The Treasury of the Siphnians has a unique porch. The typical supporting columns have been replaced with female figural supports, caryatids. These support elements were repeated later in the Erechtheion at the Acropolis. How did the architect-sculptor accommodate the role of architectural support with the role of figural sculpture?
One scholarly web site that discusses this assignment question is located at: http://www.coastal.edu/ashes2art/delphi2/sanctuary/siphnian_treasury.html.
The relevant portion of that site is copied and pasted here for you to see so you do not have to re-access the site unless you wish to do so.
In addition to the abundant gifts inside the Siphnian Treasury, the exterior was adorned with elaborate architectural elements such as caryatids, and carved reliefs on the pediments and frieze. The entrance porch of the treasury is supported by two stone caryatids (carved stone female figures called korae), rather than the commonly used columns. In order for these ...
The treasury of the Siphnians structure used unique load-bearing columns sculpted in human form. Brief discussion from Web-based reference on these columns, and Expert original commentary on how and why these were used.