Lateral Pressure Test of Vertical Joint Concrete and Formwork Optimization Design for Monolithic Precast Concrete Structure

When the vertical joints of monolithic precast concrete structures are cast by self-compacting concrete, the design of the formwork under rational lateral pressure of self-compacting concrete becomes a key technical issue. In this paper, a prototype simulation test was conducted for the pouring of self-compacting concrete in the vertical joint of precast concrete walls. The self-compacting concrete was continuously poured from the top of vertical joints with a height of 2.8 m without any assistance such as a delivery tube. The formwork pressure of self-compacting concrete was measured at different heights with varying casting time. Results showed that the lateral pressure increased with the increase in slump-flow of fresh self-compacting concrete, reaching a peak value of about 70 kPa at a height of about 600 mm from the bottom of formwork. Compared to the concrete with a slump-flow of 550 mm, the self-compacting concrete with the slump-flow reached 655 mm and 755 mm, presenting an increase in the peak lateral pressure by 31.5% and 44.9%, respectively. A method for calculating the lateral pressure of self-compacting concrete on the joint formwork is proposed using the analysis of enveloped test curves. Under the condition with enough strength and limited deformation of the joint formwork, the optimal design of aluminum alloy formwork is determined using finite element analysis. This provides a sci-tech foundation of the optimal design to lighten the weight of joint formwork to improve the installation efficiency and reduce the manual power cost