Rectangular Concrete Tanks
Section 1. lntroduction
While a cylindrical shape may be structurlñly best for tank construction, rectangular tanks frequently are preferred forspecific purposes. Special processes o r operations may make circular tanks inconvenient to use. Wlien several separate cells are required, rectangular tanks can be arranged in less space than circulartanks of the same capacity. Tanks or vats needed inside a building are therefore often made in rectangular or sqiiare shapes. For these and other reasons. breweries. tanneries. and paper millsgenerally use rectangular tanks. Data presented here are for design of rectangular tanks wliere the walls are subject t o hydrostatic pressure of zero at tlie top and maxjmum at the bottom Some of the datarnay be used for design of coiinterforted retaining walls subject to eartli pressure for wliich a hydrostatic t y p e of loading may be substituted in the design calcrrlations. Data also may be appliedt o design of circular reservoirs of large diameter where lateral stability depends on the action of counterforts built integrally with the wall. Another article on tank construction. "CircularConcrete Tanks Without Prestressing," has been published by Portland Cement Association.
Secrion 2. Moment Coefficients
Moinent coefficients wcre calciilated for individual panels considered f i e dalong vertical edpes, and coefficients were subsequently adjristed t o allow for a certain rotation about tlie vertical edges. First. three sets of edge conditions were iiivestigated, in al1 o f whichvertical edges were assumed f i e d wliile the ot tier edges were as follows: 1. T o p hinged- bottoiii liinged 2. T o p free--bottom Iiinged 3. T o p free-bottoni fixed* Moment coefficients for tlieseedge conditions are given in Tables 1, 11, and 111 resptctively. In al1 tahles. a denotes height and b width of the wall. In Taldes 1, 11, and 111. coefficients are given for nine r a ~ i o s b/a,...