| With the increasing of traffic, disease of hinge joints is becoming more and more common for fabricated hollow slab bridges.Although measures have been taken to strengthen the hinge joints to improve their mechanical property and to avoid all the force undertakened by a single slab,the problem still has not been fundamentally resolved. Specialized study was seldom done for hinge joints and the bridge codes did not make clear provisions of constructional detail.In this paper, research is carried out about the mechanical behavior and failure mode of hinge joints, and methods to check are put forward.The main work of this paper include the following aspects:(1)The disease of 308 fabricated hollow slab bridge has been investigated in site, the results of the investigation has been analysed in order to know the distory form and frequency of occurrence.General characteristics of the disease are summarized,and the destruction reasons are analysed from design,construction and operation.(2)A common FEM procedure ANSYS is used to establish a 8m,five beam model to analyze the impact of the thickness of pavement layer on the transverse load distribution,result shows that bridges with thick pavement should consider the impact of the layer on load distribution.The destroy forms of the hinge joint under the most unfavorable transverse stress and shear stress are analyzed,and results show that surface damage is the main form of destruction under the most unfavorable transverse stress,while shear destruction within the hinge is the main form of destruction under the most unfavorable shear stress.(3)For the transverse analysis,three methods are used to analyze the impact of the thickness of pavement on the load distribution, the results showed that if you used the hinged slab method,you will get a wrong result that the thicker the pavement is,the more uneven the load distribution will be.For the bridge which has a thick pavement,the deck rigid slab hinged method is the most suitable method.(4)For the longitudinal analysis, the value of the shear height is discussed, it is recommended to take the height of the concrete under compression of the hollow slab as effective shear height,to increase the effective shear height by strengthen the hinge joints.lt is recommended to add checking of longitudinal bending strength of the hinge joint,to refer to the highway reinforced concrete and prestressed concrete bridge design code (JTG D62-2004)Section5.2.2.It is recommended to check the surface,based on the EU code PrEN-1992-1-1,a simplified formula is proposed to check the combination of surface.(5)Standard figures of fabricated hollow slab bridge published by ministry of communications in 1996 and 2008 are compared,and two kinds of hinge joints are checked.The results show that vertical shear and longitudinal bending strength of the the hinge both meet the requirements, but the lower part of the joint surface can not meet the shear requirements,it is proposed to strengthen the reinforcement of the joint surface. |
