高速公路30m跨度大规格热轧H型钢简支组合梁应用经济性研究

Study on the Application Economy of 30 m Span Large-size Hot-rolled H-beam Simply-supported Composite Beam of Highway

现有热轧H型钢最大高度不大于1 100 mm,高度相对较低,难以满足高速公路上常用跨度范围的热轧H型钢组合梁的需求。因此,依托G109国道新线高速公路(西六环路—市界段)工程跨丰沙铁路安家庄特大桥引桥设计,比较了高速公路30 m跨度简支梁的梁部采用大规格热轧H型钢组合梁、焊接工字钢板组合梁和预应力混凝土小箱梁的上、下部结构工程造价,并考虑了抗震设防烈度对下部结构工程造价的影响。研究结果表明:(1)采用预应力混凝土小箱梁时的梁部造价和总造价最低,大规格热轧H型钢组合梁次之,焊接工字钢板组合梁最高;(2)采用预应力混凝土小箱梁时的下部结构造价最高、大规格热轧H型钢组合梁和焊接工字钢板组合梁时的下部结构造价基本一致;(3)抗震设防烈度越高,下部结构造价越高;(4)较高烈度地震区的高速公路,应用大规格热轧H型钢组合梁代替预应力混凝土小箱梁经济上是可行的。

That the maximum height of the existing hot-rolled H-beam is not greater than 1100 mm,which is rela-tively low,is difficult to meet the demand for hot-rolled H-beam composite beam with commonly span ranges on highway.Based on the design of the approach bridge of Anjiazhuang Grand Bridge across Fengtai-Shacheng Railway of the New-Line Project(West Sixth Ring Road to the city boundary)of National Highway 109,the cost of the super-structure and substructure of 30 m span's simply-supported beam with large-size hot-rolled H-beam composite beam,welded I-beam composite beam and prestressed concrete small box girder were compared,and the impact of seismic fortification intensity on the cost of substructure was considered.The results show that the beam cost and total cost are the lowest,followed by large-size hot-rolled H-beam composite beam,and welded I-beam composite beam is the highest when prestressed concrete small box girder was applied;The substructure cost is the highest,and the substructure cost is basically the same with large-size hot-rolled H-beam composite beam and welded I-beam com-posite beam;The higher the seismic fortification intensity,the higher the cost of the substructure.On highways in high seismic intensity areas,it is economically feasible to use large-size hot-rolled H-beam composite beam instead of prestressed concrete small box girder.