Experimental compressive behavior of novel composite wall with different width-to-thickness ratios

Ying Qin,Xin Chen,Xing-Yu Zhu,Wang Xi,Yuan-Ze Chen 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.36 No.2

Double skin composite wall system owns several structural merits in terms of high load-carrying capacity, large axial stiffness, and favorable ductility. A recently proposed form of truss connector was used to bond the steel plates to the concrete core to achieve good composite action. The structural behavior of rectangular high walls under compression and T-shaped high walls under eccentric compression has been investigated by the authors. Furthermore, the influences of the truss spacings, the wall width, and the faceplate thickness have been previously studied by the authors on short walls under uniform compression. This paper experimentally investigated the effect of width-to-thickness ratio on the compressive behavior of short walls. Compressive tests were conducted on three short specimens with different width-to-thickness ratios. Based on the test results, it is found that the composite wall shows high compressive resistance and good ductility. The walls fail by local buckling of steel plates and crushing of concrete core. It is also observed that width-to-thickness ratio has great influence on the compressive resistance, initial stiffness, and strain distribution across the section. Finally, the test results are compared with the predictions by modern codes.

Behavior of Thin-walled Circular Hollow Section Stub Columns Under Axial Compression

Lanhui Guo,Yong Liu,Hui Jiao,Shilong An 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.3

Thin-walled steel circular hollow section (CHS) is widely used in wind turbine towers, where the tube is subjected to axial load combined with bending moment. Understanding the behavior of axially loaded thin-walled tubes with large diameter-tothickness (D/t) ratios is crucial for the design of such structures. To investigate the behavior of axially loaded thin-walled circular hollow section steel tubes, 16 stub columns were tested with the D/t ratio ranging from 75 to 300. The experimental results showed that the compressive strength decreased sharply with the increase of the D/t ratio. The experimental result indicated that the tubes with smaller D/t ratios failed with outward deformation without visible local buckling. With the increase of the D/t ratio, local buckling appeared at the peak load. The finite element method was used to model the behavior of axially loaded stub columns. The experimental results were used to validate the accuracy of the finite element results. Based on the finite element model, the influences of the D/t ratio, the initial geometric deformation and the initial residual stress were analyzed. Design guidelines in Eurocode3, AISC-LRFD, AS4100 and S16-9 on thin-walled steel members were used to compare with the experimental and calculated results. Among them, the results based on AS4100 were the closest to the experimental results.

Behavior of Steel Plate Shear Wall Connected to Frame Beams Only

Lanhui Guo,Qin Rong,Xinbo Ma,Sumei Zhang 한국강구조학회 2011 International Journal of Steel Structures Vol.11 No.4

This paper presents the study of steel plate shear walls which are connected to frame beams only. As the shear walls are not connected to frame columns, the premature failure overall buckling or local buckling of frame columns can be prevented. In fact, most of both structural design engineers and architects prefer this kind of steel plate shear walls because the dimension of their opening space is relatively flexible by using several steel plates with small span-to-height ratio placed parallel to each other. In this paper, two steel plate shear walls were fabricated and tested. The influence of stiffeners on the hysteretic behavior of this kind of member was studied. The experimental results showed that this kind of specimen had good ductility and energy dissipation capacity. The energy dissipation capacity of specimen with stiffeners was larger than that of the specimens without stiffeners. Meanwhile, the finite element method was applied to analyze the behavior of steel plate shear walls, whose results were validated by comparing with the corresponding experimental results. Analytical results showed that the free edges deformed with evident out-of-plane deformation and should be constrained by stiffeners to meet the design requirements. The energy dissipation capacity is much better for steel plate shear walls with lower height-to-thickness ratio and larger span-toheight ratio. At last, the skeleton curve of steel plate shear wall was proposed for calculating the elastic rigidity and loadcarrying capacity.

횡력저항 구조로서 더블월의 접합부에 대한 구조성능 평가

오영훈,문정호,이강철 대한건축학회 2020 대한건축학회논문집 Vol.36 No.6

The purpose of research is to evaluate the structural behavior of double walls as a lateral force resisting system. A test program wasplanned with 10 double wall specimens with horizontal or vertical joints. Horizontal joint specimens are consisted of 4 double wallspecimens and 2 cast-in-place wall specimens. Vertical joint specimens are consisted of 4 double wall specimens. Test variables wereselected as wall thickness and joint reinforcing ratio. Test results of horizontal specimens were compared with cast-in-place wall specimens. Structural performance of double walls was evaluated by various evaluation methods, such as design standards, earthquake-resistantevaluation methods, performance objective evaluation methods. From such evaluation, it is concluded that double wall structures showedequal and above performance compared to cast-in-place walls. And it also showed satisfactory behavior in terms of earthquake-resistancecapacity and target-performance achievement. 본 연구는 전단벽으로서 더블월 벽체의 내진성능을 평가하는 것이다. 더블월의 접합부를 수평 및 수직 접합부로 분류하고 각 접합부 별로 실험체를 제작하여 실험을 수행하였다. 실험체의 주요 변수는 벽두께, 접합부 보강비 등으로 하였으며, 수평접합부 실험체는 현장타설 실험체와의 비교도 실시하였다. 실험결과에 대한 분석은 구조설계기준에 따른 강도 및 거동 평가, 내진성능 평가, 성능목표 평가를 수행하였다. 더블월은 현장타설형 실험체에 비해서도 동등 이상의 성능을 보였으며, 내진성능 및 성능목표 평가에서도 우수한 결과를 보였다.

Height-thickness ratio on axial behavior of composite wall with truss connector

Ying Qin,Gan-Ping Shu,Xiong-Liang Zhou,Jian-Hong Han,Yun-Fei He 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.30 No.4

Double skin composite walls offer structural and economic merits over conventional reinforced concrete counterparts in terms of higher capacity, greater stiffness, and better ductility. This paper investigated the axial behavior of double skin composite walls with steel truss connectors. Full-scaled tests were conducted on three specimens with different height-to-thickness ratios. Test results were evaluated in terms of failure mode, load-axial displacement response, buckling loading, axial stiffness, ductility, strength index, load-lateral deflection, and strain distribution. The test data were compared with AISC 360 and Eurocode 4 and it was found that both codes provided conservative predictions on the safe side.

Concrete Confinement Effect in Circular Concrete Sandwiched Double Steel Tubular Stub-Columns

U. Mashudha Sulthana,S. Arul Jayachandran 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.4

Concrete sandwiched double steel tubular (CSDST) columns have improved ductility under cyclic loads. Two CSDST columns are investigated in this paper (1) CSDST-CS with Circular outer tube and Square inner tube and (2) CSDST-CC with Circular outer tube and Circular inner tube. The confi nement of concrete between the annular spaces of the inner and outer tubes is very important for their behaviour. To the authors’ knowledge, the literature is scarce on a validated concrete confi nement model for CSDST. In this paper, the concrete confi nement mechanism in CSDST columns is explained based on thick-walled cylinder theory and a semi-analytical equation is developed. Hollowness ratio of the cross-section, width to thickness ratio of the outer steel tube, strength of the outer steel tube and sandwiched concrete strength are identifi ed as the main parameters infl uencing the confi nement eff ect in CSDST. The proposed equation is extended to CSDST-CS with inner square tube approximated as an equivalent circular tube. This assumption is validated by conducting tests on short column specimens under axial compression. With outer tubes being the same, concrete confi nement eff ect in CSDST-CS, CSDSTCC and concrete fi lled steel tubular column (CFST) are 18%, 20% and 30%, respectively. This study has demonstrated that the presence of double steel tubes does not improve the concrete confi nement in CSDST compared to CFST. Further, this study presents a modifi cation to the design equations of EN 1994-1-2 2005-1-1 (Eurocode 4: Design of composite steel and concrete structures Part 1–1: General rules and rules for buildings. European Committee for Standardization, Brussels, 2004) for CFST columns to CSDST stub columns by incorporating the eff ect of hollowness.

후육 용접 강관의 HIC 저항성 평가

서준석,김희진,유회수,Seo Jun Seok,Kim Hee Jin,Ryoo Hoi-Soo 대한용접접합학회 2005 대한용접·접합학회지 Vol.23 No.3

It is required for the steel materials used in the sour environment to have sufficient resistance to hydrogen induced cracking(HIC). For line pipe steels, HIC resistance could be varied during pipe making process due to the large plastic deformation applied in the thick-wall pipe. In order to figure out such effect, HIC tests were performed not only in the plate condition but in the pipe condition and their results were compared in terms of cracking ratio. Test results demonstrated a detrimental effect of plastic deformation to HIC resulting in a substantial increase in the cracking ratio after pipe forming process. All of the cracks found in the pipe material were located in the outer layer of pipe where the tensile strain was resulted during pipe forming stage. In order to understand the HIC resistance of the pipe but in the plate condition, it was suggested to pre-strain the plate to some extent before the HIC test.

Work Efficiency in a Double Cup Extrusion Process

노정훈,황병복 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.3

A double cup extrusion process (DCEP) has been analyzed numerically to investigate the characteristics of energy consumptions for a selected model material, AA 2024 aluminum alloy. The forming energy in a double cup extrusion process was analyzed in terms of ideal, redundant and frictional energy or work, which constitute of a total forming energy in metal forming process. Ideal and theoretical forming or deformation efficiencies were also examined for various process parameters chosen for analysis. The objective of this study is to investigate the influence of geometrical process parameters in DCEP on the characteristics of energy consumption or dissipation. It was revealed from this study that frictional energy was expected to be more dissipated for high reductions and low thickness ratios. It was also found that the theoretical work efficiency would decrease as the thickness ratio increases and the reduction decreases.

두께가 다른 이종배관 용접부 면삭 각도 변화에 따른 하중지지능력 평가

백종현(Jong-hyun Baek),김영표(Young-pyo Kim),김우식(Woo-sik Kim) 대한기계학회 2012 大韓機械學會論文集A Vol.36 No.9

두께가 다른 이종강도 배관 용접부에서 인장, 내압 및 굽힘응력에 대한 하중지지능력을 평가하였다. 1.22, 1.54, 및 1.89의 두께비를 갖는 API X65-API X80, API X42-API X65 및 API X42-API X80 배관 용접부를 유한요소해석을 통하여 하중지지능력을 평가하였다. 이종강도 배관의 두께비가 1.5 이하에서 인장강도와 최대모멘트는 면삭각도 변화에 큰 영향을 받지 않으나 두께비가 1.5 이상에서는 큰 영향을 받는다. 저강도 배관의 길이방향 면삭각도와 두께비 변화에 따라서는 내압에 의한 파열압력은 영향을 받지 않는다. The behavior of the load bearing capacity of a pipeline with unequal wall thickness was evaluated using finite element analyses. Pipelines with a wall thickness ratio of 1.22?1.89 were adopted to investigate plastic collapse under tensile, internal pressure, or bending stress. A parametric study showed that the tensile strength and moment of a pipeline with a wall thickness ratio less than 1.5 were not influenced by the wall thickness ratio and taper angle; however, those of a pipeline with a wall thickness ratio more than 1.5 decreased considerably at a low taper angle. The failure pressure of a pipeline with unequal wall thickness was not influenced by the wall thickness ratio and taper angle.

합성율과 벽체두께가 합성지하벽의 전단거동에 미치는 영향

서수연,김성수,윤용대 한국구조물진단유지관리공학회 2010 한국구조물진단유지관리공학회 논문집 Vol.14 No.1

도심지의 제한된 공간에서 대형 건축 지하구조물을 축조하기 위한 지하 굴토공사는 주변지반의 안정이 최우선 되어야 하며, 이를 위해서 흙막이 공사가 필수적으로 검토되어야 한다. 가설 흙막이 구조에서 응력부담재로 주로 사용되고 있는 H-Pile은 주열식 흙막이 벽체에서 지하외벽의 시공 이후에는 방치되므로 재료의 낭비를 초래하게 된다. 이를 개선하기 위하여 가설재인 H-Pile과 지하벽을 합성한 합성지하벽 공법이 개발되어 현재 많은 국내의 현장에 활용되고 있다. 본 연구에서는 지하합성벽의 전단내력을 평가하기 위하여 총 5개의 실험체를 제작하였다. 실험변수로는 전단연결재에 따른 합성율과 벽체 두께를 변수로 하여 실험을 실시하였으며, 기준식에서 제시하는 콘크리트 전단강도와 H-Pile의 전단강도를 실험값과 비교 분석하였다. 실험결과 합성율이 증가함에 따라 전단강도는 상승하지만 그 차이는 크지 않은 것으로 나타났다. 합성지하벽의 전단강도 산정시, 콘크리트 강재의 웨브 뿐만아니라, 강재플랜지의 기여도를 고려한 새로운 식을 제시하고 이를 이용한 계산결과와 실험결과를 비교한 결과 좋은 대응을 보이는 것으로 나타났다. When doing underground excavation works for the purpose of constructing large underground structures for a building in the limited space in downtown area, the stability of the adjacent ground must be top priority, and to accomplish this, it is essential to review the retaining wall construction carefully. H-Pile, which has been mainly used as a stress-carrying material in temporary earth-retaining structures, is most likely to be abandoned after completion of the works for the basement exterior wall in relation to contiguous bored piles, so it will result in a waste of material. To improve this situation, Composite Basement Wall(CBW) where H-Pile and basement wall are compounded, has been developed. This wall is being used most frequently in many local construction sites. In this study, five specimens are made in order to evaluate the shear resistance of CBW and tested. Test parameter is the composition ratio and wall thickness according to shear connectors. Test result shows that the shear strength is improved when the composite ratio is increased but the magnitude is not much. A formula, which considers the contribution of concrete, web of H-pile as well as flange' effect in calculation of shear strength of CBW, is suggested and used to calculation of the strength of specimens. It is found that there is a good co-relation between test result and the calculated one by the formula.