Abridge to be fabricated of steel girders is designed to be 500 m long and 12 m wide at ambient temperature (assumed 20°c). expansion joints will be provided to compensate for the change in length in the girders as the temperature varies. each expansion joint can compensate for a maximum of 20 mm of change in length. from historical records it is estimated that the minimum and maximum temperatures in the region will be -35°c and 40°c, respectively. determine (a) the minimum number of expansion joints required and (b) the length that each bridge section should be fabricated.