Monolithic Coefficient Values for Design when Seismically Strengthening RC Columns with Jackets

Restrained Concrete Shrinkage in Case of Strengthened Bridge Piers by Concrete Jacketing

“…These values were used to model a well roughened interface as it has been demonstrated [9] that using low and constant values, strength degradation at the interface due to earthquake cyclic loading can be effectively simulated [9,13].…”

“…The concrete strengths of the initial columns and jackets were 27.0 MPa and 55.8 MPa, respectively. An axial load was applied to the top of the specimens and a horizontal displacement was applied to the columns at a height of 1600 mm above the footing [13]. The cross section of the examined model and the finite element model are presented in cross section of the examined columns are presented in figure 4.…”

“…In the present study, an ultimate free concrete shrinkage value of 800 microstrains was used. This value was considered to be reduced to half (400 microstrains) in order to include the stress relaxation due to creep [13,14]. The stress distribution in the column and the jacket is presented in the following figure (figure 5).…”

“…Using this procedure, the load versus deflection curve was converted to an equivalent tri-linear distribution based on the characteristic points of yield, maximum load and failure of the specimen. These equivalent points were then used to calculate monolithic coefficient values (equation 4) [13].…”

Investigation of Force Transfer Mechanisms in Retrofitted Rc Columns With Rc Jackets Containing Welds Subjected to Axial Compression.

“…All these methods have been proven efficient in enhancing the load capacity and the ductility of elements [5], [6], [7]. The key to the strengthening design is proven to be the interface capacity in transferring loads and in terms of deformation [8], [9], [10]. More specifically, in cases of strengthening with RC jacketing the main mechanisms that act in shear transfer are concrete-to-concrete cohesion and friction (aggregate interlock) and dowel action of the reinforcement the interface between old and new concrete (dowels, tack-welds, butt-welds, bend down bars etc.…”