Said board shall meet once a month, at such stated times as it may designate, to hear complaints or reports of defective and broken bridges, to order needed repairs, and to transact such other business as may be authorized by sections 233.010 to 233.165; and in case of emergency, the president of the board may have such repairs made, and such meeting may be adjourned from time to time, and called meetings may be held, but only such business as the president may specify in the call can be transacted.