All bridges held generally the same amount of weight. The arch bridges held a little more than the other bridges. They were in the 1400-1500 gram range. The other bridges were in the 1000-1200 gram range. The bridges would not stand up on their own, so a support at each end had to be constructed. Balancing the weights on the bridges required patience. Clamps were used to hold the bridges during gluing. The bridges supported different amounts of weights because each type has different construction. The arch bridges supported the most weight because of the great natural strength of the arch. The pier bridges supported the least weight because the supporting piers broke during construction.