对木桥的负载和阻力系数的校准-------外文翻译.doc
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对木桥的负载和阻力系数的校准-------外文翻译,abstract: the paper presents the calibration procedure and background data for the development of design code provisions for wood bridges. the structural types ...
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Abstract: The paper presents the calibration procedure and background data for the development of design code provisions for wood bridges. The structural types considered include sawn lumber stringers, glued-laminated girders, and various wood deck types. Load and resistance parameters are treated as random variables, and therefore, the structural performance is measured in terms of the reliability index. The statistical parameters of dead load and live traffic load, are based on the results of previous studies. Material resistance is taken from the available test data, which includes consideration of the post-elastic response. The resistance of components and structural systems is based on the available experimental data and finite element analysis results. Statistical parameters of resistance are computed for deck and girder subsystems as well as individual components. The reliability analysis was performed for wood bridges designed according to the AASHTO Standard Specifications and a significant variation in reliability indices was observed. The recommended load and resistance factors are provided that result in consistent levels of reliability at the target levels.
DOI: 10.1061/（ASCE）1084-0702（2005）10:6（636）
CE Database subject headings: Bridges, wooden; Calibration; Load and Resistance Factor; Design; Bridge decks.
Introduction
In 1993 AASHTO adopted a new load and resistance factor design （LRFD） code for highway bridges. The new code provides a rational basis for the design of steel and concrete structures.Although wood bridge design was also included in LRFD format,the calibration was not carried out for these structures （Nowak 1995, 1999）. Therefore, there was a concern about the consistency of the reliability level for wood structures.
Previous studies showed that the reliability index for wood bridge components can be significantly different than for steel or concrete structures （Nowak 1991）. The degree of variation for wood properties varies depending on dimensions, load duration,moisture content, and other parameters. In case of wood bridges,it is important to consider the structural system or subsystem as well as individual elements/components.
内容摘要：这篇论文为木桥设计规范的确定发展提供了校准方法和基本数据。结构类型被认为包括锯成的木梁、胶合梁及各种类型的木梁板。负载和阻力参数被视为随机变量，因而，结构特性是根据可靠性指标来测定的。桥的恒载和交通活载，都是基于先前的研究结果。材料的阻值是取自可用的测试得来的数据，这些数据中包含了考虑有弹性反应作用的数据。阻力的组成和结构系统是基于可利用的实验数据和有限元分析的结果。阻力的统计参数是由梁板、梁体及个别的组件计算而得。对木桥进行可靠性分析设计应依照AASHTO标准设计规范并且要注意到可靠性指标中的一个重要变化，负载限度和阻力系数应该和可靠性程度及目标水准相一致。
DOL：10.1061/(ASCE)1084-0702(2005)10:6(636)
土木工程师数据库的关键词：桥梁、木制的、校准、负载和阻力系数、设计、桥板。
论文简介
1993年，美国国家公路与运输协会采纳了一部新的公路桥的负载和阻力因素的设计法规。这部新法规为钢结构与混凝土结构提供了一个合理的设计依据。尽管木桥的设计在设计法规中也还包含在内，但是对这些结构此校准法还没有予以实行（诺瓦克1995，1999）。因此，对于木结构的可靠性水平的一致性问题还有一些疑虑。
先前的一些研究指明木桥结构部件的可靠度与钢结构或者混凝土结构有明显的不同之处（诺瓦克 1991）。这个程度的变化对木材性质的影响则取决于尺寸大小,负载持续时间、水分含量等参数。假若是木桥，考虑到其结构体系或次要系统以及个别元件/部件是非常重要的一步。
DOI: 10.1061/（ASCE）1084-0702（2005）10:6（636）
CE Database subject headings: Bridges, wooden; Calibration; Load and Resistance Factor; Design; Bridge decks.
Introduction
In 1993 AASHTO adopted a new load and resistance factor design （LRFD） code for highway bridges. The new code provides a rational basis for the design of steel and concrete structures.Although wood bridge design was also included in LRFD format,the calibration was not carried out for these structures （Nowak 1995, 1999）. Therefore, there was a concern about the consistency of the reliability level for wood structures.
Previous studies showed that the reliability index for wood bridge components can be significantly different than for steel or concrete structures （Nowak 1991）. The degree of variation for wood properties varies depending on dimensions, load duration,moisture content, and other parameters. In case of wood bridges,it is important to consider the structural system or subsystem as well as individual elements/components.
内容摘要：这篇论文为木桥设计规范的确定发展提供了校准方法和基本数据。结构类型被认为包括锯成的木梁、胶合梁及各种类型的木梁板。负载和阻力参数被视为随机变量，因而，结构特性是根据可靠性指标来测定的。桥的恒载和交通活载，都是基于先前的研究结果。材料的阻值是取自可用的测试得来的数据，这些数据中包含了考虑有弹性反应作用的数据。阻力的组成和结构系统是基于可利用的实验数据和有限元分析的结果。阻力的统计参数是由梁板、梁体及个别的组件计算而得。对木桥进行可靠性分析设计应依照AASHTO标准设计规范并且要注意到可靠性指标中的一个重要变化，负载限度和阻力系数应该和可靠性程度及目标水准相一致。
DOL：10.1061/(ASCE)1084-0702(2005)10:6(636)
土木工程师数据库的关键词：桥梁、木制的、校准、负载和阻力系数、设计、桥板。
论文简介
1993年，美国国家公路与运输协会采纳了一部新的公路桥的负载和阻力因素的设计法规。这部新法规为钢结构与混凝土结构提供了一个合理的设计依据。尽管木桥的设计在设计法规中也还包含在内，但是对这些结构此校准法还没有予以实行（诺瓦克1995，1999）。因此，对于木结构的可靠性水平的一致性问题还有一些疑虑。
先前的一些研究指明木桥结构部件的可靠度与钢结构或者混凝土结构有明显的不同之处（诺瓦克 1991）。这个程度的变化对木材性质的影响则取决于尺寸大小,负载持续时间、水分含量等参数。假若是木桥，考虑到其结构体系或次要系统以及个别元件/部件是非常重要的一步。
