Flexural behavior of partially encased cellular beams: Tests and design implications.

• Shear connectors can be omitted in the PECB. • The PECB under flexure can behave satisfactorily. • Practical models are derived and validated for the PECB. This paper focuses on a new type of composite beam designated as the partially encased cellular beam (PECB). The PECB consists of a steel wide-flange member in which its perforated web is encased by reinforced concrete. The PECB is envisioned to be superior to the conventional partially encased beam in that it can eliminate the need of shear connectors required in the conventional partially encased beam to develop the desired composite action. This feature helps alleviate reinforcement congestion that may exists in a conventional partially encased beam and minimize construction cost and effort. To investigate the flexural behavior of the proposed PECB, five specimens with representative geometries and typical materials were designed and constructed. The specimens were monotonically loaded with the four-point bending test setup. Test results show that the proposed PECB can behave satisfactorily under flexure and that the shear connectors may not be needed in a properly designed PECB for development of the composite action. Based on the classic beam theory and idealized stress/strain diagrams, this paper develops three practical models for estimating the yield flexural strength, plastic flexural strength, and initial flexural stiffness of the proposed PECB. Comparisons of the predictions from these models with the test results show that the practical models can provide reasonable predictions and can be used for future practice. [ABSTRACT FROM AUTHOR]