Use of the Strut-and-Tie Model in the Analysis of Reinforced Cement-Stabilized Rammed Earth Lintels

This paper investigates the use of the strut-and-tie model to calculate the capacity of longitudinally reinforced cement-stabilized rammed earth deep beams with no shear reinforcement. Beams with a span-to-depth ratio (L/D) less than 10 and reinforced only by longitudinal steel bars represent the majority of lintels used to span openings such as windows, doors, and garage entrances. The strut-and-tie model is used in this work to analyze these structural members. This paper studies the failure modes and ultimate loads of 13 beams subject to two-point loading at quarter spans, with span-to-depth ratios ranging from 1.7 to 10. The results indicate that the strength of beams with span-to-depth ratios up to 10 can be predicted by the proposed method when the failure is dictated by the yielding of the tie. The compression capacity of the strut is more difficult to calculate because of the discrepancy between the compressive strength of small rammed samples and the real strength of rammed earth of large structural members. For this reason, the calculation of the capacity of beams failing for compression of the strut needs a more conservative approach and further research. DOI: 10.1061/(ASCE)MT.1943-5533.0000215. (C) 2011 American Society of Civil Engineers.