| Cable net structure is an important form of tension structure, which has the advantages of reasonable stress distribution, full use of the material strength, less steel consumption, convenient construction and beautiful architectural form. The Suzhou Swimming Stadium is a saddle shaped orthogonal monolayer cable net structure, consisting of V shaped column, saddle shaped ring beam, bearing cable, stable cable, rigid roof and curtain wall. The projection diameter of the ring beam is 106m and the fixed length double cable is applied. In this paper, on the basis of detailed summary of the characteristics and research status of cable net structure, construction plan design, zero state form-finding, construction process simulation analysis, error effect analysis and structural optimization analysis of saddle shaped cable net structure are studied by taking Suzhou Swimming Stadium for the engineering example.Firstly, types of the cable net structure are introduced to explain its compositions and mechanical properties. There have been many researches on form finding and static and dynamic behavior of the cable net structure. Form-finding methods include dynamic relaxation method, force density method and nonlinear finite element method. Studies on static and dynamic behaviors of cable net structure focus on its flexible and non-linear characteristics. Meanwhile, the paper introduces some classic construction projects of cable net structure, which are quite representative.Cable net structure for its cable number, cable clamp installation complexity and difficulties in applying prestressed and other reasons, the cable construction of the entire construction process is important and difficult. This paper abandon the traditional support construction plan and designed two more excellent cable construction programs in terms of duration, economy and maneuverability, which are integral-lifting method and upper-assembly method, respectively. On the basis of elaborating the connotations of the two construction methods, tension tooling, the degree of construction difficulty, safety, time limit and other aspects of the methods are compared to obtain their applicable conditions.The main purpose pf zero state form-finding is to obtain the assembled state of the peripheral structure of a cable net so that the structure can reach the target position and cable tension. In this paper, an iterative algorithm is applied to carry out zero state form finding for Suzhou Swimming Stadium, taking the configuration and cable tensions in dead load state as zero state form-finding analysis target and top nodes of V shaped columns as key points to calculate nodes preset values which are the basis of steel structure fabrication and installation.For the two cable construction plans, this paper uses "the nonlinear dynamic finite element method determining static equilibrium state of cable-strut system"(referred to as NDFEM) tracking the whole construction process of natatorium saddle shaped monolayer cable net structure of Suzhou Swimming Stadium and simulating the structural responses during the construction process, including cable forces, the surrounding steel structure stresses, structural configuration and lengths and types of tooling cables. In addition, it is necessary to make error effect analysis for the error sensitive structures like cable net structure, especially for the cable net structure with fixed length cables (no adjustments at cable heads). The manufacture errors of the cable length and external node installation errors are introduced into Suzhou Swimming Stadium to do the multiple error analysis. Error analysis conditions are set according to the specification and relevant engineering experience. Cable force errors under each error condition are compared to meet the requirements of the specification which is that the cable force errors should be less than 10% and according to the calculation results, suggestions to surrounding steel structure installation error requirements and cable head joints structure are given.Periphery structure of saddle shaped cable net structure is pretty important on the mechanical properties of the whole structure. This paper carries out parametric analysis of activation batch and inclination of V shaped columns and peripheral ring beam stiffness. The V shaped columns activated in batch is helpful to reduce stress level and decrease tensile force of the supports. On the other hand, before the columns are all welded, structure stiffness is low so that the cable network configuration changes greater when the roof is installed. When the ring beam has a high stiffness, the incline degrees of V shaped columns have little influence on the structure mechanical properties and upright V shaped columns are more conducive to make full use of the material. But if the ring beam stiffness is small, the inclination of V shaped columns is significant to improve the overall stiffness of the structure. The increase of ring beam stiffness will increase the structural rigidity to resist deformation, but the ring beam internal stress will increase and it will change the cable net displacement distribution which is need to be adopted cautiously.At the end of this paper, the main research content and research results are summarized systematically, and some problems and further research directions are put forward. |
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