The emperor Trajan constructed his own imperial forum in Rome accompanied by his Basilica Ulpia dedicated in 112. Trajan's Forum () was separated from the Temple of Trajan, the Ulpian Library, and his famous Column depicting the Dacian Wars by the Basilica. It was an especially grand example whose particular symmetrical arrangement with an apse at both ends was repeated in the provinces as a characteristic form. To improve the quality of the Roman concrete used in the Basilica Ulpia, volcanic scoria from the Bay of Naples and Mount Vesuvius were imported which, though heavier, was stronger than the pumice available closer to Rome. The Bailica Ulpia is probably an early example of tie bars to restrain the lateral thrust of the barrel vault resting on a colonnade; both tie-bars and scoria were used in contemporary work at the Baths of Trajan and later the Hadrianic domed vault of the Pantheon.