Research funded by the ACI Concrete Research Council has resulted in the development of a new semi-empirical concrete shrinkage and creep model, called the CPRH Model. The new model proposes a coupling between autogenous and drying shrinkage using a volume-average pore relative humidity and treats drying creep as an additional stress-dependent shrinkage, linking together all these phenomena. The proposed expressions are designed to facilitate traditional integral-type analysis, but also uniquely support rate-type calculations that can be leveraged by analysis software. Model calibration uses the Northwestern University (NU) database of creep and shrinkage tests to determine new model parameters. The proposed model uses minimal inputs that are often known or may be assumed by the design engineer. Comparison of the proposed model to historical time-dependent models indicates that the new model provides a superior fit over a wider range of inputs. This model will be incorporated into ongoing ACI Committee 209 documents, including reports on time-dependent models and structural analysis techniques.