PRESTRESSED HOMOGENIOUS STEEL BEAMS STRENGTHENED IN COMPRESSION AND TENSION – A HYPOTHETICAL CASE STUDY

Ravindra Vipparthy, Markandeya Raju Ponnada

Abstract: The technology of prestressing steel structures is relatively an old frontier in the field of structural engineering. In spite of having many advantages over prestressed concrete, prestressed steel has not been popular in academics as well as in industry. This paper is an attempt to study the variation of Load carrying capacity for same Force Factor (FF), same Eccentricity Ratio (ER), same span and same cross-section strengthened in compression and tension.ISWB600@145 was considered for study for a span of 8m to 16m. Four types of cross-sections are considered for comparison, namely 1) I-section, 2) I-section laterally strengthened in compression and tension by welding four angle sections, 3) I-section laterally strengthened in compression alone by welding two angle sections, 4) compound girder formed by welding a plate to the top flange of an I-section. A straight tendon configuration over the whole span is considered for study. The non-dimensional design parameters like FF and ER were considered as 0.4 and 0.5 respectively.The % increase in the load carrying capacity for each case was calculated with respect to the beam without prestressing. It has been observed that welding a plate to the top flange of an I-section can increase the load carrying capacity of the I-section up to 80% when prestressed. In other words, the material of the cross-section is effectively utilized when an unsymmetrical I-section is prestressed.

Keywords: External prestressing, lateral strengthening, tendon configurations, metallic carpentry, optimum parameters, stress distribution, net area, allowable span, permissible eccentricity

DOI: https://doi.org/10.15623/ijret.2015.0425037