摘要
以设计速度350km.h-1、跨度32m的预应力混凝土箱梁为例,在分析梁体基频、刚度和变形的设计值与实测值差异成因的基础上,进行高速铁路常用跨度简支箱梁优化研究。结果表明,对于铺设CRTSⅡ型板式无砟轨道的32m预应力混凝土双线整孔箱梁,实测梁体的自振频率约为设计值的1.4倍,其竖向刚度为设计值的1.7倍,混凝土弹性模量提高、二期恒载降低及桥梁与无砟轨道相互作用分别使梁体基频提高约4.9%～19.9%,4.8%～10.5%和3.6～5.7%;混凝土弹性模量提高、支座摩阻及桥梁与无砟轨道相互作用分别使梁体刚度提高10.1%～43.7%,5.9%～17.7%和7.4%～11.8%。鉴于梁体频率实测值比设计值高出较多,建议设计时梁体频率可取规范限值的0.9;梁体刚度虽可以进一步降低,但应严格控制预应力混凝土梁体的残余徐变变形,确保长期变形不大于现有箱梁的设计值。鉴于跨度32m以上简支梁桥的车桥动力响应显著降低,建议对更大跨度简支梁开展研究。
The prestressed concrete （PC） box girder with the span of 32 m and the design speed of 350 km · h-1 was taken for example. Based on analyzing the causes for the differences between the design values and the measured values of girder fundamental frequency, stiffness and deformation, study was carried through on the optimization of standard span length simply supported box girders for high-speed railway. The results show that, with regard to 32 m PC double-track whole span box girders for CTRS II ballast- less slab track, the actual natural frequency of the girder is about 1.4 times of the designed value, and the actual vertical stiffness is about 1.7 times the designed values. The fundamental frequencies of girder are increased about 4. 9%-19.9%, 4.8%-10.5% and 3.6%-5. 7% respectively by higher elastic modulus of concrete, lower secondary dead load, and the interactions between the bridge and the ballastless track. The stiffness of the girder is increased about 10. 1%-43.7%, 5.9%-17. 7% and 7.4%-11.8% respec- tively by higher elastic modulus of concrete, the bearing friction, and the interactions between the bridge and the track ballastless. Since the measured frequency value is much higher than the designed value, a correction factor of 0. 9 is suggested to apply to the design code for girder design. Although the stiffness of girder may be further reduced, it is necessary to strictly control the residual creep deformation of PC gird- er, and to ensure that the long-term deformation is not greater than the existing designed value for box girder. Because the train-bridge dynamic response of simply supported bridge with over 32 m span will be significantly reduced, it is suggested to carry out research on simply supported girder with larger span.
出处
《中国铁道科学》
EI
CAS
CSCD
北大核心
2013年第1期15-21,共7页
China Railway Science
基金
铁道部科技研究开发计划项目(JS2008-05
JS2008-06
JS200807)
关键词
高速铁路
桥梁
简支梁
箱梁
跨度
基频
刚度
变形
优化
High-speed railway
Bridge
Simply supported girder
Box girder
Span
Fundamental frequency
Stiffness
Deformation
Optimization
