Experimental Research And Theoretical Analysis On Seismic Behaviour Of Masonry Walls Strengthened By CFRP

The technique of strengthening structure with fiber reinforced polymer has been becoming mature in the field of concrete structure, while is still in an elementary stage in the field of masonry structure. There are a lot of basic researching work need to be done for the purpose of making full use of this technique and putting forward correlative technical rules. Due to the brittle materials, masonry structure has a poor performance in earthquake. By the passing of using years and heightening of seismic defensive criterion, the problem is becoming outstanding that more and more masonry structures need to be strengthened. The masonry structures existing in China and the historic buildings distributing in all over the world all need to be repaired, strengthened and protected. So it is very important and practical for us to study masonry structure strengthened by FRP.However, this kind of study just begins for a little years in our country. The studying range is still narrow and experimental quantity is small. In other countries, especially in Europe, there have been still several using examples of masonry structures strengthened by FRP, but the systemic experimental study and academic research can not be found in any searches. An all-around study on the above problem is presented in the paper. Through experimental study, calculation of carrying capacity and FEM simulation, several kinds of masonry walls are discussed. Some new points of view and strengthening measures are put forward, too. There are three detailed aspects as below:1 There are three groups of experiments on 16 piece of brick walls strengthened by carbon fiber sheet under cyclic loading were done. There are two groups of experiments on 7 brick columns strengthened by carbon fiber sheet under pressure were done, too. The strengthening effect on the seismic capacity of the walls and the compressive capacity of the columns was studied in the paper through the comparison of the data of the structures before strengthened and the strengthened ones, and the different effect of different strengthening ways was compared as well. The study indicates that the seismic capacity of the walls was improved effectively with carbon fiber sheet attached to them, while the compressive capacity of columns was enhanced just in a little range. The contents of strengthening historic buildings, anchor effect on the bottom of the walls, strengthening methods for brick walls with a window or a door and strengthening masonry columns with CFRP which should be pasted on the full surface are the innovation in this part.2 Based on the experimental study, the simplified analytical models for different kinds of walls are established and corresponding calculative formulas are brought forward. Through the comparison of the calculative data and the experimental ones, it is proved that the formulas in the paper are capable to be used in engineering. The models and formulas of walls with a window or a door are the innovation in this part.3 Based on the experimental study, the strengthening effect on two kinds of walls is discussed by using a FEM software to conduct an analytical study. The walls of different height-width ratio are discussed as well. The analysis indicates that it is effective to strengthen masonry structure with carbon fiber sheets. The finite model of masonry walls built through contact cell to simulate the property of motar is a new method to be used in the studies in future.Some problems about this research worth to be studied afterward are put up in the end of the paper.