The tied-arch action was analyzed by considering 27 reinforced-concrete beams without web reinforcements that were dismantled from a wide range of deteriorated coastal and marine structures and with varying degrees of...The tied-arch action was analyzed by considering 27 reinforced-concrete beams without web reinforcements that were dismantled from a wide range of deteriorated coastal and marine structures and with varying degrees of reinforcement corrosion. Under 2-point loading and changing shear span ratio, changes in loading capacity for beams of the same corrosion degree were studied. Formulas relating ultimate moment of reinforcements with the same corrosion level at increasing a/d ratio were then developed. Load-carrying capacity profile for beams with reinforcement corrosion of 1% and the same cross section was described. The minimum ultimate moment occurs at a/d = 2.5 and at 52% of the full flexural moment, suggesting that the difference in ultimate moment between theoretical and experimental results at the minimum point equals 11%. The results show that the developed theoretical relations compared well with experimental values.展开更多
The horizontal stiffness of the isolated layer is reduced substantially by a friction pendulum bearing(FPB)toprotectthe structure from potential damages caused by earthquakes.However,horizontal stiffness is essential ...The horizontal stiffness of the isolated layer is reduced substantially by a friction pendulum bearing(FPB)toprotectthe structure from potential damages caused by earthquakes.However,horizontal stiffness is essential to progressive collapse resistance of structures.This paper presents a simplified model to assess the progressive collapse response of beam-pier substructure isolated by FPB.Progressive collapse resistance by flexural action of the beam and additional resistance owing to the horizontal restraining force was achieved.The influences of the equivalent radius and friction coefficient of the FPB,the applied axial force on the FPB,and span-depth ratio of the beam on the additional resistance were investigated.Simulations were conducted to verify the proposed model.The results show that progressive collapse resistance provided by horizontal restraining can be reduced as large as 46%and 88%during compressive arching action(CAA)and catenary action(CA),respectively.The equivalent radius of the FPB shows limited effect on the progressive collapse response of FPB isolated structures,but friction coefficient and applied axial force,as well as depth ratio of the beam,show significant influences on the additional progressive collapse resistance capacity.Finite element method(FEM)results are in good agreement with the result obtained by the proposed method.展开更多
基金Supported by the Chinese Scholarship Council of the Educa-tion Ministry and the National Key Basic Research and Development (973) Program of China (No. 2002CB412709)
文摘The tied-arch action was analyzed by considering 27 reinforced-concrete beams without web reinforcements that were dismantled from a wide range of deteriorated coastal and marine structures and with varying degrees of reinforcement corrosion. Under 2-point loading and changing shear span ratio, changes in loading capacity for beams of the same corrosion degree were studied. Formulas relating ultimate moment of reinforcements with the same corrosion level at increasing a/d ratio were then developed. Load-carrying capacity profile for beams with reinforcement corrosion of 1% and the same cross section was described. The minimum ultimate moment occurs at a/d = 2.5 and at 52% of the full flexural moment, suggesting that the difference in ultimate moment between theoretical and experimental results at the minimum point equals 11%. The results show that the developed theoretical relations compared well with experimental values.
基金This research was supported by the National Key Research and Development Program of China(No.2017YFC0703603).
文摘The horizontal stiffness of the isolated layer is reduced substantially by a friction pendulum bearing(FPB)toprotectthe structure from potential damages caused by earthquakes.However,horizontal stiffness is essential to progressive collapse resistance of structures.This paper presents a simplified model to assess the progressive collapse response of beam-pier substructure isolated by FPB.Progressive collapse resistance by flexural action of the beam and additional resistance owing to the horizontal restraining force was achieved.The influences of the equivalent radius and friction coefficient of the FPB,the applied axial force on the FPB,and span-depth ratio of the beam on the additional resistance were investigated.Simulations were conducted to verify the proposed model.The results show that progressive collapse resistance provided by horizontal restraining can be reduced as large as 46%and 88%during compressive arching action(CAA)and catenary action(CA),respectively.The equivalent radius of the FPB shows limited effect on the progressive collapse response of FPB isolated structures,but friction coefficient and applied axial force,as well as depth ratio of the beam,show significant influences on the additional progressive collapse resistance capacity.Finite element method(FEM)results are in good agreement with the result obtained by the proposed method.
