Investigation of Fresh Concrete Lateral Pressure on Single-Sided Wall Formwork: Using Embedded Pressure Sensors

A full-scale field investigation was performed to evaluate the lateral pressure exerted by fresh concrete on a 6.67 m-high single-sided wall formwork during on-site casting. Five embedded pressure sensors were installed at various elevations to enable high-frequency, real-time monitoring of pressure evolution throughout the casting process. The experimental programme captured the combined effects of casting rate, staged placement, internal vibration, and casting interruptions, and the measured results were compared with widely used design models (ACI 347R-14, DIN 18218, and CIRIA R108). The results indicate a strongly non-hydrostatic pressure distribution, with a maximum pressure of 56 kN/m2 occurring at an intermediate height, rather than at the base, exceeding the design value by more than twice. Transient pressure peaks were closely associated with vibration, while casting interruptions promoted thixotropic structural build-up and reduced pressure recovery in lower regions. Comparison with design models demonstrates that commonly used approaches may significantly underestimate peak pressures unless conservative assumptions or calibrated parameters are applied. These findings provide rare full-scale field evidence of time-dependent and vibration-induced pressure behaviour and highlight the importance of real-time monitoring for capturing transient effects. The study contributes to an improved understanding of fresh concrete behaviour in single-sided wall systems and supports the development of safer, more reliable formwork design approaches.