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Advanced Unified Failure Model on Uniformly Reinforced Concrete Box Section Members

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Journal of Shanghai Jiaotong university(Science) 2013年第5期18卷 563-569页

作者：骆华勋刘西拉 Department of civil engineering Shanghai Jiaotong University

Based on the traditional Nielsen model,a unified failure model on the uniformly reinforced concrete box section members under combined forces was introduced by Luo and *** of their contributions is adjustment of the shear carrying capacity of concrete at the member failure *** the unified failure model,the comparison with the experimental results verified this ***,it should be pointed out that the adjustment factor of shear carrying capacity at member failure surface for the reinforced concrete members in the unified failure model is a fixed adjustment constant for all experiment data,which is basically determined by curve ***,the adjustment factor should vary with the normal stress at the member failure *** this paper,an advanced theoretical model is introduced,in which the adjustment factor of shear carrying capacity at failure surface is a variable related to the normal stress at failure ***,the advanced unified failure model on the uniformly reinforced concrete box section member can still be expressed in a simple ***,the comparison with several groups of test data has verified that this advanced model is more accurate and feasible to be used in design.

关键词： reinforced concrete adjustment factor shear failure model box section

Simulation of artificial random field considering the temporal-spatial variation

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Acta Seismologica Sinica(English Edition) 2002年第4期15卷 425-430页

作者： NI Yong-jun (倪永军) ZHU Xi (朱晞) College of civil engineering and Architecture Northern Jiaotong University Beijing 100044 China College of Civil Engineering and Architecture Northern Jiaotong University Beijing 100044 China

An apparent wave velocity varying with the frequency of seismic wave was adopted rather than an arbitrary one. The phase difference spectrum was introduced to consider the non-stationary properties of frequency contents in simulating artificial random field. The non-stationary random field on hard site considering the temporal-spatial variation was simulated by the way of spectral representation method. This random field can be used as the input of earthquake ground motion of the seismic response analysis of large-span spatial structures considering the effect of multi-supported excitation.

关键词： artificial random field apparent wave velocity phase difference spectrum

Poisson theory and integration method for a dynamical system of relative motion

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Chinese Physics B 2011年第2期20卷 321-325页

作者：张毅尚玫 College of civil engineering Suzhou University of Science and Technology School of Aerospace engineering Beijing Institute of Technology

This paper focuses on studying the Poisson theory and the integration method of dynamics of relative motion. Equations of a dynamical system of relative motion in phase space are given. Poisson theory of the system is established. The Jacobi last multiplier of the system is defined, and the relation between the Jacobi last multiplier and the first integrals of the system is studied. Our research shows that for a dynamical system of relative motion, whose configuration is determined by n generalized coordinates, the solution of the system can be found by using the Jacobi last multiplier if （2n-1） first integrals of the system are known. At the end of the paper, an example is given to illustrate the application of the results.

关键词： dynamics of relative motion Poisson theory method of integration Jacobi last multiplier

Microscopic and Dynamic Rheological Characteristics of Crumb Rubber Modified Asphalt

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Journal of Wuhan University of Technology(Materials Science) 2010年第6期25卷 1022-1026页

作者：王岚 College of civil engineering Inner Mongolia University of Technology

A test for crumb rubber modified asphalt containing 20% crumb rubber particles（30 mesh） was performed using a scanning electron microscope（SEM）.The experimental results indicate that the crumb rubber particles are evenly distributed in the *** rate sweep and shear-temperature sweep tests on the crumb rubber modified asphalt at-20-80 ℃ using a dynamic shear rheology（DSR） instrument,were carried *** tests show that the complex modulus decreases with increasing temperature;at equivalent temperature,higher load frequencies lead to a larger complex modulus,and this value increasingly decreases as the temperature increases;the phase angle increases with temperature and decreases as the load frequency *** can be concluded that the rutting resistance limiting temperature of crumb rubber modified asphalt is 78 ℃,and the anti-fatigue limiting temperature is 16 ℃,which shows that the asphalt has preferable rutting resistance characteristics at high temperature,as well as anti-fatigue *** addition,the complex modulus master curve at different temperatures was plotted according to the time temperature equivalence principle,which allows the study of the dynamic state behavior of crumb rubber modified asphalt at a wide range of load frequency.

关键词： crumb rubber modified asphalt microcosmic characteristic rheology characteristic complex modulus phase angle

Scattering of plane P waves by a semi-cylindrical hill: analytical solution

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Earthquake engineering and engineering Vibration 2005年第1期4卷 27-36页

作者：梁建文张彦帅 Vincent W Lee Department of civil engineering Tianjin University Tianjin 300072 ChinaProfessor Department of civil engineering Tianjin University Tianjin 300072 ChinaGraduateStudent Department of civil engineering University of Southern California Los AngelesCA 90089-2531USAProfessor

An analytical solution for scattering of plane P waves by a semi-cylindrical hill was derived by using the wave function expansion method, and convergence of the solution and accuracy of truncation were verified. The effect of incident frequency and incident angle on the surface motion of the hill was discussed, and it was shown that a hill greatly amplifies incident plane P waves, and maximum horizontal displacement amplitudes appear mostly at the inclined incidence of waves, which are located at the half-space; and maximum vertical displacement amplitudes emerge mostly at the vertical incidence of waves, which are situated at the hill.

关键词： hill plane P waves scattering analytical solution amplification

Study on seismic damage of SRHSC frame columns

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Science China(Technological Sciences) 2011年第11期54卷 2886-2895页

作者： ZHENG ShanSuo WANG Bin LI Lei HOU PiJi WANG Wei Department of civil engineering Xi＇an University of Architecture and Technology Xi＇an 710055 China Department of civil and Architecture engineering Xi＇an Technological University Xi＇an 710032 China

The damage evolution in steel reinforced high strength concrete(SRHSC) frame columns was studied based on the test results of cyclic reversed loading experiment of 12 frame column specimens with various axial compression rations,stirrups ratios,steel rations and loading *** variation law of the ultimate bearing capacity,ultimate deformation and ultimate hysteretic energy dissipation of specimens under different loading protocols was *** seismic damage characteristics,as well as strength and stiffness degradation,of SRHSC frame columns were *** on the analysis of the nonlinear double parameters combination of deformation and energy,a damage model that can well reflect the mechanical characteristics of members subjected to a horizontal earthquake action was established by considering the effects of the number of the loading cycles on the ultimate resistance capacity(ultimate deformation and ultimate energy dissipation capacity) of members,and the loading history on damage,*** to the test results,the related parameters of the damage model were ***,the damage model proposed was validated by the test *** indicated that the proposed damage model is theoretically more reasonable and can accurately describe the seismic damage evolution of the SRHSC frame *** results also can be used as a new theoretic reference for the establishment of damage-based earthquake-resistant design method of SRHSC members.

关键词： SRHSC frame columns experimental study damage analysis damage model model parameters

Effect of frequency and flexibility ratio on the seismic response of deep tunnels

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Underground Space 2017年第2期2卷 125-133页

作者： Eimar Sandoval Antonio Bobet Lyles School of civil engineering Purdue UniversityWest Lafayette 47906United States School of Civil Engineering and GeomaticsUniversidad del ValleCaliColombia

Two-dimensional dynamic numerical analyses have been conducted,using FLAC 7.0,to evaluate the seismic response of underground structures located far from the seismic source,placed in either linear-elastic or nonlinear elastoplastic *** interaction between the ground and deep circular tunnels with a tied interface is *** the simulations,it is assumed that the liner remains in its elastic regime,and plane strain conditions apply to any cross section perpendicular to the tunnel *** elastoplastic constitutive model is implemented in FLAC to simulate the nonlinear *** effect of input frequency and relative stiffness between the liner and the ground,on the seismic response of tunnels,is *** response is studied in terms of distortions normalized with respect to those of the free field,and load demand(axial forces and bending moments)in the *** all cases,*** linear-elastic and nonlinear ground models,the results show negligible effect of the input frequency on the distortions of the cross section,for input frequencies smaller than 5 Hz;that is for ratios between the wave length and the tunnel opening(k=D)larger than ten for linear-elastic and nine for nonlinear *** normalized distortions are obtained for the nonlinear than for the linear-elastic ground,for the same relative stiffness,with differences increasing as the tunnel becomes more flexible,or when the amplitude of the dynamic input shear stress *** has been found that normalized distortions for the nonlinear ground do not follow a unique relationship,as it happens for the linear-elastic ground,but increase as the amplitude of the dynamic input *** loading in the liner decreases as the structure becomes more flexible with respect to the ground,and is smaller for a tunnel placed in a stiffer nonlinear ground than in a softer nonlinear ground,for the same flexibility ratio.

关键词： Deep circular tunnel Dynamic numerical analysis Flexibility ratio Distortion Seismic response

Hydrodynamic Conditions in Front of a Vertical Wall with an Overhanging Horizontal Cantilever Slab

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Journal of Ocean University of China 2017年第6期16卷 978-990页

作者： KISACIK Dogan OZYURT Gulizar TROCH Peter Institute of Marine Sciences and Technology Dokuz Eylül University Department of civil engineering Middle East Technical University Department of civil engineering Ghent University

Transforming wave heights from offshore to the shoreline is the first step of any coastal engineering work. Wave breaking is analyzed to understand hydrodynamic conditions. For vertical breakwaters and sea walls, wave reflection is an important process that affects the determination of the wave height. Many of the design formulas presented in the literature depend on empirical studies based on the structures tested. In this study, the hydrodynamic conditions in front of a vertical wall with an overhanging horizontal cantilever slab with a foreshore slope of 1/20 are determined experimentally under regular wave conditions to assess the applicability of the formulas of Goda(2000) for predicting the nearshore wave height and breaker index equation(Goda, 2010). The selection of wave measurements used to determine the design wave height, the reflection coefficients, and wave breaking is also analyzed, and the reflection equations are derived from the dataset covering different breaker types. Small-scale tests show that the incident wave height is a good representative of the design wave height and that the values predicted by Goda are in good agreement with actual measurements. However, the predicted Hmax values are overestimated. In addition, the inception of the wave breaking point is postponed because of the reflection and/or turbulence left over from preceding waves, which is an effect of the vertical wall. At higher water levels, the effect of the vertical wall on the inception point becomes more significant.

关键词： wave breaking wave reflection wave shoaling vertical structure horizontal cantilever slab

Topology-Based Quantitative Assessment of Structural Robustness

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Journal of Shanghai Jiaotong university(Science) 2014年第3期19卷 257-264页

作者：高扬刘西拉 Department of civil engineering Shanghai Jiaotong University

Local damages to a structure will cause disproportional collapse if the system is lack of *** structural safety cannot be guaranteed by traditional ways, such as reliability analysis tools and construction management approaches. Therefore, it is very important to develop related theories for structural *** paper presents a methodology to quantitatively assess the structural robustness from the topological point of view. In the proposed method, the structural failure is viewed as a feedback process. The transformations between the damage input and failure output form a closed-loop. The decisive factor of the operation of such a closed-loop is thought as the structural topology. Furthermore, the damage input and the failure output of the structure are measured by the uncertain disturbance and the change of the topology, respectively. After the sensitivity of the structural topology to the uncertain disturbance is studied, the transfer matrix is discovered to indicate the rationality of the topological relationship. The importance of each loading path, the structural robustness and the most vulnerable part of the system can be found concisely in accordance with this matrix.

关键词： structural robustness structural topology closed-loop system transfer matrix