Palladio's wooden bridges

In Book 3 of hisFour Books on Architecture(1579), Palladio gives alternative designs for a wooden trussed bridge to span a river 100ft wide. The designs are ingenious, and analysis of Palladio's proposals shows that the bridges would have been effective. Some of the details, however, seem to be at variance with the expected structural action of the bridges, and there remain problems (not fully answered here) of practical construction.