Section 1706: Design Strengths of Materials
2018 Philadelphia Building Code (Chapter 17: Special Inspections and Tests)
1706.1 Conformance to Standards
The design strengths and permissible stresses of any structural material that are identified by a manufacturer’s designation as to manufacture and grade by mill tests, or the strength and stress grade is otherwise confirmed to the satisfaction of the building official, shall conform to the specifications and methods of design of accepted engineering practice or the approved rules in the absence of applicable standards.
1706.2 New Materials
For materials that are not specifically provided for in this code, the design strengths and permissible stresses shall be established by tests as provided for in Section 1707.
💡 Special Inspector's Commentary
A structural design is only as good as the materials actually delivered to the job site. Section 1706 mandates that the physical materials must meet the exact design strengths and permissible stresses specified by the Registered Design Professional.
As a Philadelphia Structural Engineer, Viking Engineers ensures compliance with this section by rigorously reviewing mill test reports (MTRs) for structural steel, verifying concrete mix designs, and checking manufacturer designations before materials are permanently installed. When a contractor substitutes an unverified material, it falls outside of "accepted engineering practice." Our Special Inspections provide the documented proof to Philadelphia L&I that the materials used match the structural capacity required by the approved plans.