New Composite Construction Material for Low Cost Underground Water Tanks

There is a great need for developing designs and construction technologies for low cost water tanks, specially for rain water harvesting. This research was carried out to introduce such tanks with the use of low cost materials like brickwork and ferro-cement. A computer program was developed to analyze cylindrical tanks with spherical shell bottom and roof under various boundary conditions based on membrane and bending theory of shells. The computer program is capable of analyzing tanks with flat bottom as well as inverted spherical dome. Both fully underground and partially underground tanks can be analyzed using this program. A parametric study was carried out by using the computer program. The results revealed that the maximum capacity that can be achieved by using brickwork for the spherical roof and the cylindrical wall of the tanks is only about 10 m 3 . The governing factor in deciding the capacity is the flexural strength of brickwork. Hence, brickwork reinforced with wire mesh was considered for the cylindrical wall. Extensive experimental investigations were carried out to obtain material properties of brick work, ferro-cement and the reinforced brickwork with wire mesh. The experimental investigations revealed that the flexural strength could be increased considerably with this new composite construction material named "Brickwork Reinforced with Wire Mesh (BRWM) ". According to the results of the parametric study, maximum tank diameter that can be achieved for a partially underground tank having a ferro-cement spherical roof, BRWM cylindrical wall and a Ferro cement inverted spherical bottom is about 6 m which resulted in an approximate capacity of 100 m 3 .