Structural Behavior of Ultra-High-Performance Concrete Beams Under Flexural and Shear Action: A Review

Ultra-high performance concrete (UHPC) has a higher tensile strength than conventional concrete by about 6-times, besides a compressive strength greater than 150 MPa. It also exhibits linear and non-linear behavior on loading because of strain hardening and strain softening in compression and tension. Therefore, the effect of these mechanical properties can reflect in the beam behavior produced by UHPC. This paper deals with the methods and approaches adopted by some guidelines and recommendations that transact with the analysis and design of UHPC beams. The prevalent style of the methods is based on the equilibrium of the beam's section for the induced forces above the neutral axis, which represents the compression forces in concrete, and below the neutral axis, which designates the tensile forces in longitudinal rebars and that one in concrete. Since the tensile strength of UHPC is relatively high and cannot be ignored; therefore, it is considered in the analysis and design approach. The flexural capacity depends on the induced moment due to these forces. The structural analysis of UHPC depends on the stress-strain relationship in compression and tension. The linear portion of compression relation continues to about 80% of the compressive strength; therefore, it is considered in the analysis and design process.