In the recent DLSU-CES Popsicle Stick Bridge Building Contest held last Feb. 13, 2010, 31 bridges were tested for the Strength Category. A Universal Testing Machine (UTM) was used to test the bridge. Two 14 mm rebars spaced at a specified distance, were placed on the bridge deck. Then a hollow “cage” was placed on the rebars, on which the load from the UTM was transferred. A displacement transducer was attached to the UTM to measure the bridge displacement (D) in mm. The load P (kg) when the load dial of the UTM stops was noted indicating bridge strength. The Strength Rating is computed as (1000x P)/(D x W), where P in kg, D in mm and W = actual weight of the bridge in kg. The strength rating S is the bridge stiffness (kg/m) per unit weight (kg).The 2nd place bridge was from Pamantasan ng Lungsod ng Maynila (PLM) which had a score S=9.15 with P=36 kg, D=8.87 mm and W=443.7 g. The 3rd place goes to another entry from TIP-Manila with S=9.01, P=45kg, D=10.78 and W=463.11 g.
Bridge entry no. 13 from the Technological Institute of the Philippines (TIP) of Manila has the highest score. The bridge has only a weight of about 390.4 g. With P = 43 kg and d = 11.8 mm, its score S = 9.33. Observe the connections at the joints - knowing that failure will occur at the connections, the connections were glued together properly with additional cover.
Congratulations to the winners and all participants. You were all winners!