Complex sentence: Garvin remained as supervising architect through the beginning and completion of the project from 1905 to 1914, where by that juncture the population increased to over 500,000, and the total construction cost of the building amounted to $2,000,000.
Split into simpler sentences: Garvin remained as supervising architect through the beginning and completion of the project from 1905 to 1914. The population increased to over 500,000 and the total construction cost of the building amounted to $2,000,000.