In the process of cantilever construction of the Longtan river bridge,the WZP-035 thermally sensitive as measured points of temperature were buried into two segments of box-girder,and the temperature field of box-girder concrete was observed for three days. The temperature field and its variation laws of box girder bridge were discussed based on measured data. A vertical and transverse thermal gradient model of PC box girder,which could apply in central south China,was presented. This model was compared with the measured data and the thermal effect was analyzed.Results show that the calculated...