A series-parallel model of rib beam-anchor system in reliability analyses of anchored retaining wall is presented. Regarding the rib beam as a continuous beam and the anchors as an elastic support

introducing a composite stiffness coefficient of anchor and the soil around anchorage section

the application loads acting on each anchor are obtained by displacement method. Considering the correlation of performance functions

based on the system reliability theory

a series system of three failure models for single anchor and a parallel system for multiple anchors are developed

while the calculation method of system reliability for the two systems is derived. The corresponding program of new method herein is used to compute the reliability in an engineering example. The calculation results show that the three failure models for single anchor are related and they have different effects on anchor’s reliability

yet the parallel system failure probability of three anchors is approximately equal to sum of the three single anchor’s failure probability at the condition of other anchors is not failure.