RU2057833C1 - Suspension bridge - Google Patents

Abstract

FIELD: bridge building. SUBSTANCE: suspension bridge includes stiffening beam, carrying cables, placed on opposite sides of bridge lengthwise axis and interconnected with cable suspensions to stiffening beam, two waterside two-stand abutment, and a device for resting on thrusts. Slopes of the suspensions to vertical line increase steadily from abutments towards bridge span center. Units of resting carrying cables on abutment heads are placed on straight lines in bridge plan. The lines form angles to lengthwise bridge axis with tangents equal to relations between bridge width and bridge span length with straight lines intersected in the middle of the span. Connection unit is provided for carrying cables in the middle of bridge span to increase horizontal stiffness of the bridge. This unit is connected to stiffening beam faces using tension members. EFFECT: high strength. 3 cl, 3 dwg

Description

 The invention relates to bridge construction, in particular to structures with cable trusses.

 Suspension bridges are known, including load-bearing cables connected by cable suspensions to a stiffener, a pylon for suspending load-bearing cables and devices for perceiving their struts. Suspension along the facade of the bridge is parallel, vertical in the transverse direction.

The disadvantage of the prototype bridge is its relatively low resistance to horizontal loads, which is determined by the large linear length of the suspension bridge and almost completely "passive" cable trusses under such loads. The “passivity” of cable trusses is explained by the location of the support nodes of the bearing cables to the pylon heads on straight lines parallel to the longitudinal axis of the bridge. In this embodiment, only the vertical loads of the initial state of the structure resist the horizontal loads.
In FIG. 1 depicts a suspension bridge, facade; in FIG. 2 -4 is the same plan; in FIG. 3, section AA in FIG. 2.

 The suspension bridge includes a stiffener 1, bearing ropes 2, located on different sides from the longitudinal axis of the O-O bridge and connected by cable suspensions 3 with a stiffener 1, two coastal two-post pylons 4 and devices for receiving struts 5. Bearing ropes 2 together with suspensions 3 form a cable truss connected to the outer faces of the stiffener 4. The tilt angles of the suspension 3 cable trusses to the vertical increase in tons from the pylons 4 to the middle of the span of the bridge C.

 The nodes of the support of the supporting cables 2 to the heads 5 of the pylons 4 are located in the plan of the bridge on straight lines forming angles with the longitudinal axis of the O-O bridge, the tangents of which are equal to the ratio of the width of the bridge “2B” to the length of its span L, while the straight lines intersect in the middle of the span Bridge C.

 To increase the horizontal stiffness of the bridge, the supporting cables 2 in the middle of the span of the bridge C have a direct nodal connection and this node is connected to the edges of the stiffener by means of cable drafts DC and CB.

 In comparison with the prototype, all suspension of cable trusses are initially inclined to the vertical by their own, individual angle each; as a result, the cable trusses of the bridge have a pronounced spatial character, and the tilt angles of the suspensions to the vertical increase in the direction from the bridge supports to the middle of its span.

 The role of the angle of inclination of the suspensions to the vertical consists in the appearance of the horizontal components of the full force in the suspensions at the initial stage of the bridge’s operation, which increases the resistance of the entire structure to horizontal loads.

 The introduction of the direct connection node of the load-bearing cables in the middle of the span forms an integral spatial truss, a feature of which is the simultaneous participation of both load-bearing cables in the perception of external influences.

 The attachment of this assembly to the faces of the stiffener beam using cable suspensions introduces an additional element of geometric immutability triangle D C B into the bridge circuit, which allows the spatial cable farm to “acquire” an additional intermediate support when perceiving horizontal influences.

In FIG. 1, 3, interlocking geometric parameters are additionally indicated, which determine the dimensions of a real structure: Н _п pylon height 4 and h "clearance gates" height to meet the requirements of design standards in terms of minimum permissible cross-section sizes AA according to the conditions for safe passage of automobile loads on the bridge.

 The scope of the invention is suspension bridges with spans of more than 200 m.

Claims (3)

 1. DANGEROUS BRIDGE, including a stiffener, bearing cables located on opposite sides of the longitudinal axis of the bridge and connected by cable suspensions with a stiffener, two coastal two-post pylons and devices for receiving struts of bearing cables, characterized in that the nodes of the bearing of the supporting cables to the ends the pylons are located in the plan of the bridge on straight lines forming angles with the longitudinal axis of the bridge, the tangents of which are equal to the ratio of the width of the bridge to the length of its span, while the straight lines intersect in the middle of the span of the bridge.  2. The bridge according to claim 1, characterized in that in the middle of the span of the bridge, the bearing cables have a direct nodal connection.  3. The bridge according to claim 2, characterized in that the node for the direct connection of the bearing cables in the middle of the span is connected to the faces of the stiffener by means of cable braces.

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