and grouting tubes 154 are provided for each bar so that the annular space in each sheath may be grouted upon completion of the wall to complete the construction and prestressing of the semicircular walls angles such as the angle 182 are attached to the wall 28 at a point which is sufficiently beyond the connection point to insure appropriate transfer of forces between the semicircular end wall and the straight wall to which it is attached in the case of a 205 foot long straight wall section it has been found to be appropriate for the angle to be placed a distance about 30 feet from the connection point after the prestressing wires are anchored and tensioned the same are coated with an outer coating of shotcrete the construction at point of connection 56 is essentially the same as the construction at point of connection 62 except that in this case the wall 40 need not be preshrunk since it is not a wall which must resist hydraulic pressure rather wall 40 is simply a baffle wall utilized for the purpose of directing the flow of fluid in the tank during operation thus the bars 156 through 170 do not need to run the full length of the wall and instead are used simply to secure the keystone 204 at connection point 56 and facilitate appropriate transfer of forces between wall 40 and end walls 50 and 52 the constructional details of the tank at connection point 56 are shown in fig9 during the construction of the tank the diaphragm 41 is erected and the threaded bars 156 through 170 are positioned along with their respective sheaths and corresponding grout tubes as set forth above the bars 156 through 170 do not extend the.