Applied Mechanics and Materials Vols. 166-169

Abstract: The supporting measure and stability analysis of adjacent deep pits are problems worth to be noted. This paper discusses the feasibility of using the soldier pile wall as the supporting measure for two adjacent deep pits. Use is made of the finite deferential model to simulate the two pits. The authors analyze the failure state and deformation characteristic of the surrounding soil mass and soldier piles, the failure zone of the surrounding soil is sporadically distributed and the lateral displacement calculation results of the soldier piles are found to be very tiny and in excellent agreement with the monitor ones, which indicates that the pits are stable and the selected supporting measure is effective and applicable.

Abstract: In Japan, fatigue through-thickness cracks have been reported in steel bridges. Some of the cracks are originated by out-of-plane bending. For performing more efficient maintenance against the fatigue damages, it is essential to identify the crack propagation behavior of the through-thickness crack under out-of-plane bending. As an important factor to assess the crack propagation behavior, generally, stress intensity factor for through-thickness crack under bending was determined by some assumptions that crack front shape is straight in thickness direction. However, the actual crack front is curved under out-of-plane bending. In this paper, in order to identify the propagation behavior of through-thickness crack under out-of-plane bending, the fatigue test on through-thickness cracked plate was carried out. Moreover, through finite element analysis on the test specimen, the stress intensity factor along curved crack front was investigated.

Abstract: FE models of both the single-layer Kiewitt-8 reticulated domes with a span of 60m and the cylindrical impactor were developed incorporating ANSYS/LS-DYNA. Afterward, fourteen groups impact are simulated by changing the impact position or impacted angle on reticulated dome, and impact velocity and mass of impactor are changed for each group impact. On the basis of large numbers of numerical simulations, characteristics of dynamic response for reticulated dome under impact are shown. And four failure modes (Members slightly damaged, Local collapse of dome, Global collapse of dome, Members shear failed) are presented for single-layer Kiewitt-8 reticulated dome under diverse impact. The distributing of failure modes for the fourteen types impact are different from each other, and the adverse position and angle are summrized.

Abstract: The high-rise concrete residential market has been a gradually urban mainstream in recent years, and frame-shear wall structure is more used for high-rise residential structures now. This kind of structure has the advantage that the combination of frame and shear wall make the space free and flexible, and therefore the whole structure has considerable rigidity. The structure can not only satisfy the needs for people living in comfortable, but also has good dynamic and static load bearing capacity. This paper analyzed the mechanics characteristics of the structure and summarized the two kinds of main failure modes of shear wall and frame structure in earthquake. On this basis, the main principles are put forward to improve the seismic behavior of the shear wall. And further some of specific measures and suggestions which can improve the seismic performance for the frame-shear structure are introduced.

Abstract: This paper demonstrates a new abnormal index based on frequency change for structural health monitoring (SHM) which utilizes probability and statistics method. And it was introduced to analyze a steel frame. The results show it could indicate the abnormity of corresponding test cases clearly.

Abstract: Based on the determination of bending displacement-load experiments, the bending elastic modulus of Glass Fiber Reinforced Plastic commonly used on monopole communication tower is studied first in this paper. The experiments prove that the bending elastic modulus is low and indicate that 1:1 bi-directional glass cloth pavement does not meet the mechanical requirements of monopole tower and is not an economic design. In order to achieve mechanical characteristics of monopole tower, GFRP is adjusted to pavement of 4:1. Cross ply unidirectional glass cloth is used as main reinforced material, and the angle to horizontal direction is 90 degree and 0 degree. The bending elastic modulus of this secondary design is as nearly 10 times as the original design, and the result is proved by theory and experiments.

Abstract: The needs of environmental conservation and speed development in construction industry today have forced the search for better technologies in structural roof truss construction. Cold-formed section is a better choice for roof truss system in sustainable design with several advantages e.g. reduce cutting down of trees, speedy in construction, stronger, lighter and flexible in erection. However the stability issues occurred when wide-span roof truss is implemented with thin-walled cold-formed steel member. A full scale testing for a 25 meter wide-span roof truss system was carried out at Universiti Teknologi Malaysia to study the structural performance. The overall span of the truss is 25m in length with the height of 4.7m and the width of 1.2 m, built up by cold-formed steel channel sections of 150 mm and 74 mm in depth. Uniform loads were placed on the top and bottom chords of the truss using cement bags. The roof truss deformed at a total load of 63.77 kN or 52.7% of the designed load. Failure modes of the truss system were being observed and discussed for further improvement of the truss design.

Abstract: A structural health monitoring system by fiber Bragg grating (FBG) sensing technology was installed on 8 # berthing pier of cylinder caisson in a new 300,000 DWT crude oil berth pier of Dalian Port. The system can realize the timely strain monitoring and timely cumulative damage identification of the structure. By analyzing the monitoring data of 8# cylinder caisson under wave load, this paper gives the strain rules and provides the reference for the safety assessment. The study results also have pratical significance on similar structures’ further research.

Abstract: In this paper, a new stability criterion of time-delay analysis is established for active controlled structure system. Based on an improved upper bound for the inner product of two vectors, the maximal value of time delay can be obtained by using LMI control toolbox of Matlab. According to the new method, the maximal delay varying with parameters of controlled structure system is discussed for SDOF system. The criterion is applicable to the theoretical analysis for the delay-dependent stability of SDOF vibrating system. The longer the delay is the worse the efficiency of control strategy. But the system is still asymptotically stable so long as the time-delay lies in the interval of permitted time delay.

Abstract: Ductility is important in the design of reinforced concrete structures. In seismic design of reinforced concrete members, it is necessary to allow for relatively large ductility so that the seismic energy is absorbed to avoid shear failure or significant degradation of strength even after yielding of reinforcing steels in the concrete member occurs. This paper aims to present the basic data for the ductility evaluation of reinforced HPC (high performance concrete) beams. Accordingly, 10 flexural tests were conducted on full-scale structural concrete beam specimens having concrete compressive strength of 40, 60, and 70 MPa. The test results were then reviewed in terms of flexural capacity and ductility. The effect of concrete compressive strength, tension steel ratio, and shear span to beam depth ratio on ductility were investigated experimentally.