Hamedy Shehab El-Den- Mohamed Husain
Faculty of Engineering, Zagazig University
This paper introduces the construction, instrumentation and the experimental work of prestressed voided slab
models pretensioned with deformed reinforcing bars of grade 360/520. The objective is to examine their flexural
behavior at service and at collapse, as well as the potential of using reinforcing steel instead of prestressing steel
in the pretensioning of such systems. Three pretensioned voided slabs of 1500 mm length, 650 mm width, and
70 mm thickness were built and tested under monotonically increasing uniformly distributed load. The process
of pre-tensioning and anchoring is presented including the design and building of a prestressing steel frame. The
specimens were constructed with low-shrinkage concrete in order to reduce the prestress losses due to shrinkage.
A reinforced concrete reference specimen with the same dimensions was built and tested for comparison
purposes. Experimental work was conducted on the specimens to evaluate their flexure behavior (load-deflection
relation) and their ultimate capacity. Their structural adequacy was evaluated and the gain of prestressing found
to reduce cracking and significantly increases their flexural resistance (about 38 %). However, this occurs in
exchange with little reduction in their flexural ductility, about 25 %.