Abstract: In order to master timely and accurately construction quality of high performance concrete, detection of compressive strength of high performance concrete can be tested non-destructively, rapidly and accurately. The paper did preliminary research on high performance concrete with redound method, furthermore, it established estimation model between rebound value and compressive strength. Experiment shows that rebound method can effetely test compressive strength of high performance concrete. Construction quality of Cement concrete structure or component can timely grasped in period of construction with the method.
Abstract: Aluminium alloy members under axial force have broad application in structural field. Owing to low elastic modulus, aluminium alloy members are easier buckling than steel members. Based on the reasonable and equivalent calculation model and the related calculation formulas of rotational restraint stiffness kφ, lateral restraint stiffness kx, and distortional buckling critical half-wave length λ that provided by lipped channel web plate to flange under longitudinal distribution stress, the distortional buckling load calculation formula of the lipped channel is derived combining the thin-walled bar buckling theory in elastic medium. The distortional buckling loads and distortional buckling critical half-wave lengths at the different wall thickness have been calculated using the calculation formulas of this paper, and the results have been comparatived with the finite strip method. The comparison results show that: the average ratio of caculation results from formulas of this paper and results from CUFSM is 0.997and0.971 respectively,the corresponding variance is 2.9*10-5and 7.5*10-5. So the calculation results of this paper is in good agreement with the finite strip software, the calculation formula of this paper has enough calculation precision and good stability. At the same time, the calculation results of this paper is more concise than calculation formula for the same type, easy to be applied, may be used in practical applications and taken account into design codes and guidelines.
Abstract: Free field response of partially saturated sands to cyclic loading, with a particular attention to soil liquefaction has been studied. The study has been conducted using a numerical model elaborated for the liquefaction of partially saturated soils together with a cyclic elastoplastic constitutive relation implemented in a finite element program. The numerical model and the analysis of the influence of soil saturation on the free field response, for different positions of the water table have been investigated respectively. The result shows that the soil saturation degree largely affects the free field response to cyclic loading, with a decrease in soil saturation leading to a decrease in the rate of generation of excess pore-water pressure, and consequently to a reduction in the liquefaction risk.
Abstract: The tunnel, the construction safety of which is the most important part of highway to put into operation in time, is an important part of the mountain region road. Based on the characteristics of New Austrian Tunneling Method, the importance of safety monitoring system for grasping the rock deformation in the construction process goes without saying. This paper presents a safety monitoring program through the construction of the sage Mei Shan Highway, Lung Hang Tunnel, providing theoretical and operational support for the sage Mei Shan Highway through analyzing the construction process, the principle of safety monitoring, frequency of monitoring items, monitoring and early warning system, measures to ensure measurement accuracy, measurement data analysis, feedback of early warning system.
Abstract: This paper analyzes key noises within digital strong-motion acceleration recording that can result in baseline offset, and according to their specific position provide a baseline correction scheme for preserving the long-period ground motion. This correction method is then applied to the digital acceleration records from the 2008 Wenchuan earthquake, and also, when compared with GPS data (including some high frequency of 1Hz GPS data), it is shown that this method can well restore displacement of ground motion, including permanent displacement which is the main concern of seismologists. Furthermore, compared with other methods that aim to restore the ground displacement, it has much greater stability.
Abstract: A 3D Finite Element model of a continuous rigid-frame bridge is constructed by the Midas/Civil bridge finite element analysis program in this paper, where fiber elements and plastic hinges are used for bridge piers. The lump mass method is used to simplify the infinite-degree-of-freedom continuous rigid-frame bridge into a multi-degree of freedom model. The energy solution of continuous rigid-frame bridge is given, and the time-history analysis of the bridge is applied. In addition, the energy response of continuous rigid-frame bridge with different pier height and reinforcement ratio are given based on the energy method, revealing the impact of pier height and reinforcement ratio on the displacement and energy response of continuous rigid-frame bridge.
Abstract: Numerical simulation for dynamic response of EPS geofoam seismic buffers placed behind the rigid retaining walls was carried out with the Fast Lagrangian Analysis for Continuum method (FLAC) .The considerations of setting boundary condition of the numerical model, inputting and correcting the dynamic time series of seismic acceleration, and selecting the proper damping were discussed. The coincidence relations of compression-time for EPS geofoam buffers and the horizontal soil pressure -time for retaining wall were numerically calculated by using the proposed model. The calculating results were compared with the physical testing results. The comparisons showed that there were good agreements between the numerical data and the measured data. The numerical results indicate that EPS panels placed between the rigid retaining wall and the backfill soil have a good effect on reducing horizontal earth force during shaking acceleration and can act as seismic buffers against earthquake. The FLAC model provides a feasible way to analyze the dynamic response of EPS geofoam seismic buffers for further researches.
Abstract: The increase of ships crossing encounter in the intersection water of bidirectional navigation Y-fairway (YF) seriously decreases the port service level. So it is necessary to study the ship traffic rules in YF intersection water to improve this phenomenon. This paper first analyzes the ship navigation characteristics in YF intersection water. Then a simulation model for ship sailing operation system of YF is built to study the influence of different traffic rules on port service level. Traffic rules separately are First Come First Serve (FCFS), Larger Ship Priority (LSP) and Ship Leaving Port Priority (SLPP). Finally, a case study is introduced to analyze the influence of each rule on port service level. The results show that traffic rules have little effect on port service level for smaller scale ports. But LSP maintains higher port service level with the increase of port scale, while SLPP reveals obvious advantage if port scale continues increasing. And the advantage of SLPP is more and more obvious with the increase of port scale.
Abstract: Empirical Mode Decomposition(EMD) suffers some difficulties in separating dense frequencies. The Wavelet Packet Transform (WPT) and Singular-Value Decomposition (SVD) as signal preprocessors were used to decompose a simulated signal with dense frequency components and the performances of two signal preprocess technologies were compared in this paper. The results show that Singular-Value Decomposition (SVD) as preprocessor was better in separating dense frequencies than Wavelet Packet Transform (WPT).
Abstract: This paper compares the provisions of near-fault effect factors considered in the representative design codes in the world. It is found that the different codes carry out different near-fault effect values. Chinese, American, and New Zealand seismic design codes clearly present the near-fault effect factors, and Chinese seismic design code relatively presents the smallest near-fault effect values among the three codes. While Japanese code accounts for near-fault effect using empirical method and strong motion evaluation employing earthquake source model. The consideration of the near-fault effects in European Standard is the simplest among the five codes.