高速铁路预制拼装箱梁桥抗弯及接缝抗剪试验研究与理论分析
发布时间：2019-06-12 18:07
【摘要】：节段预制拼装技术是将结构整体分段预制后利用预应力技术再组装为整体的手段,主要应用在大跨桥梁结构中,具有预制标准、质量可控、对施工机械要求低、施工工期短、受环境影响小等优点,是桥梁结构一个十分重要的施工技术。预制拼装结构与整体现浇结构本质的区别是普通钢筋在接缝处不连续,接缝处主要通过不同的形式进行拼接连接,极限状态下结构的受力性能有较大的差别,需要对其进行系统的研究。现有的设计理论主要集中在几个关键问题上：节段预制拼装桥梁的抗裂性能,不同荷载阶段下梁体的刚度,极限状态下的抗弯承载能力,极限状态下的抗剪破坏模式及其承载力。抗弯方面本文基于对节段预制拼装梁与整体梁破坏本质认识的基础上建立了节段预制拼装简支梁及节段预制拼装连续梁的体外预应力筋应力增量计算公式,并通过有限元模型对节段预制拼装连续梁的内力重分布进行了分析,建立了不同荷载阶段下的抗弯刚度计算公式。抗剪方面对单键剪力键受剪破坏形式以及多键剪力键破坏形式进行了系统的分析,提出了相应的数值计算模型并进一步提出了简化计算模型,对节段预制拼装梁的抗剪破坏模式进行了探讨并形成了抗剪承载力的计算公式。设计了10个剪力键抗剪试验以及4根简支梁、1根三跨连续梁进行试验并对理论分析进行了验证,本文的主要研究内容及成果如下：(1)推导了节段预制拼装桥梁受力全过程的刚度计算公式。基于粘结-滑移理论提出了接缝截面刚度影响范围的概念,以节段为单位,按等效后转角相同的方法推导了不同荷载等级下的节段预制拼装梁等效刚度计算公式,其采用三折线形式-分为未开裂阶段,正常使用阶段,极限状态阶段,物理意义明确,结果精度高。(2)推导了节段预制拼装梁体外预应力筋的极限应力增量的计算公式。讨论了现有的简支梁体外预应力筋应力增量的计算方法,基于等效塑性铰理论,建立体外预应力整体简支梁应力增量与极限位移的计算模型。提出了节段简支梁与整体简支梁极限位移的比例系数概念,推导了节段预制拼装简支梁极限位移的计算公式。根据梁体跨中位移与体外预应力筋应力成线性比例的关系,得到预制拼装简支梁体外预应力筋的极限应力增量计算公式,并形成了简化计算公式。(3)提出了连续梁塑性铰位置修正系数χ概念,基于等效塑性铰理论推导了连续梁跨中极限位移的计算公式,并形成了体外预应力节段预制拼装连续梁体外预应力筋极限应力增量的计算公式,通过试验结果进行了验证。采用纤维梁单元模型,考虑了节段梁截面刚度影响区域长度,建立了节段预制拼装连续梁力学模型,并进行了内力重分布影响因素分析,为节段预制拼装连续梁的考虑内力重分布的塑性设计提供了依据。(4)受弯方面进行了4个简支梁(1个整体、3个节段)及1个三跨节段连续梁受弯试验,根据试验结果提出了节段预制拼装梁抗裂分析的参数取值,并对建立的应力增量计算公式等进行了验证。进行了10个不同接缝形式节段预制拼装梁接缝抗剪试验,考虑了水平压力大小、干结与胶结、键齿大小、平接与键齿接缝等因素,对建立的简化计算公式进行了验证。(5)采用ABAQUS有限元软件自带混凝土CDP材料模型进行了初步分析,了解了剪力键抗剪破坏的机理,并与现有单键破坏试验进行比对,给出了抗剪分析时CDP模型的参数设置建议。针对CDP模型的缺点,在分析剪力键受剪破坏原理的基础上,开发了基于ABAQUS有限元软件VUMAT子程序的混凝土抗剪模型,模型中体现了混凝土破坏准则、Ⅱ型断裂能、剪断后摩擦剪应力对剪力键受剪破坏的影响,通过已有剪力键受剪破坏试验确定了混凝土抗剪模型参数取值,并验证了模型的正确性,揭示了剪力键受剪破坏的原理。(6)利用开发的混凝土抗剪模型对剪力键受剪构件进行了参数分析,考虑键齿形状、水平压力大小、键齿数目、接缝连接方式等因素对剪力键受剪承载力的影响,建立了接缝抗剪破坏承载力计算模型,形成了不同接缝形式接缝抗剪破坏承载力的计算公式,公式物理意义明确,形式参数统一,与试验结果相比具有较高的精度。(7)在分析了节段预制拼装梁与整体梁抗剪差异的基础上,归纳了节段预制拼装梁抗剪破坏的不同破坏形式及破坏机理。分析了不同接缝形式对混凝土部分抗剪承载力影响,根据混凝土的压剪破坏准则,考虑了受压翼缘对抗剪承载力的贡献,编制了接缝抗剪破坏的计算分析程序,并采用简化方式利用平衡方程对混凝土的抗剪承载力进行推导,形成接缝抗剪破坏的抗剪承载力计算公式,并进行了试验数据的验证。根据不同算例的试算结果给出了节段预制拼装梁接缝抗剪破坏的产生条件,可用于桥梁的初期抗剪设计。
[Abstract]:The segment pre-assembly technology is a method for reassembling the whole structure of the structure by using the pre-stress technology, and is mainly applied to the large-span bridge structure, has the advantages of the prefabricated standard, the controllable quality, low requirements on the construction machinery, short construction period, small environmental impact and the like, It is a very important construction technology for bridge structure. The difference between the prefabricated assembly structure and the integral cast-in-place structure is that the common steel bar is not continuous at the joint, the joint is mainly spliced and connected in different forms, and the stress performance of the structure under the limit state is greatly different, and the system research is needed. The existing design theory is mainly focused on several key problems: the crack resistance performance of the segment pre-assembled bridge, the stiffness of the beam body at different load stages, the bending bearing capacity under the extreme state, the shear failure mode in the extreme state and the bearing capacity thereof. In the aspect of bending, this paper establishes the calculation formula of the stress increment of the in-vitro pre-stressed bar of the section pre-assembled simply-supported beam and the section pre-assembled continuous beam based on the understanding of the nature of the section-section pre-assembled beam and the whole beam's failure. The internal force redistribution of the continuous beam is analyzed by the finite element model, and the calculation formula of the bending stiffness at different load stages is established. The shear failure form of the single bond shear key and the damage form of the multi-key shear key are analyzed in the shear field. The corresponding numerical calculation model is proposed and the simplified calculation model is further put forward. The shear failure mode of the section precast assembly beam is discussed and the calculation formula of the shear bearing capacity is formed. Ten shear-key anti-shear tests and four simple and three-span continuous beams are tested and the theoretical analysis is verified. The main contents and results of this paper are as follows: (1) The formula for calculating the stiffness of the whole process of the segmental pre-assembled bridge is derived. Based on the theory of bond-slip, the concept of the influence range of the joint cross-section stiffness is put forward, and the equivalent stiffness calculation formula of the segment pre-assembled beam at different load levels is derived in the same way as the equivalent rear corner. The formula of the three-fold line-divided into the non-cracking stage, The normal operation stage, the limit state stage, the physical meaning is clear, and the result precision is high. (2) The calculation formula of the limit stress increment of the pre-stressed bar of the segmental pre-assembled beam is derived. In this paper, the calculation method of the stress increment of the in-vitro pre-stressed bar of simply-supported beam is discussed, and the calculation model of the stress increment and the limit displacement of the in-vitro pre-stressed integral simple-supported beam is established based on the equivalent plastic hinge theory. The concept of the ratio coefficient of the limit displacement of the simply-supported beam and the integral simple-supported beam is proposed, and the calculation formula of the limit displacement of the simple-supported beam is derived. According to the relationship between the displacement of the span of the beam body and the stress of the external prestressed tendon in a linear proportion, the formula for calculating the ultimate stress increment of the pre-assembled simple-supported beam external prestressed rib is obtained, and a simplified calculation formula is formed. (3) The concept of the position correction coefficient of the continuous beam plastic hinge is proposed, and the calculation formula of the limit displacement of the continuous beam span is derived based on the equivalent plastic hinge theory, and the formula for calculating the limit stress increment of the external prestressed tendon in the external prestressed section is formed. The results of the test were verified. In this paper, the section length of the section beam section is considered, the mechanical model of the section pre-assembled continuous beam is established, and the influence factor analysis of the internal force re-distribution is carried out, and the basis for considering the plastic design of the inner force redistribution of the section pre-assembled continuous beam is provided. (4) The bending test of four simple-supported beams (one whole, three sections) and one three-span section was carried out in the bending, and the parameter value of the crack-crack analysis of the segmental pre-assembled beam was put forward according to the test results, and the calculation formula of the stress increment was verified. In this paper, the shear test of the joint in 10 different joint-type segments is carried out. The simplified calculation formula is verified by considering the factors such as the horizontal pressure, the dry-knot and the cementation, the size of the key teeth, the flat-joint and the key-tooth joint. (5) The initial analysis of the concrete CDP material model with ABAQUS finite element software is carried out, the mechanism of shear-key anti-shear failure is understood, and compared with the existing single-bond failure test, the parameter setting suggestion of the CDP model is given. A concrete shear model based on the ABAQUS finite element software VUMAT subprogram is developed on the basis of analyzing the shear failure principle of the shear bond, and the effect of the shear stress on the shear failure of the shear bond is shown in the model. The parameter value of the shear model of the concrete is determined by the shear failure test of the existing shear key, and the correctness of the model is verified, and the principle of shear failure of the shear key is revealed. and (6) using the developed concrete shear model to perform the parameter analysis on the shear key subject to shear, taking into account the influence of the key tooth shape, the horizontal pressure size, the number of the key teeth, the joint connection mode and the like on the shear bearing capacity of the shear key, and establishing a calculation model of the shear failure bearing capacity of the joint, The calculation formula of the shear failure bearing capacity of the joint in different joint forms is formed, the formula is of clear physical meaning and the formal parameters are uniform, and the formula has higher precision compared with the test result. (7) On the basis of the analysis of the difference between the segmental pre-assembled beam and the overall beam, the different types of damage and the failure mechanism of the section pre-assembled beam's anti-shear failure are summarized. The influence of different joint forms on the shear bearing capacity of the concrete part is analyzed. According to the criterion of the compression and shear failure of the concrete, the contribution of the pressure flange to the shear bearing capacity is considered, and the calculation analysis program for the shear failure of the joint is developed. In this paper, the shear bearing capacity of the concrete is derived by using the equilibrium equation in a simplified way, and the calculation formula of the shear bearing capacity of the joint shear failure is formed, and the verification of the test data is carried out. According to the test results of different examples, the generation condition of the joint shear failure of the segment pre-assembled beam is given, and the initial shear design of the bridge can be used.
【学位授予单位】：东南大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U446
，
本文编号：2498201
[Abstract]:The segment pre-assembly technology is a method for reassembling the whole structure of the structure by using the pre-stress technology, and is mainly applied to the large-span bridge structure, has the advantages of the prefabricated standard, the controllable quality, low requirements on the construction machinery, short construction period, small environmental impact and the like, It is a very important construction technology for bridge structure. The difference between the prefabricated assembly structure and the integral cast-in-place structure is that the common steel bar is not continuous at the joint, the joint is mainly spliced and connected in different forms, and the stress performance of the structure under the limit state is greatly different, and the system research is needed. The existing design theory is mainly focused on several key problems: the crack resistance performance of the segment pre-assembled bridge, the stiffness of the beam body at different load stages, the bending bearing capacity under the extreme state, the shear failure mode in the extreme state and the bearing capacity thereof. In the aspect of bending, this paper establishes the calculation formula of the stress increment of the in-vitro pre-stressed bar of the section pre-assembled simply-supported beam and the section pre-assembled continuous beam based on the understanding of the nature of the section-section pre-assembled beam and the whole beam's failure. The internal force redistribution of the continuous beam is analyzed by the finite element model, and the calculation formula of the bending stiffness at different load stages is established. The shear failure form of the single bond shear key and the damage form of the multi-key shear key are analyzed in the shear field. The corresponding numerical calculation model is proposed and the simplified calculation model is further put forward. The shear failure mode of the section precast assembly beam is discussed and the calculation formula of the shear bearing capacity is formed. Ten shear-key anti-shear tests and four simple and three-span continuous beams are tested and the theoretical analysis is verified. The main contents and results of this paper are as follows: (1) The formula for calculating the stiffness of the whole process of the segmental pre-assembled bridge is derived. Based on the theory of bond-slip, the concept of the influence range of the joint cross-section stiffness is put forward, and the equivalent stiffness calculation formula of the segment pre-assembled beam at different load levels is derived in the same way as the equivalent rear corner. The formula of the three-fold line-divided into the non-cracking stage, The normal operation stage, the limit state stage, the physical meaning is clear, and the result precision is high. (2) The calculation formula of the limit stress increment of the pre-stressed bar of the segmental pre-assembled beam is derived. In this paper, the calculation method of the stress increment of the in-vitro pre-stressed bar of simply-supported beam is discussed, and the calculation model of the stress increment and the limit displacement of the in-vitro pre-stressed integral simple-supported beam is established based on the equivalent plastic hinge theory. The concept of the ratio coefficient of the limit displacement of the simply-supported beam and the integral simple-supported beam is proposed, and the calculation formula of the limit displacement of the simple-supported beam is derived. According to the relationship between the displacement of the span of the beam body and the stress of the external prestressed tendon in a linear proportion, the formula for calculating the ultimate stress increment of the pre-assembled simple-supported beam external prestressed rib is obtained, and a simplified calculation formula is formed. (3) The concept of the position correction coefficient of the continuous beam plastic hinge is proposed, and the calculation formula of the limit displacement of the continuous beam span is derived based on the equivalent plastic hinge theory, and the formula for calculating the limit stress increment of the external prestressed tendon in the external prestressed section is formed. The results of the test were verified. In this paper, the section length of the section beam section is considered, the mechanical model of the section pre-assembled continuous beam is established, and the influence factor analysis of the internal force re-distribution is carried out, and the basis for considering the plastic design of the inner force redistribution of the section pre-assembled continuous beam is provided. (4) The bending test of four simple-supported beams (one whole, three sections) and one three-span section was carried out in the bending, and the parameter value of the crack-crack analysis of the segmental pre-assembled beam was put forward according to the test results, and the calculation formula of the stress increment was verified. In this paper, the shear test of the joint in 10 different joint-type segments is carried out. The simplified calculation formula is verified by considering the factors such as the horizontal pressure, the dry-knot and the cementation, the size of the key teeth, the flat-joint and the key-tooth joint. (5) The initial analysis of the concrete CDP material model with ABAQUS finite element software is carried out, the mechanism of shear-key anti-shear failure is understood, and compared with the existing single-bond failure test, the parameter setting suggestion of the CDP model is given. A concrete shear model based on the ABAQUS finite element software VUMAT subprogram is developed on the basis of analyzing the shear failure principle of the shear bond, and the effect of the shear stress on the shear failure of the shear bond is shown in the model. The parameter value of the shear model of the concrete is determined by the shear failure test of the existing shear key, and the correctness of the model is verified, and the principle of shear failure of the shear key is revealed. and (6) using the developed concrete shear model to perform the parameter analysis on the shear key subject to shear, taking into account the influence of the key tooth shape, the horizontal pressure size, the number of the key teeth, the joint connection mode and the like on the shear bearing capacity of the shear key, and establishing a calculation model of the shear failure bearing capacity of the joint, The calculation formula of the shear failure bearing capacity of the joint in different joint forms is formed, the formula is of clear physical meaning and the formal parameters are uniform, and the formula has higher precision compared with the test result. (7) On the basis of the analysis of the difference between the segmental pre-assembled beam and the overall beam, the different types of damage and the failure mechanism of the section pre-assembled beam's anti-shear failure are summarized. The influence of different joint forms on the shear bearing capacity of the concrete part is analyzed. According to the criterion of the compression and shear failure of the concrete, the contribution of the pressure flange to the shear bearing capacity is considered, and the calculation analysis program for the shear failure of the joint is developed. In this paper, the shear bearing capacity of the concrete is derived by using the equilibrium equation in a simplified way, and the calculation formula of the shear bearing capacity of the joint shear failure is formed, and the verification of the test data is carried out. According to the test results of different examples, the generation condition of the joint shear failure of the segment pre-assembled beam is given, and the initial shear design of the bridge can be used.
【学位授予单位】：东南大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U446
，
本文编号：2498201
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