Strengthening under Load: Experimental and Numerical Research

Strengthening of Steel Columns under Load: Torsional-Flexural Buckling

“…Using a combination of numerical (only to determine residual stress) and experimental results, it seems that the shorter flange of specimens from set (F) started to yield in average at 21 kN higher load than in the case of specimens from set (E). This behaviour and a slight increase in load resistance were also observed in previous experimental research by the authors [22] and in the literature, for example, by Nagaraja Rao and Tall [6]. However, it seems that specimen E1 had higher initial nonintended eccentricity in supports which resulted in the lower load resistance.…”

“…The temperature load from thermal analyses was used to model the effects of the continuous weld with a throat thickness of 4 mm. The temperature load corresponded with the deformations measured in these experiments and similar experiment performed by authors [22] and the longitudinal stresses available in the literature (e.g., [23][24][25]). The residual stress of bare plates was neglected.…”

Stability of steel columns with bolted strengthening under preload: Experimental study

“…Vild and Bajer [36][37][38][39] conducted several experimental and numerical studies on the strengthening of steel columns using welded plates. The tests that focused on the local buckling and torsional-flexural buckling of columns [36,37] indicated that the average ultimate load capacity of the columns strengthened under load was similar to and even slightly higher than that of columns strengthened without preloads. The investigations of columns failing through flexural buckling [38,39] indicated that the ultimate load capacity of steel columns strengthened under load was decreased by the preload but only slightly.…”

“…Considering only the experimental tests in the literature, five types of sections were investigated: H-shaped sections (comprised of two steel channels and a plate) strengthened by bolting four plates to the inside of the flanges [26], welded H-shaped sections strengthened by welding cover plates onto the flanges [27,32,34,35,38,39], H-shaped sections transformed into box sections by welding steel plates [39], T-shaped sections transformed into uniaxial symmetric H-shaped sections by welding a new flange [36,37], and steel angles strengthened by welding additional angles [41]. Some tests indicated that the preload was unfavorable [35,38,39], some indicated that the effect of the preload was negligible [26,27,32,34,41], while others indicated that the preload slightly increased the ultimate load capacity [36,37]. Furthermore, among the aforementioned papers, only O'Sullivan [26] investigated columns strengthened using bolting, and all the other researches focused on strengthening by welding.…”