The Technical Committee of the ACI - Kuwait Chapter, in association with Kuwait Institute for Scientific Research, organized a technical symposium entitled: Testing of RC beams and ribbed slabs with embedded pipes.
The symposium was held under the patronage of the Kuwait Institute for Scientific Research Director General Dr. Naji Al-Mutairi who is also a past president of ACI - Kuwait. The symposium was held on Tuesday, 9th June 2009 at Manhal Hall, Kuwait Institute for Scientific Research.
Participated in this symposium were Dr. Amr Sadek (Research scientist at Kuwait Institute for scientific research), Dr. Moetaz El-Hawary (Research scientist at Kuwait Institute for scientific research, Director and past president of ACI-Kuwait), Dr. Hasan Kamal (Research Associate at Kuwait Institute for scientific research and President of ACI-Kuwait) and Eng. Tarek Abu Laban ( Initiator of the presented technique).
In this symposium the results of two research activities conducted at the Kuwait Institute for Scientific Research to investigate the validity and adequacy of utilizing reinforced concrete beams and ribbed slabs with embedded pipes as a new improved and more economical construction system, were presented. The studies were conducted as per the request of Eng, Tarek Abu-Laban to examine a new system for design and construction of flexural reinforced concrete members consisting of embedding PVC or steel tubes in the concrete members with the objectives of reducing the own weight and quantities of concrete as well as enhancing strength and serviceability characteristics of concrete members.
For this purpose extensive experimental program was conducted using full scale specimens to assess the strength, serviceability and durability characteristics of the new system as compared to the conventional system. Seven beam specimens of 6000 mm span were tested up to failure using four point test setup. A standard loading test as per ACI-318 was conducted on two ribbed slabs of 10000 mm span with and without embedded steel tubes. For durability analysis, seven short specimens of 900 mm span were subjected to accelerated wetting and drying cycles and their properties were examined.
It was concluded that beams with embedded steel tubes showed very favorable behavior when tested up to failure as compared to conventional control beam. Ultimate moment capacity was considerably increased by as much as 113% of the control case. Substantial increase of the stiffness in the elastic range was observed as compared to the control case. This feature was clearly manifested in the reduced deflection values for specimens with steel tubes.
Beams with embedded PVC pipes, while having the advantage of reduced own weight due to the embedded pipes, maintained essentially same response as compare to the control case in terms of carrying capacity as well as elastic stiffness. Standard loading test was conducted as per ACI-318 requirements on two ribbed slabs of 10000 mm span with and without steel tube. The performance of the alternative system with steel tubes was found to be far superior to the conventional system on the two accounts of the standard loading test. Durability investigation showed that no significant difference in durability characteristics was observed between conventional reinforced concrete members and those with steel tubes or PVC pipes.
The event attracted wide newspaper coverage and was attended by a large number of ACI members and interested engineers that exceeded one hundred, many of them participated in the discussion session that followed the presentations.