Concrete Slab Followed ASTM E119 for 2 hours Gradually reduced air-temperature until 600  C Furnace Specifications Elin Jensen, Jacob Van Horn, Nabil Grace, and Mena Bebawy College of Engineering, Civil Engineering Department New Large-Scale Structural Fire Chamber: Initial Experimental Considerations Objective: Define design fires for assessing structural fire performance. Verify the performance characteristics of the new test facility. Experimental Considerations: Furnace specifications Design fires & furnace response Standard air temperature-time curve – ASTM E119 High intensity short duration - Fire A Progressive burning – Fire B Specimen shadow effect Test repeatability Slab T-beam Left: Small slab subjected to air temperature – time curve (ASTM). Right: Deflected slab after test View on left: right front corner of slab & environmental thermocouple in rod New facility located in the Center for Innovative Materials Research (CIMR) at Lawrence Tech, Southfield, MI The internal workload dimensions are 6.0 m x 1.5 m x 1.5 m. Max workload equivalent to 5.5 m 3 of concrete subjected to ASTM E119 standard temperature-time curve Heating capabilities Nine burners - 555,00 MJ/hour – natural gas Three control zones Variable air-gas mixture Forced air ejector stack Mechanical loading of P max = 490 kN (compression) Controller & Data Acquisition Closed loop temperature control system 70 set-points available in each temperature-time curve 100 thermo-couple channels Temperature uniformity in workload area Characteristics Mean: 1004  C Max: 1016  C Min: 983  C St. dev: 6.3  C Variation: 0.6 % Furnace meets the requirements Standard Fire - ASTM E119: Standard air temperature-time curve Allowable deviation from standard curve Test repeatability Concrete Test Slab Information: Dimensions:Length (1.82 m) Width (1.82 m) Thickness (12.5 cm) Concrete grade: 32 MPa Age: 4 years Humidity levels at core:RH 74% - 77% at T air = 25  C Standard Fire – ASTM E119 Radiation Effect Shadow Effect During Slab Testing The furnace roof is covered with white ceramic blanket and the furnace floor is covered with fire brick. The fire bricks heat up slower showing an offset between temperature below and above slab. Temperature offset decreases from 100  C after 6 minutes to 25  C after 1 hour. Furnace capable of producing Standard Fire - ASTM E119. Repeated tests fall within allowable deviation from standard. Real Fires Motivation Design Fires: A short duration high intensity fire is a result of burning highly combustible materials. Progressive burning is a result of temporary oxygen depletion in a deep room. Capability of Fire Furnace in producing a fire with 1.0 m 3 of concrete Fire A – fire bricks cover the floor Modified Fire A – ceramic blanket added over fire bricks Fire B – fire bricks cover the floor Internal Temperature Profiles Good agreement between predicted and measured temperature development in concrete slab. Variable radiation effect not modeled. CFRP Prestressed Concrete Beam: Concrete Beam Information: Dimensions: Length (3.99 m) Cross Section Shown in sketch Concrete grade: 48 MPa Age: 9 months Humidity levels at core:RH 84% - 87% at T air = 25  C Temperature Development in T-Beam: Development of internal beam temperature in agreement with expected trends. Post-construction installation of thermocouples is successful. Acknowledgement: Center for Innovative Materials Research (CIMR) College of Engineering, Lawrence Tech University, Southfield, MI National Science Foundation, Award Assistance from: Charles Elder Cody Telgheder Daniel Ziemba 735°C after 1 hr 20 min Effect after 5 h 1020°C after 2 hr 19 min Large Scale Structural Fire-Load Furnace Thermocouples steel columns Effect of brick support on temperature development K-type thermocouples