Advanced Materials Research Vols. 368-373

Abstract: In this paper, the elasto-plastic dynamic analysis on the steel spatial arch truss with 60m span and 0.1 rise-span ratio is carried out under earthquake wave with SAP2000. In the analyses, the geometric and material nonlinear effects are considered at the same time based on the plastic-hinge theory. Under the action of EL wave with the peak increasing gradually, its elasto-plastic dynamic responses have been obtained. The results show that its failure mode under the earthquake action is elasto-plastic dynamic buckling; that its critical peak acceleration of EL earthquake wave when applied in horizontally direction is 678gal, and is 624gal when applied in vertically direction; The ratio of its maximal node horizontal and its structural height is 1/961, and its displacement ductility coefficient is 1.14 and the ratio of its bars with plastic hinge appearing when buckling is 2.15% when EL-Centro waves applied on structure in X direction; The ratio of its maximal node vertical and its structural span is 1/660, and its displacement ductility coefficient is 1.17 and the ratio of its bars with plastic hinge appearing when buckling is 6.09% when EL-Centro waves applied in Z direction.

Abstract: This paper addresses a new damage alarming method of structural health monitoring (SHM) which utilizes statistic method on information in frequency domain. The emphasis in this paper is on the application of this method to the benchmark structure by introduced an abnormal index. The results show this method could indicate the abnormity of corresponding test cases clearly.

Abstract: Research status of ground motion parameters of seismic appraisal for existing structures is analyzed. According to the theory of the probabilistic distribution of seismic intensity which fits Extreme Value Type Ш, the relation of multi-value seismic intensity to seismic basic intensity from different seismic hazard characteristic zone is studied in this paper. Under the principle of all the seismic actions of each fortification level have the same exceeding probability, the basic intensity for seismic assessment of buildings with different residual service lives is given to each zone. At last, after giving full consideration to the seismic hazard differences to different areas, the modification factors of seismic action of buildings at the three zones with different seismic hazard characters are given in this paper. At last, this paper provides a base for the structure designers to choose a rational seismic action during the seismic appraisal for existing structures.

Abstract: On construction quality detection in high earth rock-filling dam, it is difficulty for testing the relative density Dr Value of large particle size filter materials. In this paper, we have effectively controlled the filling quality of filter material II in Nuozhadu core dam, and at the same time, explored and applied the rapid detection method of Dr Value of filter material II. Then studied the relationship between maximum, minimum dry density of the different grade material in the case of same compacted function and soil gradation parameters, and put forward a method of maximum and minimum dry density associated with particle composition, fitting relation curve between dry density and particle content less than 5mm(S5). By detecting the content of S5, it can be directly reached maximum and minimum dry density, and then calculate the Dr Value.

Abstract: Fiber-reinforced polymer (FRP) has been applied to reinforce wood structure with its many advantages. But results of experimental study and engineering practice have showed that the failure is generally caused for lack of bong strength between FRP and wood, so the bond behavior between FRP and wood is very important. In this paper, based on the shear bond experiment between wood and CFRP sheet, the bond properties are researched such as failure character, characteristic of strain distribution, effective bond length and bond strength. Results showed that: at the loaded-end, the strain of the CFRP sheets is the maximum, and then strains decrease quickly with the increase in distance from the loaded-end. Strain distribution along cross direction is not uniform and the strains of the center location are bigger obviously than that of the edge location. The effective bond length between CFRP sheet and wood is more than 120mm.

Abstract: This paper presents Integrated Cooperative Time-variation System (ICTS) and its application for constructional process of complex steel structures. ICTS is based on integrated model comprised of structures, boundary conditions, loads, material properties, construction facilities, where all those are supposed to be time-variation associated with a complex construction process. ICTS can deal with mainly time-variation analysis of construction processes, including pre-set deforming, integrated lifting, temporary support removal, rotation pulling, sliding and tensioning. Besides, several key control technologies of structural force and configuration during structure construction process are introduced, such as obtaining error criteria of cable’s length in tensile structures, controlling influence of constructional environmental temperature, estimating differences between internal and external tubes’ vertical deformation of skyscrapers due to shrinkage and creep of concrete of internal tube, evaluating residual internal force of complex welding structures. ICTS and these key control technologies reinforce traditional construction analysis by keeping continuity of constructional process and simulating interaction of different parts in integrated model precisely, and reach to a design-required structural state accurately after finishing constructional process.

Abstract: External components loss injuries caused by various defects of steel material performance, design, production and construction, and adverse factors such as overloading, repeated load, high-temperature, corrosive media or mismanagement, direct impact on security of steel structure in the course of subsequent use. Based on the investigation of single layer steel structure industry workshop, from two aspects of nature and quantify, the effect of initial geometry defect on bear of axle pressure component and crane runway partiality on bear of crane beam system is analyzed, which is the basis of regularity uses、consolidating and monitors of the building. The result shows that through the computation of axle pressure component with initial geometry defect or crane runway partiality, the component's bearing capacity reduces many and the effect of security is big, and when the initial geometry defect or crane runway partiality surpasses the standard stipulation the certain proportion, bearing capacity will continue to reduce, the structure will be more unsafe. The effect of crane runway partiality on the crane beam web plate upper extreme edge's intensity and web plate horizontal stiffening rib's intensity is little.

Abstract: The steel plate reinforced concrete shear wall (abbreviated as SPRCW) is an innovative type of lateral force resisting structural member potentially used in steel-concrete composite structures, especially in high-rise buildings. This paper presents an experimental study on seismic behavior of such kind of shear walls. The test specimens include five SPRCW models and one ordinary specimen RCW-1 built at the aspect ratio is 2. The combination of the following wall parameters is varied: thickness of the steel plate, thickness of the SPRCW, axial compression ratio, and detailing such as lateral ties cross the steel plate. The experimental program is developed to evaluate the damage patterns, hysteretic response, strength, stiffness and ductility behavior of the walls under axial compressive loads and cyclic horizontal forces. In addition, the experimental results are analyzed in comparison with those of anthoer ordinary RC shear walls. The investigation shows that this type of shear wall has the potential to offer strength adequate for resisting forces from earthquake and stiffness appropriate for limiting drift for tall buildings with less size than ordinary RC walls. It is also observed that steel plate encased in the wall plays a major role in bearing loads, while concrete provides lateral restraint for steel plate, and hence increasing global stability and deformation capacity of the wall.

Abstract: To research the applicability of equal strength substitution method applied to concrete beams with steel plates, the effects on application range of equal strength substitution method by the initial reinforcement ratio and the strengthened moment design value are discussed．In this paper, the calculation methods of equivalent substitution and Design Code for Strengthening Concrete Structure are adopted to calculate five kinds of single-reinforced rectangular cross-section concrete beams of typical section size by adjusting the initial reinforcement ratio and the strengthened moment design value．The dosage of steel plates is obtained through the comparison of the equal strength substitution and code calculation methods, which is used to obtain the relationship of initial reinforcement ratio, the area ratio of steel plates calculated by the equal strength substitution and code calculation methods and the moment ratio of strengthened and initial ultimate moment． The result shows that equal strength substitution method is not applicable universally, which is feasible only within the scope of certain．

Abstract: Based on fatigue tests of pre-stressed concrete (PC) and ordinary concrete beams for 15 specimens after different times of freezing-thawing circle, the degradation process for the tested beams of the relative dynamic elastic modulus is conducted. The experimental study shows that the pre-stressing level and times of freezing-thawing circles are main influence factors to durability of test beams. The results of this study are useful for the exploration of the mechanism of the PC structure’s damage and the improvement of design theory concerning the durability of the PC structures.