Advanced Materials Research Vols. 163-167

Abstract: This paper illustrates the results of an experimental study on the bending performance of concrete beams strengthened with near-surface mounted (NSM) FRP reinforcement. The critical parameter of the embedded length of NSM-FRP plates was investigated in particularly. The test results indicated that NSM-FRP reinforcement can significantly improve the strength and crack resistance capacity of the concrete beam, reducing the size of cracks. The embedded length of the NSM-FRP plate has distinct influence on the cracking and bending capacity, the flexural stiffness, and the crack developments of the concrete beam. As the embedded length increased, the bending capacity and the flexural stiffness increased correspondingly and the crack developed more intensively.

Abstract: Finite element models, established using ANSYS, given the soil - structure interaction phenomena produced at the interface between the reinforced concrete structure and the soil, have been used to perform a parametric study of the strengthening design of the foundation and the sluice chamber within mining subsidence area. High pressure jet grouting pile is adopted to reinforce the foundation, this analysis model is simplified by the transformation from the pile foundation to the solid foundation, which reflects the characteristic of pile foundation. The strengthening design of the sluice chamber is a renovation from open style to frame, to increase the integral property. It is indicated that, using high pressure jet grouting pile to reinforce the foundation can apparently improve the stability of sluice in mining area. Nevertheless, it can't improve the stability of sluice through reinforcing the sluice chamber.

Abstract: As a new kind of structures, Multi-ribbed wall structure is now widely used in new-built buildings and old structures needed to be strengthened. In the field of strengthening, Masonry structure with bottom frame is often mentioned for it is vulnerable to earthquake. However, it is still widely applied in China for its agility for arrangement. So how to guarantee the safety of this kind of structure is very important. There are many methods to reinforce this style of structure, but every way has its limitations. Compared with other methods, Multi-ribbed wall structure is more proper, because its stiffness and mass can easily be changed through optimal design of different kinds of materials inside.

Abstract: Longmen Grottoes is the famous cultural heritage. Many factors should be considered in reinforcement project of the plank way slab. Considering the characteristics of the tourist area, many reinforcement schemes are put forward, at last, the method with CFRP sheet is selected to reinforce the plank way slab. The reinforcement effect shows that this method increases very little weight of the structural members. The appearance of the reinforced members are harmonious to the surrounding environment.

Abstract: The settlement law during the underpinning process of a frame structure was analysed using the three-dimensional finite element model based on ANSYS program. The birth and death technique was adopted to simulate the work state of the underpinning structure and the underpinned piles. The secondary settlement deformations in the process of foundation underpinning can be simulated when the settlement values of the column bases before underpinning were applied to the underpinning structure. The settlement-location curves of the frame column bases before and after underpinning can be gained through path operation. The analysis results show that the settlement values and the differential settlements of the underpinning location increase obviously after underpinning, the medial deflection of the underpinning beam increases, and the settlement value of corresponding frame becomes bigger. The deformation of the underpinning beam occupys big proportion in the total settlement deformation. When the length diminishes and the diameter augments of the underpinning pile, the stiffness of the pile increases, therefore the settlement values and the differential settlements decrease. When the span diminishes and the height augments of the underpinning beam, the stiffness of the beam increases, accordingly the settlement values and the differential settlements decrease obviously. The width change of the underpinning beam has little influence on the settlement values and the differential settlements.

Abstract: Excavations on steep slopes are common problems in practice; little work has been done on the geotextile reinforcement effect in such a situation. Two centrifuge model tests were conducted to simulate the excavation of cohesive slopes with and without reinforcement. The tests results showed that the geotextile greatly enhanced the slope stability and the effects of reinforcement mainly emerge in two aspects as follows: (1) to diminish the deformation and to unify deformation distribution; (2) the reinforcement effect was achieved mainly through friction forces.

Abstract: With the nonlinear finite element method and the program based on ANSYS which is redeveloped by APDL in it, the ultimate bearing capacity of reinforced concrete box girders strengthened with carbon fiber sheets is analyzed in the paper. The material nonlinearities of concrete, steel bars and carbon fiber sheets are taken into account in the three-dimensional finite element models in which the technology of "element birth and death" is used to consider the secondary loads of carbon fiber sheets. Four strengthened RC box girders same with above calculation models are made for experimental researches. The finite element calculation results are in good accord with those of the experimental researches, which verifies that the proposed numerical calculation method for the analysis of the ultimate bearing capacity of reinforced concrete box girders strengthened with carbon fiber sheets is rational and reliable.

Abstract: This study is the first part of investigation into the interfacial mechanics performances of cracked reinforced concrete (RC) beam strengthened with prestressed hybrid fiber reinforced polymer (HFRP). Finite element (FE) analysis models were established for such beams with different concrete crack height in this paper. The analysis results indicate that the existing of the flexural cracks obviously affect the stress distribution in the interface between concrete and HFRP, and a sudden change of the stress would arise at the cracks. For cracked RC beams strengthened with prestressed HFRP, both the shearing stress and normal stress of the adhesive layer and fiber sheet are much larger than those without cracks, and the growth rate increases with the crack height.

Abstract: One reinforced concrete coupling beam and two strengthened reinforced concrete coupling beams by bolted steel plates are analyzed by nonlinear finite element method. Two-dimensional finite element model is employed with material nonlinearities and geometrical nonlinearities. A special ring region, which simulates the slip effect between concrete and steel plates, is developed an incorporated into the numerical analysis model. The load-displacement relationship, cracking/crushing type and steel plates internal are compared and found to be in good agreement with those in test.

Abstract: Firstly, it simulates different depth at nanmaquan and civil mines respectively with the software of MIDAS to carry out in phases; secondly, it discusses the rule of vertical settlement surrounding rock and cover rock in the mined-out areas; lastly, it analyzes furtherly the rules of changes with the method of adding different load in order to research the stability of the foundation under load in the old mined-out areas. The filling grouting of falling belt and cracks belt have been explored and analyzed on the basis of a series of different methods such as total filling grouting, part decreasing stride, separating rock and board, and independent rooting, and so on. Afterwards, it applies XBHV-10-foot steel settlement instruments to measure on the scene and analyze the effect. Minded-out areas reached the desired treatment effect.