LAUSR

The aim of research is to study the influnce of concrete strength , case of loading, percentage and distribution of shear connectors on shear transfer of one way composite preslabs composed of two concrete layers with different compressive strength the first layer (normal strength concrete and the second layer high strength concrete). An expermental program has been performed to investigate the research point,where fourteen specimens were supported on two edge supports to represent the case of one way simply supported slab and tested under the case of uniformly distributed loads, one concentrated line load and two concentrated line loads . Specimens were grouped into four groups to study the influence of dowel distribution, percentage and surface condition between two slab layers. It was concluded that Increasing of shear connectors ratio with uniform distribution leds to increasing in ultimate load and shear strength, decrease in dowels’ strain, decrease in horizontal slippage in case of roughening the interface surface and Increasing in ductility for pre-slabs. Key wordsShear transferHigh strength concreteInterface roughnessDowels