Title: Ferrocement Cylindrical Tanks: Cracking and Leakage Behavior

Author(s): Antonio J. Guerra, Antoine E. Naaman, and Surendra P. Shah

Publication: Journal Proceedings

Volume: 75

Issue: 1

Appears on pages(s): 22-30

Keywords: costs; cracking (fracturing) ; crack width spacing; cylindrical shells; ferrocement; loads (forces);permeability; pressure; reinforced concrete; tensile stress; water tanks.

DOI: 10.14359/10472

Date: 1/1/1978

Abstract:
Cylindrical ferrocemnt tanks were subjected to the increasing internal water pressures to study the influence of reinforcing parameters on their cracking and leakage behavior. It is found that cracking in the ferrocement shell occurs at an average tensile stress of about 500 psi and that the average crack width within a given tensile stress in the composite decreases with an increase in volume fraction and/ or the specific surface of reinforcement. It is also found that the comosite stress at the onset of leakage increases with an increase in specific surface and, everthing else being equal, that the leakage or loss of water increases with the stress in the steel mesh and decreases with wall thickness. Based on the information generated in this study, allowable tensile stresses of about 30,000 psi in the steel are recommended for the design of virtually watertight ferrocement tanks. This allowable stress - which is almost twice higher than that recommended by the ACI committee on reinforced concrete sanitary engineering structures - is used in a cost comparision study of water tanks made with ferrocement, reinforced concrete, and steel. It is estimated that for current United States prices, properly dimensioned and designed ferrocement water tanks of up to 300,000 gal. Capacity would be cost competitive with reinforced concrete and steel tanks and would have at least equal performance.