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Office of Structural Materials
The Office of Structural Materials (OSM) inspects various structural materials used on the State's highways and bridges. The Office tests materials and conducts evaluations of new products and processes. The responsible Branches within OSM are:
- The Quality Assurance and Source Inspection Branch does source inspection of miscellaneous items and fabricated products such as steel girders, concrete girders and welded sign structures used on the State highway system. The branch includes Structural Material Representatives that work with the Caltrans inspectors, Resident Engineers and Structure Representatives and contractors to assure materials are inspected and resolve related issues. The branch also administers various Facility Audit requirements.
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Prestressing steel in a concrete girder |
Welded connections in light poles |
Welded connection for steel piles |
- The Structural Materials Testing Branch tests products that include reinforcing and prestressing steel, elastomeric bearing pads, prestress anchorage systems, seismic bearings and restrainers, steel plates and rebar coupling systems. The branch has available universal testing machines capable of tension, compression and cyclic loads of one to one million pounds force.
- Concrete Materials Testing Branch
The Aggregate Lab determines if the aggregates proposed for use in portland cement concrete on State contracts comply with the California Standard Specifications and ASTM Standards. The tests performed to determine compliance include: grading, specific gravity, absorption, sand equivalent, Los Angeles Rattler, cleanness value, durability, soundness, color, crushed particles and R-value.
The Cement Lab performs tests on the cement used in portland cement concrete to determine if they comply with the California Standard Specifications and ASTM Standards. These tests include Blaine fineness, compressive strength of mortar cubes, consistency, setting time, autoclave expansion and shrinkage of mortar bars. The Cement Lab also performs sand mortar testing for the Aggregate Lab.
The Concrete Lab produces concrete mixes that may be used to check on a Contractor’s proposed design or to determine the amount of cement required to produce concrete of a specified strength. Concrete can be tested for compressive and flexural strength, modulus of elasticity, shrinkage of concrete specimens, and freeze-thaw resistance for concrete to be used in mountain areas. Fast setting materials are tested for repair and rehabilitation of concrete structures, which include the use of polyester and methacrylate resins. Additionally, the Section tests aggregate and concrete for alkali silica reactivity (ASR) as well as chlorides and the cement content of hardened concrete.
- The Corrosion Technology Branch is responsible for technologies and design practices that prevent, control or mitigate corrosion on transportation facilities.