الفهرس Only 14 pages are availabe for public view
 |  | from | 195 |  |  |
| | | from | 195 | | |
Abstract
Shear interface transfer between new an old concrete has a several
factors that affect on the value of its ultimate shear resistance. To study the
behavior of shear dowels connected reinforced concrete jacket with
footing, an experimental program consists of two groups of specimens were
casted and tested. Group I consists of 16 push-off specimens representing
14 different cases of placing dowels were tested under static load. Two
control specimens without dowels were tested. Group 11 consists of 4
push-off specimens representing 4 different cases of placing dowels with
smooth interfaces and strain gauges fixed on dowels representing the
position 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 in
surfaces Al (column head surfaces) the ultimate load increased and placing
dowels in surfaces A2 and A3 (horizontal surface of footing and vertical
surfaces of footing) respectively decreased the displacement. When dowels
placed in three surfaces AI, A2, A3 together, the ultimate load was
increased and displacement was decreased. The actual effect of placing
dowels in surfaces A2 and A3 did not appeared bacause of high steel
reinforcement ratio of jacket which resist the increament of loading that
was noticed from test results of group Il.
A new proposed modification of the Japanese code (JCI) formula was
presented and compared with the experimental test results and other
formulae.