• Structural Engineering and Mechanics
• /
• 제60권6호
• /
• pp.979-999
• /
• 2016

Stainless steel wire mesh (SSWM) is an alternative material for strengthening of structural elements similar to fiber reinforced polymer (FRP). Finite element (FE) method based Numerical investigation for evaluation of axial strength of SSWM strengthened plain cement concrete (PCC) and reinforced cement concrete (RCC) columns is presented in this paper. PCC columns of 200 mm diameter with height 400 mm, 800 mm and 1200 mm and RCC columns of diameter 200 mm with height of 1200 mm with different number of SSWM wraps are considered for study. The effect of concrete grade, height of column and number of wraps on axial strength is studied using finite element based software ABAQUS. The results of numerical simulation are compared with experimental study and design guidelines specified by ACI 440.2R-08 and CNR-DT 200/2004. As per numerical analysis, an increase in axial capacity of 15.69% to 153.95% and 52.39% to 109.06% is observed for PCC and RCC columns respectively with different number of SSWM wraps.

• Steel and Composite Structures
• /
• 제30권5호
• /
• pp.417-432
• /
• 2019

This paper presents the results of axial compression testing and numerical modeling on reinforced concrete columns (RCC) with normal concrete (NC) and high-strength concrete (HSC), RCC confined by glass-fiber reinforced plastic pipes (GRP) casing as well as carbon fiber reinforced polymer (CFRP), The major parameters evaluated in the experiments were the effects of concrete type, GRP casing and CFRP wrapping, as well as the number of CFRP layers. 12 cylindrical RCC ($150{\times}600mm$) were prepared and divided into two groups, NC and HSC. Each group was divided into two parts; with and without GRP casing. In each part, one column was without CFRP strengthening layer, a column was wrapped with one CFRP layer and another column with two CFRP layers. All columns were tested under concentrated compression load. Numerical modeling was performed using ABAQUS software and the results of which were compared with experimental findings. A good agreement was found between the results. Results indicated that the utilization of CFRP wrapping and GRP casing improved compression capacity and ductility of RCC. The addition of one and two layer-FRP wrapping increased capacity in the NC group to an average of 18.5% and 26.5% and in the HSC group to an average of 10.2% and 24.8%. Meanwhile, the utilization of GRP casing increased the capacity of the columns by 3 times in the NC group and 2.38 times in the HSC group. The results indicated that although both CFRP wrapping and GRP casing increased confinement, the GRP casing gave more increase capacity and ductility of the RCC due to higher confinement. Furthermore, the confinement effect was higher on NC group.

• Computers and Concrete
• /
• 제27권5호
• /
• pp.437-445
• /
• 2021

Retrofitting of structures has gained importance over the recent years. Particularly, Reinforced Cement Concrete (RCC) column strengthening has become a challenge to the structural engineers, owing to the risks and complexities involved in it. There are several methods of RCC column strengthening viz. RCC jacketing, steel jacketing and Fiber Reinforced Polymer (FRP) wrapping etc., FRP wrapping is the most promising alternative when compared to the others. The large research database shows FRP wrapping, through lateral confinement, improves the axial load carrying capacity of the columns under concentric loading. However, its confining efficiency reduces under eccentric loading. Hence a relative newer technique called Near Surface Mounting (NSM), in which Carbon FRP (CFRP) strips are epoxy grouted to the precut grooves in the cover concrete of the columns, has been thrust domain of research. NSM technique strengthens the column nominally under concentric load case while significantly under eccentric case. A novel configuration of NSM in which the vertical NSM (VNSM) strips are being connected by horizontal NSM (HNSM) strips was numerically investigated under both concentric and eccentric loading. It was found that the configuration with 6 HNSM strips performed better under eccentric loading than under concentric loading, while the configuration with 3 HNSM strips performed better under concentric loading than under eccentric loading. Hence an optimum of 4 HNSM strips is recommended as strengthening measure for the given column specifications. It was also found that Aluminum alloy cannot be used instead of CFRP in NSM applications owing to its lower mechanical properties.