NEW TUAKAU BRIDGE

Sun (Auckland), Volume IV, Issue 993, 9 June 1930, Page 10

NEW TUAKAU BRIDGE

EXPLANATION FROM DESIGNERS Contending that Mr. D. Gordon Jack was under a misapprehension concerning the nature and function of a “bowstring” bridge, according to his statement in Saturday’s Sun, on the new JTiakau structure, the designers, Messrs. Jones and Adams, have furnished a statement on the subject. Mr. Jack’s statement was to the effect that the Tuakau bridge would not be the first reinforced concrete “bowstring” bridge in the Dominion. “Dealing categorically with Mr. Jack’s contenions, the designers state that the true bowstring is not a truss bridge, and, in fact, does not contain a single truss member. , “Secondly, the entire design of the Tuakau bridge is different from that of the Westshore and Opawa bridges, and not only in a few minor details, as stated by Mr. Jack. As an instance the designers call attention to the fact that the bows in the Tuakau bridge are designed as two pinned arches, whereas in the case of the Westshore 'and Opawa bridges the upper curved member is merely the upper chord of a truss. “Thirdly, the design of the Opawa and Westshore bridges was discussed some years ago after they were built (in 1925) with Mr. J. D. Holmes, M. Inst., C.E., their designer, who stated that the type was not a good one, and that if he had a similar bridge to design he would use the bowstring. There was no confusion in Mr. Holmes’s mind between a bowstring and a hogbacked truss. “Finally, Mr. Jack may perhaps be excused for confusing the two types as there is a slight similarity in appearance, and such terms are often used very loosely even by professional men,” the statement concludes.