Applied Mechanics and Materials Vols. 578-579

Abstract: Through repair and reinforcement of breaking reinforced concrete beams by epoxy resin and carbon cloth, and its experiment, the crack and deformation and bearing capacity as well as ductility of such beams are obtained. Experimental results show that the ultimate bearing capacity of beams after reinforcement increased by 210%, the structure ductility fell by 170%, structural failure form is similar to failure in normal cross section.

Abstract: Through strengthening experiment of four limit damage reinforced concrete beams by CFRP, the performance index of the carrying capacity, the stiffness and the ductility compared with before strengthening of reinforced concrete beams, and analyzed before and after reinforcement. It shows that the ultimate load, the stiffness and the ductility of limit damage reinforced concrete beams by CFRP have different degrees of increase and can be widely used in practical engineering.

Abstract: The combined connection with welds and bolds mainly refers to Interaction of weld and high-strength bolts. Both bolts and welds show influence on the performance of the combined connection. In practical engineering, because of limited joint size, only welds’ performence can increase bolts number or load. Therefore, it need to explore the influences of weld on joint performance. Moreover, for given determined bolt connection, it is necessary to discuss the influences of weld size, weld length and weld height, on the performance of a certain weld joint.

Abstract: The damaged characteristic and damaged factors of brick structure buildings have been analyzed according to the survey datum of 138 damaged brick structure buildings in Zhengzhou, the laws of damaged characteristics and the effect degree of damaged factors have been discussed.

Abstract: This paper expounds the model pile of various types and different loading measurement method, and introduces the model test of pile foundation; big full scale model test of pile foundation, pile foundation indoor common model test research and its limitations, this paper expounds the advantages and disadvantages of different test methods.

Abstract: The splitting test for concrete specimens in four different dimensions were carried out in order to build the relative even micro-crack damage fields. The real-time whole-field displacements of concrete surface were measured omni-directionally by DSCM(Digital Speckle Correlation Method). Through analyzing the obtained experimental data, two kinds of micro-crack damage parameter are established :one is damage area based on the MCOD (Micro-Crack Opening Displacement) and another is damage variable based on the weighting-damping elastic modulus, which provides a new index and method for characterization of concrete micro-crack damage.

Abstract: Freeze-thaw cycles can affect the chloride diffusivity of concrete to a certain extend. The experimental study of plain concrete specimens with different strength grade were carried out, suffering 0, 50, 100 and 150 cycles of freeze-thaw. Chloride ion penetration under different strength, different cycle-index and the concrete mass-loss caused by freeze-thaw cycles are analyzed. Using this method the relationship of chlorion permeability with concrete strength is established when the concrete specimens reach to a particular value of freezing and thawing cycles.

Abstract: Brick masonry cracks only variety, shapes, and the phenomenon is more common, it may affect the beauty of buildings, resulting in infiltration Water Leakage, or reduce the bearing capacity, stiffness, stability and integrity, durability of building structure, but also can lead to an overall collapse of serious quality accidents. Therefore, the correct analysis of the reasons of cracks, puts forward the prevention measures is very necessary.

Abstract: Cable corrosion is a serious problem in cable-stayed bridge. The paper analyzes the reason of cable corrosion and introduces the method of damage monitoring and detection.

Abstract: The strain measurement is a most important and absolutely necessary task on the probing into the constitution of the materials. The ways of strain measurement are theoretically divided as the mechanical type, vibrating-string type, inductive type and bonded resistance type, and the last one is widely used for its high precision and convenience. The geogrid, which has been widespread in the reinforcement structures, is more and more popular for its high strength, good toughness, corrosion resistant, anti-fatigue and effective interaction with soil. The geogrid is made of polymer, its ultimate strain can reach above 10%, and it is sensitive to the time, furthermore it usually has significant relative displacement with soil in the tests. Then some measures have to be taken to make the measuring range wider and make the all gauges achieving synchronization, measures also should be conducted to prevent the strain gauges separated from the geogrid when it has slightly bending, prevent the wires break when the gauges going forward and reduce the influences from the forward preventing measures. Some researchers have showed their techniques to avoiding part of the above problems. Based on a series of pullout tests of geogrid, this paper gives the contrast and analysis on those techniques above, and lists the relative measures that used in these tests, especially for the gauge sticking techniques and preventive measures.