共查询到20条相似文献,搜索用时 31 毫秒
1.
Yan Han Zhengqing Chen Shidong Luo Shankui Yang 《Frontiers of Architecture and Civil Engineering in China》2009,3(2):165-172
Based on the spatial model, a reliable and accurate calculation method on the shape finding of self-anchored suspension bridge
with spatial cables was studied in this paper. On the principle that the shape of the main cables between hangers is catenary,
the iteration method of calculating the shapes of the spatial main cables under the load of hanger forces was deduced. The
reasonable position of the saddle was determined according to the shape and the theoretical joint point of the main cables.
The shapes of the main cables at completed cable stage were calculated based on the unchanging principle of the zero-stress
lengths of the main cables. By using a numerical method combining with the finite element method, one self-anchored suspension
bridge with spatial cables was analyzed. The zero-stress length of the main cables, the position of the saddle, and the pre-offsetting
of the saddle of the self-anchored suspension bridge were given. The reasonable shapes of the main cables at bridge completion
stage and completed cable stage were presented. The results show that the shape-finding calculation method is effective and
reliable.
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Translated from Journal of Hunan University (Natural Sciences), 2007, 34(12): 20–25 [译自: 湖南大学学报(自然科学版)] 相似文献
2.
Ying WANG Zhaoxia LI Baijian WU 《Frontiers of Architecture and Civil Engineering in China》2008,2(3):197-204
The monitoring of fatigue stress of steel bridge is a key issue of bridge health monitoring and safety assessment. This paper
aims to find out the strain history features of the girder components of Runyang Suspension Bridge (RYSB) under vehicle and
environmental loading during its first year of service based on the strain-history data recorded by structural health monitoring
system installed in the bridge. The fatigue stress spectrums of steel box girders under normal traffic load, heavy trucks
and typhoon loads were studied as well as the correlation between varying strain and temperature based on real-time monitoring
of temperature histories. The results show that, monitoring on local strain in health monitoring systems of RYSB can effectively
provide the information on fatigue stresses. The range of the equivalent fatigue stress on the monitoring location of the
bridge is currently low, mainly due to varying traffic loading and temperature. There exists significant correlation between
varying temperature and mean value of fatigue stress. Effect of the passing of heavy trucks on bridge fatigue is quite significant
since the value of the cumulative fatigue damage generated by heavy trucks is 10 to 100 times larger than that by normal traffic.
Therefore, the effect on fatigue cumulative damage due to heavy trucks or overloaded vehicles needs to be monitored and paid
much attention to.
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Translated from Journal of Southeast University (Natural Science Edition), 2007, 37(2): 280–286 [译自: 东南大学学报(自然科学版)] 相似文献
3.
Minshui Huang Wenzeng Guo Hongping Zhu Lin Li 《Frontiers of Architecture and Civil Engineering in China》2008,2(2):139-144
The dynamic characteristics of bridge structures are the basis of structural dynamic response and seismic analysis, and are
also an important target of health condition monitoring. In this paper, a three-dimensional finite-element model is first
established for a highway bridge over a railroad on No.312 National Highway. Based on design drawings, the dynamic characteristics
of the bridge are studied using finite element analysis and ambient vibration measurements. Thus, a set of data is selected
based on sensitivity analysis and optimization theory; the finite element model of the bridge is updated. The numerical and
experimental results show that the updated method is more simple and effective, the updated finite element model can reflect
the dynamic characteristics of the bridge better, and it can be used to predict the dynamic response under complex external
forces. It is also helpful for further damage identification and health condition monitoring.
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Translated from Chinese Journal of Huazhong University of Science and Technology (Urban Science Edition), 2006, 23(4): 57–60 [译自: 华 中科技大学学报(城市科学版)] 相似文献
4.
Junhai Ma Airong Chen Jun He 《Frontiers of Architecture and Civil Engineering in China》2009,3(1):50-56
Based on a detailed illustration for bridge life cycle design which comprises the processes of service life design, aesthetics
design, performance design, environmental and ecological design, inspection, maintenance and repair design as well as cost
analysis, this paper presented a general framework for bridge life cycle design comprising three design phases and six design
processes.
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Translated from Journal of Tongji University (Natural Science), 2007, 35 (8): 1003–1007 [译自: 同济大学学报(自然科学版)] 相似文献
5.
Liu Liqin Tang Yougang Li Hongxia 《Frontiers of Architecture and Civil Engineering in China》2007,1(3):361-366
The methods for constructing safe basins of ships and predicting their survival probability in random waves were studied.
The nonlinear differential equation of the rolling motion of ships in random beam seas was established considering nonlinear
damping, nonlinear restoring moment, and random waves. The random rolling differential equation was solved in the time domain
by applying the harmonic acceleration method and by synthetically considering the instantaneous state of ships and the narrowband
wave energy spectrum. The numerical simulation of random capsizing course was brought forward, the safe basins were constructed
for safe navigation, and the survival probabilities of ships were calculated. As an example, the safe basins on the rolling
initial value plane were constructed for a 30.27-meter-long fishing vessel according to different initial conditions and random
wave parameters. The survival probabilities of the fishing vessel under different significant wave heights were predicted.
Thus, the survival probabilities of ships in random seas can be predicted quantitatively by the proposed method.
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Translated from Journal of Tianjin University, 2006, 9(2): 165–169 [译自: 天津大学学报] 相似文献
6.
Baoguo Chen Rui Ding Junjie Zheng Shibiao Zhang 《Frontiers of Architecture and Civil Engineering in China》2009,3(2):158-164
A field test was conducted to investigate the distribution of temperature field and the variation of thermal stress for a
prestressed concrete (PC) box-girder bridge. The change of hydration heat temperature consists of four periods: temperature
rising period, constant temperature period, rapid temperature fall period and slow temperature fall period. The peak value
of hydration heat temperature increases with the increasing casting temperature of concrete; the relation between them is
approximately linear. According to field tests, the thermal stress incurred by hydration heat may induce temperature cracks
on the PC box-girder. Furthermore, the nonlinear distribution of temperature gradient and the fluctuation of thermal stress
induced by exposure to sunlight were also obtained based on continuous in-situ monitoring. Such results show that the prevailing
Chinese Code (2004) is insufficient since it does not take into account the temperature gradient of the bottom slab. Finally,
some preventive measures against temperature cracks were proposed based on related studies. The conclusions can provide valuable
reference for the design and construction of PC box-girder bridges.
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Translated from Journal of Huazhong University of Science and Technology (Urban Science Edition), 2007, 24(4): 83–97 [译自: 华中科技大学学报 (城市科学版)] 相似文献
7.
Weiming Gong Guoliang Dai Haowen Zhang 《Frontiers of Architecture and Civil Engineering in China》2009,3(2):228-233
The application of pile-end post-grouting piles for super-large bridge pile foundations in some important projects was introduced
in this paper. There are totally 21 test piles. The maximum pile diameter varies from 2.5 m to 3 m, and the maximum length
is 125 m; the bearing capacity of the post-grouting piles is over ten thousands tons. Based on the test results, the bearing
capacity, displacement, and bearing characteristics before and after grouting were analyzed. The results show that the bearing
capacity of the piles is increased in different degrees after grouting although the technical parameters, including the patterns
of grouting pipes, pressure, dosages of cement, duration of grouting lasting time, are different. However, the obtained values
are very discrete. In addition, the calculation formula for the post-grouting piles under specified grouting condition was
deduced based on the statistics analysis results of 57 test piles. The research results have been applied in the design of
bridge foundation.
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Translated from Journal of Southeast University (Natural Science Edition), 2007, 37(6): 1066–1070 [译自: 东南大学学报 (自然科学版)] 相似文献
8.
Peiheng Long Xianting Du Weizhen Chen 《Frontiers of Architecture and Civil Engineering in China》2008,2(3):274-280
The formula for the contribution of prestressed reinforcement on embedded reinforcement element is derived according to the
mechanical behavior of PC bridges and the foundational principle of finite element method. Mechanical concept is definite
and examples validate the calculation results. Reinforcement element model allows generating a finite element mesh without
taking into consideration the layout of reinforcements. Furthermore, the prestressing tendon may pass through the concrete
elements in an arbitrary manner. It is an effective approach that the no-node loads are diverted from the tendons to the adjacent
concrete elements. A useful arithmetic analysis of the spatial curved tendon PC Bridges is provided.
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Translated from Journal of Tongji University (Natural Science), 2007, 35(4): 455–460 [译自: 同济大学学报(自然科学版)] 相似文献
9.
Tests were conducted on 3 specimens to study the flexural behavior of fiber reinforced polymer (FRP)-concrete-steel double-skin
tubular members (DSTMs). The strip method was used to calculate the section momentcurvature curves of the 3 specimens and
12 models. A theoretical formula is presented for the flexural strength of DSTMs. The test results show that the tension zone
of the specimen FRP tubes was in hoop compression while the compression zone was in hoop tension. The load-carrying capacity
did not decrease even when the mid-span deflection reached about 1/24 of the span length. The tests, simulation and theoretical
analysis resulted in a simplified formula for the flexural strength of DSTMs and a tri-linear moment-curvature model was expressed
as a function of the section bending stiffness for DSTMs.
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Translated from Journal of Tsinghua University (Science and Technology), 2008, 47(12): 2105–2110 [译自: 清华大学学报(自然科学版)] 相似文献
10.
Fuyou Xu Airong Chen Zhe Zhang Cailiang Huang 《Frontiers of Architecture and Civil Engineering in China》2009,3(3):272-278
The causes of the nonlinearity of self-excited aerodynamic force of bridge are interpreted from such two aspects as amplitude
and wind velocity. The concept of “generalized flutter derivative” is proposed, and its physical meaning is illustrated. The
graphs of the generalized flutter derivatives of plate and Sutong Bridge section model are plotted. The characteristics of
all generalized flutter derivatives are compared and analyzed, and their superiorities are verified. The results indicate
that the physical meaning of generalized flutter derivatives are more explicit compared to the traditional ones. It is more
convenient to understand the nonlinearity properties of self-excited aerodynamic force of bridge according to the generalized
flutter derivatives graphs with the wind velocity as the horizontal coordinate.
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Translated from Journal of Wuhan University of Technology (Transportation Science and Engineering), 2008, 32(4): 607–610 [译自: 武汉理工大学学报(交通科学与工程版)] 相似文献
11.
Jiancheng YU Hao TONG Wei HUANG 《Frontiers of Architecture and Civil Engineering in China》2008,2(1):37-42
A tied arch bridge without wind bracing was built over the Bin Jiang River, with oblique angle of 20°. Its main design details
are described and mechanical performances are analyzed. The stability analytical types are also introduced and the first elastic
stability theory is used. A space finite element model has been built to analyze the stability performances in both construction
and operation stages for single span or continuous, orthogonal or oblique bridge. The influence of stiffness of the end crossbeam
is also analyzed. The result shows that out-plane buckling occur for a rigid tie and similar no matter whether it is single
span or continuous and orthogonal or oblique. When there are more and stronger inner crossbeams, the influence of the end
crossbeams on arch stability becomes unremarkable.
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Translated from Journal of Southeast University, 2006, 36(6): 1007–1012 [译自: 东南大学学报] 相似文献
12.
Yiqun TANG Ping YANG Feng SHEN Nianqing ZHOU 《Frontiers of Architecture and Civil Engineering in China》2008,2(3):242-245
The behavior of dark green silty soil of the 6th storey is studied by means of scanning electron microscopy (SEM). The shape,
size and contact condition of the basic elements of the soil microstructure, and the shape and the size of the pore are further
studied. In addition, a comparative study is made to analyze the experiment results of Cu and dynamic test. The mechanic characteristics
of common soil and those of melted soil are presented and their influences on dark silty soil after being frozen are theoretically
illustrated from a microscopic perspective.
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Translated from Journal of Tongji University (Natural Science), 2007, 35(1): 6–9 [译自: 同济大学学报(自然科学版)] 相似文献
13.
Zhe Zhang Huili Wang Sifeng Qin Xiaomeng Ge 《Frontiers of Architecture and Civil Engineering in China》2009,3(3):286-291
The limit span of self-anchored cable-stayed suspension bridge is deduced. The relations among the geometrical parameters,
loads and material characteristics are also analyzed. Based on the material strength and commonly used materials, the limit
spans of self-anchored cable-stayed suspension bridges with concrete girder or steel girder under vertical static load are
discussed in detail. The corresponding upper limit spans and the effect of the factors on the span are given. The results
indicate that increasing rise-span ratio, height-span ratio and cable-stayed segment length or reducing the second dead load
could increase the cooperation system span.
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Translated from Journal of Dalian University of Technology, 2008, 48(3): 387–391 [译自: 大连理工大学学报] 相似文献
14.
Li Jie 《Frontiers of Architecture and Civil Engineering in China》2007,1(1):34-40
In this paper, an overview is given on several key issues and related research progress made in lifeline engineering. The
research topics include: numerical modeling of random seismic waves, probabilistic density evolution analysis for nonlinear
structural responses, and seismic reliability analysis of large-scale lifeline networks. In addition, a comparison is made
between the domestic and international studies on the aforementioned topics. Several examples are included in the paper as
the case studies. Recommendations are given for further development of the lifeline engineering research.
Translated from China Civil Engineering Journal, 2006, 39(1):1–6, 37 [译自: 土木工程学报] 相似文献
15.
Hanlong Liu Xuanming Ding 《Frontiers of Architecture and Civil Engineering in China》2009,3(2):180-186
The three-dimensional effects of pile head and the applicability of plane-section assumption are main problems in low-strain
dynamic tests on cast-in-situ concrete thin-wall pipe piles. The velocity and displacement responses were calculated by a
theoretical formula deduced by the authors. The frequency and influencing factor of high-frequency interference were analyzed.
A numerical method was established to calculate the peak value and arrival time of incoming waves on top of the piles. The
regularity along circumferential and the influence of radius or impulse width were studied. The applicability of plane-section
assumption was investigated by comparison of velocity responses at different points in the sections at different depths. The
waveform of velocity response at different points forked after the first peak, indicating that the propagation of stress waves
did not well meet the plane- section assumption.
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Translated from Chinese Journal of Geotechnical Engineering, 2008, 30 (3): 414–419 [译自: 岩土工程学报] 相似文献
16.
Wang Xiekang Wang Xianye Lu Weizhen Liu Tonghuan 《Frontiers of Architecture and Civil Engineering in China》2007,1(2):211-216
Channel confluences are common in natural rivers and hydraulic engineering, and the flow behavior at confluences becomes very
complex because of the interaction between the tributary and the main river. In this study, the experiments were performed
in a combined flume with a 30° angle between the main and tributary flume located at Sichuan University. The velocity was
measured by using a three-component acoustic Doppler velocimeter (ADV) over a grid defined throughout the junction region.
Based on the analysis of the velocity at the confluence, the distinctive characteristics of a channel confluence flow may
be divided into several zones including a zone of separation immediately downstream of the junction branch channel, the maximum
and minimum velocity regions at the upstream and downstream in the confluent channel, and a shear plane developed between
the two combining flows downstream of the confluent channel. In addition, secondary circulations in different directions at
the higher and lower velocity zones are observed as well.
Translated from Journal of Sichuan University (Engineering Science Edition), 2006, 38(2): 1–5 [译自: 四川大学学报 (工程科学版)] 相似文献
17.
It is necessary to study how vehicles influence the vortex-excited resonance of vehicle-bridge systems, because lock-in wind
speed is low and vortex-excited resonance is sensitive to any change in the main girder sections. Based on the Shanghai Bridge
over the Yangtse River, the vortex-excited resonance of a 1:60 scale sectional model was tested in a TJ-1wind tunnel, with
or without vehicles at the attack angle of 0°, + 3 and − 3°, respectively. The conversion relationships between the resonant
amplitudes of the sectional model and that of the prototype bridge were also established by mode shape correction. The result
indicates that: 1) for the bridge with vehicles, the vertical vortex-excited resonance is accompanied by torsion vibration
with the same frequency, and vice versa, 2) the amplitude of vortex-excited resonance of the bridge with vehicles is much
larger than that of the bridge without vehicles, and 3) the lock-in wind speed of the vortex-excited resonance becomes smaller
due to the disturbance of vehicles. It is obvious that vehicles bring about changes in the aerodynamic shape of the main girder.
Therefore, the influence of vehicles on vortex-excited resonance performance of vehicle-bridge systems, in terms of both amplitude
and mode, should not be ignored.
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Translated from China Civil Engineering Journal, 2007, 40(8): 61–66 [译自: 土木工程学报] 相似文献
18.
Jingfeng Wang Guoqiang Li 《Frontiers of Architecture and Civil Engineering in China》2008,2(2):116-122
Stresses and deflections were measured in various semi-continuous composite beams. The bending and rotational capacities of
the composite connections were measured in terms of beam curvatures and deflections by using two full-scale semi-rigid composite
frames with monotonic loadings. The effect of semi-rigid connections on the performance of composite beams with various loadings
was compared with predictions and codes. The tests show that the semi-continuous composite beams are more economic and effective
than the simple or continuous composite beams. The semi-rigid connections affect the bending capacities and beam deflections,
so the connection behavior should be considered in the design of composite beams. Yielding analysis of the steel beam bottom
flange has some influence on the deflection calculation of composite beams.
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Translated from J Tsinghua Univ (Sci & Tech), 2007, 47(3): 313–318 [译自: 清华大学学报(自然科学版)] 相似文献
19.
Liu Qijian Yang Linde Wu Jun 《Frontiers of Architecture and Civil Engineering in China》2007,1(4):443-447
Based on the disturbed state concept (DSC), a new model of load transfer function for pile analysis is established by the
idea that the deformed material between pile and soil can be treated as a mixture of two constituent parts, which are in intact
or critical state and assumed to obey random distribution. Starting from the homogenization theory of heterogeneous materials
and statistics method, a parameter D to describe the disturbance degree is proposed, and a formula to determine the parameter has been derived by using the plastic
displacement of a pile as distribution variable. In the model, shear intensity of elements in an intact state are simulated
by Duncan-Zhang model and that in a critical state by Mohr-Coulomb criterion. The model of this paper has few parameters,
which can reflect the aspects of load transfer function, such as hardening, softening and the effects of confining pressure.
The well agreement between the in-situ data and the predicted shows that the validity of the model herein. So the proposed
model in this paper is easy to be used in engineering practice.
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Translated from Journal of Tongji University (Natural Science Edition), 2006, 34(2): 165–169 [译自: 同济大学学报 (自然科学版)] 相似文献
20.
Cheng Weiping Liu Guohua 《Frontiers of Architecture and Civil Engineering in China》2007,1(2):205-210
Based on the Backus-Gilbert inverse theory, the singular value decomposition (SVD) for general inverse matrices and the optimization
algorithm are used to solve the channel friction inverse problem. The resolution and covariance friction inverse model in
matrix form is developed to examine the reliability of solutions. Theoretical analyses demonstrate that the convergence rate
of the general Newton optimization algorithm is in the second-order. The Wiggins method is also incorporated into the algorithm.
Using the method, noise can be suppressed effectively, and the results are close to accurate solutions with proper control
parameters. Also, the numerical stability can be improved.
Translated from Journal of Zhejiang University (Engineering Science), 2005, 39(10): 1 603–1 608 [译自: 浙江大学学报(工学版)] 相似文献