Applied Mechanics and Materials Vols. 501-504

Abstract: Modal identification technique is an effective measure of health diagnosis, structural rehabilitation, retrofitting and strengthening or optimization design of structures and materials in structural engineering field. The modal identification theories of random decrement technique and time-series method under ambient excitation are presented in this paper. The two methods are combined to become a joint algorithm for identifying modal parameters effectively. The numerical simulations of a three-layer architecture are carried out to verify the feasibility and practicability of the joint algorithm.

Abstract: With the development of energy-saving in buildings, new energy-saving block masonry with multi-row cores is commonly used. In this paper, from the study of typical bearing capacity of multi hole concrete block masonry of combining multiple rows of holes, holes in the multi block wall masonry capacity test of heat insulation material characteristics. Test results show that, in the process of multi hole masonry brittle failure characteristics, built-in straw block in the insulation at the same time, can improve the compressive strength of masonry; masonry local diffusion mechanism under the action of stress is significant; and offer the engineering measures.

Abstract: Fire-resistance performance of beams can be improved if the beam strengthened by carbon fiber sheet bonded with inorganic adhesive instead of organic epoxy adhesive with low softening temperature. However, Fire-resistance performance of the strengthened beams is not understood fully. Considering this issue, finite element analysis is done. Stating from building valid model of finite element, computing results are compared with experimental results, and rationality of the model is verified. Then plenty of parameter analysis is done. Effect of some parameters, such as Range of carrying capacity increase by sheet, reinforcement ratio, load ratio to carrying capacity and width of section, on fire-resistance performance of the strengthened beams is analysis. The results demonstrates that reinforcement ratio and load ratio to carrying capacity is the main factors influencing fire-resistance performance of the beam strengthened by carbon fiber sheet bonded with inorganic adhesive, While, range of carrying capacity increase by sheet and width of section have little influence on it. Beams, strengthened by carbon fiber sheet bonded with inorganic adhesive, and protected by Thick-typed Fireproof Coating, perform good fire behavior.

Abstract: Elastic buckling modes of cold-formed thin-walled steel member have three relevant types: local, distortional and global. The complicated and important thing is to differentiating buckling modes and resolving buckling stress for engineers. It will be given for Cold-formed thin-walled lipped channel member with multiple intermediate stiffeners. The theoretical analysis coincide exactly with the experimental results, it can be used as a reference for engineers.

Abstract: With in the development of high-speed railway countrys China is one of the competent use of ballast less track spreader and largely applied on sub grade, in order to ensure high speed, safe and comfortable run of the train, the sub grade structure must provide smoother and more stable support for the upper track structure, but the problems caused by non uniformity sub grade structure performance are increasingly prominent. There have many serious problems such as low precision of measurement, low degree of automation, compaction mechanism, sometimes consolidation time and high interference of human factors. This paper described as the structural characteristics of longitudinal coupled prefabricated slab track System similar to bögl from German, a model for static analysis has been developed. Based on the model, the slab track element is presented. This element includes rail, rail fastening, prefabricated slab, CA mortar, and base plate and sub grade.

Abstract: By using the simple stiffness matrix formula of reinforced concrete (RC) cross-section under bending and compression, some RC cross-sections under bending and compression were traced through full path. Based on the numerical analysis, the damage of each point was calculated in a cross section, and the damage distribution of one member under the ultimate load was analyzed. This was agreement with experimental phenomena. In cross-section level, cross-section whole damage index was given and researched; and it could well explain cross-section mechanical behaviors.

Abstract: To study on the mechanical property for haunch-reinforced seismic connection, the simplified calculation model of haunch connection is introduced. The force analysis of beam with haunch connection is carried through to research value influence on mechanical property of haunch connection; Combining American design specification with Chinese design specification, the design procedure for welded haunch connection is shown, and the differences in design between two countries are summarized. At last, it is studied through beam-column joints case analysis that the influence of the different node parameter on the mechanical property of haunch connection. The results can be got that with the increase of thevalue, the beam moment at column face becomes smaller, which will be better to protect the beam form brittle fracture. But if is larger than one,beam web shear in the haunch region will increase. In the design the reasonable value should be close to one but less than two. When haunch height is invariant, with the increase of haunch length,became smaller; the value and the top and bottom beam flange groove weld stress reduce gradually; The required minimum section area of haunch flange became larger; The axial force of haunch flange and haunch web shear increase gradually. The reasonable haunch length should be as close to the middle of the (0.5 to0.6) times of height beam as possible. The reasonable haunch flange section area should make close to, such materials are made full use. Key words: haunch connection; force analysis; parameter of reinforced-plate; mechanical property

Abstract: According to the common girder with side main rib section of PC cable-stayed bridge with double cable planes, a computational model of two-dimension temperature field is presented. Temperature gradient of main rib, small longitudinal rib, top plate and flange plate was computed respectively, and then the stress and strain of each section are derived through plane cross-section assumption. For the cable-stayed bridge, member structure FEM is applied to compute node equivalent load and displacement, which resulted from both sunshine and seasonal thermal difference. Finally, a case study is analyzed, the results showed: computed and measured deflection of girder that result from thermal effect are very close, therefore, this method is feasible.

Abstract: the workover rig is always fixed by anchor piles in land oilfields. Good load capacity of anchor pile is the key factor to the guarantee of safe workover operation. The load capacity test of anchor pile is complete by connecting vibration test and method of mechanical impedance. The reduction coefficient must be used in calculating the anti-pulling load capacity because of difference of soil kinds. To testify the results from mechanical impedance method, the system of pulling pile directly is built. The average error of data from this system is within 5%. It can conclude that the method of mechanical impedance and vibration test can be popularized widely to load capacity of anchor pile, especially in different kinds of soil. The research can enrich the theories of uniform section pile and give the theoretical foundation to fix the anchor piles safely during workover rig operations.

Abstract: In order to meet the needs of large span project for Vegetable expo, supporting building system consisting of prestressed single-surface Double-layer Cable was put forward. Based on the assumption analytical solution of the double-layer cable planar support structure system was given. Using ANSYS finite element software simulation analysis on the double-layer cable system was carried out, the discrete finite element solution was acquired, and by comparing the analytical solution was verified to be accurate. Finally, the construction methods and means of monitoring during construction were given, and these can provide references for design and construction of similar projects.