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Applied transverse prestressing reinforcement Fabricated Hollow Slab research

Author: ZhangYunNa
Tutor: ChenHuai
School: Zhengzhou University
Course: Structural Engineering
Keywords: Fabricated Hollow Slab Transverse prestressing Reinforcement Finite Element Method
CLC: U445.72
Type: Master's thesis
Year: 2007
Downloads: 309
Quote: 9
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Abstract

Prefabricated Prestressed Concrete Hollow Slab due to lower building height, precast convenient timber and economic advantages are widely used in bridge engineering bridge. 1970s and 1980s had built prefabricated prestressed concrete slab bridge, there is a bridge carrying capacity is low, and multi-purpose concrete hollow slab between tongue and groove joints for small hinged connection defects. With the rapid development of modern economy, heavy trucks and overloaded vehicles frequent. So in recent years, this kind of bridge between the often hollow tongue and groove along a longitudinal seam cracks, pits and collapse, and the hollow hinge joints between concrete crushing, falling, a large area of ??leakage, resulting in failure of horizontal linkages between the plates, appear veneer force, seriously affecting traffic safety, as the entire road transport bottlenecks. Thus, this type of reinforcement of bridges disease has important practical value. In response to these prefabricated prestressed concrete slab bridge existing diseases, by applying proposed a transverse prestressing tendons to govern the reinforcement method. Its reinforcement mechanism: by applying lateral pre-stress on the assembly of prestressed concrete hollow horizontal lower edge of the concrete in compression to balance the transverse bending moment can be passed between hollow vertical shear and bending moments, variable hinge plate structure in the form of rigid board structure, in order to enhance the lateral assembled Itabashi connectivity. Also, because the hollow board lateral connections from the hinge becomes rigid, improving the lateral load distribution, is conducive to work each hollow traffic load sharing, and ultimately improve the carrying capacity of the entire slab bridge. This method is simple in principle clear reinforcement, although in some practical projects have used, but its actual reinforcement effect is theoretically lacking specific data, so we can not quantify the effectiveness of awareness of the law. In this paper, the use of MIDAS / Civil finite element program, the use of three-dimensional block element for prefabricated prestressed concrete slab bridge finite element modeling of the entire bridge to establish a three-dimensional solid element calculation model. In the finite element modeling of the cross-section at the roof area reinforced with ordinary reinforced concrete roof translated elastic modulus at ordinary reinforced consideration the impact on the bottom of the prestressing steel prestressing strip using the equivalent simulation; Bridge panel, hinge joints, concrete pavement and parapets etc. with solid elements, used only by the lateral tendon pull compression truss element. On the analysis of the effectiveness of Hollow Slab reinforcement method, but also compared the magnitude of the applied transverse prestressing, the vertical bridge to a different location, the bridge width to span ratio on the bridge reinforcement effect. For quadrature bridge, in order to get the size of the transverse prestressing reinforcement effect, followed by the seven lateral load is set in Prestressed 100kN / root, 150kN / root, 200kN / root three cases for analysis. To get Lateral Load Distribution influence lines, respectively, in place across the board from 1 to 8, at the center of each plate is applied to unit load for each unit load, and then sub-four kinds of conditions: Condition 1: Only the unit load; workers Case 2: Unit load 100kN / root lateral tendons load; case 3: Unit load 150kN / root lateral tendons load; case 4: Unit load 200kN / root lateral tendons loads of full-bridge has 32 kinds of working conditions. This paper studies using the same method is applied transversely Skew Hollow Slab using external tendons effectiveness of reinforcement and Skew Hollow Slab different inclination on the reinforcement effect. The results show that: Use this method Hollow Slab reinforcement, simple construction, reinforcement effect is obvious, Skew Hollow Slab reinforcement effect is not orthogonal Hollow Slab good; applied transverse prestressing reinforcement effect of the size of the impact is not Large; bridge in the longitudinal direction, the same number across the board at both ends of the reinforcing efficiency than high; smaller the ratio of width to span more favorable effect on the reinforcement; Skew Hollow Slab reinforcement slope greater for the more unfavorable. These conclusions reinforce the bridge there is a certain kind reference. Since China Prefabricated Prestressed Hollow Slab currently widely used, the use of common, a large number of prefabricated prestressed hollow slab bridge exists between the tongue and groove joints along the longitudinal cracking and other defects, it is widely promote this reinforcement technology, the defective assembly type Prestressed Hollow Slab reinforcement will have greater social significance and practical value.

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