Behavior and analysis of shear resistance capacity for shear resistance capacity for shear dowels connected r.c. jacket with R.c. foundation

Shear interface transfer between new an old concrete has a severalfactors that affect on the value of its ultimate shear resistance. To study thebehavior of shear dowels connected reinforced concrete jacket withfooting, an experimental program consists of two groups of specimens werecasted and tested. Group I consists of 16 push-off specimens representing14 different cases of placing dowels were tested under static load. Twocontrol specimens without dowels were tested. Group 11 consists of 4push-off specimens representing 4 different cases of placing dowels withsmooth interfaces and strain gauges fixed on dowels representing theposition of all dowels were tested under static load., concrete of 250 kg/ern”,350 kg/cm were casted for footings and jacket.Different percentages of shear dowels in different surfaces of R.e.footing were studied and test results showed that in placing dowels insurfaces Al (column head surfaces) the ultimate load increased and placingdowels in surfaces A2 and A3 (horizontal surface of footing and verticalsurfaces of footing) respectively decreased the displacement. When dowelsplaced in three surfaces AI, A2, A3 together, the ultimate load wasincreased and displacement was decreased. The actual effect of placingdowels in surfaces A2 and A3 did not appeared bacause of high steelreinforcement ratio of jacket which resist the increament of loading thatwas noticed from test results of group Il.A new proposed modification of the Japanese code (JCI) formula waspresented and compared with the experimental test results and otherformulae.