Decreasing the Displacements of a Composite Saddle-Shaped Cable Roof

2015

ETR

Limited raw materials and energy resources are actual national economy problems which can be solved by the decrease of weight, increase of span and durability of load bearing structures. The largest structural spans were achieved by application of cable structures. The roofs are one of the most widely used in practice type of cable structures. However, increased deformability and necessity of the special methods of stabilizing are significant cable roofs disadvantages. The prestressing of one or several groups of cables is one of the probable methods for stabilizing of cable roofs. According to the recommendations available in the literature, all cables of the roof must be prestressed by the equal forces. But after applying of design vertical load, values of the forces, acting in the cables of the roof, changes within the wide limits. So, using of structural materials will not be rational in this case, taking into account, that the cables cross-sections are constant because the cables cross-sections were determined basing on the maximum axial force, acting in the all cables.Possibility to decrease materials consumption by the changing of prestressing forces for cables of the roof was checked on the example of saddle-shaped cable roof with the rigid support contour and dimensions 60x60 m in the plan. Initial deflections of main suspension and stressing cables of the roof were equal to 7m. Suspension and stressing cables of the net were placed with the step equal to 2.828 m. Steel ropes with modulus of elasticity in 1.5∙105 MPa were considered as a material of suspension and stressing cables of the roof. Suspension and stressing cables were divided into the groups, which are differed by the prestressing forces. Amount of cables groups changes within the limits from 1 to 27. Values of prestressing forces for cables groups change within the limits from 20 to 80% from the cables breaking force. The dependences of material consumption and maximum vertical displacements of cable roof on the amount of cables groups and prestressing forces were determined as second power polynomial equations. It was stated, that division of suspension and stressing cables on the 18 groups enables to decrease cables material consumption by 19.2%. Values of prestressing forces for suspension and stressing cables of the roof were equal to 57 and 80 %, from it load-carrying capacity, correspondingly.

Section: Introductionmentioning

confidence: 97%

“…1, c). The decreased ratio between applied load and structural dead weight save raw materials and energy resources [3], [4]. According to the recommendations available in the literature, all the cables of the load carrying net must be prestressed by the same force [5], [6].…”

Section: Introductionmentioning

confidence: 99%

Materials Consumption Decrease for Long-Span Prestressed Cable Roof

Stuklis

2015

ETR

“…Usage of a prestressed cable truss is another method of fixing the problem of increased kinematic displacements under the action of unsymmetrical load (Serdjuks, Rocens 2004;Goremikins et al 2011). Different types of cable trusses are known, such as convex cable trusses, convexconcave cable trusses, cable trusses with centre compression strut or parallel cable trusses (Schierle 2012).…”

Section: Introductionmentioning

confidence: 99%

Hybrid composite cable for prestressed suspension structure

Rocēns

Proceedings of the International Conference „Innovative Materials, Structures and Technologies”

et al. 2014

Abstract.A prestressed suspension structure is a type of structures that allows covering long spans due to rational use of structural materials. Prestressing of a suspension structure allows minimizing cinematic displacements. The prestressed suspension structure with the main span equal to 200 m was considered as an object of investigation. Replacement of a single steel main cable of the prestressed suspension structure by the hybrid composite cable with CFRP (Carbon Fibre Reinforced Polymer) middle layer and external steel layers with cross-section variable by the cable length considerably decreases dead weight of the cable. Hybrid composite cable ensures functioning of the structure in case of destruction of the middle CFRP layer. The considered prestressed suspension structure was investigated by the FEM software ANSYS. Rational steel distribution by the cable length was determined by optimization. Behaviour of the hybrid composite main cable in the case of destruction of the middle CFRP layer was experimentally tested using the physical model. The dynamic coefficient was obtained.

“…Usage of prestressed cable trusses is another method of fixing the problem of increased kinematic displacements under the action of unsymmetrical load [14][15]. Different types of cable trusses are known, such as convex cable trusses, convexconcave cable trusses, cable trusses with centre compression strut or parallel cable truss [16].…”

Section: Introductionmentioning

confidence: 99%

Simplified Method of Determination of Natural-Vibration Frequencies of Prestressed Suspension Bridge

Rocēns

et al. 2013

Procedia Engineering

A suspension bridge is the most suitable type for a long-span bridge. Increased kinematic displacements are the major disadvantage of suspension bridges. This problem can be solved by application of prestressed cable truss. Dynamic approach is one of regulated bridge design parts. Simplified determination method of natural-vibration frequencies of prestressed suspension structure and its experimental validation is presented in this paper. Natural-vibration frequencies and mode shapes of the model depending on the prestressing level were determined. It was experimentally proved, that mode shape with one half-wave does not appear for the model. The difference between results, which were calculated by the developed simplified determination method of natural-vibration frequencies of prestressed suspension structure and experimentally achieved by the model testing, does not exceed 20%. Therefore the method is applicable for preliminary dynamic analyses of structures.