الفهرس 
Evaluation of punching shear in flat slabsOnly 14 pages are availabe for public view
 |  | from | 130 |  |  |
| | | from | 130 | | |
Abstract
Punching shear is one of the main design criteria in flat slabs construction due to its brittle nature. In addition to the vertical load, unbalanced moment is generated and resulted in considerable increase in the punching shear stress in the slab. The presence of such moments results in unsymmetrical punching shear stresses around the column. Flat slabs of the existing structures may require strengthening due to a variety of reasons: to accommodate the increase in acting loads as a result of changing building usage; improve the performance of already existing concrete that did not satisfy the required design value; and/or to fortify void-cut areas within the column vicinity.
This thesis aims to investigate the Punching behavior of RC slabs retrofitted with different strengthening schemes using carbon fiber reinforced polymers (CFRP) under eccentric loading. The experimental program consists of six RC two-way specimens with overall dimensions equal to 1800 x 1800 x 150-mm with clear spans equal to 1500 x 1500-mm. Different fiber amount, spacing and distribution were used in the specimens to evaluate the best strengthening scheme. The fibers were stitched in the specimens to form the punching shear reinforcement. The obtained results show that CFRP were able to enhance the ultimate load capacity of specimens by values up to 59% and increase the ductility by values up to 113% compared to the unstrengthened control specimen. On the other hand, the experimental results show decrease in the ultimate load carrying capacity for the eccentrically loaded specimens than the concentrically loaded ones which were tested by others by ratios varied from 10 to 20%. Experimental results were also compared to the predicted values using ACI 318, BS 8110 and Euro code 2 provisions. On average, all codes/provisions underestimated the punching shear capacity by values varied from 14 to 20%.