部分斜拉桥的结构行为与设计实践
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摘要
近年来，在PC箱梁桥和PC斜拉桥之间出现了一种新的桥梁结构形式，并在若干个国家得以应用。最初提出这种新型桥梁结构形式的法国工程师J．Matlivat将之命名为超配量(extradosed)体外索PC桥；日本的桥梁界将其统称为斜拉桥。而我国著名桥梁专家严国敏先生则把它定义为“部分斜拉桥”。由于结构性能优越，经济指标良好，部分斜拉桥显示出巨大的发展潜力。
本文首先回顾这种桥梁的发展，然后简要介绍部分斜拉桥的结构特点及受力机理，结合兰州小西湖黄河大桥(82m+136m+82m)三跨预应力混凝土部分斜拉桥的设计实践和有限元分析计算，对部分斜拉桥的构造、受力特征和设计要点以及其在中、长跨度桥梁中的应用前景进行了分析和探讨。本文主要研究以下问题：
1 在桥跨布置方面，主边跨的比例更接近连续梁，但跨越能力较连续梁大。当支点梁高相同时，部分斜拉桥的跨度比连续梁大一倍以上。
2 主梁的高跨比值较斜拉桥大，一般介于斜拉桥与连续梁之间。由于整体刚度大，变形小，尤其适用于荷载大、标准高的铁路桥梁。
3 塔高较矮。塔高一般为跨度的1／12～1／8间。
4 斜拉索较为集中，通常布置在边跨跨中及中跨1／3附近，边跨梁端无锚固索。
5 斜拉索集中在塔顶鞍座上通过。
6 斜拉索应力变化幅度小，可采用较高的应力。一般情况下，斜拉桥拉索的应力为标准强度的0.4～0.45倍，而部分斜拉桥可用至0.5～0.6倍，从而减少钢材用量。
7 主梁的施工更接近于梁式桥。主梁抗弯刚度大，可采用梁式桥施工方法，而无需像斜拉桥那样采用大型牵索挂篮，极大地方便施工。
8 适用跨径宜在100～300m之间，若主梁采用钢与混凝土混合结构，跨径有望突破400m。
In recent years, a new type bridge appears between PC box-girder bridge and PC cable-stayed bridge and is accepted and applied in some countries. It is called extradosed exterior cable PC bridge by a French engineer - J. Malival who advances this new structural concept and structural type of bridge originally. In Japan, this new type bridge is generally entitled cable-stayed bridge. But in china, it is called partial cable-stayed bridge by Mr. Yan Guo min who is a famous expert in bridge engineering field. Due to its predominant structural behavior and favorable economic index, partial cable-stayed bridge has good application potential.
Firstly, the development of this type bridge is presented. Then some characters and basic mechanical principle of partial cable-stayed bridge are introduced. On the base of design practice and finite element analysis of three-span partial cable-stayed bridge, Xiaoxihu Yellow River Bridge in LanZhou, some key points in design practice and structural details are recommend. Finally, this paper discusses the application of partial cable-stayed bridges in middle span and long span and educes several conclusions as below:
1 On arranging bridge span, the radio of middle-span and side-span of partial cable-stayed bridge is close to continuous beam even more, but its main span is longer than continuous beam. When girder height in middle fulcrum is same, the span of partial cable-stayed bridge can be longer one times over than that of continuous beam.
2 Depth-span radio of main beam of partial cable-stayed bridge is larger than that of cable-stayed bridge and is generally between continuous beam and cable-stayed bridge. Due to partial cable-stayed bridge's higher stifmess and letter deformation, it is especial for high standard railway bridge carrying heavy loads.
3 Tower height is lower. It is generally only 1/12-1/8 of main
span.
4 Stayed cables are centralized relatively. They are generally disposed nearby middle of side-span and 1/3 middle-span. There has no anchorage cable at the end-girder of side-span.
5 Stay cables are centralized together through saddle at top of the tower.
6 The range of stress of stayed cables is small, so higher stress can be adopt In common case, stayed cable's stress of cable-stayed bridge is 0.4-0.45 times standard strength, but that of partial cable-stayed bridge is 0.5-0.6 times, so steel amount can be reduced.
7 Construction method of main beam of partial cable-stayed bridge is analogical to those of girder bridge. Because it has bigger bending stiffness, construction method of general girder bridge can be adopt . It does not need to use larger suspended wangon, so it is more safe for building.
8 Its applicable span is between 100~300m. If main beam adopts mixed concrete and steel structure, the span will reach 400m.
本文首先回顾这种桥梁的发展，然后简要介绍部分斜拉桥的结构特点及受力机理，结合兰州小西湖黄河大桥(82m+136m+82m)三跨预应力混凝土部分斜拉桥的设计实践和有限元分析计算，对部分斜拉桥的构造、受力特征和设计要点以及其在中、长跨度桥梁中的应用前景进行了分析和探讨。本文主要研究以下问题：
1 在桥跨布置方面，主边跨的比例更接近连续梁，但跨越能力较连续梁大。当支点梁高相同时，部分斜拉桥的跨度比连续梁大一倍以上。
2 主梁的高跨比值较斜拉桥大，一般介于斜拉桥与连续梁之间。由于整体刚度大，变形小，尤其适用于荷载大、标准高的铁路桥梁。
3 塔高较矮。塔高一般为跨度的1／12～1／8间。
4 斜拉索较为集中，通常布置在边跨跨中及中跨1／3附近，边跨梁端无锚固索。
5 斜拉索集中在塔顶鞍座上通过。
6 斜拉索应力变化幅度小，可采用较高的应力。一般情况下，斜拉桥拉索的应力为标准强度的0.4～0.45倍，而部分斜拉桥可用至0.5～0.6倍，从而减少钢材用量。
7 主梁的施工更接近于梁式桥。主梁抗弯刚度大，可采用梁式桥施工方法，而无需像斜拉桥那样采用大型牵索挂篮，极大地方便施工。
8 适用跨径宜在100～300m之间，若主梁采用钢与混凝土混合结构，跨径有望突破400m。
In recent years, a new type bridge appears between PC box-girder bridge and PC cable-stayed bridge and is accepted and applied in some countries. It is called extradosed exterior cable PC bridge by a French engineer - J. Malival who advances this new structural concept and structural type of bridge originally. In Japan, this new type bridge is generally entitled cable-stayed bridge. But in china, it is called partial cable-stayed bridge by Mr. Yan Guo min who is a famous expert in bridge engineering field. Due to its predominant structural behavior and favorable economic index, partial cable-stayed bridge has good application potential.
Firstly, the development of this type bridge is presented. Then some characters and basic mechanical principle of partial cable-stayed bridge are introduced. On the base of design practice and finite element analysis of three-span partial cable-stayed bridge, Xiaoxihu Yellow River Bridge in LanZhou, some key points in design practice and structural details are recommend. Finally, this paper discusses the application of partial cable-stayed bridges in middle span and long span and educes several conclusions as below:
1 On arranging bridge span, the radio of middle-span and side-span of partial cable-stayed bridge is close to continuous beam even more, but its main span is longer than continuous beam. When girder height in middle fulcrum is same, the span of partial cable-stayed bridge can be longer one times over than that of continuous beam.
2 Depth-span radio of main beam of partial cable-stayed bridge is larger than that of cable-stayed bridge and is generally between continuous beam and cable-stayed bridge. Due to partial cable-stayed bridge's higher stifmess and letter deformation, it is especial for high standard railway bridge carrying heavy loads.
3 Tower height is lower. It is generally only 1/12-1/8 of main
span.
4 Stayed cables are centralized relatively. They are generally disposed nearby middle of side-span and 1/3 middle-span. There has no anchorage cable at the end-girder of side-span.
5 Stay cables are centralized together through saddle at top of the tower.
6 The range of stress of stayed cables is small, so higher stress can be adopt In common case, stayed cable's stress of cable-stayed bridge is 0.4-0.45 times standard strength, but that of partial cable-stayed bridge is 0.5-0.6 times, so steel amount can be reduced.
7 Construction method of main beam of partial cable-stayed bridge is analogical to those of girder bridge. Because it has bigger bending stiffness, construction method of general girder bridge can be adopt . It does not need to use larger suspended wangon, so it is more safe for building.
8 Its applicable span is between 100~300m. If main beam adopts mixed concrete and steel structure, the span will reach 400m.
引文
[1] 严国敏．试淡“部分斜拉桥”，国外桥梁，1996．1．
[2] 严国敏．现代斜拉桥．成都，西南交通大学出版社．1996．7．
[3] 《公路钢筋混凝土及预应力混凝土桥涵设计规范》 (JTJ023-85)
[4] 《公路斜拉桥设计规范》(试行)(JTJ027-96)
[5] 《公路工程抗震设计规范》(JTJ004-89)
[6] 唐小萍，平行钢绞线拉索与平行钢丝拉索的特性、经济性比较分析，桥梁建设，1997(4)：17～19
[7] 唐明翰，李义，现代斜拉索，桥梁建设，1997(4)：29～32
[8] 杨进，华有恒，汕头宕石大桥主桥斜拉索选型及锚固方案，桥梁建设，1997(4)：13～16
[9] 唐明翰，李义，现代斜拉索，公路，1997(10)：1～8
[10] 姜辉译，斜拉索的可靠防腐，国外桥梁，1996(1)：30～32
[11] 张晓东，陈宁，王应良，郑凯峰编译，斜拉桥的数学建模，国外桥梁，1998(2)：52～56．
[12] 党志杰，斜拉索的疲劳抗力，桥梁建设，1999(4)18～21．
[13] 郝超，斐岷山，强士中，斜拉桥索力测试新方法——磁通量法，公路，2000(11)：30～31．
[14] 刘建新，胡兆同，李子青，不同桥型桥梁抗风设计特点，第十二届全国桥梁学术会议论文集，1996：654～660．
[15] 斜拉桥拉索的风振与防振措施，国外桥梁，1992(3)：59～67
[16] 杨高中，粘性剪切阻尼器(VSD)在铜陵长江大侨上的应用，公路 2000(3)：66～67
[17] 汪正兴，阻尼减振技术及其在桥梁与塔式结构中的应用，桥梁建设，1999(4)：22～25．
[18] 伏晓宁，洞庭湖大桥拉索风雨振控制新技术，公路，2003(2)：14～17．
[19] 林元培．斜拉桥[M]．北京：人民交通出版社，1995．
[20] 周念先．预应力混凝土斜张桥[M]．北京：人民交通出版社，1989．
[21] [日]小西一郎．钢桥(第四分册)[M]．戴振藩译．北京：人民交通出版社．
[2] 严国敏．现代斜拉桥．成都，西南交通大学出版社．1996．7．
[3] 《公路钢筋混凝土及预应力混凝土桥涵设计规范》 (JTJ023-85)
[4] 《公路斜拉桥设计规范》(试行)(JTJ027-96)
[5] 《公路工程抗震设计规范》(JTJ004-89)
[6] 唐小萍，平行钢绞线拉索与平行钢丝拉索的特性、经济性比较分析，桥梁建设，1997(4)：17～19
[7] 唐明翰，李义，现代斜拉索，桥梁建设，1997(4)：29～32
[8] 杨进，华有恒，汕头宕石大桥主桥斜拉索选型及锚固方案，桥梁建设，1997(4)：13～16
[9] 唐明翰，李义，现代斜拉索，公路，1997(10)：1～8
[10] 姜辉译，斜拉索的可靠防腐，国外桥梁，1996(1)：30～32
[11] 张晓东，陈宁，王应良，郑凯峰编译，斜拉桥的数学建模，国外桥梁，1998(2)：52～56．
[12] 党志杰，斜拉索的疲劳抗力，桥梁建设，1999(4)18～21．
[13] 郝超，斐岷山，强士中，斜拉桥索力测试新方法——磁通量法，公路，2000(11)：30～31．
[14] 刘建新，胡兆同，李子青，不同桥型桥梁抗风设计特点，第十二届全国桥梁学术会议论文集，1996：654～660．
[15] 斜拉桥拉索的风振与防振措施，国外桥梁，1992(3)：59～67
[16] 杨高中，粘性剪切阻尼器(VSD)在铜陵长江大侨上的应用，公路 2000(3)：66～67
[17] 汪正兴，阻尼减振技术及其在桥梁与塔式结构中的应用，桥梁建设，1999(4)：22～25．
[18] 伏晓宁，洞庭湖大桥拉索风雨振控制新技术，公路，2003(2)：14～17．
[19] 林元培．斜拉桥[M]．北京：人民交通出版社，1995．
[20] 周念先．预应力混凝土斜张桥[M]．北京：人民交通出版社，1989．
[21] [日]小西一郎．钢桥(第四分册)[M]．戴振藩译．北京：人民交通出版社．