关键词：钢铁；钢管；防腐；排水

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In the present study,the failure of basic redundant steel structural systems is investigated.By considering that each member of the system has brittle,semi-brittle,or perfectly plastic properties,the statistical behavior of perfectly brittle systems,semi-brittle systems,perfectly plastic and combination systems are evaluated,and the effects of the coefficient of variation (CoV) of members on the systems are investigated.Uncorrelated strengths with the same mean are considered for the system elements.By using the Monte Carlo simulation (MCS) method,maximum strength,yield strength and residual strength of the redundant steel structural systems are evaluated.The CoV of member strength is an essential parameter for statistical assessment of steel structural systems.In this study,the strength is defined random variable a selected normal distribution represents the random variable,for the member strength.The deformation capacity of the member is strongly depends to the characteristics of member strength,but the post failure factor has deterministic values,only for the combination system.The post failure factor is a random variable that represents the uncertainty,uniform distribution is selected to represents random variable,in combination system post failure factor.

关键词：钢铁;单调荷载;强度;变形

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Portable Concrete Barriers (PCBs) are used to redirect errant vehicles to keep them passing to opposing lanes and to ensure safety of the people and any objects behind the barriers. In the state of Indiana, increments to the PCBs, such as L-Shape steel plates, have been applied to enhance the safety performance of these barriers. In this study, Finite Element (FE) analyses are performed to evaluate the safety performance of PCBs with and without the increments and get thorough information about the increments applied. A full-scale crash test (INDOT, 2001) was executed for an impact to the PCBs with a 2000 kg pickup truck at an angle of 25 degrees and an initial velocity of around 100 km/hr in accordance with National Cooperative Highway Research Program (NCHRP) Report 350 guidelines for Test Level 3 safety performance. Aforementioned full-scale crash test data are used to validate the FE model constructed. Roadside Safety Verification and Validation Program (RSVVP) was used to compare the crash test and FE model results quantitatively. Validating the results of the initial FE Model leaded the way in confidence to implement the increments in the following FE Models.

关键词：钢铁；有限元法；碰撞试验；钢板

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The paper is focused on issues related to the behavior of reinforced soil walls at working stress and near failure, and the prediction accuracy of internal stability working stress and limit equilibrium (LE) design methods. The paper identifies the key variables, principles and assumptions that affect the accuracy of these methods considering the full range of conditions from working stress to failure. The strain at peak strength of a granular soil wall backfill is identified as a key parameter for understanding the differences between working stress and LE design methods. Both geosynthetic and steel reinforced wall systems are examined using measured reinforcement strain and loads taken from full-scale walls under both working stress (operational) conditions and at incipient collapse (failure).

关键词：钢铁；工作压力；极限平衡；钢筋

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Gravity structures play a prominent role today in North Sea oil development.These structures are not supported by piles as are most ocean structures but rather sit directly on the ocean bottom, and depend on their foundation geometries and large weights to resist severe environmental loadings.A number of structural and foundation configurations have been proposed; however,attention will be restricted in this discussion to a general configuration typical of the most prominent structures being constructed at present (1975). An example of a gravity structure is illustrated in Fig. 1. The structure foundation consists of a large caisson placed directly on the unprepared seabed surface.The deck is supported by large columns extending from the caisson.Various combinations of steel and reinforced concrete have been proposed, but the majority of structures are being constructed almost entirely of reinforced and prestressed concrete.

关键词：钢铁;重力式结构;石油;钢筋混凝土

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The paper presents experimental data generated for calibrating finite element models to predict the performance of reinforced concrete panels with a wide range of construction details under blast loading. The specimens were 1.2 m square panels constructed using Normal Weight Concrete (NWC) or Fiber Reinforced Concrete (FRC). FRC consisted of macro-synthetic fibers dispersed in NWC. Five types of panels were tested: NWC panels with steel bars; FRC panels without additional reinforcement; FRC panels with steel bars; NWC panels with glass fiber reinforced polymer (GFRP) bars; and NWC panels reinforced with steel bars and external GFRP laminates on both faces. Each panel type was constructed with three thicknesses: 152 mm, 254 mm, and 356 mm. FRC panels with steel bars had the best performance for new construction. NWC panels reinforced with steel bars and external GFRP laminates on both faces had the best performance for strengthening or rehabilitation of existing structures. The performance of NWC panels with GFRP bars was strongly influenced by the bar spacing. The behavior of the panels is classified in terms of damage using immediate occupancy, life safety, and near collapse performance levels. Preliminary dynamic simulations are compared to the experimental results.

关键词：钢铁；混凝土；纤维；玻璃纤维；性能

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Fracture toughness and fatigue properties of pipeline steels play a critical role in developing advanced high-pressure hydrogen infrastructure for alternative fuel pipelines program. The reliability of structure components, particularly resistance to damage and failure in the intended service environment, is highly dependent on the selected materials. An effective surveillance program is also necessary to monitor the material degradation during the course of service. Steels have been proven to be desirable for hydrogen infrastructure. However, hydrogen embrittlement is an important factor that limits steel performance under high-pressure hydrogen conditions. In order to reach the above goal, we have proposed an innovative technology, based on spiral notch torsion test (SNTT) methodology, to effectively investigate the material performance of X52 pipeline steel. The SNTT approach was successfully demonstrated and extended to X52 steels during the performance period. In addition to single notch front geometry, the crack growth behavior of the SNTT process has been effectively established using an integrated experimental, numerical and analytical approach. The results indicate that the proposed protocol not only provides significant advance in understanding the compliance evolution of the SNTT specimen, but also can be readily utilized to assist future development of hydrogen infrastructures. In FY2011, an extensive study was performed to characterize the fracture toughness degradation of AISI 4340 high-strength steel exposed to high-pressure hydrogen using in situ spiral notch torsion tests. This effort included equipment setup and calibration, sample design and fabrication, finite element simulation of the specimen fracture, and fractographic characterization using advanced microscopic techniques. The detailed description of the results is summarized in by Wang (Wang 2011).

关键词：管道；钢；断裂强度；缺口冲击试验

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In construction stage, a large buffeting response would endanger construction safety and quality for a long span concrete-filled steel tube (CFST) arch bridge. Developing the study on buffeting security is indispensable to CFST arch bridge in construction stage. Combining random vibration analysis of structure with modern probability theory, taking an actual large span CFST arch bridge as example, dynamic reliability of buffeting responses research and analysis is developed, which is based on the buffeting analysis on time domain at the longest cantilever construction stage. The paper gives quantitative valuation on wind-vibration safety performance of the bridge in construction phase and offers a new thought and reference for homologous project.

关键词：钢铁;钢管混凝土管;拱桥;施工阶段

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This paper focused on the uniaxial ultimate-bearing-capacity of large size concrete filled steel tubular (CFST) columns. Two aspects were investigated experimentally. To verify the feasibility of similarity principles for large size components, a series of uniaxial compressive experiments were conducted using different scaled specimens, the prototype of which is a CFST arch rib in an authentic arch bridge. Meanwhile, two specimens with same scale were tested axially and eccentrically to investigate the difference of bearing capacity resulted from the pierced-column. The experimental results show that the size effect on the bearing capacity of the rib is so insignificant that the scaled specimen can be used to obtain the maximum capacity of the full-scale component. The inserted steel tubes in the middle of the column cause the reduction of its capacity and the reduction factor from axial loading is bigger than that from bias load. Moreover, the eccentricity reduces the effect of piercing on the capacity of CFST column.

关键词：钢管混凝土（CFST）柱;单轴压缩;承载力;大口径柱

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The primary objective of the research project was to investigate alternatives to open grid steel decks. Three alternative deck systems, including aluminum deck, ultra-high performance concrete (UHPC) high-strength steel (HSS) deck, and UHPC-fiber reinforced polymer (FRP) tube deck, were developed and studied in the first phase of the research project. The UHPC-HSS deck showed a great potential to serve as a viable alternative. However, more studies were needed on its components and system design before it was deemed ready to be implemented. Accordingly, this phase of the project covered all the studies needed for the design and implementation of the UHPC-HSS deck system. Also, suitability of an FRP bridge deck system as an alternative to open grid steel decks was evaluated. The UHPC-HSS deck was experimentally investigated at both the component and system levels. Studies included the deck-to-girder connection test for shear and uplift forces, deck-to-deck connection test, multi-unit specimen tests to determine the lateral distribution of live loads, full-scale test for fatigue loading and residual strength, and pullout and beam tests to evaluate the development length. The deck-to-girder and the deck-to-deck connections both proved to be adequate for the loading conditions expected from the HS20 truck and wind forces. Tests for the live load distribution showed that most of the load is taken by the ribs under or immediately next to the load. The deck panels and connections successfully endured two million cycles of repeated loading and had a residual strength beyond their target design load. It was shown that the development length of HSS rebars in UHPC can be reasonably predicted by ACI 408R-03. The dowel action of longitudinal steel reinforcement in UHPC and the uniaxial fatigue behavior of UHPC specimens were also evaluated through both experimental and analytical studies. It was shown that the dowel action would contribute considerably to the shear resistance in reinforced UHPC structures. In another part of the research, an FRP deck system was tested under static and fatigue loading. The FRP deck withstood two million cycles of AASHTO-specified repeated loading with no sign of damage or failure, while its deflection under service load significantly exceeded the deflection limit suggested by AASHTO LRFD.

关键词：钢铁；钢格甲板；可移动的桥梁；轻型甲板；电梯桥梁

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