Abstract
The typical types of the Riyadh's houses are limited in villas, duplexes and low-rise apartment buildings. Most of these dwelling houses are constructed using reinforced concrete framed structures with reinforced concrete flat roof deck slabs, ribbed slabs, joist floor slab (Hordy). Unfortunately, there are some construction problems that occurred due to wrong practice by the contractors. One of these problems is what we can call "phenomenon of penetration of vertical pipes into the horizontal members such as beams and slabs of concrete structure". This phenomenon practiced in some dwelling houses deserves consideration regarding its possible serious impact on the structure. The seriousness of this phenomenon lies in its hidden influence, which might happen suddenly or gradually, partially or totally in the form of cracking or collapsing. If this practice continues without evaluation, it may cause damage and severe failure in the structure. This paper emphasizes the serious effect of this practice by using a computer simulation program, which indicate that the severe cracking in the beams would make the structure and walls to fail in the course of time. Almost all the research conducted in this field is on web openings in the beams. However, a practice has been seen in Riyadh that the contractors are opening a hole vertically across the depth the beams and other structural members for easy placement of building services conduits purposes. An attempt has been made in this paper to conduct a research to evaluate the effect of opening a hole across the depth of the beam as seen in the local practice in the local construction. This incorrect construction has been discussed in this research by introducing vertical holes with different sizes and locations into the horizontal members of Concrete Structure. Comparison has been made with correct analysis and design for different cases of holes with beams without openings using a computer program. Spacing of bars, cracking of concrete due to a vertical hole and the difficulty in the bars arrangements has been discussed.