Bursting and Spalling in Pretensioned U-Beams - Ferguson ...

For the beams in this study, special interest was paid to the maximum temperatureand the temperature variation with the 45˚-skewed end blocks. The two designalternatives require different volumes of concrete: the large triangular end block is threetimes the size of the other design (Figure 3.5). All end blocks were instrumented withthermocouples throughout a cross section crossing their centroid. Typical thermocouplelocations are shown in Figure 3.30. Spacing of thermocouples varied from 10 to 24 in.Figure 3.30 Thermocouple placement in small skewed end block (Beam 1)All thermocouples consisted of copper and constantan wires (Type T, Omega).Thermocouples measure temperature using the electrostatic potential between the twometals, which varies as a known function of temperature. Thermocouples were preparedby stripping the wire sheathing and twisting the wire ends together at a measurementlocation. Thermocouples whose data was to be recorded by the match-curing system wereplugged into the system’s wireless transponder. Data from other thermocouples wererecorded using a Campbell Scientific C21X datalogger. A multiplexer was used toincrease the channel capacity of the datalogger. Care was taken to prevent thethermocouple wires from touching at points other than the intended measurementlocation.129