Papers by Keyword: Frame Column

Abstract: This article through to the two common cast-in-situ frame structure (casting of a whole, with a construction joint) and 6 root not construction joints under axial pressure ratio through concrete columns of different processing low reversed cyclic loading experiment, study their experimental phenomena, hysteresis curves, displacement ductility, stiffness degradation, thus draw the conclusion: 1, the existence of the construction joint can lead to the decline of ductility of frame structure. 2. When the test axial pressure is relatively low, the presence or absence of construction joints and different treatment methods will obviously affect the ductility of the cast-in-place frame structure. 3. When the test axial pressure is relatively high, the presence or absence of construction joints and different treatment methods will not have a significant impact on the ductility of the cast-in-place frame structure.

Abstract: The construction joint is the weak part of the structure, and the P-δ effect is mostly ignored when considering the second-order effect, so it is necessary to study the influence of second-order effect on frame columns. Based on the above considerations, under different axial compression ratios, the mechanical properties of the construction joints of the frame columns with construction joints and the cast-in-situ frame columns were studied by low cycle repeated load testsand analyzed the influence of the second-order effect on the shear capacity of frame columns with joints. The test results indicate that the existence of construction joints reduces the shear-bearing capacity of the specimens, and the second-order effect has a greater impact on the columns with joints under the same axial compression ratio, and the shear capacity decreases more. With the increase of the axial compression ratio, the second-order effect will be weakened on the frame column with seam, but when the axial compression ratio exceeds a certain limit, the second-order effect will be increased.

Abstract: The artificial neural networks (BP-ANN) established by the back-propagation algorithm and early stopping technique. By inputting the properties of geometries and material, BP-ANN model can predict the ultimate shear strength of reinforced concrete frame column. The BP-ANN model based on feed-forward neural network is built, trained and tested using the available test data of 82 RC frame column collected from the technical literature. And the test results are compared and analyzed with predictions based on the current the code of China and ACI code. It shows that the reinforced concrete frame column shear strengths obtained by the simplified model based on BP-ANN are in good agreement with test results, and they are closer to the experimental values than the results designed by models in codes. The BP-ANN model can be used in the shear strength prediction and design for reinforced concrete frame column.

Abstract: Steel structure is designed by limiting condition generally. Checking its stability is important in design. Calculating the effective length of the column is a key of stability checking. Some charts and formulas are written on Code for Design of Steel Structures, which is not applicable to the structural systems because of some assumptions. What is more, finding some values is not easy and the trend of the values is not obvious. In the paper the effective length of the column in the action of the fore with variable directions is derived by the equilibrium condition method and the effective length of the column chart is also drawn. Using these charts can quickly determine the effective length, and there is an intuitive tendency which the effective length varies with parameters.

Abstract: The principle and processof finite element model of ANSYS software for RC frame column was introduced firstly,and then the cracking and development rules of RC columns under monotonic load were analyzed with ANSYSsoftware. The results show that: with the stirrup ratios increasing, the short columnwith rectangle hoop, rectangle cross brace hoop and tic tac toe stirrups appearsuccessively few inclined cracks and more vertical cracks; with the axialcompression ratio increasing, more length of horizontal cracks extend to naturalaxis, more vertical cracks appear and appeared cracks are higher along thecolumn height direction for middle length HSC frame columns; the length of OSCframe columns is not so long than that of HSC frame columns, and the crack distributionis dense and crack forms mesh, which show better ductility.

Abstract: The frame column and frame structure with column end of steel-concrete composite joint is a new-type architectural structure. To obtain the mechanical property of the new-type frame column and frame structure, comparative tests between 6 new-type columns and 3 ordinary columns and comparative tests between new-type frames and ordinary frames are carried out. This paper elabrately introduces the specimen design, experiment load, test program, test results and others. Thus, the transformation and failure characteristics of new-type long and short columns at different axial compression ratios and the transformation and failure characteristics of new-type grames at different prestresses are obtained. They are respectively compared with the ordinary long and short columns and frames. Results show that the seismic performance of the new-type column and frame structure is obviously superior to that of the ordinary ones. The tests can achieve the expected test objectives and are proved successful.

Abstract: Based on the horizontaldisplacements and loads of column at top end deduced according to sectionalbalanceable conditions at yield of high-strength frame columns, the lateralmaximum loads of column at top end calculated according to the Chinese currentconcrete code and involved regressive formulas, the resilience model ofhigh-strength concrete frame columns were established. The main results show:the resilience models of high-strength concrete frame columns proposed in thispaper consider influenced multi-facts and conveniently applied to engineering.

Abstract: Determining the frame column effective length is a key part of the structure stability calculation in practical engineering. This specification for design of steel structure and specification for design of concrete are given in some relevant calculation formula and forms, but these formulas and tables can only be applied to the simple situation. In the complex situation, such as the frame column axial force and height is large, the formula is not applicable, may leads to unsafe results. In this paper. the formulas are deduced by using second-order displacement method in order to solve these problems,and the chart for determining the effective length is also obtained. The chart can be used to calculate the effective length factor quickly and concisely.

Abstract: In this paper,in order to study the load-bearing capacity of frame columns with construction joint under low-cyclic reversed loading, nine specimens were made, divided into three groups.Every group had three specimens, the first were made without construction joint, the second had fine processing construction joint, the third had simple processing construction joint. The three groups were loaded in axial compression ratio of 0.23,0.34,0.46 respectively.The results show that the influence of different processing with construction joint to crack position ultimate bearing capacity,skeleton curves.

Abstract: Calculation of effective length of columns is key of stability checking in design, therefore some formulas and tables are given in Code for Design of Steel Structures (GB 50017-2010), which show some application Limitations. These formulas and tables are made based on assumptions for regular frames. For some special cases, such as existence of the large difference of the column axial force or column length among the framework columns, these formulas and tables are no longer applicable. The practical calculation charts are derived by authors by using the displacement method with the second-order theory, which can be used to quickly determine column effective length and show intuitive trends of the lengths.