mentioned devices has permitted ensuring complete anti-seismic protection for bridges without the need to strengthen existing structural elements, particularly piers and foundations. In other words, the seismic demand has been reduced below the actual capacity of the structure. In conclusion, the paper describes in detail the testing procedures, the acceptance criteria and the results of the five different severe tests: two for the shock-transmitters and three for each type of isolator. The tests were conceived so as to simulate both, long term service actions and seismic attack conditions and necessitated the use of specialized equipment.

DOI:

10.14359/14314


Document: 

SP164-06

Date: 

November 1, 1996

Author(s):

P. Giannattasio, L. Alifano, M. Crispino, B. Festa, and V. Nicolosi

Publication:

Symposium Papers

Volume:

164

Abstract:

Buried joints are frequently used in small and medium span bridges because they are serviceable and comfortable. This paper illustrates a theoretical method and an experimental equipment setup for the study of buried joint systems, in particular to evaluate the influence of some parameters that affect their fatigue life, with the aim of supplying references for the design of new optimal buried joint systems. The theoretical analysis is developed by applying a calculation method set up at the Department of Transportation Engineering of the University of Naples "Federico II" (D. I. T.). The results of this analysis are discussed; some interesting indications for the design of buried joints based on these results are given. As for the experimental study, this paper also describes a prototype equipment for testing the buried joint systems, evaluating their capability to reduce the deformations and to increase, therefore, the fatigue life. The equipment had been purposely designed and set up at D. I. T. Some experimental tests have been conducted using this equipment. The results of the tests have confirmed the validity of the design method developed.

DOI:

10.14359/1438


Document: 

SP164-54

Date: 

November 1, 1996

Author(s):

G. Szefer and M. Wazowski

Publication:

Symposium Papers

Volume:

164

Abstract:

Since the assumed model of constraint is decisive for predicting longitudinal structural movements, for better predicting movements, some new models of constraints were introduced. The proposed models take into account the dynamic character of frictional forces in sliding bearing with PTFE elements. The applied models analysed by simulation program show notable consequences for both the designing and control of bearings. The presented problem of Structural Movement may concern the installation projects of joints and bearings for new bridges as well as routine control of existing bridges.

DOI:

10.14359/14340


Document: 

SP164-22

Date: 

November 1, 1996

Author(s):

David C. Monroe and Gary A. Busch

Publication:

Symposium Papers

Volume:

164

Abstract:

Effective sealing of expansion joints in parking structures requires a thorough understanding of structural behavior and the service condition, as well as the properties and limitations of available expansion joint systems. Factors contributing to volume change, traffic conditions, detailing, and installation will all play a role in the ultimate success of the joint system selected. Commercial types of expansion joint seals commonly available include the urethane "T" joint, compression seals, steel and aluminum strip seals, winged seals with headers, and inflated structural seals. Each have certain advantages and limitations which must be considered relative to the usage condition in order to make a proper selection. Detailing considerations, such as joint opening size, movement considerations, traffic volume and loading, directional change, and termination requirements and drainage patterns all have an impact on performance. Periodic maintenance should be expected and planned for through an established program. Today, a wide variety of effective expansion joint sealing systems are available to help avoid the many problems previously associated with parking structure applications. Success depends on understanding the requirements of the service condition and the limitations of the various systems considered for use. Only with care in the specification and detailing of expansion joint requirements at the design stage will the installing contractor be positioned to most effectively install any expansion joint system.

DOI:

10.14359/1553


Document: 

SP164-08

Date: 

November 1, 1996

Author(s):

Joseph V. Muscarella and Joseph A. Yura

Publication:

Symposium Papers

Volume:

164

Abstract:

In this study, sponsored by the Texas Department of Transportation, bearing performance was analyzed on the basis of elastomer hardness, shape factor, reinforcing shim orientation, degree of taper, and compressive stress level. Emphasis was placed on comparing the behavior of flat versus tapered pads. Experimentation included shear, compressive, and rotational stiffness tests; shear and compression fatigue loading; long term compressive loading; and tests to determine compressive stress limits. Bearings were intentionally loaded nonuniformly to define safe limits for bearing/girder slope mismatches. Research showed that tapered bearings performed as well as flat bearings and that manufacturing tapered bearings with steel shims oriented parallel to one another, rather than radially, is advantageous. Bearings made from lower hardness elastomers displayed several advantages over those made from harder material, particularly, a greater ability to accommodate girder end rotations. More highly reinforced bearings performed better in compression fatigue tests and easily accommodated compressive stresses well over 7.0 MPa (1000 psi).

DOI:

10.14359/1518


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