钢-混凝土组合梁桥设计优化研究与工程建设应用

Study on Design Optimization of Steel-concrete Composite Beam Bridge and Its Engineering Construction Application

摘要:

利用钢梁与混凝土的组合性能优势和技术，将市政快速路大跨径简支预制板组合梁方案优化设计为叠合板组合梁桥面体系，新方案实现桥梁结构高度降低17.3%，用钢量降低20.2%。优化方案有限元模型验算结果显示，在最不利工况荷载下，边梁抗弯最不利应力为162 MPa，混凝土最不利压应力为-14.2 MPa；中梁抗弯最不利应力为165 MPa， 混凝土最不利压应力为-13.8 MPa； 边梁挠度39.3 mm， 挠跨比为1/1 399，中梁挠度36.6 mm， 挠跨比为1/1 503，均满足设计规范要求。成桥静力载荷试验结果显示，在公路-I级荷载水平下，结构最大挠度值为17 mm，最大挠跨比为1/3 235，最大压拉应力值为24.68 MPa，最大压应力值为50.16 MPa，远小于Q345钢材应力设计值，桥梁结构性能满足规范要求。

Abstract:

By utilizing the combined performance advantages and technology of steel beam and concrete, the long-span simply supported prefabricated slab composite beam is optimized and designed as a composite slab beam deck system for the municipal expressway. The new scheme realizes the reductions of bridge structure height by17.3% and steel amount by 20.2%. The finite element model checking results of the optimized scheme show that under the most unfavorable load, the most adverse bending stress of the side beam is 162 MPa and its most adverse compressive stress of concrete is -14.2 MPa. The most unfavorable bending stress of the middle beam is 165 MPa and its most unfavorable compressive stress of concrete is -13.8 MPa. The deflection of the side beam is 39.3 mm and its deflection span ratio is 1/1399. The deflection of the middle beam is 36.6 mm and its deflection span ratio is 1/1503. All meet the requirements of design specifications. The static load test results of finished bridge show that under the level of highway - I load, the maximum deflection of the structure is 17 mm, its maximum deflection span ratio is 1/3 235, its maximum compressive tensile stress is 24.68 MPa and its maximum compressive stress is 50.16 MPa, which are far less than the stress design value of Q345 steel and the structural performances of the bridge meet the standard requirements.