In the current construction services business activities, service users are increasingly innovative with the use of construction methods. This they do in addition to reduce production costs (project implementation costs), is also done to speed up construction time. One method of construction implementation used is the topdown method. Topdown method is a method that has not been widely used in Indonesia. In the Indonesian Project 1, the system of basement work performed using topdown method. The topdown method uses the kingpost structure as the main structure of temporary column replacement. The kingpost structure has a function to hold the floor load above it in order to continue the work of the floor structure underneath. In the implementation of contractors encountered many problems, one of which is the tilt of kingpost structure that impact on design changes, design changes in this case is the magnification of the dimensions of the basement column structure. The purpose of this research is to find the variables that cause the slope of kingpost structure in the project with the implementation system using the topdown method, determine the most dominant variable that affect the slope of kingpost structure in Indonesian Project 1 – Jakarta Pusat.
The research method used in this research is a quantitative descriptive approach with questionnaires distributed to respondents in this case is a competent source and directly related to the topic being discussed. From result of research got 12 factor which become cause of slope of kingpost structure. After analyzing using SPSS vs.20 software, there are 4 most dominant factors such as: Skill from unpopular workforce, work tool reading error, weather condition condition, and coordination among deviations that do not work well.