Advanced Materials Research Vols. 1025-1026

Abstract: In evaluating wind load effects on large-scale structures, correlations in the frequency domain (i.e., coherences) and power spectra of fluctuating wind speed should be evaluated in advance. Most existing formulas for coherence are expressed as exponential functions based on field measurement data for ease of mathematical treatment. However, these simple mathematical expressions have many limitations. In the present study, after examining the existing coherence formulas, a semi-theoretical formula was proposed, and the corresponding along-wind force power spectrum of a tall building with a square cross-section was numerically calculated. A comparison showed that both the coherence and along-wind power spectrum were in good agreement with those of actual wind tunnel data.

Abstract: Fuzzy clustering method was used in the comprehensive evaluation on the water abundance of sandstone aquifer at the bottom of P₂xs (K3) in the Wolonghu Coal Mine. Then this paper contrastively analyzed the characteristics of water-inrush and hydrogeochemistry of adjacent mines. The results show that the water abundance of northern sandstone is rich, the direct water-inrush source of working face is K3 sandstone aquifer, and there is a hydraulic relation between this aquifer and the water of sandstone in adjacent mines. They have the same water source and the north of the coal mine gets a supply from external sources.

Abstract: Ambient truck classification and weight data have been used in numerous transportation applications, focusing on highway safety. Specifically, ambient truck characteristics identified from Weight-In-Motion (WIM) data obtained from vehicle weigh stations have been considered to be likely candidates to better understand structural response of highway bridges to live-load events. This paper provides a framework to explicitly identify WIM-based ambient truck characteristics specific to highway bridges of interest. As an application of the framework, a highway steel I-girder bridge in the United States was selected and a network of strain sensors was installed on the bridge deck. Multiple strain time history data sets resulting from ambient trucks were measured and evaluated via a structural health monitoring (SHM) system with strain sensors. Each set of strain data representing a single truck, which cross the bridge, was used to identify its features, such as axle numbers and spacings. WIM trucks specific to each set were also characterized by examining the monitored strain time history patterns. These patterns make it possible to the identification of ambient WIM truck configurations. WIM data were obtained from weigh stations located adjacent the bridge. It is anticipated that this work will result in the creation of ambient truck pools on a specific bridge. Their pools will be used as live load inputs in the bridge model to investigate the structural behavior and to evaluate the bridge health conditions..

Abstract: In the modern building construction, different size of openings are provided in the web of reinforced concrete (RC) deep beams to accommodate utility pipes and ducts of essential services such as electricity cable, telephone network and air-conditioning network. However, accommodation of such openings caused reduction in beam strength, stiffness and caused excessive cracking and deflection. Many investigations were conducted to study the behaviour of openings in beams and relevant strengthening options to reinstate the lost capacity. One of the strengthening options considered lamination of fiber reinforced polymer (FRP) sheets due to its superior properties such as high tensile strength and stiffness, high resistance to corrosion, excellent fatigue performance and good resistance to chemical attack. FRP lamination has been widely accepted by the research community and practicing engineers in the construction industry as the material for strengthening and rehabilitation of common problems. However, quite limited literatures contained the use of FRP to strengthen RC deep beams with openings. This paper discussed the review of eleven different articles contained study of RC deep beams with openings together with effects of strengthening using FRP sheets. The outcome of this review paper outlined the way forward and future research focus in this area.

Abstract: Wind power generator produces electric energy using wind. Since fuel for operating a wind power generator costs almost nothing, it is receiving attention as a power generator for the next generation. A wind power generator consists of a device that absorbs and converts the energy of wind power, power train, and control device. Each element is connected as a whole while it performs its function. In this study, we used the patent IPC information related to segmented technologies of this wind power generator to establish a two-mode network, measure eigenvector centrality value and identify the field with the highest influence among the fields of wind power energy. In the result, the field of generator was found to have the highest influence, followed by operation system and blade. It was analyzed that the field of generator had the highest influence since H02K and H02P, the IPC codes in the field, were the important technologies that influenced on other fields. In addition, H02N and H02N, which are main IPC codes in the field of solar cell, were analyzed to have connection with the field of generator.

Abstract: A difference in frequency of loading during the test may give a different number of cycles to failure, especially at a higher frequency. The difference becomes more evident when higher frequency was applied at the same stress value. The change of frequency should be analyzed to define its effect on the fatigue life of the Extended Hollobolt to concrete filled hollow section. A number of tests are conducted to determine this effect. Frequencies between 0.25 and 5.0 Hz were applied. Analysis of the result indicates that frequency below 3 Hz does not significantly affect the fatigue life of Extended Hollobolt.

Abstract: The theoretical study of galloping can effectively promote anti-galloping techniques. Cable element is utilized to imitate the bundled conductor, and beam elements are used to simulated the spacers, established galloping finite element analysis model which can consider sub-conductors wake interference. The finite element equation was solved by time integration method and the calculation program was compiled by MATLAB. Through numerical simulation analysis, compared the dancing in the case of considering the effect of the sub-conductor wake and ignoring the effect of the sub-conductor wake. The results showed that considering the effect of the wake on aerodynamic loads has a greater vertical vibration amplitude. This method can provide reference for the study of prevention technology on dancing.

Abstract: Exploitation of geothermal resource results the decrease of fluid pressure in geothermal reservoir. In production process, the analysis of reservoir condition is made by observing the pressure state. When the fluid is pumped into the reservoir, the value of pressure varies with time which is called as transient state. The plot of pressure versus time will create a curve with a certain slope. From the graph of the pressure the reservoir condition can be analyzed. The solution of the pressure transient is identified as exponential integral equation E_i(x). When the input to the function is really small for example at x < 0.01, the equation will form an asymptotic curve. Analytical solution involves logarithm natural and Euler constant (γ). In this paper we try to approach the solution of exponential integral equation by numerical integration. The objective of this study is to make a numerical model of the pressure change in a geothermal reservoir and to compare the result between numerical method and analytic. There are two methods used in this study, first is Picard-McLaurin iteration to solve the ordinary differential equations (ODE), and the second is trapezoidal integration to calculate the function of E_i(x). The modeling shows that the result of the calculation with the numerical method matched with the analytic with the range of error between 0.0008 to 4.5 % for drawdown test and 0.19 to 7.7 % for buildup test.

Abstract: The economics and productivity of any reservoir is strongly connected to the ultimate recovery of the reservoir, this is chiefly govern by the strength or performance of that reservoir. In order to be able to understand the ability of the formation to produce fluid and characterize the reservoir properly, well testing is use to carry out this analysis.

Abstract: This paper explores rotational capacities and demands in thick top-and-seat (cleated) angle partially restrained connections subjected to monotonic and cyclic loads. The results of test on full-scale angle connections are described first, and are then compared to published curve-fitting models for these types of connections. The data indicates that the curve-fitting constants of some existing mathematical models cannot be extrapolated to thick angles. The results indicate that these connections are capable of providing very ductile behavior and constitute an ideal back-up structural system in steel frames.