In order to study the effect of asymmetric construction loads on the reasonable finished state of cable-stayed suspension bridge,taking the construction of the G3 Tongling Yangtze River dual-purpose steel truss stiffening girder bridge with a main span of 988 m as the project background,a spatial nonlinear finite element model of cable-stayed suspension bridge is established through numerical method,to study the stress,deformation,closure adjustment measures and the reasonable finished state of the kilometer-span flexible bridge structures under asymmetric and symmetric construction loads.The results indicate that,the structural responses of the cable-stayed suspension bridge system do not differ significantly under symmetric and asymmetric construction loads,but the internal forces of the structure are smaller under asymmetric construction loads,with an increase in the maximum displacement of the main girder's top chord by 2 m.The space between the beam segments at the closure gap is smaller than that at the closure section,with a height difference of 7.6 cm between the beam segments.Adjustment measures,including the application of a 5 000 kN pushing force at the closure gap and tensioning temporary hangers with a force of 300 kN,can effectively adjust the geometric shape of the closure gap to meet the closure construction requirements.After the closure of the entire bridge,the mid-span area of the main truss exhibits an upward arching trend,with a maximum vertical displacement of 2.6 m.Upon implementation of stay cables in the cable transition zone,the upward curvature of the main truss increases,with a maximum vertical displacement reaching 2.9 m,and finally the main girder achieves the desired design alignment after the installation of the secondary permanent pavement.
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