Specializing Park’s Compressive Membrane Theory

Park’s compressive membrane theory has been used for many years to predict the capacity of laterally edge restrained reinforced concrete (LERRC) thin slabs. This note examines his compressive membrane theory and presents a methodology which proved to be successful in predicting, in a different manner, the capacity of LERRC thin and thick slabs. The suggested methodology employs the point of peak thrust, rather than a midspan deflection estimate, to select the peak compressive membrane load capacity for LERRC one-way slabs. Comparison of averaged values of normalized load capacities $(w_{\mathrm{theory}}∕w_{\mathrm{test}})$ selected using the experimentally measured peak capacity deflection (i.e., $w_{\mathrm{theory}}∕w_{\mathrm{test}}=0.91$ ) or the calculated peak thrust (i.e., $w_{\mathrm{theory}}∕w_{\mathrm{test}}=0.85$ ) at peak compressive membrane capacity showed that using the peak thrust to select the load capacity was almost as good as using the experimentally measured deflections, especially for thick slabs used in protective construction. The calculation of generated thrust is already inherent within Park’s compressive membrane theory, whereas additional testing is required to accurately predict the midspan deflection at peak compressive membrane load capacity for an acceptable range of span-to-thickness ratios. The limited experimental data set for LERRC one-way slabs ranged from a span-to-thickness ratio of 2.7 to 28.3.