高强钢焊接薄腹工形截面双向压弯构件的稳定性

应用ANSYS有限元,分析了Q460高强钢焊接薄腹工形截面双向压弯构件的稳定性能,提出了可供实际应用参考的设计公式。分析中考虑的主要参数有腹板高厚比,构件长细比,翼缘宽厚比及荷载偏心率。结果表明,对受压为主的构件,腹板局部屈曲对构件稳定承载力影响较大,而对受弯为主的构件,这一因素对构件稳定承载力影响较小。有限元分析结果与现行规范方法计算结果比较表明,目前规范方法尚不能较好地计算高强钢焊接薄腹工形截面双向压弯构件的稳定承载力,因而提出了修正直接强度法,该法精度较好且偏于安全。     

Finite Element Analysis of the Influence of Steel Strength on Beam-to-column Composite Connections

Because high material strength and composite load-bearing are emphasized in constructing members for high-rise steel frame structures, in a composite connection, steel strength has a dramatic influence on both the bearing performance and the composite action of the concrete slab. Based on a finite element analysis, we discuss the composite effect and the connection breaking mode, focusing on the performance change of the composite effect in adopting high strength steel. It can be found from the results that, along with the improvement of the steel strength, the elastic and plastic ultimate strength of the composite connection will increase, the ductility will decrease to a certain extent, and the composite effect of the concrete slab will diminish. The collapse of the concrete in a positive moment side contacting the column flange is viewed as the limiting state of the connection.     

Experiment and FEM Analysis on the Joint of Inserted Steel Beam

A new composite structure which is composed of steel beam and concrete girder is introduced in fuel electric plant construction. With different height of concrete girders with or without anchor bar, two scale models from an actual project were designed and tested. It is shown that the maximum restraining moment of ends of steel beams is approximately 60kN*m; influence of anchor bar is little; the one with 600mm high concrete beam is damaged by shear, and the others steel beam is damaged by bending failure. Finite element models were built for supplementary analysis, and the result indicates that critical value of the height of concrete beam of different failure modes is 700mm; stiffness of shear key and thickness of floor have great influence on the structure; size of anchor bar has little influence; and width of the end of the steel beam has certain influence.     

Test and FEM Analysis of Junior Beam Deflection Influenced by Steel Floor Sheet

For light gauge steel floor,the structure testing and finite element method were applied to study the junior beam's inflection capability influenced by steel floor sheet.Analysis results show that the thin steel floor sheet affects junior beam's deflection very strongly.This conclusion has value for design of new structure or evaluating load support capability to the steel floors.     

Experimental study on the mechanical behavior of eccentrically loaded steel tubular columns filled with structural steel and concrete

Considered strength classes of concrete, ratio of structural steel to concrete, ratio of steel tube to concrete and eccentricity ratio of load, 6 test specimens of steel tubular columns filled with structural and concrete are designed. The damage phenomena of specimens are described in detail and the failure mechanism is analyzed. The results show the initial failure of the specimens are began from the yield of steel tube, the ultimate failure are ended from the buckling of steel tube caused by the expansion of core concrete. Due to the existence of structural steel, the ductility of specimens is superior to steel tubular columns. Before the yield of steel tube, the plane cross-section assumption of specimens can be put into use. The ultimate bearing capacity of specimens is increased with the increase of strength classes of concrete, ratio of structural steel to concrete and ratio of steel tube to concrete. But the ultimate bearing capacity and ductility are decreased with the increase of eccentricity ratio.     

Finite Element Analysis of Hysteretic Behavior of PR Steel Frame-steel Plate Shear Wall

In order to investigate the seismic behavior of partially-restrained steel plate shear wall (Steel Plate Shear Wall, SPSW), the effects of partially-restrained connection on the hysteretic behavior, lateral bearing capacity, stiffness, energy dissipation of SPSW with strong and weak steel frame were simulated under low cyclic loading via equivalent strip model that had been verified by experiment. The results show that hysteretic behavior of SPSW has dual characters. The hysteretic curves of SPSW with strong surrounding steel frame become fat, and the hysteretic curves of SPSW with weak surrounding steel frame become narrow. With the increase of the bending capacity of PR connection, the hysteretic curves of SPSW become fat gradually, and the capacity of energy dissipation and lateral bearing increase. However, the effect on lateral stiffness of PR connection of SPSW with strong steel frame is higher than the one with weak steel frame.     

The effect of volatile component on the heat value of wastewater and sludge samples from WWTP

The municipal wastewater biology treatment process includes both pollutants transferring and energy utilization. The wastewater and sludge samples of several WWTP (wastewater treatment plant) in Chongqing are investigated. The heat value, volatile component and element content of those samples are determined. The effect of volatile component on heat value is analyzed. The results show that it has a good correlation between volatile component and heat value. The heat value has a negative correlation with volatile component when volatile component is below 30%, while it has a positive correlation with volatile component when volatile component is above 37%. The heat value is also calculated by the Dulong formula. The conclusions are pretty close: heat value has a negative correlation with volatile component when volatile component is below 28.26%, while has a positive correlation with it when volatile component is above 28.26%. It indicates that the analysis method for heat value of wastewater and sludge in this paper is effective, and it can be used in wastewater measurement.     

Y形偏心支撑高强钢框架结构抗震性能

在Y形偏心支撑高强钢框架结构抗震性振动台试验的基础上,建立了试验试件的有限元模型,并验证了分析的正确性。设计了一个9层的Y形偏心支撑高强钢框架结构,以耗能梁段长度、耗能梁段腹板高厚比、高跨比为参数,对9层结构进行了非线性动力时程分析,研究了以上参数对结构抗震性能的影响。研究结果表明,改变耗能梁段长度、高跨比对结构层间侧移、耗能梁段性能、框架柱弯矩、耗能能力均有不同程度的影响,对框架柱轴力、基底剪力无显著影响;改变耗能梁段腹板高厚比对结构耗能能力有影响,对结构层间侧移、耗能梁段性能、框架柱受力、基底剪力无显著影响,并给出了相关设计建议。