STRENGTH AND BEHAVIOR OF ELLIPTICAL STEEL TUBE BEAMS

Transcription

1 International Journal of Civil Engineering and Technology (IJCIET) Volume 10, Issue 01, January 2019, pp , Article ID: IJCIET_10_01_238 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed STRENGTH AND BEHAVIOR OF ELLIPTICAL STEEL TUBE BEAMS Civil Engineering Department, the University of Diyala, Diyala, Iraq ABSTRACT The main idea of this research is to study the practical efficiency of the behavior of hollow steel beam with an elliptical section, called Elliptical Hollow Steel tube Beams (EHSB), subjected to four points load. The experimental study included three models. All elliptical steel beams experimentally tested under static load to find out the essential behaviors of beams. The chosen measurable factor that were adopted in the study is diameter to thickness ratio (Aspect Ratio). The concentrated applied load versus mid span deflection curve was plotted, the strain for each beam at four places of the examined beams have been measured by strain gauge along the length of beam at bottom face under load, at bottom face at center, middle center, and upper face at center. Test results show that the resistance of the specimen is increased as the aspect ratio is increased and the ductility decreased as aspect ratio is increased. Keywords: Elliptical Hollow Steel tube Beams; Aspect Ratio; static load; ductility. Cite this Article:, Strength and Behavior of Elliptical Steel Tube Beams, International Journal of Civil Engineering and Technology, 10(01), 2019, pp INTRODUCTION Steel beams with elliptical cross section amalgamate the advantage of classic circular sections that known as the fixed axes and sections have different main and secondary axes such as rectangular section. The geometry of this type of section not only adds aesthetic architecture but is also appropriate, for reducing wind resistance. Of the engineering projects that have incorporated the elliptic sections in their construction are Heathrow station in the United States Fig. (1-a) and Airport Guadeloupe Pole Caribbean in France as in Fig. (1-b). These sections are characterized by their durability and high resistance compared to the circular sections, as well as the possibility of passing electrical wires and protected it instead of making of holes in the ceilings [1, 2, 3]. Previous studies have confirmed the existence of many studies on behavior of concrete filled elliptical column [4-8], elliptical beam-column connection [9], elliptical hollow section

2 steel column [10-12] and behavior of concrete filled steel tubes with circular, square and rectangular section column and beam [13-16]. While very few research studied the behavior of steel beams with elliptical hollow section under bending. Therefore, this study has been devoted to the study of such models. (a) Heathrow station in the United States (b) Airport Pole Caribbean in France Figure. (1) Engineering projects used elliptical hollow steel section 2. LABORATORY TESTING OF ELLIPTICAL HOLLOW STEEL TUBE BEAMS (EHSB) 2.1. Fabrication Process of EHSB Specimens Due to the lack of elliptical sections on the market, they were made manufactured locally by using rectangular steel plates the samples were all manufactured from steel plates. Firstly, the plate rolled to circular section and welded. Then it was converted by pressing into an elliptical section. All samples used in the test are made of one type of steel plate with thickness 3 mm. six coupons were used in the standard tensile testing device, the average yielding strength MPa and the elastic modulus is 208 GPa. Three models of steel hollow beams with elliptical section used in experimental program it was named EHSB1, EHSB2 and EHSB3 as shown in Figures 2 to. 4. In order to prevent sample movement during the examination, rings were made with an elliptical section to ensure that the model is compiled as shown in Fig. 5 Figure.2 Geometry of EHSB1 Figure.3 Geometry of EHSB editor@iaeme.com

3 Strength and Behavior of Elliptical Steel Tube Beams Figure.4 Geometry of EHSB3 Figure.5 Geometry of Rings 3. DETAILS OF SAMPLES Three steel beams with elliptical section has been selected in this study has symbols EHSB1, EHSB2. And EHSB3. All tested specimens have a cross section as shown in Fig 6. Where B, D represent the larger and smaller dimeter of specimen or depth and width respectably while t represents thickness of steel tube. All specimen has length 2000 mm and thickness 3mm but vary by aspect ratio (D/B). EHSB1 has dimensions ( ) with aspect ratio 1.4 was considered a reference model, EHSB2 has dimensions ( ) with aspect ratio 1.65, and EHSB3 has dimensions ( ) with aspect ratio 2.0. Table 1 illustrate properties material of tested specimens. Figure.6 Cross Section Geometry of EHSB Table (1) Properties of tested specimens Model D B D/ B L t Axis EHSB Major EHSB Major EHSB Major 4. SETUP AND INSTRUMENT The general appearance of the test device that has been installed in the laboratory for the purpose of examining the models is shown in Fig.7. The samples were loaded with a 2000 KN hydraulic machine tool with a solid edge to lay a balanced load on the samples. 40 mm thick metal sheeting was used to ensure that the sample is stable during the loading period. To measure deflection of specimen dial gauge has been pertained to the bottom part at centerline of specimen. For strain mensuration four gages pertained at four positions. the first editor@iaeme.com

4 at top face at centerline, the second at bottom face at center line to measure the maximum axial stain caused by applied load at compression and tension zones. To measure the surrounding strain a strain gage pertained at center height also the strain was measured under the load area as illustrated in Fig. 7. All strain gages used in the examination showed in Fig. 7. The gauges were pertained, using CN-E material gluey, to the surface of the pre-treated area of the specimen by PS-XC09F two ingredient gluey as shown in Fig 9. The setup of tested beams shown in Fig. (10) To Fig. (12). Figure 7 Test setup configuration Figure.8 Adhesive materials Figure.9 Strain gauges Figure.10 setup of EHSB editor@iaeme.com

5 Strength and Behavior of Elliptical Steel Tube Beams Figure.11 Setup of EHSB2 5. LABORATORY RESULTS Figure.12 Setup of EHSB Behavior of Load-Deflection Fig. 13 to Fig. 15 demonstrates the curved behavior of load-deflection at centerline of bottom face point for all three EHSB chosen for laboratory examination which were obtained from the flexural examination. During the test the maximum applied load for each sample was recorded as demonstrated in Table 2. From the shapes shown, it can be observed that increasing the aspect ratio increases the maximum load of the specimen with more ductility of the sample. At the beginning of the applied load mode, the relationship between load and mid span deflection linear in an elastic mode until yielding stage the relationship becomes is not linear to the arrival of the failure

6 Table.2 Ultimate load of tested specimens Model Applied D/B load % Pu % increasing in Pu Ref. P u EHSB EHSB EHSB Figure. 13 curve of Load versus deflection for EHSB1 Figure. 14 curve of Load versus deflection for EHSB editor@iaeme.com

7 Strength and Behavior of Elliptical Steel Tube Beams Figure. 15 curve of Load versus deflection for EHSB Strains of Elliptical Hollow Steel Beam The strains for elliptical tested steel beams calculated and plotted at four positions namely top face at centerline, bottom face at centerline, bottom face at applied load and center of height. Fig. 16 to 18, show the strain of all selected test beams at four positions for each specimen. (a) (b)

8 (c) (d) Figure. 16 Load - strain curve for EHSB1 at (a) bottom face under applied load (b) bottom face at centerline (c) middle height (d) top face at centerline (a) (b) (c) (d) Figure. 17 Load - strain curve for EHSB2 at (a) bottom face under applied load (b) bottom face at centerline (c) middle height (d) top face at centerline editor@iaeme.com

9 Strength and Behavior of Elliptical Steel Tube Beams a b c d Figure. 18 Load - strain curve for EHSB2 at (a) bottom face under applied load (b) bottom face at centerline (c) middle height (d) top face at centerline 6. DUCTILITY Ductility is one of the most important mechanical characteristics of the steel sample. it's the mensuration of the deformation at plastic stage to which the sample is exposed. The term ductility represents the numerical value resulting from dividing the maximum deflection at the center and deflection at yielding stage of the sample. Figures 19 to 21 showed the ductility values of elliptical steel beams and explain that as the aspect ratio (D/B) increased the ductility increased editor@iaeme.com

10 Figure. 19 Ductility value of EHSB1 Figure. 20 Ductility value of EHSB

11 Strength and Behavior of Elliptical Steel Tube Beams Figure. 19 Ductility value of EHSB3 7. CONCLUSIONS Depending on the study carried out using the flexural examination device for the elliptical hollow steel beam samples. It has been shown that the resistance of the specimen to the applied load is increased as the aspect ratio (D/B) is increased. For EHSB3 the ultimate load increased by 283 percent comparison with reference specimen EHSB1 when the aspect ratio increased from 1.4 to 2.0 and the result showed that the ductility decreased as aspect ratio is increased. The EHSB3 with aspect ratio 2.0 has ductility 2.52 while the specimen EHSB3 with aspect ratio 1.4 has ductility REFERENCES [1] Qusay W. Ahmed '' Strength and behavior of reinforced concrete one-way slabs with opening in flexural ''1st International Scientific Conference of Engineering Sciences -3rd Scientific Conference of Engineering Science, ISCES [2] Wissam D. Salman, Ahmed Abdullah Mansor and Mohammed Mahmood, "BEHAVIOR OF REINFORCED CONCRETE ONE-WAY SLABS STRENGTHENED BY CFRP SHEETS IN FLEXURAL ZONE" International Journal of Civil Engineering and Technology (IJCIET) Volume 9, Issue 10, October 2018, pp [3] Ahmed Abdullah Mansor, Wissam D. Salman, Ali Laftah Abbas and Hutheifa J. Khalifa, "Additional Steel Reinforcement Surrounded Opening as Strengthening in Reinforced Concrete One Way Slabs"International Journal of Civil Engineering and Technology (IJCIET), Volume 9, Issue 11, November 2018, pp [4] X.L. Zhao and, J.A.Packer '' Tests and design of concrete-filled elliptical hollow section stub columns'' Thin-Walled Structures 47 (2009) [5] Wissam D. Salman "STRENGTH AND BEHAVIOR OF COMPOSITE STEEL TUBE CONCRETE BEAM" Diyala Journal of Engineering Sciences, Vol. 08, No. 02, pp , June [6] H. Yang, D. Lamc, L. Gardner '' Testing and analysis of concrete-filled elliptical hollow sections'' Engineering Structures 30 (2008) 3771_3781 [7] T. Sheehan, X.H. Dai, T.M. Chan, D. Lam '' Structural response of concrete-filled elliptical steel hollow sections under eccentric compression'' Engineering Structures 45 (2012)

12 [8] Jingfeng Wang, Qihan Shen, Han Jiang, Xuebei Pan '' Analysis and Design of Elliptical Concrete Filled Thin Walled Steel Stub Columns Under Axial Compression'' International Journal of Steel Structures, June 2018, Volume 18, Issue 2, pp [9] J. Yang, T. Sheehan, X. H. Dai, D. Lam'' Experimental study of beam to concrete-filled elliptical steel tubular column connections'' Thin-Walled Structures 95 (2015)16. [10] Man-Tai Chen, Ben Young '' Material properties and structural behavior of cold formed steel elliptical hollow section stub columns'' Thin-Walled Structures 134 (2019) [11] Amer Mohamed Ibrahim, Ahmed Abdullah Mansor, Wissam D. Salman, Mohammed Jaafar Hamood,"Strength and Ductility of Bubbled Wide Reinforced Concrete Beams with Diverse Type of Shear Steel Plates", International Journal of Engineering and Technology (UAE), 7 (4.20) (2018) [12] Durgesh Nandan Verma, Sudhir Malik, Ajeet Kumar '' Effect of Severe Temperatures and Restraint on Instability and Buckling of Elliptical Steel Columns'' IJETSR, Volume 5, Issue 4, April 2018 [13] Cheng Fang, Feng Zhou, and Wei Wu '' Performance of Elliptical Hollow Sections under Combined Compression and Cyclic Bending'' J. Struct. Eng., 2018, 144(8) [14] Elchalakani M, Zhao XL, Grzebieta RH. "Concrete-filled circular steel tubes subjected to pure bending". Journal of Constructional Steel Research 2001;57: 1141_68. [15] Gho Wie-Min, Liu Dalin. "Flexural behavior of high-strength rectangular concrete-filled steel hollow sections". Journal of Constructional Steel Research 2004; 60 :16 81_96. [16] Amer Mohamed Ibrahim, Ahmed Abdullah Mansor, Muthafer Hameed, "Structural Behavior of Strengthened RC Beams in Shear using CFRP Strips", The Open Civil Engineering Journal, V.11, April 2017, pp editor@iaeme.com