Compared with traditional in-pipe robots, tensegrity robots have exhibited many advantages such as light-weight, compliant, collapsible, low-cost, and rapidly manufacturable characteristics. However, published tensegrity in-pipe robots still have limited load capacity, because they rely on the stress between obliquely arranged rigid struts and pipe to provide supporting force, and the rigid struts are easy to slide under external loads. In this paper, a soft umbrella-shaped tensegrity robot that use compressed elastic struts to apply stress nearly perpendicular to pipe is proposed to enhance its load capacity. The static and kinematic models guiding the prototyping and controlling of the tensegrity robot are built based on discretization method. To assess the effectiveness of the elastic struts, a prototype is developed and subjected to a series of experiments. The results demonstrate that compared with other tensegrity in-pipe robots, the usage of elastic struts improves the payload-to-weight ratio of the proposed robot by three times, while still maintaining good mobility and adaptability.