Double timber pilings were rammed into the bottom of the river , the most upstream and downstream pilings were slanted and secured by a beam , and multiple segments of these then linked up to form the basis of the bridge .
Double timber pilings were rammed into the bottom of the river by winching up a large stone and releasing it , thereby driving the beam into the riverbed . 
 The most upstream and downstream pilings were slanted and secured by a beam , and multiple segments of these then linked up to form the basis of the bridge .