sentences:  Steel truss and timber frame buildings, accommodating the loading and unloading of ships are built upon the piers, with open aprons for circulation.These were the only group of piers in the Port of San Francisco dedicated chiefly to inland trade and transport.These connections facilitated the growth of communities in the Sacramento and San Joaquin Valleys and fostered California's agricultural business that led the state to become the richest in the nation, as well the fifth largest economy in the world.