混凝土桥面铺装层层间抗拉分析

当桥面水泥混凝土出现裂缝时,针对垂直荷载作用下的防水层在裂缝上产生的变形,建立了计算防水层延伸率和抗拉强度的模型,可以有效计算出在此工况下防水层须具备的最小延伸率和拉伸强度。计算表明,延伸率低的防水层,要求有高的抗拉能力,而在裂缝宽度一定时,变形能力大的防水层适应能力强。利用有限元法分别对直接加铺沥青混凝土和设防水层的两种桥面铺装结构进行实体建模,研究了在行车荷载作用下,当沥青混凝土面层出现开裂时,桥面各铺装层的模量、厚度对铺装层层间法向拉应力的影响。结果表明,对直接加铺沥青混凝土面层的铺装结构,沥青面层厚度在一定范围内变化可以使铺装结构具有较好的受力性能,对于设防水层的桥面铺装结构,防水层模量是影响层间法向拉应力的主要因素。

ANALYSIS ON TENSILE STRESS OF THE BRIDGE DECK PAVEMENTS WITH CRACKS

Considering the deformation of the waterproofing layer on the cracks of concrete leveling layer under the traffic loads,the paper puts forward the model of calculating the tensile stress of waterproofing layer.Mak- ing use of the model,it can get the needed least ratio of elongation and the needed tensile stress of the water- proofing layer.In addition,if the waterproofing material has less ratio of elongation,it needs strong tensile stress;but under the condition of fixed width crack,the waterproofing material needs strong deformability.Ai- ming at two structures of concrete bridge deck pavement with cracks,the bridge deck pavement without water- proofing layer and the bridge deck pavement with waterproofing layer,the paper studies the influences of the modulus and the thickness of the pavements on the interlayer direct tensile stresses when the deck pavement bears the traffic loads.The results show that the thickness of asphalt pavement within a certain thickness range can im- prove the mechanical behavior of the pavement structure without waterproofing layer,and the modulus of water- proofing layer is the main influential factor on the interlayer direct tensile stress of the pavement structure with waterproofing layer.