**1.1. Past research about the wind tunnel on the horn-shaped membrane structures**

Wind pressure coefficients of typical building type such as box-type are defined in guidelines and standards in each country, but wind pressure coefficients of complicated shapes such as the horn-shaped membrane roof have not been sufficiently reported yet.

The basic studies, which were about the theory and the analysis method, on the horn-shaped membrane roof were reported by F. Otto, M. Saitoh et al and also were shown the windpressure coefficients of the horn-shaped membrane roof under regulated conditions in several

Rest Dome (1989)

Tsukuba Expo., Japan (1985) Hyper Dome E (1990)

Kashiwa no Mori (2008)

**Figure 1.** Horn-shaped membrane roof

reports and books (Otto, 1969; Saitoh & Kuroki, 1989; Nerdinger, 2005). In the recent years, studies on the numerical simulation against the horn-shaped membrane roof were reported by J. Ma, C. Wang et al (Ma et al., 2007; Wang et al., 2007). Furthermore, dissertation by U. Kaiser indicated wind effects on weak pre-stressed membrane structure which is 30m horn shaped membrane by aero-elastic models (Kaiser, 2004).

In this way, there are many other references on this field. However, the basic date for the windforce coefficient of the horn-shaped membrane roof has not been sufficiently reported yet. Based on this background, the authors have carried on the wind tunnel test, and report these results.
