As building codes are updated, some of the existing important structures may fall short of complying with current standards even though they may have been properly designed and constructed according to earlier codes. Many existing structures may be inadequate and may pose severe risk during seismic events. Rehabilitation measures to upgrade the capacity of these structures can be performed at some point in their useful lives especially when located in seismically active zones. A new method for improving the seismic performance of existing reinforced concrete structures is by jacketing the deficient connections using corrugated steel jackets. An experimental program was conducted to evaluate this method of rehabilitation. Corrugated steel jacketing addresses the particular weakness that is often found in existing reinforced concrete structures, namely the lack of sufficient shear reinforcement and the required confining reinforcement within the joints and in adjoining beams and columns. The performance of four reinforced concrete connections was determined experimentally. The test specimens include one connection representing existing structures, one designed according to current seismic codes and two rehabilitated connections. The test results showed satisfactory performance at high cyclic load levels and significant increase in the shear capacity and ductility of connections rehabilitated with corrugated steel jackets.
A manual method for calculating the design live load longitudinal moments in superstructures of most right bridges is presented. The bridge types that can be analysed by this method are: slab bridges. beam and slab bridges incorporating both steel and concrete beams, bridges incorpor-ating wooden beams, and slabs on hollow trapezoidal o r other such torsionally stiffbeams.The proposed method was developed by orthotropic plate theory, and was checked by the grillage analogy method. The basis of the method and details of development methodology are presented. The effect of the various parameters on the transverse distribution of longitudinal moments is discussed.The method is useful not only for the ease with which design longitudinal moments can be obtained, but also because it enables the designer to investigate the effects of making changes in the design on distribution characteristics.To demonstrate the simplicity of the solution a worked example is included. On u mis au point une methode d e calcul manuel des moments longitudinaux dus I la surcharge dans les superstructures de la plupart des ponts droits. Cette nlethode s'applique aux types d e ponts suivants: ponts-dalles, pont i poutres et dalle (poutres d'acier ou d e beton), pontscomportant des poutres de bois, et ponts 5 dalle sur caisson trapezo'idal ou d e rigidit6 torsionnelle analogue. La methode decoule de la theorie des dalles orthotropes et a ete ve~ifike au moyen d e I'analogie du grillage. Dans I'article, on retrouve le principe de la methode, les details d e son elabo~.ation et une discussion portant sur I'influence des divers parametres sur la repartition t~.ansversale des moments longitudinaux. La methode se revtle utile non seulenlent r' l cause d e la facilite qu'elle apporte au calcul des moments longitudinaux, mais aussi parce qu'elle permet i I'ingenieur d'etudier I'effet, s u r la repartition des efforts, d e changements apportes i certains parametres.Un exemple expose en detail illustre la simplicit6 d e la solution.Can. J. Civ. Eng.. 6 , 3 6 5 0 (1979) [Traduit par la revue]
Substantial damage sustained during several recent earthquakes was non structural in nature. The economic consequence in terms of non structural component damage far exceeded the structural damage. Currently, there are several analytical studies that address the interaction between non structural components or Secondary systems (S-systems) and the main supporting structure or Primary system (P-system). Only a few of these analytical approaches have been proposed to evaluate and characterize the response of the S-systems attached to torsionally coupled P-systems. In addition, the experimental verification for the analytical approaches is scarce.In the current study, the results and observations of an experimental research program conducted to characterize the behavior of both stiffness eccentric and mass eccentric torsionally coupled Primary-Secondary systems (PS-systems) are presented. From this experimental investigation it was found that the torsional yielding of the primary system has significant implications on the deamplification of near tuned secondary system response. The location of the S-system mounted on the P-system affects the peak response amplification, and interaction with the coupled P-system.
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