All projects or matters that fall within the purview of the duties of the planning commission as specified in this chapter coming before the city council shall be referred to the planning commission for investigation and report before any final action shall be taken thereon; provided, that if the planning commission fails to make an investigation and report on any matter or subject referred to it for a period of thirty (30) days, such failure shall be considered a refusal to approve the proposed plan or project, and the city council shall be under no obligation to wait longer for the reports or recommendations concerning said projects. (1991 Code § 1-1055)