Abstract: High falseworks are in the most dangerous state during concrete placement. In order to investigate the working state in that period, in-situ static and dynamic tests of member axial forces were carried out in two construction projects. The test results show that the maximum loads on vertical tubes occur during the pouring process, rather than the end of pouring. The falsework works as a whole structure. In addition, a special phenomenon is found that one of measured vertical tubes stops sustaining load gradually, leading to a significant increase of the axial forces of vertical tubes at juxtaposition; this phenomenon was analyzed in this paper. Based on the results of tests and analyses, the working state of high falseworks was addressed. It is suggested that, during concrete placement, fresh concrete load should be treated as a live load and the dynamic effects caused by placing concrete and vibrating concrete can be neglected.