The Asian Development Bank (ADB) said on Saturday that it was ready to work with the China-led Asian Infrastructure Investment Bank (AIIB) so long as standards were met, while also announcing changes to boost its own lending capacity by billions of dollars. China has said 57 countries have signed up to become founding members of the AIIB, but so far the United States has chosen to remain outside the bank, seen as a rival to the U.S.-dominated World Bank.