A New Strut-and-Tie Model for Thick Cap with Six Piles

Abstract

The strut-and-tie model is supposed to be a more appropriate design method for pile caps than the general flexural member approach. A new strut-and tie model, therefore, is put forward for caps with six piles including truss action, direct arch action, or a combination of both actions. In the model, comprehensive factors were considered such as selection of truss/direct arch/both actions, solution of pile reaction force, load type including concentrated, and distributed load, as well as distribution of pile reaction force and so forth. The designing and checking process was programmed by Matlab language. Designing methods of related node and calculations of inclined struts with variable cross-section are analyzed. Specific designing and checking methods about the struts, ties, and nodes are obtained after a comprehensive comparison. The new model proposed is validated by specific test cap samples with six piles. High accuracy is reached in computing the ultimate load and failure mechanism compared to corresponding test results. There is certain economy in reducing the amount of reinforcement and effectively utilizing all members.