Full Scale Load Testing BPEX Project, Maptaphut Rayong

5.2.2 FLEXURAL SHEAR CRACKSFlexural shear cracks were observed at the east side of the beam next to the framingbeam as shown in Figure 17. During testing, the crack propagates into thecompression zone of the member but the crack width remained small. No spalling ofconcrete was observed. The crack partially closed upon reloading.FIGURE 17. FLEXURAL SHEAR CRACK5.2.3 INTERFACE SHEAR CRACK BETWEEN SLAB AND BEAMDuring the last loading stage, cracks were observed at the interface of slab and beamon the east side of the structure near the column support as shown in Figure 18. Nosuch crack was observed on the west side of the beam. This crack occurred due tolarge shear transfer at the beam and slab interface. Calculation has shown that theconcrete friction between the interface alone is not sufficient to transfer such shearforce. Thus, steel reinforcement was required to transfer the interface shear.According to the drawing and calculation, this beam fulfill this interfacereinforcement by extending the beam’s stirrup reinforcement into the slab;Therefore cracking of concrete at the interface may be allowed. The crack widthremained less than 1 mm even after sustained loading and partially closed uponunloading.18