Abstract:Long span halfthrough arch bridges have the flexible space structure. Wind loads on the arches are usually the key factor to the whole bridge. Taking an example of the Chongqing Caiyuanba Yangzi River Bridge in P. R. China, wind tunnel tests of single arch and double arches section models were conducted. The results of a single arch in the smooth flow show that arch drag variability is small, and the lift and moment variability are significantly large. The results of double arches testing show that the static forces of the windward arch are similar to the single arch. The three force coefficients of leeward arches vary with the space width ratio and the angle between the two arches. Static forces testing was simulated by the CFD software FLUENT. The static forces from the testing and the simulation were compared. The results show that the values match quite well with testing, and the drag forces mainly varied with the space width ratio.